Viscoelastic and textural properties of canary seed starch gels in comparison with wheat starch gel

Accepted Manuscript Viscoelastic and textural properties of canary seed starch gels in comparison with wheat starch gel

Mahdi Irani, Seyed M.A. Razavi, El-Sayed M. Abdel-Aal, Pierre Hucl, Carol Ann Patterson PII: DOI: Reference:

S0141-8130(18)32870-8 https://doi.org/10.1016/j.ijbiomac.2018.11.216 BIOMAC 11093

To appear in:

International Journal of Biological Macromolecules

Received date: Revised date: Accepted date:

11 June 2018 22 November 2018 23 November 2018

Please cite this article as: Mahdi Irani, Seyed M.A. Razavi, El-Sayed M. Abdel-Aal, Pierre Hucl, Carol Ann Patterson , Viscoelastic and textural properties of canary seed starch gels in comparison with wheat starch gel. Biomac (2018), https://doi.org/10.1016/ j.ijbiomac.2018.11.216

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ACCEPTED MANUSCRIPT Viscoelastic and textural properties of canary seed starch gels in comparison with wheat starch gel

Mahdi Irani1, Seyed M. A. Razavi1, El-Sayed M. Abdel-Aal2, Pierre Hucl3 and Carol Ann

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Patterson4 1

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Food Hydrocolloids Research Centre, Department of Food Science and Technology, Ferdowsi University of Mashhad (FUM), POBox: 91775-1163, Mashhad, Iran

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Agriculture and Agri-Food Canada, Guelph Research and Development Centre, Guelph, N1G 5C9, Ontario, Canada 3

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University of Saskatchewan, Crop Development Centre, 51 Campus Dr., Saskatoon, SK, Canada, S7N 5A8 4

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The Pathfinders Research & Management Ltd., 1124 Colony St., Saskatoon, SK, Canada, R3C 3G7

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Abstract

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In this study, viscoelastic properties and textural profile analysis of starches from two canary seed

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varieties (CDC Maria and C05041) were compared with wheat starch. Based on amplitude sweep, the limiting strain values were 5.7%, 5.4% and 16.3% for CDC Maria, C05041, and wheat starch

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gels, respectively. The yield stress values at the linear viscoelastic limit (τy) and flow point (τf) of wheat starch (25.4 & 35.5 Pa, respectively) were higher than CDC Maria (14.3 and 24.2 Pa, respectively) and C05041 (6.5 and 9.1 Pa, respectively) starches. On the other hand, canary seed starches showed higher modulus at flow point (Gf, 51.2-108.4 Pa) than wheat starch (41.2 Pa). In frequency sweep, canary seed starch gels showed lower frequency dependency (n'=0.033-0.009)

 Corresponding author: Tel./Fax: +98- 51- 38805763, Email: [email protected]

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ACCEPTED MANUSCRIPT in comparison with wheat starch gel (n'=0.063), categorizing the samples between weak and strong gels. On the basis of creep parameters of Burger model, CSSs illustrated more elastic behavior than wheat starch. The results of dynamic temperature sweep showed that canary seed starches exhibited higher peak, final, breakdown and setback viscosities in compare to wheat starch.

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Textural profile analysis provided the values of hardness (32-101 g), adhesiveness (0.03-0.17 mJ),

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cohesiveness (0.60-0.97) and gumminess (24.7-83.3 g) for the gels (15% w/w).

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Keywords: Pasting; Rheology; Spreadability; Starch; Texture; Viscoelasticity

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1. Introduction

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Canary seed offers a new starch source, which can be used in various food and non-food systems

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due to its unique characteristics as compared with wheat starch [1]. The hairless canary seed varieties were developed for human consumption and are being evaluated for regulatory approvals

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as a wholegrain cereal food. The seeds have received GRAS status from the USA-FDA in 2015

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(GRAS Notice No. GRN 000529) [2] and recently it has been approved by Health Canada as a novel food [3]. The new regulatory approvals will open up new markets.

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New starches must be characterized in order to use in food and non-food applications [4]. Rheological properties of starch dispersions can provide useful information about their structure and behavior at different conditions used in food processing [5]. Oscillatory rheology measurements are usually used to explore the viscoelastic behavior of starch gels. Small amplitude oscillatory shear (SAOS) analyzes is one of the most important dynamic rheological tests which stress and strain are varied harmonically with time in the linear viscoelastic region (LVE) [6].

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ACCEPTED MANUSCRIPT Starch gels are known as viscoelastic materials, thus dynamic measurements are proper methods to evaluate the rheological properties of starch gel systems. The gelling ability of starch is another important function in food processing. For quality control and development of starchy foods and products, the control of gel properties seems to be crucial. Textural properties of starch gels have

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been investigated mostly in practical foods and their model systems. Actually, in order to

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understand the basic factors and mechanisms involved in the gelling and to characterize the gel

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properties investigations, on the starches in the simplified systems should be considered. In our previous studies, we have investigated comprehensively the physicochemical, thermal,

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pasting, functional, dilute solution and steady shear rheological properties of starches from two

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varieties (CDC Maria and C05041) of hairless canary seeds in comparison with wheat starch. According to dilute solution properties, wheat starch showed higher intrinsic viscosity, molecular

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weight, coil radius, and coil volume than canary seed starches. Moreover, the results from shape

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factor demonstrated the spherical and ellipsoidal macromolecule structures for C05041 starch and ellipsoidal for CDC Maria starch and wheat starch [7]. Also, there were some differences in

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molecular structure of two canary seed starch varieties based on dilute solution properties, like

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intrinsic viscosity, molecular weight, shape factor and so on, which can affect textural and rheological properties of them. Wherever CDC Maria starch showed higher intrinsic viscosity value

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(1.397 dl/g) than C05041 starch (1.325 dl/g). The shape factor suggested a spherical and ellipsoidal structure for CO5041 starch and an ellipsoidal for CDC Maria starch. The molecular weight, coil radius and coil volume of CDC Maria starch were higher than C05041 starch [7].

Investigation of physicochemical and functional properties revealed that canary seed starches had uniform and small granules (average 2.6 μm and 19.9 μm for canary seed starches and wheat starch, respectively), and relatively low amylose content (22.5-23.6%) in comparison with wheat starch (25.6%). Canary seed starches showed A-type crystal structure like wheat starch, but they 3

ACCEPTED MANUSCRIPT exhibited more amylose-lipid complex than wheat starch. Also, canary seed starches presented higher gelatinization transition and melting temperatures than wheat starch. In addition, from pasting properties, canary seed starches showed higher peak, tough, final, breakdown and setback viscosities than wheat starch [8]. As a result, compositional and morphological properties of two

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canary seed starches are so similar to each other, but there are some differences; for example in

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thermal properties, CDC Maria starch showed a higher onset temperature and gelatinization

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transition temperature range (58.5 oC and 20.8 oC, respectively) than C05041 starch (60.9 oC and 19.7 oC, respectively). Also in pasting properties, CDC Maria starch exhibited lower peak time

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and breakdown viscosity and higher trough viscosity (10.27 min, 610.5 cP, and 1864.0 cP,

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respectively) than C05041 starch (10.03 min, 783.5 cP, and 1741.5 cP, respectively) [8]. The steady shear rheological properties of canary seed starches demonstrated the shear-thinning and

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thixotropic behavior of them. The Power-law and Casson models were the best models to describe

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time-independent behavior, whereas the first-order stress decay model was fitted for time-

CDC Maria starch [9].

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dependent behavior. C05041 starch showed higher pseudoplasticity and extent of thixotropy than

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As it clear, wheat is the king of the cereal grain in the word, then when scientists want to investigate a new source of grain, it could be a good idea to compare it to wheat. It was shown that

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microstructure of canary seed is similar to famous cereal like wheat, oats, barley, and rice [10]. In addition, canary seed groats exhibited a relatively similar amount of two main ingredients of cereal groats means starch (60%) and protein (18.7%) to wheat [11]. The phytochemical and heavy metals profiles of canary seed were so close to wheat [12]. Moreover, based on nutrient content and functionality in bread making of canary seed, it has the potential as a food crop in comparison with wheat [10], So, in this study, we attempted to characterize both viscoelastic properties

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ACCEPTED MANUSCRIPT (amplitude sweep, frequency sweep, temperature sweep and creep tests) and textural attributes (texture profile analysis) of the starch gels from two varieties (CDC Maria and C05041) of canary seed, which usually grow alongside with wheat in farms, and compare them with wheat starch to present a complete rheological profile of them from small to large deformations and shed light on

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the potential applications of this new source of starch.

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2. Material and methods

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2.1. Materials

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Two varieties of hairless canary seed including; CDC Maria and C05041 were obtained from the Crop Development Centre at the University of Saskatchewan, Canada. The canary seed samples

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were dehulled using an abrasive dehuller according to the procedure described by Abdel-Aal et al.

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[13]. Native wheat starch (WS) was purchased from Sigma-Aldrich Company (St. Louis, MO, USA). Amylose content of starch samples was measured using assay kit (Megazyme Int. Ltd,

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Wicklow, Ireland). According to this method the amylose content of CDC Maria, C05041 and

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wheat starches were 23.6%, 22.5%, and 25.6%, respectively [8].

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2.2. Sample preparation

Canary seed starch (CSS) samples were extracted according to the procedure described by AbdelAal et al. [13]. For dynamic rheological test, CSS and WS samples were dispersed in distilled water for 30 min with gentle magnetic agitation at concentrations of 6% (w/w), and then gelatinized by heating at 95 º C for 30 min (using boiling water bath which provide constant 95° C temperature) with agitation provided by magnetic stirrer of 160 rpm, and finally cooled to room

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ACCEPTED MANUSCRIPT temperature (25º C), which took 1 h, before going through any test procedure (at least two separate gels for each sample were prepared). During the preparation of the samples, the top of the container was covered by a thin layer of polypropylene and aluminum foil at the same time to prevent water evaporation. For texture test, the starch sample (15% w/w) was prepared according to Majzoobi

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and Beparva [14], where starch samples were dispersed in distilled water for 30 min with gentle

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magnetic agitation at concentrations of 15% (w/w), and then gelatinized by heating at 95 º C for

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30 min with agitation provided by magnetic stirrer of 160 rpm and then cooling to 50 ºC. The warm paste was transferred into a cylindrical plastic container with diameter and height of 1 × 1

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cm and refrigerated at 4 ºC for 24 h before instrumental texture analysis.

2.3. SAOS measurements

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A Physica MCR 301 rheometer (Anton Paar, Germany) equipped with a cone and plate geometry

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(5 cm diameter, 2◦ angle, 206 μm gap size) was used to perform small deformation oscillatory measurements. The samples were loaded onto the lower plate of the rheometer equilibrated at 25º

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C and a thin layer of low-density silicone oil was used around the plate to prevent evaporation. All

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samples were allowed to equilibrate at the measuring temperature (25 ºC) for 10 min before the start of the test. The temperature of the samples was regulated and maintained precisely (±0.01◦C)

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during the experiments using a Peltier-plate system. Physica Rheometer Data Analysis software (Rheoplus/32, version V3.40) was used for calculation of dynamic rheological characteristics including the storage modulus (G’), loss modulus (G”), loss tangent (tan δ), and complex viscosity (η*) and analyze the rheological results. Each oscillatory measurement was carried out at least in duplicate.

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ACCEPTED MANUSCRIPT 2.3.1. Amplitude sweep test The dynamic mechanical (yielding and strength) properties of starch gels were evaluated through stress sweep test (0.1–200 Pa) at a constant frequency (1 Hz) and temperature (25 ºC). The determined parameters were included: limiting value of strain (γc), elastic modulus at LVE (G’LVE),

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loss tangent at LVE (tan δLVE), yield stress at the limit of LVE range (τy) (when the G’ started to

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decrease (in G’ series) with more than 5% deviation from at least 3 previous G’ values, the stress

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of this point was chosen as τy.), and yield stress at flow point (τf) with corresponding modulus, Gf

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(G’ = G”).

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2.3.2. Frequency sweep test

Linear viscoelastic region (LVE) for starch gels was determined through a strain sweep test (0.01–

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10000 %) at a constant frequency (1 Hz) and temperature (25 ºC). Then, frequency sweep test was

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performed by subjecting a new and identical aliquot of the sample to oscillatory measurements at a frequency range of 0.01–10 Hz from high to low and a constant strain at LVE region (0.5%).

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Accordingly, the mechanical spectra were characterized by values of elastic modulus (G’, Pa), loss

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modulus (G”, Pa), loss tangent (Tan ) and complex viscosity (*, Pa.s) as a function of frequency

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at 25°C. Each measurement was carried out at least in duplicate.

2.3.3. Dynamic temperature sweep (DTS) test The effect of temperature at the range of 50 to 95 °C (at 0.5% strain and 1 Hz frequency) on viscoelastic properties of starch samples was evaluated according to the method developed by Mohammad Amini et al. [15]. For this purpose, starch dispersions (6% w/w) were loaded on Peltier plate at 50°C, and heated from 50 to 95 °C at the rate of 3°C/min. Then, held at 95°C for 1 min,

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ACCEPTED MANUSCRIPT and finally cooled down from 95 to 50 °C at the rate of 5°C/min. Based on mechanical spectra of samples as a function of temperature (Fig. 5), the parameters of Ts (the temperature that complex viscosity (η*) starts to increase suddenly at heating period), Tmax (the temperature corresponding to maximum η* at heating period), η*max (the value of maximum η* at heating period), B (breakdown,

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the difference between maximum and minimum η*), η*f (the value of η* at the end of cooling period,

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50 °C), η*min (the value of minimum η*) and SB (setback, the difference between the η*f and the

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η*min) were calculated. These parameters were extracted from the DTS test to match with the Rapid Visco-Analyser (RVA) parameters [15]. Each DTS measurement was carried out at least in

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duplicate.

2.4. Creep test

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The creep test was performed at 0.5 Pa for 300 s in the linear viscoelasticity region, the shear strain

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(γ) was recorded as a function of time. The creep compliance (JC, Pa-1) was the resulting of strain divided by the applied stress (τ) during creep period. Compliance experimental data were fitted

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using of the four parameters Burger’s model (Eq. 1): 𝑡

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𝑟𝑒𝑡

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JC = J0C + J1C [1- exp (− 𝜆 )] + ɳ

(1)

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Where J0C is the instantaneous elastic compliance (Pa-1) of the Maxwell spring, J1C is the elastic compliance (Pa-1) of Kelvin-Voigt unit, λret is the retardation time (s) of the Kelvin-Voigt component, and 0 is the Newtonian viscosity (Pa. s) of the Maxwell dashpot.

2.5. Textural profile analysis (TPA) The selected starch gels (15% gel concentration) were removed from the container, the size of the container was 1 cm diameter and 1 cm height and tested for their textural properties using a texture 8

ACCEPTED MANUSCRIPT analyzer (CT3 Texture Analyzer, Brookfield, USA). The gels were compressed at a pretest speed of 5 mm/s, the test speed of 1 mm/s, the post-test speed of 5 mm/s, the time interval of 10 s and strain deformation of 25% using a cylindrical plunger with a diameter of 2.54 cm. All the textural parameters were measured and calculated by the instrument software from the resulting force-

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deformation curves, including hardness (g), adhesiveness (mJ), resilience, gumminess (g) and

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cohesiveness (dimensionless). The TPA measurement was carried out more than three times.

2.6. Statistical analysis

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The data were analyzed with general linear model (GLM) and Duncan multiple range test to

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determine significant differences among samples using the SPSS ver. 22 statistical software. Data

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3. Results and discussion

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0.05 was considered as significant.

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were obtained at least in duplicate and presented as the mean ± standard deviation. The P value <

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3.1. Amplitude sweep rheological properties Storage module (G’) and Loss module (G”) are almost constant in the linear viscoelastic region

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with increasing stress or strain. On the other hand, in the nonlinear viscoelastic region, both moduli (G’ and G”) start to decrease. As seen in Fig. 1, G’ remained constant until stress/strain reached to critical point, the point that G’ begins to decrease sharply. Actually, critical stress (τy) or strain (γc) values demonstrate the strength/ deformability of the starch samples, respectively. Linear viscoelastic region for gels is higher than concentration solutions and this is higher than dilute solutions [16]. For natural biopolymer gels, the strain is equal 1% or can be more than 1%

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ACCEPTED MANUSCRIPT in a large LVE [17]. It is declared that LVE region for most soft solid foods had been within the range of 0.1 – 2% [18]. Here two varieties of canary seed (CDC Maria & C05041) and wheat starch gels were conducted to evaluate the material stability (yielding properties) and gel strength by applying stress ramp (0.1

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– 600 Pa), and some rheological parameters of stress sweep including: limiting values of strain

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(γc), tan δLVE, yield stress or stress at the limit of the LVE range (τy), G’LVE and G”LVE along with

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flow-point stress (τf) and modulus at crossover point (Gf, G’ = G”) were determined at frequency of 1 Hz and 25 ºC (Table 1). The results showed that the strain of 0.5% was within LVE region for

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CDC Maria, C05041, and wheat starch gels at different concentrations (4, 6, and 8% w/w), where

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the weak gel networks do not get damaged by using stress/strain during measurements. Mohammad Amini et al. [15] and Yousefi and Razavi [19] declared the strain of 0.5% for LVE

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region of corn and wheat starches, respectively. According to Table 1, γc values were from 1.91%

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to 21.75% for all concentrations of CDC Maria, C05041 and wheat starches, respectively, which were high within biopolymers. These results show that CSS samples at all concentrations provide

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more deformable gel than wheat starch which means CSS samples deform by a smaller force than

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WS sample. Within the CSS samples, CDC Maria starch gel was remained more in LVE region at all concentrations, indicating stronger than C05041 starch during increasing stress/strain. Yousefi

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and Razavi [19] reported 1.5 and 2.2% of γc value for wheat starch at 8 and 12% (w/w) concentration, respectively. Differences between the γc values of the wheat starch gel of our finding and Yousefi and Razavi [19] may attribute to different wheat variety, difference amount of amylose/amylopectin content and difference of starch concentration. Rosalina and Bhattacharya [20] reported 10% of γc value for cornstarch (10% w/w).

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ACCEPTED MANUSCRIPT In all cases, the storage modulus was 5 to 30 times of magnitude greater than the loss modulus over the entire linear viscoelastic range, indicating the presence of strong network structure or a solid-like behavior (Table 1). There was a significant difference (P<0.05) between G’LVE and G” LVE of

starch gel samples. According to Table 1, the G’LVE and G” LVE values of CDC Maria starch

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gel at all concentrations were higher than C05041 and wheat starch gels. Yousefi and Razavi [19]

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reported the G’LVE = 344.1 Pa and G” LVE = 58.5 Pa for wheat starch at 8% concentration that were

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higher than results were obtained for wheat starch gel (G’LVE = 279.5 Pa and G” LVE = 32.6 Pa) in this study. It may be attributed to the difference in the source of the wheat and amount of

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amylose/amylopectin ratio. It was found that starches with larger granules exhibit higher G’ values

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than medium and small granules, which is related to the higher tendency of the swollen large-size granules towards deformation. However, phospholipid content of starches can affect thermal and

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rheological properties of starches [21]. As mentioned before, WS have larger granule than CSS

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samples, but CDC Maria sample showed larger G’LVE than WS, which can be attributed to the presence of phospholipid [8]. The C05041 sample showed lower G’LVE than WS sample at 6%

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concentration, however; it was higher at 4% and 8% concentrations about 48% and 13%,

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respectively. The lower G’LVE of C05041 sample in comparison with CDC Maria sample may be related to the lower molecular weight of this starch, as the molecular weight of WS, CDC Maria

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sample and C05041 sample were 33.1×106 Da, 27.7×106 Da, and 23.7×106 Da, respectively [22]. It was reported that there is a relationship between G’ and concentration by a power law: G'~C n, where n is the power-law exponent [23]. In this study, the n value of CDC Maria (n = 3.21, R2 = 0.90), C05041 (n = 3.45 R2 = 0.99) and wheat starch (n = 3.95, R2 = 0.96) is achieved from the plot of log G’ vs. log C at different concentrations. Also, the n value of canary seed starches was close the wheat starch. The n value approximately 2 was reported for one-component thermos-reversible

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ACCEPTED MANUSCRIPT gels [24,25]. In addition, the dependency of storage modulus on starch concentration typically reported being from 2.1 to 2.9 [26,27]. As seen in Fig. 1, strain overshoots for G” can be observed for all gel samples, which were stronger for canary seed starches than wheat starch. Sim et al. [28] classified nonlinear viscoelastic behavior of distinctive kinds of complex material as strain

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amplitude increasing, which include Type 1 (strain-thinning), both the loss and storage moduli

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decline; Type II (strain-hardening) both the storage and loss moduli increase; Type III (weak

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strain-overshoot) the storage module declines, by contrast, the loss module first increases and then decreases, and finally Type IV (strong strain-overshoot) which both the storage and loss moduli

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increase first and then decrease. Biopolymer solutions that form weak microstructural complex

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like our samples usually show strain overshoot [29]. When particles of suspensions flocculated, strain G” overshoot happens with the formation of weak structural complexes [30]. In other words,

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when strain is imposed, network structure resist against deformation up to a certain strain (G”

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increase). Then the structure is destroyed via large deformation (certain strain), after that the microstructure segments align with the flow, and G” start to decline [28]. In agreement to our

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study, weak strain overshoots have been announced for gelatinized starch dispersions at about 50%

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strains, probably caused by the large deformation of the ghost granules [31]. It was illustrated that ghost granules are highly flexible and fragile structures [32]. In gels, like the ones in this study,

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where suspended particles are close enough to interact with each other through hydrodynamic interactions, colloidal interactions, or entanglement, flocculation may lead to the formation of a three-dimensional network of aggregated particles [33]. Suspended particles, which form flocs through aggregation, usually have fractal structures, and their effective volume fraction is attributed to the size and dimension [34]. As small strains are imposed, flocs can drive together, increase their size, and cause an increase in viscosity. When strain reaches a critical value, the

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ACCEPTED MANUSCRIPT flocs are disrupted following past another and viscosity decreased. If the reforming of some bonds with increasing strain happened again, reorganization of flocs network structure will occur and relatively high shear strain causes to the G” overshoot [35]. Sim et al. [36] also declared that the overshoot may be related to the balance between the formation and destruction of the network

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junction. So, the overshoots phenomena in this study may be related to the ghost particle and

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balance between the formation and destruction of the network junction. In particular, since the n

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value of all samples, discussed before, were more than 2, it can be concluded that the starch gels may have heterogeneous particles and the overshoots attributed to the formation and destruction

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of the network junction, as it reported that the n value of heterogeneous particulate gels is higher

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than 2 [26,27].

The tan δLVE (the ratio of G”LVE to G’LVE) is a rheological parameter that indicates the physical

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behavior of a system. The tan δLVE for the studied samples were between 0.07 and 0.18 (Table 1).

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CSS samples showed a lower amount of tan δLVE, indicating more elastic behavior than wheat starch. All in all, CSS and wheat starch gels at all concentrations showed predominantly elastic

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behavior at LVE region. It was reported that starches with higher swelling power (SP) exhibit

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higher tan δ [37]. Wheat starch showed higher SP (at the range of 55-85oC) than CSS samples [8]. So, this relationship observed in this study as WS sample showed higher tan δ than CSS samples.

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The yield stress is another important criterion that can be provided by stress sweep. Actually, it shows the maximum deformation that a gel system can remain without any structure breakdown. Then, determination of critical strain at LVE region can be used as a criterion of structural power versus the mechanical stresses [38]. The stress that causes this strain is considered of the yield stress or in other words, the tension that prompts the first non-linear changes in the structure [39]. As shown in Table 1, wheat starch gel showed a higher amount of τy than CSS gels at 6%

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ACCEPTED MANUSCRIPT concentration, however; it was lower than CSS samples at 4% concentration. Among CSS samples, CDC Maria starch showed higher τy than C05041 starch at 4% and 6% concentrations, indicating more resistant to applied stress. The τy of the wheat starch gel at 8% concentration (60.65 Pa) was higher than wheat starch gel (11.9 Pa, 8% w/w) reported by Yousefi and Razavi [19]. Also, the

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yield stress of biopolymers like starch gels can be used as a criterion of the capacity or the ability

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of them to keep ingredients of food formulation in place [40]. There are different rheological

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methods with various assumptions to determine yield stress [16,41]. In our previous study, the yield stress values estimated by Casson model (steady shear experiments) were 2.2, 23.9, 35.4 and

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5.2, 27.2, 54.2 Pa for CDC Maria and C05041 starch gels at 4%, 6% and 8% w/w, respectively

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[9]. The yield stress values obtained by amplitude sweep method were different from steady shear measurement (extrapolation method), which seems to be more accurate. Actually, the methods

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used to determine the yield stress are different, so it is expected to have different results which this

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point has been mentioned by many researchers, for example; Rafe and Razavi [42] reported lower yield stress values based on oscillatory shear measurements than steady shear ones for basil seed

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gum (BSG). In contrast, Yousefi and Razavi [19] found higher yield stress values through

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amplitude measurement for wheat starch gel. Yield stress at flow point (τf), where the storage modulus is equal to loss modulus and structural

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rupture occurred at macroscopic scale; with more increasing the stress value, the loss modulus is going to be more than storage modulus and then flow begins to occur, similar to τy, the τf of wheat starch gel at 4% and 6% concentrations (18.9 and 35.5 Pa) was higher than CDC Maria (18.0 and 24.2 Pa) and C05041 (6.5 and 9.13 Pa) starch gels. These results indicated that CSS samples have more tendency to flow than wheat starch, in another word; wheat starch gel showed more resistant to flow than CSS starch gels at those concentrations. Exceeding a critical strain/stress amplitude

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ACCEPTED MANUSCRIPT resulted in a decrease in (G’) followed by a transition where (G”) exceeded (G’), signifying a change from a behavior of a viscoelastic solid gel to viscoelastic liquid gel. The stress at the crossover of the moduli (Gf, G’=G”) indicates the gel strength at the start of flow point. According to Gf, values shown in Table 1, at 4% and 6% concentrations CDC Maria had the highest strength,

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which was higher than C05041 and wheat starch gels. However, at 8% concentration, C05041

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sample showed the highest gel strength (136.7 Pa).

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When the values of tan δ vs shear stress plotted at the non-linear region, the slope of the plot can be considered as an indication of the spreadability index (SI) of a gel after flow point, as shown in

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Fig. 2. The higher slope value means higher spreadability of a gel. As seen in Fig. 2, the wheat

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starch gel represented the higher slope of tan δ (0.032, 0.299 and 0.008 at 4%, 6%, and 8% concentrations, respectively) than canary seed starches, indicating more spreadability of this

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starch. Between canary seed starches, the C05041 sample (0.031, 0.18 and 0.004 at 4%, 6% and

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8% concentrations, respectively) showed significantly (P<0.05) higher SI than CDC Maria sample (0.025, 0.023 and 0.003 at 4%, 6% and 8% concentrations, respectively). This result was in

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agreement with those reported in our previous paper where the C05041 sample represented more

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shear-thinning behavior (np), the flow behavior of power low model, than CDC Maria sample [9]. The results from amplitude sweep rheological properties showed that WS and CSS samples can

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be applied as a thickener to keep product ingredients in place like gel-like foods and a stabilizer where products need more resistance to flow after threshold stress like thickened foods.

3.2. Mechanical spectra Frequency sweep can provide information about classification of dispersions including; (1) dilute solution, (2) entanglement network system (concentrated system), (3) week gel, and (4) strong gel

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ACCEPTED MANUSCRIPT [16]. Gels can be classified into two main categories, the weak and strong gels [43]. Under small deformation, the strong gels behave like viscoelastic solids and, above a critical deformation value, they start to rupture. On the other hand, weak gels under small deformation behave like strong gels in their mechanical behavior, and with increasing of deformation, the three-dimensional networks

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start to progressive breakdown into smaller clusters. Actually, weak gels demonstrate intermediate

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rheological properties between concentrated solutions and strong gels [19].

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Fig. 3a shows changes in storage modulus (G’) and loss modulus (G”) of canary seed starch (CDC Maria and C05041) and wheat starch gels as a function of frequency (0.01 – 10 Hz). The storage

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modulus (G’) was significantly greater than loss modulus (G’’) over the measured frequency range

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and no crossover occurred. Then, all samples behave like a weak gel and the deformation will be elastic and recoverable. G’ did not show any dependence on low frequencies (0.01–1 Hz), but at

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higher frequency (1–10 Hz), very small dependency was observed especially for wheat starch gel

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(Fig. 3a). This behavior demonstrates the gel properties between weak and strong-gel [44]. Yousefi and Razavi [19], Yoneya et al. [45], Rosalina and Bhattacharya [20], Morikawa et al. [46], Kim

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and Yoo [47] and Lee and Yoo [48] reported the same behavior for wheat starch, cross-linked

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potato starch, cornstarch, hydroxypropylated potato starch, rice starch and hydroxypropylated sweet potato starch, respectively.

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Log G’ versus log ω plot has zero slope for true gel, while for weak gels and concentrated dispersions, the same plots have positive slopes and G’ usually has greater value than G” [17,49]. According to polymer dynamics theory, there is a frequency dependency of G’ values based on power-law relation for a physical gel [25]. Thus, the power-law parameters were used to model the frequency dependency of G’ values in this study: G’ = K’ (ω)n’

(2)

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ACCEPTED MANUSCRIPT Where, ω (rad/s) is the oscillation frequency, K’ is a constant and the exponent n’ is the slope of log-log plot of G’ versus ω. From a structural point of view, n’ = 0 is a covalent gel or a true gel, however for a physical gel n’ is larger than 0. Actually, the n’ value can be used as a criterion to compare a physical gel to a true gel. Lower n’ values near to 0 are characteristic of an elastic gel,

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while n’ values near to 1 are considered as a viscous gel [19]. The n’ value of samples was 0.033,

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0.009 and 0.063 for CDC Maria, C05041 and WS gels, respectively. CSS gels showed lower n’

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values in comparison with wheat starch gel (0.063 ± 0.001), indicating the more elastic behavior of them. Among CSS gels, C05041 sample exhibited lower value of n’ (0.009 ± 0.003) than CDC

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Maria sample (0.033 ± 0.007). Wang et al. [50] reported that the percentage of longer chains

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(mainly amylose) affect the positively solid-like behavior of rice starch gels. Also, the size of starch granules can play an important role in the starch gel elasticity, because after gelatinization,

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the residual solids act as mass connecting elastic springs within the three-dimensional network.

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Therefore, smaller granules lead to a more uniform distribution of the stress applied to the gel. Canary seed starches used in this study have monomodal small granules with a mean diameter of

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2.6 µm, while wheat starch has bimodal granules with a mean diameter of 18.7 µm [8]. Then, the

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stronger elastic behavior of CSS gels based on n’ values may be attributed to their uniform smaller granules, although they had lower amylose content than wheat starch.

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The G’ of CDC Maria (327.0 Pa) starch gel was significantly higher than C05041 (220.0 Pa) and wheat starch (294 Pa) gels (about 1.5-fold and 1.1-fold, respectively), indicating more structural strength of the formed network. Han et al. [51] and Tsai et al. [52] reported that G’ of starch paste can be affected by the rigidity of starch granules. Irani et al. [8] reported the amylose content of CDC Maria, C05041 and wheat starch applied in this study were 23.6%, 22.5%, and 25.6%, respectively. Lii et al. [53] reported that higher inherent amylose content could improve the rigidity

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ACCEPTED MANUSCRIPT of the starch granule structure and causes higher G’, therefore higher G’ of CDC Maria and wheat starch gels may be attributed to their higher amylose content in compare to C05041 starch gel or even higher DP, degree of polymerization, of them as Irani et al. [7] reported higher DP of CDC Maria starch than C05041 starch and higher DP of wheat starch than canary seed starches.

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Actually, amylose with higher DP can form more entangled networks of glucose chains, which

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results in higher viscosity and rigidity of the starch granule structure [54].

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The other dynamic rheological property is loss tangent (tan δ), the ratio of G”/G’, which describes the viscoelastic behavior. Tan δ is directly related to the energy lost per cycle divided by the energy

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stored per cycle. The values of tan δ <1 and tan δ >1 indicate predominantly elastic and viscous

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behaviors, respectively. Observations of polymer systems give the following numerical ranges for tan δ: very high for dilute solutions, 0.2-0.3 for amorphous polymers, low (near 0.01) for glassy

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crystalline polymers and gels [16]. The values of tan δ of selected starch gels were 0.050, 0.047

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and 0.126 for CDC Maria, C05041, and wheat starch, respectively. The CSS samples showed the lowest tan δ (0.047 – 0.050), indicating stronger elastic gel behavior than wheat starch gel (0.126).

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Yousefi and Razavi [19] found tan δ in the range of 0.14-0.64 for native wheat starch at 8 and 12%

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concentrations.

As seen in Fig. 3b, the complex dynamic viscosity (η*) of starch gels decreased linearly with

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increasing frequency. This trend demonstrated that the starch samples have non-Newtonian shear thinning flow behavior. The same behavior was seen for the starch from wheat [19], corn [20], sweet potato [55], Peruvian carrot [56] and acorn [57]. Within CSS gels, the CDC Maria starch (46.20 Pa.s) gel had higher complex viscosity than C05041 (27.90 Pa.s) about 1.6-fold, indicating the good potential of this starch as a thickener in food systems. Wheat starch gel showed lower complex viscosity with CDC Maria, on the other hand, it exhibited higher η* (41.8 Pa.s) than

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ACCEPTED MANUSCRIPT C05041 sample about 1.5 times. Complex viscosity was found to be 39.5 and 5.0 (Pa.s) for wheat starch (8% w/w) [19] and sweep potato starch (6% w/w) [55], respectively. The slope of η* for C05041 starch (-0.093) was higher than two other starch samples (CDC Maria: -0.97 and WS: 1.02) significantly (P<0.05), indicating the more shear-thinning behavior of C05041 starch. In our

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previous study, similar results were found for C05041 starch gel through steady shear experiments

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and using the power-law model [9].

3.3. Cox-Merz rule

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There is an empirical relationship between the apparent viscosity (ηa) of polymers as a function of

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shear rate (𝛾̇ ) and the complex viscosity (η*) as a function of frequency (ω) developed by Cox and Merz [58] as follow:

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|η*| (ω) = η (𝛾̇ ) |ω = 𝛾̇

(3)

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The Cox-Merz rule equates ηa measured in shear flow to η* measured with oscillatory rheometry, where ω is taken as 𝛾̇ in the frequency sweep test. It has been proved that the Cox-Merz rule can

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be used to forecast the steady shear properties of a material from the dynamic rheological

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properties [59]. Fig. 4 showed the relationship between steady-shear and oscillatory rheological properties of CSS gels at 6% and 25 ºC at the same frequency and shear rate range, to assess the

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achievement of the Cox-Merz relationship. For both CSS gels, η* was higher than ηa at all deformation rates, showing disrupting the CSS gels structure under continuous shear rate and disobey the Cox-Merz rule. Existence of rigid chain conformation in improved entanglement and tendency of inter-chain association can demonstrate this deviation from the Cox-Merz rule [60– 62]. The presence of amylose-lipid complexes in the cereal starches has also contributed to the rigidity of the CSS gels [63]. Irani et al. [8] reported that canary seed starch (CDC Maria and

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ACCEPTED MANUSCRIPT C05041) have sufficient amount of amylose-lipid complex. It is noticeable that at high deformation rate, the deviation between complex viscosity and apparent viscosity was much lower than low deformation rates. This difference may be explained by an elastic gel-like structure, which was not affected during small amplitude oscillatory measurements. Generally, at equal ω and 𝛾̇ values, the

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η* of most food dispersions are much higher than ηa [49]. This difference in Cox-Merz rule could

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be related to high shear rates during steady shear measuring, resulting in a low apparent viscosity.

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It is reported that the difference between the two values (η* and ηa) decreased with an increase in

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the concentration [64]. Then, the deviation from the Cox-Merz rule for CSS gels at 6% concentration may be related to the low concentration of them. Yosefi and Razavi [19], Moreira

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et al. [65] and Kim and Yoo [57] reported the mentioned deviation of Cox-Merz rule at low

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concentration for wheat, chestnut and acorn starch, respectively.

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3.4. Dynamic temperature sweep (DTS) properties With heating starch granules in excess water at relatively high temperatures (50 to 95°C), they

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absorb water, swell and gelatinize resulting in an increase in viscosity of starch slurries. The

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measurement of viscosity during heating and cooling can determine the stability of starch slurries, and also their behavior during processing and storage can help to evaluate their suitability in

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different food and non-food applications. The DTS curves and the extracted rheological parameters are shown in Table 2 and Fig. 5, respectively. Ts, the temperature at which complex viscosity (η*) starts to increase suddenly, were 67.8, 84.9 and 64.7°C for CDC Maria, C05041 and wheat starches, respectively (Table 2). The higher Ts of CSS samples in comparison to WS sample may be related to the higher lipid-amylose complex of them [8]. The temperature related to the maximum η*, Tmax, of C05041 sample (92.7

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ACCEPTED MANUSCRIPT °C) was higher than CDC Maria and WS samples (85.9 and 87.7 °C, respectively). The higher Tmax of C05041 sample is associated to its higher swelling power (SP) in comparison with other samples as Irani et al. [8] reported the higher SP of C05041 in compare to the CDC Maria and WS samples at 95 °C. There is a highly correlated between starch paste peak viscosity and swelling power [66].

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The value of maximum complex viscosity (η*max) of CSS samples was higher than WS sample

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(Table 2). These observations were in agreement with that reported by Irani et al. [8] using RVA

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test. In fact, the trend of η*max is similar to the peak viscosity trend in RVA experiment. During the holding period, the starch dispersions are subjected to high temperature and mechanical

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shear stress, which cause starch granules disruption resulting in amylose leaching out and

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alignment causing a decrease in viscosity [67]. According to the DTS method used in this paper, the breakdown viscosity (B) was defined as the difference between η*max and η*min. As shown in

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Table 2, CSSs showed higher B values than WS, indicating higher paste stability of WS in compare

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to CSS samples. RVA results also demonstrated the higher paste stability of WS against CSS samples [8].

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During cooling (from 95 to 50°C), rearrangement occurs between amylose chains which result in

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gel formation and increase in final viscosity (η*f). As a result, the η*f of CSS samples were much higher than WS (about 9 times, as shown in Table 2 and Fig. 5). In addition, the same results were

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observed in setback viscosity (SB), the difference between η*f and η*min based on RVA test. Some factors such as amylose content, chain length and its state of dispersion can affect the final and setback viscosities [68]. Both higher η*f and SB of CSS samples in comparison with WS indicated more gelling ability and retrogradation tendency of them. Although WS had higher amylose content than CSS samples and we expect to show higher η*f and SB, this contrast may be related to higher DP (degree of polymerization) of its amylose molecules [69]. Consequently, the major

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ACCEPTED MANUSCRIPT differences between the behavior of CSS and WS samples were observed in the holding and cooling period during measurement of DTS. Also, because of noticeably higher final viscosity and the gelling ability of CSSs in the cooling period, they can be considered as thickening agents and

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suitable alternative for wheat starch in food applications.

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3.5. Creep behavior

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In creep test, with applying stress, a sharp and instantaneous increase in strain was happened followed by a slight increase over time, which can be related to some rearrangement of network

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structure. The fitting of Jc = f(t), in 0-300 s, for all samples studied and based on R2 > 0.88 and

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RSME<0.004 in all cases, Burger model of four parameters was reasonable to describe starch samples creep behavior. Table 3 shows the values of the parameters of Burger’s model obtained

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from creep test. The instantaneous elastic compliance (J0C) depicts immediate shear creep

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compliance at the initial time, which is related to the undisturbed hydrocolloid network structure [70]. A larger amount of J0C reflects a higher degree of non-retarded Hookean-type (elastic)

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deformation, which represents that the network is relatively free to rearrange cross-links [71]. In

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this study, the C05041 starch exhibited the lower value of J0C than wheat and then CDC Maria starch, which means this starch is more rigid (Table 3). These results were in agreement with our

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results obtained from frequency sweep, where like J0C, the tan δ and n values of C05041 were lower than wheat and CDC Maria starches (see section 3.2). The retarded compliance, J1C, illustrates the principal component of the viscoelastic behavior of starch gels. The lower value of J1C refers to a more solid (elasticity) of Kelvin-Voigt element in the systems. Here in all cases, the contribution of J1C to the total deformation was larger than J0C, reinforcing the idea of a behavior close to a viscoelastic material. There were statistical differences (P<0.05) between J1C of the gels,

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ACCEPTED MANUSCRIPT the wheat starch showed higher retarded compliance than CSSs, and between CSSs the CDC Maria showed higher J1C than C05041 starch (Table 3). It was reported that retarded compliance had a direct relationship with amylose content and amylose-lipid complex [72]. Actually, higher amylose or amylose-lipid complex contents result in more crystal growth, higher molecular order and

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greater rigidity of gel [73]. So, because of the higher amylose-lipid complex content of CSSs [8],

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the lower value of J1C was expected, indicating more solidity of CSS gels. The Newtonian viscosity

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of the free dashpot (0) measures the mechanical fluid behavior of the system. In other words, this parameter is linked with the breakdown of the gel network structure [16]. Here, the C05041 starch

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showed higher 0 than CDC Maria and wheat starches (Table 3), which means a greater resistance

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to flow at the longer time of this starch. Therefore, the C05041 starch would seem to retain more of its solid like viscoelastic structure than CDC Maria and wheat starches. Another parameter of

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Burger’s model is retardation time (λret) which is unique for each material. In general, the higher

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the retardation time of a system, the longer it takes to reach full deformation with the imposing of

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shear stress [16]. In addition, it was declared that retardation time is related to the network viscoelasticity in the opposite manner. In this study, the C05041 sample showed a higher value of

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λret than CDC Maria and wheat starch samples (Table 3). The results obtained from the creep test,

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like the results obtained from frequency sweep (tan δ and n values), illustrated that CSSs have more elastic behavior than wheat starch and between CSSs, C05041 starch showed more solid-like structure than CDC Maria starch (see section 3.2).

3.5. Textural attributes After cooling the gelatinized starch, a gel network is formed. The amylose content of a starch is the main factor that contributes to starch gel strength, actually, there is a high relationship between

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ACCEPTED MANUSCRIPT the amylose and forming connected double-helix aggregates [74]. Textural properties of the selected starch gels, including; hardness, adhesiveness, resilience, cohesiveness, and gumminess, were determined by TPA test (Table 4). Gel hardness generally related to the retrogradation of starch. As can be seen, the C05041 starch

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showed higher hardness than CDC Maria starch, although there was no significant difference

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(P>0.05) between them. Teng et al. [75] reported a positive correlation between gel hardness and

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the amylose content of the starch and also declared that high-amylose starches produce a harder gel. Actually, linear amylose molecules reassociate more easily than highly-branched amylopectin

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molecules. The hardness of wheat starch was about 3.1 and 2.4 times higher than CDC Maria and

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C05041 starch gels. This difference between the hardness of CSS gels and wheat starch gel can be attributed to higher amylose content of wheat starch [8]. Majzoobi and Beparva [14] reported about

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106 g for the hardness of wheat starch (15% w/w with the same size of 1 cm diameter and 1 cm

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height) that was close to wheat sample in this study (101 g). Teng et al. [75] showed higher hardness for corn and wheat starches (high amylose content) than sago and tapioca starches (low

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amylose content). Shevkani et al. [76] and Mua and Jackson [77] found the similar attribution of

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amylose and long chain amylopectin to the hardness of wheat and corn gel starches, respectively. Cohesiveness is a measure of how well a starch gel resists the second deformation according to its

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behavior in the first deformation [78]. In other words, it is a criterion of how well a starch gel can keep its structure after the first bite. Starch gels with good gel setting and high acceptability in starchy food are identified by high cohesiveness. The low amount of cohesiveness means a gel has a plastic nature rather than elastic, which means it can undergo intensive textural changes and proper for chewing food material [79]. The C05041 starch gel represented the lower amount of cohesiveness (0.60) than CDC Maria (0.97) and wheat starch gels, which indicating higher

24

ACCEPTED MANUSCRIPT plasticity and more resistance towards severe textural damages than CDC Maria and wheat starch gels. The lower cohesiveness of C05041 gel may be related to lower molecular weight and smaller chains in comparison with CDC Maria and wheat starch gels as Hansen et al. [74] reported that starches with higher molecular weight and longer chains generate stronger gel. The cohesiveness

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of 0.71 was reported for wheat starch (15% w/w) [14]. In another study, Teng et al. [75] reported

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w/w starch with caster sugar at 30.29% w/w), respectively.

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the cohesiveness of 0.47, 0.50, 0.94 and 0.90 for wheat, corn, sago and potato starches (at 7.69%

Gumminess (hardness × cohesiveness) is characteristic of semi-solid foods, which demonstrate a

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low degree of hardness and a high degree of cohesiveness. In other words, gumminess is the

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energy required to break up a semisolid food to ready it for swallowing [78]. Among CSS gels, the CDC Maria starch gel showed higher gumminess than C05041 starch gel about 27%. The

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gumminess of wheat starch was higher than CSS gels, these results indicating that CDC Maria and

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C05041 starch need less energy to be ready for swallowing about 2.6-fold and 3.4-fold than wheat starch, respectively. The gumminess of wheat starch was 83.3 g, while it was reported between

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15.3 and 27.5 g for different varieties of Indian wheat starches (20% w/v) [76]. The other criterion

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of TPA test is resilience, the measure how well the starch gel fights to regain its original position [78]. The starch samples in this study exhibited the range of 0.82 to 0.86 for resilience (Table 4).

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CSS gels showed higher resilience than wheat starch gel, but there were no significant differences between them (p>0.05). Adhesiveness is the work essential to remove the sample from plunger surface and in the mouth from palate or tongue [78]. The CDC Maria starch gel showed about 82% less adhesiveness (0.03 mJ) than C05041 and wheat starch gels (0.17 mJ). In another research, the adhesiveness of wheat starch at the same concentration (15% w/w) and the situation was reported about 0.30 (mJ) [14].

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ACCEPTED MANUSCRIPT A positive relationship between textural features and dynamic rheological properties was observed. For all samples, G’ and η* are positively correlated with cohesiveness, while tan δ, n’ and SI show positive correlations with gumminess. Oleyaei et al. [80] also reported a positive correlation between SI and gumminess in sage seed hydrogel. So, it may be concluded that the

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dynamic rheological method can overcome the deficiency of conventional TPA measurements

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such as poor reproducibility and hard operability.

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4. Conclusion

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The viscoelastic properties and textural profile analysis of two varieties of canary seed starch (CSS) gels were compared with wheat starch (WS) gel. Dynamic behavior of CSS gels was

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typically classified as a strong gel, indicating the potential of them to use in food applications as

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an interesting gelling agent. The higher yield stress of CSS starches in comparison with wheat starch indicate the good potential of them as a stabilizer in jellylike food products, in desserts

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especially fruity desserts to keep dessert components in place or where a close behavior to solids

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at the static state is needed. It seems that CDC Maria starch variety can be used as thickener agent in food systems as it showed higher complex viscosity than wheat and C05041 starches. The higher

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cohesiveness and lower gumminess of CSS gels in comparison with WS gel could identify better gel setting and high acceptability of starchy foods which produce with them, where the softer texture of them are desirable. The specific dynamic rheological properties (higher elasticity, final viscosity, and setback viscosity) and textural properties (higher cohesiveness) of the CSS gels in comparison with WS gel suggest the potential of canary seed as a non-conventional starch source in the food and pharmaceutical systems. For further investigation, it is needed to study the

26

ACCEPTED MANUSCRIPT influence of concentration, temperature and modification methods on rheological and textural properties of CSS gels.

5. Acknowledgments

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The authors wish to thank the Guelph Food Research Centre (GFRC) and Biophysics Lab of

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Ferdowsi University of Mashhad (FUM), Iran, for providing canary seeds and laboratory facilities,

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respectively.

E. Abdel‐ Aal, P. Hucl, F.W. Sosulski, Characteristics of canaryseed (Phalaris canariensis

AN

[1]

US

6. References

L.) starch, Starch‐ Stärke. 49 (1997) 475–480.

US FDA, Agency Response Letter GRAS Notice No. GRN000529, US Food Drug Adm.

M

[2]

ED

(2015).

http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/NoticeInventory/ucm440

HC, Health Canada, Food and Nutrition, Novel Foods, Heal. Canada, Food Nutr. Nov.

CE

[3]

PT

610.htm (accessed March 29, 2016).

Foods. (2016). http://www.hc-sc.gc.ca/fn-an/gmf-agm/appro/canary-seed-lang-grain-

[4]

AC

alpiste-eng.php. (accessed March 29, 2016). B. Wischmann, T. Ahmt, O. Bandsholm, A. Blennow, N. Young, L. Jeppesen, L. Thomsen, Testing properties of potato starch from different scales of isolations—A ring test, J. Food Eng. 79 (2007) 970–978. [5]

S. Park, M.G. Chung, B. Yoo, Rheological properties of octenylsuccinated corn starch pastes, Starch/Stärke. 56 (2004) 431–438.

27

ACCEPTED MANUSCRIPT [6]

M.A. Hesarinejad, A. Koocheki, S.M.A. Razavi, Dynamic rheological properties of Lepidium perfoliatum seed gum: Effect of concentration, temperature and heating/cooling rate, Food Hydrocoll. 35 (2014) 583–589. doi:10.1016/j.foodhyd.2013.07.017.

[7]

M. Irani, S.M.A. Razavi, E.S.M. Abdel-Aal, P. Hucl, C.A. Patterson, Dilute solution

T

properties of canary seed (Phalaris canariensis) starch in comparison to wheat starch, Int.

M. Irani, E.S.M. Abdel-Aal, S.M.A. Razavi, P. Hucl, C.A. Patterson, Thermal and

CR

[8]

IP

J. Biol. Macromol. 87 (2016) 123–129. doi:10.1016/j.ijbiomac.2016.02.050.

functional properties of hairless canary seed (Phalaris canariensis L.) starch in

US

comparison with wheat starch, Cereal Chem. 94 (2017) 341–348. doi:10.1094/CCHEM-

[9]

AN

04-16-0083-R.

M. Irani, S.M.A. Razavi, E.S.M. Abdel-Aal, M. Taghizadeh, Influence of variety,

M

concentration, and temperature on the steady shear flow behavior and thixotropy of canary

ED

seed (Phalaris canariensis) starch gels, Starch/Staerke. 68 (2016) 1203–1214. doi:10.1002/star.201500348.

PT

[10] E.M. Abdel-aal, P. Hucl, S.S. Miller, C. Ann, D. Gray, Microstructure and nutrient

CE

composition of hairless canary seed and its potential as a blending flour for food use, Food Chem. 125 (2011) 410–416. doi:10.1016/j.foodchem.2010.09.021.

AC

[11] P.J. Hucl, F.W. Sosulski, Structural and Compositional Characteristics of Canaryseed ( Phalaris canariensis L .), (1997) 3049–3055. [12] E.M. Abdel-aal, P. Hucl, C. Ann, D. Gray, LWT - Food Science and Technology Phytochemicals and heavy metals content of hairless canary seed : A variety developed for food use, LWT - Food Sci. Technol. 44 (2011) 904–910. doi:10.1016/j.lwt.2010.10.019. [13] E.-S.M. Abdel-Aal, P. Hucl, C.A. Patterson, D. Gray, Fractionation of hairless canary

28

ACCEPTED MANUSCRIPT seed (Phalaris canariensis) into starch, protein, and oil, J. Agric. Food Chem. 58 (2010) 7046–7050. [14] M. Majzoobi, P. Beparva, Effects of acetic acid and lactic acid on physicochemical characteristics of native and cross-linked wheat starches, Food Chem. 147 (2014) 312–

T

317.

IP

[15] A.M. Amini, S.M.A. Razavi, S.A. Mortazavi, Morphological, physicochemical, and

CR

viscoelastic properties of sonicated corn starch, Carbohydr. Polym. 122 (2015) 282–292. [16] J.F. Steffe, Rheological methods in food process engineering, Freeman press, 1996.

US

[17] A.H. Clark, S.B. Ross-Murphy, Structural and mechanical properties of biopolymer gels,

AN

in: Biopolymers, Springer, 1987: pp. 57–192.

[18] D.R. Heldman, D.B. Lund, C. Sabliov, Handbook of food engineering, CRC Press, 2006.

M

[19] A.R. Yousefi, S.M.A. Razavi, Dynamic rheological properties of wheat starch gels as

ED

affected by chemical modification and concentration, Starch/Staerke. 67 (2015) 567–576. doi:10.1002/star.201500005.

PT

[20] I. Rosalina, M. Bhattacharya, Dynamic rheological measurements and analysis of starch

CE

gels, Carbohydr. Polym. 48 (2002) 191–202. [21] N. Singh, L. Kaur, Morphological, thermal, rheological and retrogradation properties of

AC

potato starch fractions varying in granule size, J. Sci. Food Agric. 84 (2004) 1241–1252. doi:10.1002/jsfa.1746. [22] A. Heydari, S.M.A. Razavi, M. Irani, Effect of temperature and selected sugars on dilute solution properties of two hairless canary seed starches compared with wheat starch, Int. J. Biol. Macromol. (2018), 108, 1207-1218. [23] C. Mao, S. Rwei, Cascade analysis of mixed gels of xanthan and locust bean gum, 47

29

ACCEPTED MANUSCRIPT (2006) 7980–7987. doi:10.1016/j.polymer.2006.09.032. [24] B. Koltisko, A. Keller, M. Litt, E. Baer, A. Hiltner, Mechanical properties of thermoreversible atactic polystyrene gels, Macromolecules. 19 (1986) 1207–1212. [25] J.D. Ferry, Viscoelastic properties of polymers, John Wiley & Sons, 1980.

T

[26] C.G. Biliaderis, B.O. Juliano, Thermal and mechanical properties of concentrated rice

IP

starch gels of varying composition, Food Chem. 48 (1993) 243–250.

CR

[27] K.R. Reddy, S.Z. Ali, K.R. Bhattacharya, The fine structure of rice-starch amylopectin and its relation to the texture of cooked rice, Carbohydr. Polym. 22 (1993) 267–275.

US

[28] H.G. Sim, K.H. Ahn, S.J. Lee, Large amplitude oscillatory shear behavior of complex

AN

fluids investigated by a network model : a guideline for classification, 112 (2003) 237– 250. doi:10.1016/S0377-0257(03)00102-2.

M

[29] K. Hyun, M. Wilhelm, C.O. Klein, K.S. Cho, J.G. Nam, K.H. Ahn, S.J. Lee, R.H. Ewoldt,

ED

G.H. McKinley, A review of nonlinear oscillatory shear tests: Analysis and application of large amplitude oscillatory shear (LAOS), Prog. Polym. Sci. 36 (2011) 1697–1753.

PT

[30] W.E. Rochefort, S. Middleman, Rheology of xanthan gum: salt, temperature, and strain

369.

CE

effects in oscillatory and steady shear experiments, J. Rheol. (N. Y. N. Y). 31 (1987) 337–

AC

[31] C. Hernández-Jaimes, L.A. Bello-Perez, E.J. Vernon-Carter, J. Alvarez-Ramirez, Plantain starch granules morphology, crystallinity, structure transition, and size evolution upon acid hydrolysis, Carbohydr. Polym. 95 (2013) 207–213. [32] M.R. Debet, M.J. Gidley, Why do gelatinized starch granules not dissolve completely? Roles for amylose, protein, and lipid in granule “ghost” integrity, J. Agric. Food Chem. 55 (2007) 4752–4760.

30

ACCEPTED MANUSCRIPT [33] R. Pal, Rheology of emulsions containing polymeric liquids, Encycl. Emuls. Technol. 4 (1996) 93. [34] L.G.B. Bremer, B.H. Bijsterbosch, P. Walstra, T. van Vliet, Formation, properties and fractal structure of particle gels., (1993).

T

[35] G.A. Rosa, M. Meraz, Impact of ghosts on the viscoelastic response of gelatinized corn

IP

starch dispersions subjected to small strain deformations, 110 (2014) 156–162.

CR

[36] H.G. Sim, K.H. Ahn, S.J. Lee, Large amplitude oscillatory shear behavior of complex fluids investigated by a network model: a guideline for classification, J. Nonnewton. Fluid

US

Mech. 112 (2003) 237–250.

AN

[37] J.Y. Li, A.I. Yeh, Relationships between thermal, rheological characteristics and swelling power for various starches, J. Food Eng. 50 (2001) 141–148. doi:10.1016/S0260-

M

8774(00)00236-3.

ED

[38] Q. Guo, S.W. Cui, Q. Wang, H.D. Goff, A. Smith, Microstructure and rheological properties of psyllium polysaccharide gel, Food Hydrocoll. 23 (2009) 1542–1547.

PT

[39] T. Alemzadeh, M.A. Mohammadifar, M.H. Azizi, K. Ghanati, Effect of two different

(2010).

CE

species of Iranian gum tragacanth on the rheological properties of mayonnaise sauce,

AC

[40] M.A. Rao, J.F. Kenny, Flow properties of selected food gums, Can. Inst. Food Sci. Technol. J. 8 (1975) 142–148. [41] D.D. Christianson, E.B. Bagley, Yield stresses in dispersions of swollen, deformable cornstarch granules, Cereal Chem. 61 (1984) 500–503. [42] A. Rafe, S.M.A. Razavi, Dynamic viscoelastic study on the gelation of basil seed gum, Int. J. Food Sci. Technol. 48 (2013) 556–563. doi:10.1111/j.1365-2621.2012.03221.x.

31

ACCEPTED MANUSCRIPT [43] R. Lapasin, S. Pricl, Industrial applications of polysaccharides, in: Rheol. Ind. Polysaccharides Theory Appl., Springer, 1995: pp. 134–161. [44] A.E. Labropoulos, S. HSU, Viscoelastic Behavior of Whey Protein Isolates at the Sol‐ Gel Transition Point, J. Food Sci. 61 (1996) 65–68.

T

[45] T. Yoneya, K. Ishibashi, K. Hironaka, K. Yamamoto, Influence of cross-linked potato

IP

starch treated with POCl 3 on DSC, rheological properties and granule size, Carbohydr.

CR

Polym. 53 (2003) 447–457.

[46] K. Morikawa, K. Nishinari, Effects of concentration dependence of retrogradation

US

behaviour of dispersions for native and chemically modified potato starch, Food

AN

Hydrocoll. 14 (2000) 395–401.

[47] C. Kim, B. Yoo, Rheological properties of rice starch-xanthan gum mixtures, J. Food Eng.

M

75 (2006) 120–128. doi:10.1016/j.jfoodeng.2005.04.002.

ED

[48] H.L. Lee, B. Yoo, Effect of hydroxypropylation on physical and rheological properties of sweet potato starch, LWT-Food Sci. Technol. 44 (2011) 765–770.

PT

[49] H.-S. Chan, Biophysical methods in food research, Published for the Society of Chemical

CE

Industry by Blackwell Scientific Publications, 1984. [50] L. Wang, B. Xie, J. Shi, S. Xue, Q. Deng, Y. Wei, B. Tian, Physicochemical properties

AC

and structure of starches from Chinese rice cultivars, Food Hydrocoll. 24 (2010) 208–216. [51] X.-Z. Han, O.H. Campanella, H. Guan, P.L. Keeling, B.R. Hamaker, Influence of maize starch granule-associated protein on the rheological properties of starch pastes. Part II. Dynamic measurements of viscoelastic properties of starch pastes, Carbohydr. Polym. 49 (2002) 323–330. [52] M.-L. Tsai, C.-F. Li, C.-Y. Lii, Effects of granular structures on the pasting behaviors of

32

ACCEPTED MANUSCRIPT starches, Cereal Chem. 74 (1997) 750–757. [53] C.-Y. Lii, M.-L. Tsai, K.-H. Tseng, Effect of amylose content on the rheological property of rice starch, Cereal Chem. 73 (1996) 415–420. [54] K.J. Shon, S.T. Lim, B. Yoo, Rheological properties of rice starch dispersions in dimethyl

T

sulfoxide, Starch-Starke. 57 (2005) 363–369. doi:10.1002/star.20400353.

IP

[55] D. Kim, B. Yoo, Rheological behaviors of hydroxypropylated sweet potato starches

CR

influenced by guar, locust bean, and xanthan gums, Starch‐ Stärke. 62 (2010) 584–591. [56] K.M. Albano, C.M.L. Franco, V.R.N. Telis, Rheological behavior of Peruvian carrot

US

starch gels as affected by temperature and concentration, Food Hydrocoll. 40 (2014) 30–

AN

43.

[57] W. Kim, B. Yoo, Rheological behaviour of acorn starch dispersions: effects of

M

concentration and temperature, Int. J. Food Sci. Technol. 44 (2009) 503–509.

ED

[58] W. Cox, E. Merz, Polym, Sci. 28 (1958) 619–620. [59] P.M.S. Da Silva, J.C. Oliveira, M. a. Rao, Rheological properties of heated cross‐ linked

PT

waxy maize starch dispersions, Int. J. Food Prop. 1 (1998) 23–34.

CE

doi:10.1080/10942919809524562. [60] S.M.A. Razavi, S.W. Cui, Q. Guo, H. Ding, Some physicochemical properties of sage

AC

(Salvia macrosiphon) seed gum, Food Hydrocoll. 35 (2014) 453–462. [61] H. Karazhiyan, S.M.A. Razavi, G.O. Phillips, Y. Fang, S. Al-Assaf, K. Nishinari, R. Farhoosh, Rheological properties of Lepidium sativum seed extract as a function of concentration, temperature and time, Food Hydrocoll. 23 (2009) 2062–2068. [62] H. Karazhiyan, S.M.A. Razavi, G.O. Phillips, Y. Fang, S. Al-Assaf, K. Nishinari, Physicochemical aspects of hydrocolloid extract from the seeds of Lepidium sativum, Int.

33

ACCEPTED MANUSCRIPT J. Food Sci. Technol. 46 (2011) 1066–1072. doi:10.1111/j.1365-2621.2011.02583.x. [63] D.J. Thomas, W.A. Atwell, Starches. Practical Guides for the Food Industry St. Paul Minnesota, USA: American Association of Cereal Chemists, (1999). [64] B. Yoo, Steady and dynamic shear rheology of glutinous rice flour dispersions, Int. J.

T

Food Sci. Technol. 41 (2006) 601–608.

IP

[65] R. Moreira, F. Chenlo, M.D. Torres, J. Glazer, Rheological properties of gelatinized

CR

chestnut starch dispersions: Effect of concentration and temperature, J. Food Eng. 112 (2012) 94–99.

US

[66] G.B. Crosbie, The Relationship Between Starch Swelling Properties, Paste Viscosity and

AN

Boiled Noodle Quality in Wheat Flours, 13 (1991) 145–150. doi:10.1016/S07335210(09)80031-3.

M

[67] S. Ragaee, E.-S.M. Abdel-Aal, Pasting properties of starch and protein in selected cereals

ED

and quality of their food products, Food Chem. 95 (2006) 9–18. [68] M. Glicksman, Gum technology in the food industry, (1969).

PT

[69] S. Mishra, T. Rai, Morphology and functional properties of corn, potato and tapioca

CE

starches, Food Hydrocoll. 20 (2006) 557–566. [70] S.M. Fitzsimons, J.T. Tobin, E.R. Morris, Synergistic binding of konjac glucomannan to

AC

xanthan on mixing at room temperature, Food Hydrocoll. 22 (2008) 36–46. [71] H.S. Koop, C.E. de Oliveira Praes, F. Reicher, C.L. de Oliveira Petkowicz, J.L.M. Silveira, Rheological behavior of gel of xanthan with seed galactomannan: Effect of hydroalcoholic–ascorbic acid, Mater. Sci. Eng. C. 29 (2009) 559–563. [72] Y. Xu, S. Xiong, Y. Li, S. Zhao, Study on creep properties of indica rice gel, 86 (2008) 10–16. doi:10.1016/j.jfoodeng.2007.09.002.

34

ACCEPTED MANUSCRIPT [73] S. Varavinit, S. Shobsngob, W. Varanyanond, P. Chinachoti, O. Naivikul, Effect of amylose content on gelatinization, retrogradation and pasting properties of flours from different cultivars of Thai rice, Starch‐ Stärke. 55 (2003) 410–415. [74] M.R. Hansen, A. Blennow, S. Pedersen, L. Nørgaard, S.B. Engelsen, Gel texture and

T

chain structure of amylomaltase-modified starches compared to gelatin, Food Hydrocoll.

IP

22 (2008) 1551–1566.

CR

[75] L.Y. Teng, N.L. Chin, Y.A. Yusof, Rheological and textural studies of fresh and freezethawed native sago starch–sugar gels. II. Comparisons with other starch sources and

US

reheating effects, Food Hydrocoll. 31 (2013) 156–165.

AN

[76] K. Shevkani, N. Singh, S. Singh, A.K. Ahlawat, A.M. Singh, Original article Relationship between physicochemical and rheological properties of starches from Indian wheat lines,

M

(2011) 2584–2590. doi:10.1111/j.1365-2621.2011.02787.x.

ED

[77] J.P. Mua, D.S. Jackson, Retrogradation and Gel Textural Attributes of Corn Starch Amylose and Amylopectin Fractions 1, 27 (1998) 157–166.

PT

[78] M. Bourne, Food texture and viscosity: concept and measurement, Academic press, 2002.

CE

[79] B.S. Roopa, S. Bhattacharya, Alginate gels: I. Characterization of textural attributes, J. Food Eng. 85 (2008) 123–131.

AC

[80] S. Amir, S. Mohammad, A. Razavi, K.S. Mikkonen, International Journal of Biological Macromolecules Physicochemical and rheo-mechanical properties of titanium dioxide reinforced sage seed gum nanohybrid hydrogel, Int. J. Biol. Macromol. 118 (2018) 661– 670. doi:10.1016/j.ijbiomac.2018.06.049.

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ACCEPTED MANUSCRIPT Table caption

Table 1. Elastic modulus in the linear viscoelastic range (GLVE), limiting strain (γc), and loss-tangent in the LVE range (tan δLVE), yield stress in the LVE range (τy), and flow-point stress (τf), with corresponding

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modulus (Gf: G = G) for starch gels from wheat and different varieties of canary seed, as determined by

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stress sweep test (0.01 – 200 Pa) at 1 Hz frequency and 25 ºC a (6% concentration).

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Table 2. The rheological parameters of dynamic temperature sweep test determined for canary seed and wheat starches at the concentration of 6% w/w (f =1 Hz; 0.5% strain).

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Table 3. Creep parameters of the Burger’s model (Eq. 1) determined for canary seed and wheat starches (6% w/w, 25 ℃).

AC

CE

PT

ED

M

AN

Table 4. Textural parameters of the canary seed starch gels (15% w/w) determined by TPA test.

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ACCEPTED MANUSCRIPT Table 1. Elastic modulus in the linear viscoelastic range (GLVE), limiting strain (γc), and loss-tangent in the LVE range (tan δLVE), yield stress in the LVE range (τy), and flow-point stress (τf), with corresponding modulus (Gf: G = G) for starch gels from wheat and different varieties of canary seed at different concentrations (4-8%), as determined by stress sweep test (0.01 – 600 Pa) at 1 Hz frequency and 25 ºC a. G’ LVE (Pa)

G” LVE (Pa)

γc (%)

Tan δ LVE

τy (Pa)

CDC Maria (4%)

37.25 ± 1.20Ca

2.79 ± 0.03Aa

2.24 ± 0.08Aa

0.07 ± 0.00Aa

0.83 ± 0.00Ba

CDC Maria (6%)

250.00 ± 1.56Cb

28.50 ± 1.20Cc

5.69 ± 0.02Bb

0.11 ± 0.11Ac

CDC Maria (8%)

320.50 ± 12.02Ac

25.85 ± 0.78Ab

18.90 ± 0.71Ac

0.08 ± 0.00Ab

C05041 (4%)

31.10 ± 1.56Ba

2.53 ± 0.21Aa

1.91 ± 0.11Aa

0.08 ± 0.00Aa

C05041 (6%)

120.50 ± 0.14Ab

15.00 ± 0.65Aab

5.400 ± 0.04Ab

C05041 (8%)

342.50 ± 20.51Ac

26.40 ± 8.91Ab

17.70 ± 0.99Ac

Wheat (4%)

19.18 ± 1.59Aa

2.42 ± 0.11Aa

Wheat (6%)

153.00 ± 0.56Bb

27.10 ± 0.74Bb

Wheat (8%)

279.50 ± 33.23Ac

32.60 ± 8.34Ab

D E

Starch gel (w/w %)

T P

T P

τf (Pa)

Gf (Pa)

18.00 ± 0.00Ba

16.36 ± 0.34Aa

14.30 ± 0.07Bb

24.20 ± 0.28Ba

108.40 ± 1.55Cb

60.80 ± 0.00Ac

285.50 ± 9.19Cb

111.00 ± 6.51Ab

0.59 ± 0.00Ba

6.49 ± 0.01Aa

13.50 ± 0.93Ba

0.12 ± 0.05Ba

6.53 ± 0.07Ab

9.13 ± 0.00Ab

51.25 ± 1.80Bb

0.08 ± 0.03Aa

60.75 ± 0.07Ac

129.00 ± 0.00Bc

136.75 ± 0.49Bc

0.13 ± 0.00Ba

0.51 ± 0.12Ba

18.90 ± 0.28Ca

4.85 ± 0.06Aa

16.30 ± 1.10Cb

0.18 ± 0.08Cb

25.40 ± 0.05Cb

35.50 ± 0.30Cb

41.24 ± 0.12Ab

21.75± 2.62Ac

0.12 ± 0.02Aa

60.65 ± 0.07Ac

88.35± 0.07Ac

116.6 ± 7.50Ac

2.60 ± 0.42Aa

M

C S

U N

A

I R

E C

Mean±SD

a–c: The different small letters in each column show significant differences for concentrations of each variety. (p<0.05)

C A

A–B: The different capital letters in each column show significant differences for varieties of each concentration. (p<0.05)

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ACCEPTED MANUSCRIPT

Table 2. The rheological parameters of dynamic temperature sweep determined for canary seed and wheat starches at the concentration of 6% w/w (f =1 Hz; 0.5% strain)

Tmax (°C)

η*max (Pa.s)

B (Pa.s)

η*f (Pa.s)

SB (Pa.s)

CDC Maria

67.8

85.9

17.2

15.7

28.7

27.2

C05041

84.9

92.7

21.9

14.5

Wheat

64.7

87.7

15.9

13.2

39.0

31.6

5.6

2.9

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CR US AN M ED PT CE AC

38

T

Ts (°C)

Starch gel

ACCEPTED MANUSCRIPT

Table 3. Creep parameters of the Burger’s model (Eq. 1) determined for canary seed and wheat starch gels (6% w/w, 0.5 Pa, 25 ℃) J0C (10-3 Pa -1)

J1C (10-3 Pa -1)

λret (s)

ɳ0 (103 Pa s)

R2

RMSE

CDC Maria

6.075 ±0.003c

12.000 ± 0.005b

0.649 ± 0.096b

33.090 ± 1.047b

0.881

0.003

C05041

3.560 ± 0.000a

4.414 ± 0.001a

1.582 ± 0.080c

66.000 ± 0.075c

0.928

0.004

Wheat

5.907 ± 0.003b

53.760 ± 0.033c

0.412 ± 0.010a

15.280 ± 1.064a

0.952

0.002

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CR

Mean±SD

T

Sample

a–c: The different small letters in each column show significant differences for concentrations of each

AC

CE

PT

ED

M

AN

US

variety. (p<0.05)

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ACCEPTED MANUSCRIPT

Starch gel

Adhesiveness

Resilience

Cohesiveness

Gumminess

(g)

(mJ)

(-)

(-)

(g)

CDC Maria

32.00 ±1.73a

0.03 ±0.06a

0.88 ±0.04a

0.97 ±0.27bc

31.33 ±9.07a

C05041

41.33 ±3.21a

0.17 ±0.06b

0.86 ±0.12a

0.60 ±0.06a

24.67 ±3.79a

Wheat

101.33 ±8.39b

0.17 ±0.06b

0.82 ±0.04a

0.83 ±0.02ab

83.33 ±4.93b

CR

Mean±SD

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Hardness

T

Table 4. Textural parameters of the canary seed starch gels (15% w/w) determined by TPA testa

AC

CE

PT

ED

M

AN

US

a) Mean values in the same column with different letters are significantly different (p<0.05).

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ACCEPTED MANUSCRIPT Figure caption

Fig. 1. Stress (a) and Strain (b) sweep dependency of storage modulus (G’) and loss modulus (G”) for canary seed and wheat starch gels at 25 ºC (frequency: 1 Hz).

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Fig. 2. The slope of the plot of loss tangent (Tan δ) vs shear stress data in the non-linear region

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determined as spreadability index (SI) of CDC Maria, C05041 and wheat starches (6% concentration).

CR

Fig. 3. Frequency sweep of canary seed and wheat starch gels (0.5% strain; 25°C) at concentrations of 6% w/w, showing the variation of storage modulus (G’) and loss modulus (G”) (a) and the influence of

US

frequency on complex viscosity (η*).

Fig. 4. Cox-Merz rule (ηa, η*) for CDC Maria (a) and C05041 (b) starch dispersions at 25 ºC (6% w/w).

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Fig. 5. Temperature sweep of canary seed and wheat starches at the concentration of 6% w/w (f=1 Hz;

AC

CE

PT

ED

M

0.5% strain), showing the pasting profile of the samples.

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ACCEPTED MANUSCRIPT A

1000

G' CDC Maria G" CDC Maria G' C05041

100

G' Wheat

10

G" Wheat

T

1

IP

G' & G" (Pa)

G" C05041

0.01

0.1

1

10

B

10000

G' CDC Maria

M

G" CDC Maria G' C05041 G" C05041

ED

100

G' Wheat G" Wheat

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10

1

0.1

AC

0.01 0.001

CE

G' & G" (Pa)

1000

AN

Strain (%)

1000

100

US

0.01 0.001

CR

0.1

0.01

0.1

1

10

100

1000

Stress (Pa)

Fig. 1.Typical Stress (a) and Strain (b) sweep dependency of storage modulus (G’) and loss modulus (G”) for canary seed and wheat starch gels at 25 ºC and 6% w/w (frequency: 1 Hz)

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ACCEPTED MANUSCRIPT 100

CDC Maria

C05041

Wheat

T

1

IP

Tan δ

10

US

CR

0.1

0.01 0.1

1.0

10.0

100.0

1000.0

AN

0.0

Shear stress (Pa)

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Fig. 2. The slope of the plot of loss tangent (Tan δ) vs shear stress data in the non-linear region

AC

CE

PT

ED

determined as spreadability index (SI) of CDC Maria, C05041 and wheat starches (6% concentration).

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ACCEPTED MANUSCRIPT

1000 G' CDC Maria

A

G" CDC Maria G' C05041

IP

T

G" C05041

10

G' Wheat G" Wheat

US

CR

G' & G" (Pa)

100

1 0.1

1

Frequancy (Hz)

10

M

AN

0.01

10000

PT

Wheat

100

AC

CE

η* (Pa.s)

1000

10

C05041

ED

B

CDC Maria

1

0.01

0.1

1

10

Frequency (Hz)

Fig. 3. Frequency sweep of canary seed and wheat starch gels (0.5% strain; 25°C) at concentrations of 6% w/w, showing the variation of storage modulus (G’) and loss modulus (G”) (a) and the influence of frequency on complex viscosity (η*)

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ACCEPTED MANUSCRIPT 10000 Complex viscosity Apparent Viscosity

100

T

10

IP

η*, ηa (Pa.s)

1000

CR

1

0 0

1

10

100

1000

US

0

AN

ω (Hz), γ˙ (1/s)

10000

b

0

M

Apparent Viscosity

PT

10

1

Complex Viscosity

ED

100

CE

η*, ηa (Pa.s)

1000

AC

0

0

1

10

100

1000

ω (Hz), γ˙ (1/s)

Fig. 4. Cox-Merz rule (ηa, η*) for CDC Maria (a) and C05041 (b) starch dispersions at 25 ºC (6% w/w)

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ACCEPTED MANUSCRIPT

CDC Maria

C05041

Wheat

Temperature

45

100

40

95

T

25

80

IP

η* (Pa.s)

85

30

75

CR

20 15

65

US

10

70

AN

5 0 5

10

15

Time (min)

60 55 50

20

25

M

0

Temperature (° C)

90

35

30

ED

Fig. 5. Temperature sweep of canary seed and wheat starches at the concentration of 6% w/w (f=1 Hz;

AC

CE

PT

0.5% strain), showing the pasting profile of the samples

46

ACCEPTED MANUSCRIPT

T

Research highlights

CR

 CSS gels were typically between weak and strong gel.

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 CSS exhibited stronger elastic & shear thinning behaviour than WS.

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 CDC Maria starch showed higher G’, G” and η* than WS and C05041 starch.  CSS had lower yield stresses than WS.

AC

CE

PT

ED

M

AN

 CSS has comparable cohesiveness and less gumminess than WS.

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