Effect of industry-scale microfluidization on structural and physicochemical properties of potato starch

Innovative Food Science and Emerging Technologies 60 (2020) 102278

Contents lists available at ScienceDirect

Innovative Food Science and Emerging Technologies journal homepage: www.elsevier.com/locate/ifset

Effect of industry-scale microfluidization on structural and physicochemical properties of potato starch ⁎

Xiao-hong Hea, Shun-jing Luoa, Ming-shun Chena, Wen Xiab, Jun Chena, , Cheng-mei Liua,

T

⁎

a

State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China Key Laboratory of Tropical Crop Products Processing of Ministry of Agriculture, Agricultural Products Processing Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang 524001, China b

A R T I C LE I N FO

A B S T R A C T

Keywords: Microfluidizer Potato starch Physical modification Gelatinization Properties

A recently designed “industry-scale microfluidizer” (ISM) was applied to treat potato starch, then the structural and physicochemical properties of potato starch treated at different ISM pressure (30, 60, 90, and 120 MPa) were investigated. As ISM pressure increased, starch granule size was firstly increased, and subsequently declined at 120 MPa. A remarkable destruction of starch granules was observed, and all the large granules disintegrated into irregular block-like structures after treatment at 120 MPa. Both crystalline and short-range ordered structure were progressively disrupted with the increase of pressure. The structural destruction was attributed to starch gelatinization, which depended on ISM pressure. ISM treatment could arbitrarily adjust pasting viscosity and increase setback value of potato starch. Moreover, moduli and mechanical rigidity of starch pastes were enhanced by ISM treatment. These results implied that ISM treatment could be a potential choice to modify starch containing large granules at an industrial level. Industrial relevance: Microfluidization was an available physical technique to improve functional properties of starch. However, it was difficult for conventional microfluidizer to treat starch containing big granule sizes both in laboratory and industrial scale owing to the drawbacks of devices. A recently designed “industry-scale microfluidizer” (ISM) in our laboratory could be applied to treat potato starch containing large granules. This preliminary study gave important indications that the practical industrial applications of potato starch could be widen by safe and simple microfludization technology, and ISM may be used for processing whole grains flour to obtain nutritional products.

1. Introduction Starch is one of the most abundant natural resources, which has been widely used as a thickener, stabilizer, and gelling agent in food industries, and there is also a great demand for starch in other non-food applications (Singh, Kaur, & Mccarthy, 2007; Singh, Singh, Kaur, Sodhi, & Gill, 2003). However, these applications were restricted owing to some undesirable properties of native starch, such as uncontrolled paste consistency, poor solubility (Choi, Kim, Park, Kim, & Baik, 2009) and lack of stability under conditions of shear, acid pH and refrigeration (Luo et al., 2017). Starch modification was an effective way to enhance and improve its functional properties in accordance with the intended end-use. Physical modification techniques have been gaining wider acceptance because of simple and economical processes and no question of chemical or biological reagents (Ashogbon & Akintayo, 2014). Dynamic high-pressure microfluidization (DHPM) was a physical

⁎

treatment technique accompanied by powerful shear, turbulence, highvelocity impaction, high-frequency vibration, instantaneous pressure drop, and cavitation forces (Chen et al., 2012), which has been previously applied to modify starch. For example, Li et al. (2018) reported that DHPM changed the morphology and decreased the crystallinity of rice starch, thus enhancing the degree of octenyl succinic anhydride modification. The microfluidization weakened the structure and decreased the gelatinization enthalpy of cassava starch (Kasemwong, Ruktanonchai, Srinuanchai, Itthisoponkul, & Sriroth, 2011). The surface characteristics and structure of rice amylose, as well as interactions between amylose and other molecules could also be modified by DHPM as concluded by Wang et al. (2018). Moreover, texture properties of maize amylose were affected by DHPM (Tu et al., 2013). Despite of being an available approach in the aforementioned papers, the application of microfluidization in starch modification was still limited. Owing to the easily precipitating characteristics of starch and the

Corresponding authors at: Nanchang University, 235 Nanjing East Road, Nanchang, China. E-mail addresses: [email protected] (J. Chen), [email protected] (C.-m. Liu).

https://doi.org/10.1016/j.ifset.2019.102278 Received 18 August 2019; Received in revised form 8 December 2019; Accepted 16 December 2019 Available online 17 December 2019 1466-8564/ © 2019 Elsevier Ltd. All rights reserved.

Innovative Food Science and Emerging Technologies 60 (2020) 102278

X.-h. He, et al.

foods, and starch syrup (Zhou, Zhang, Chen, & Chen, 2017). The alterations in morphology, long- and short-range ordered structures of ISM-treated PS (ISM-PS) were determined by SEM, XRD, and FTIR accordingly. Furthermore, damaged starch content, granule size distributions, thermal, pasting and rheological properties were also investigated. The information obtained from this study could provide reference for application of the new microfluidizer in starch processing industry. 2. Materials and methods 2.1. Materials Potato starch was acquired from Wei Fang Bellany Trading CO., Ltd. (Shandong, China). It contained 40.36% amylose, 0.22% proteins, 0.60% free lipids, 10.60% moisture content, and 0.36% ashes. Starch Damage Assay Kit was purchased from Megazyme International Ireland Ltd. (Wicklow, Ireland). All other reagents and chemicals used were analytical grade. 2.2. ISM treatment of potato starch 63.6 kg starch suspension (6% w/v) was thoroughly mixed through a stirring rod and then treated by ISM (Fig. 1) for one pass at 30, 60, 90, and 120 MPa in succession, respectively. The treated samples at the initial stage of reaching set pressure were discarded in order to guarantee that the collected samples were processed under corresponding pressure. The treated starch suspensions were centrifuged at 1790g for 10 min, and the resulting precipitates were freeze-dried, ground into a powder and passed through 80 mesh sieves. PS samples treated by ISM pressure at 30, 60, 90, and 120 MPa were labeled as ISM-PS30, ISMPS60, ISM-PS90, and ISM-PS120, respectively. In addition, freeze-dried potato starch without ISM treatment (PS) was prepared by centrifuging and freeze-drying potato starch suspension (6% w/v), and used as the control. The obtained powder samples were stored in a desiccator for further analysis.

Fig. 1. (A) Schematic diagram of industry-scale microfludizer (ISM); (B) Schematic drawing of micro-channel.

narrow size of micro-channels of conventional microfluidizers (< 200 μm for series of Microfluidizer®), the devices have troubles of being blocked while treating starch (especially for starch containing big granules). In addition, just small batch capability was provided for traditional microfluidizers. For example, the maximum processing capability of M-110P, M-110EH, and M-110Y Microfluidizer® was only 120, 450, and 600 mL/min, respectively. In order to solve the problem of being blocked during treating starch and widen the application of microfluidization in starch processing industry, it is important to develop a practicable and feasible equipment with suitable micro-channels. In our laboratory, researches about DHPM have been conducted for more than a decade (Liu et al., 2009). Recently, a device named “industry-scale microfluidizer (ISM)” was designed, and the principal parts of ISM were shown in Fig. 1A. An advantage of ISM is that enough big reaction chamber as well as feed inlet in the micro-channel (Fig. 1B) allows starch suspensions with a wide range of granule sizes to flow smoothly through pipeline. The available orifice diameters are in the range of 300–500 μm, which is bigger than that of conventional microfluidizers. The impact modes in the reaction chamber are also different from those of in the traditional microfluidizers such as Y- and Ztype. The fluid entering feed inlet of micro-channel is powered by threeplunger high pressure pump and forced to divide into two microstreams to the high shear zone. The fluid velocity increases rapidly due to the great decrease of pipe diameter from broad feed inlet to high shear zone (300 μm). These microstreams straightly collide with the wall of high impact zone at tremendously high speeds up to 300 m/s, and subsequently impact with each other in a vertical direction. Ultimately, the fluids are ejected to low pressure outlet with enlarged size of 500 μm. Additionally, the processing capacity of this equipment reaches 83.3 L/ min, which is far beyond that of traditional microfluidizers, so as to achieve industrial processing level. Therefore, the aim of this study was to assess the effects of ISM treatment on properties of starch, and potato starch inherently containing large granules was chosen as the treated target. Moreover, potato starch was used because it is one of the most important crops all over the world (Castanha, da Matta Junior, & Augusto, 2017), and also widely applied in food products such as starch-based noodles, bakery

2.3. Scanning electron microscopy (SEM) PS and ISM-PS samples were stuck onto one side of double-adhesive tape attached to circular specimen stub, and then sputter coated with a thin film of gold. Subsequently, microstructure of the samples was imaged on a SEM (Quanta-200, FEI Company, Netherlands) at ×1000 magnifications with an accelerating voltage of 5.0 kV (Liu et al., 2016). 2.4. Determination of damaged starch Degree of damage to starch granule was determined in accordance with the approved method 76–31 of American Association of Cereal Chemists (AACC), by using Megazyme starch damage assay kit (Megazyme International Ltd., Co., Wicklow, Ireland). In this method, damaged starch granules are hydrated and hydrolyzed to dextrins by fungal α-amylase. Amyloglucosidase is then used to convert dextrins to glucose, which is specifically determined spectrophotometrically after glucose oxidase/peroxidase treatment. The partial procedural details of the measurement and calculation were the same as described by Asmeda, Noorlaila, and Norziah (2016). 2.5. Granule size distributions The granule size distributions of PS and ISM-PS were determined (expressed in % volume) using a Malvern MasterSizer 3000 (Malvern Instrument, Ltd., UK) by referring the method of Monroy, Rivero, and García (2018). The samples were dispersed in absolute ethanol, and then added into the diffractometer cell and sonicated by a sonicator attached to the Mastersizer 3000 prior to analysis. Measurements were 2

Innovative Food Science and Emerging Technologies 60 (2020) 102278

X.-h. He, et al.

added to 25 mL of deionized water in RVA aluminum test canister to form uniform starch suspension. The “standard 2” thermal program offered by the supplier was used to determine RVA profiles. The suspensions were held at 50 °C for 1 min, and then raised to 95 °C at a speed of 6 °C/min. They were maintained at 95 °C for 5 min, cooled to 50 °C at the same rate, and held at 50 °C for 2 min to develop the final viscosity. The rotation speed of the plastic paddle was 960 rpm for the first 10 s and then maintained at 160 rpm. RVA parameters, including peak viscosity (PV), trough viscosity (TV), final viscosity (FV), breakdown (BD) and setback (SB) were obtained from the report of RVA program. All measurements were made in triplicates.

performed in triplicate at room temperature once the shading rate reached 15%. The particle size was evaluated as volume-weighted mean diameter (μm). 2.6. X-ray diffraction (XRD) X-ray diffractograms of PS and ISM-PS were obtained using an X-ray diffractometer (D8 Advance, Germany) operated at 40 kV and 40 mA with Cu Kα radiation. Before measurements, samples were stored in a desiccator where a saturated solution of NaCl maintained a constant humidity atmosphere (relative humidity = 75%) at 25 °C for 1 week. The XRD patterns were scanned over a diffraction angle (2θ) ranged from 2° to 50° at a step size of 0.02° (2θ) per second. The amorphous area and crystalline area were integrated between 3° and 40° (2θ) using the Origin software (Version 7.0, Microcal Inc., Northampton, MA, USA). The relative crystallinity (RC) was calculated as the ratio of the crystalline area to the total area (Liu et al., 2019).

2.10. Dynamic rheological measurement The dynamic rheological properties of PS and ISM-PS pastes obtained from RVA were determined using MCR302 Rheometer (Anton Paar, Austria), which was equipped with a stainless steel cone-plate geometry (40 mm diameter, 1° cone angle and 0.102 mm gap). Sample pastes were loaded onto rheometer plates, and excess pastes were wiped off with a rubber spatula. All samples were allowed to condition at 25 °C for 2 min before the tests. Firstly, deformation sweeps at a constant frequency (10 rad/s) were carried out to determine the maximum deformation attainable by all samples in the linear viscoelastic range. Subsequently, dynamic frequency sweep over a frequency range of 0.01–10 Hz was performed by applying a constant strain (0.5%), which was within the linear region. Storage moduli (G′), loss moduli (G″) and loss tangent (tan δ) as a function of frequency were obtained. During the determination, edge of the gap was covered by a thin layer of low-density silicon oil (dimethylpolysiloxane, 50 cP viscosity) to minimize moisture evaporation.

2.7. Fourier transform infrared (FTIR) spectroscopy The short-range molecular order of starch samples was determined using a Nicolet iS10 FT-IR Spectrometer (Thermo Scientific, Madison, WI, USA). PS and ISM-PS were placed on the surface in contact with attenuated total reflectance (ATR) on a multi-bounce plate of ZneSe crystal at 25 °C for the measurement. All spectra were background corrected using an air spectrum, which was renewed after each scan. The spectrum was obtained at a resolution of 4 cm−1 with an accumulation of 32 scans (Ahmed, Thomas, Arfat, & Joseph, 2018). The FTIR spectra from 4000 to 650 cm−1 were recorded in transmission mode and resolved using OMNIC software (Version 9.0, Thermo Scientific, Madison, WI, USA). Afterwards, the spectra were baseline-corrected and deconvoluted from 1200 to 800 cm−1 with a half-band width of 40 cm−1 and an enhancement factor of 1.9. The ratio of absorbances at 1047/1022 cm−1 was obtained to compare the short-range ordered structure of starch samples.

2.11. Statistical analysis The statistical analysis of the data was performed using the SPSS (version 16.0, Chicago, United States) by one-way analysis of variance (ANOVA). The experiments were performed in triplicate, and the results were expressed as mean ± standard deviations and compared by Duncan's multiple test (p < 0.05).

2.8. Differential scanning calorimetry (DSC) Thermal properties of PS and ISM-PS were determined using a differential scanning calorimeter (DSC) (7000×, Hitachi, Japan) according to the method of Liu, Wang, Chang, and Wang (2015) with appropriate modification. Starch samples (approximately 3 mg, dry basis) were weighed accurately into an aluminum pan, where distilled water was added with a microsyringe to obtain a starch/water ratio of 1:2 (w/w). The pans were hermetically sealed and allowed to stand 4 h at room temperature before DSC analyses. Then the pan was heated from 20 to 100 °C at a rate of 10 °C/min under a continuous flow of dry N2 gas with an empty aluminum pan as a reference. The onset (To), peak (Tp), conclusion (Tc) and gelatinization enthalpy (ΔH) were analyzed by the instrument software (Universal Analysis Program, Hitachi Corp., Japan) to characterize thermal properties of PS samples. All measurements were performed in triplicate. The degree of gelatinization (DG) was calculated according to eq. (1):

DG =

ΔHPS − ΔHISM − PS × 100% ΔHPS

3. Results and discussion 3.1. Morphology PS and ISM-PS granules were examined through SEM to observe changes in appearance after ISM treatment (Fig. 2). It was noticed that PS contained both large and small granules, and showed typical spherical and oval shapes with smooth surface (Fig. 2A), which was similar with the observation of native potato starch (Wang, Tang, Xiong, Huang, & Zhang, 2016). It was implied that freeze-drying had no effect on the morphology of potato starch granule. Shapes of ISM-PS30 granules remained unchanged, but a few short filaments were appeared on granule surface (Fig. 2B). ISM-PS60 exhibited coalescence of granules, and granule surface became rough with small thin flakes (Fig. 2C). As the pressure increased further, granule was disrupted and collapsed. ISM-PS90 displayed obvious destruction which even adhered to each other, but some intact starch granules were still noticeably viewed (Fig. 2D). When ISM pressure level at 120 MPa was imposed on starch (ISM-PS120), almost all large granules were collapsed into irregular block-like debris (yellow arrows in Fig. 2E), and small starch granules drastically lost definition of the edges (yellow circles in Fig. 2E). Elevated pressure level resulted in destruction of granules, which was possibly ascribed to the promotion of starch gelatinization by high pressure treatment as commonly recognized in the literatures (Ahmed, Thomas, Taher, & Joseph, 2016; Li et al., 2011; Li et al., 2015). By comparison, ISM treatment induced more severe destroying on starch granules at same pressure than the work of Kasemwong et al. (2011)

(1)

where ΔHPS (J/g) and ΔHISM-PS (J/g) are the gelatinization enthalpies of PS and ISM-PS, respectively. 2.9. Rapid Visco Analyzer (RVA) Pasting properties of PS and ISM-PS were determined by Rapid Visco Analyzer (RVA, TecMaster, Perten Instruments, Warriewood, Australia) based on the method of Huang, Zhou, Jin, Xu, and Chen (2016) with some modifications. Starch samples (1.5 g, dry basis) was 3

Innovative Food Science and Emerging Technologies 60 (2020) 102278

X.-h. He, et al.

Fig. 2. SEM micrographs of (A) PS, (B) ISM-PS30, (C) ISM-PS60, (D) ISM-PS90, and (E) ISM-PS120. Magnification was 1000×. Table 1 Thermal properties of PS and ISM-PS.a Samples

Damaged starch content (%)

Relative crystallinity (%)

1047 cm−1/1022 cm−1

To (°C)

PS ISM-PS30 ISM-PS60 ISM-PS90 ISM-PS120

0.52 ± 0.01e 0.96 ± 0.01d 2.13 ± 0.02c 15.39 ± 0.30b 21.87 ± 0.20a

25.24 21.45 19.43 16.26 15.38

0.999 0.698 0.644 0.583 0.434

56.81 54.60 51.79 56.82 57.42

a

± ± ± ± ±

0.51a 0.07b 0.21c 0.23d 0.02e

± ± ± ± ±

0.011a 0.009b 0.023c 0.008d 0.015e

Tp (°C)

± ± ± ± ±

0.25e 0.20c 0.06d 0.11b 0.45a

59.25 57.21 56.41 60.45 63.25

Tc (°C)

± ± ± ± ±

0.09e 0.09c 0.03d 0.11b 0.25a

64.75 60.45 60.66 66.80 70.64

± ± ± ± ±

0.12c 0.04d 0.04d 0.07b 0.29a

ΔH (mJ/mg)

DG (%)

11.87 ± 0.29a 11.55 ± 0.21a 9.92 ± 0.11b 8.06 ± 0.08c 5.61 ± 0.32d

0 2.69 ± 1.79d 16.42 ± 0.95c 32.07 ± 0.68b 52.76 ± 2.69a

Reported results correspond to mean ± standard deviation. Different letters within the same column indicate significant differences (p < 0.05).

the slope which implies the dependence of temperature of suspensions on ISM pressure was 0.235 °C/MPa. When ISM pressure was 60 MPa, the calculated value of temperature was 38.2 °C (actual value 37.7 °C), low pressure and temperature were insufficient to cause noticeable damage of starch granules. Nevertheless, temperature of starch-water suspensions rose to 47.8 °C and 50.5 °C at ISM pressure of 90 MPa and 120 MPa, respectively. In spite of slightly lower than the critical gelatinization temperature (56.81 °C, as determined in Section 3.6) of PS, these two temperatures combined with high pressure were able to promote starch gelatinization (Wang et al., 2008), leading to severe breakage and fusion of PS granules.

and Tu et al. (2013), who reported that starch granule was not broken while treated by conventional microfluidizers above 150 MPa. It must be pointed out the fact that conventional small-scale microfluidizers were equipped with a heat exchanger for controlling temperature of samples, while the process of ISM treatment was accompanied by increasing temperature of starch-water suspensions. The temperature rise of starch-water suspensions was possibly attributed to acute change of pressure in a very short time. According to measured experimental data, linear regression equation between pressure (P) and temperature (T) (T = 0.235 × P + 24.1, R2 = 0.951) was obtained to model the effect of pressure on temperature of starch-water suspensions. The intercept that represents the initial temperature of suspensions was 24.1 °C, and 4

Innovative Food Science and Emerging Technologies 60 (2020) 102278

X.-h. He, et al.

Fig. 3. Particle size distributions of PS and ISM-PS samples. Fig. 4. X-ray diffraction patterns and relative crystallinity of PS and ISM-PS. Means in the same line with different letters are significantly different (p < 0.05).

3.2. Damaged starch The damaged starch contents of potato starch after ISM treatment were listed in Table 1. It was found that damaged starch content of PS was 0.52%, which was similar with the result of Tester (1997) and Yusuph, Tester, Ansell, and Snape (2003). The damaged starch contents gradually increased to 0.96%, 2.13%, 15.39% and 21.87% for ISMPS30, ISM-PS60, ISM-PS90, and ISM-PS120, respectively. Damaged starch contents of ISM-PS30 and ISM-PS60 were relatively low, implying that ISM pressure below 60 MPa did not caused serious damage on starch granules. Nevertheless, damage level was increased sharply while ISM pressure reaching 90 MPa. These results were consistent with the changes in morphology, where ISM-PS90 and ISM-PS120 showed broken granules.

exhibited significant differences in X-ray diffraction pattern, which displayed the single peak at 17.2°(2θ) and a merged broad peak between 22.2 and 24.0°(2θ). This finding indicated that freeze-drying had an effect on the crystallinity of potato starch, which was consistent with the result of Wang et al. (2017). ISM-PS displayed similar X-ray diffraction patterns with PS, but ISM treatment weakened the intensity of the peaks. When the pressure was beyond 60 MPa, the intensity of the peaks at 17.2° and 22.2° were observably decreased, which lead to significant loss in crystallinity. Consistent with the progressive indistinction of diffraction peaks, the RC was found to be decreased from 25.24% (PS) to 21.45%, 19.43%, 16.26%, and 15.38% for ISM-PS30, ISM-PS60, ISM-PS90, and ISM-PS120, respectively. These results suggested that the internal crystalline structure of potato starch was considerably damaged by ISM treatment, and was more susceptible to be destructed at high pressure level, which supported the SEM observations.

3.3. Granule size distributions Granule size distributions of the starch samples were shown in Fig. 3. PS displayed unimodal granule size distribution, which was similar to earlier report on Chinese sweet potato starch (Chen, Schols, & Voragen, 2010). ISM treatment at 30 MPa appeared to have little effect on granule size distribution. Nevertheless, higher ISM pressure resulted in a shift of the curve. The peak progressively shifted towards right with increase of pressure level from 30 to 90 MPa, and a subsequent shift to the left was observed for ISM-PS120. The volume-weighted mean particle diameters were 46.4, 46.5, 75.4, 104.0 and 41.9 μm for PS, ISMPS30, ISM-PS60, ISM-PS90, and ISM-PS120, respectively. As analyzed in the result of morphology, starch gelatinization was possibly occurred with increase of ISM pressure. The higher the pressure was, the stronger ability of starch for absorbing water and swelling was, leading to bigger granule of ISM-PS. Nevertheless, in regard to ISM-PS120, excessive pressure accompanying with high temperature was responsible for sufficiently rupturing starch granules and turning them into debris as shown in the morphology (Fig. 2E), which gave rise to a shift to the left for distribution curve. Destroyed morphology and altered granule sizes may affect the internal structure of starch granules, so the long- and short-range ordered structures were discussed in the next sections.

3.5. Short-range ordered structure The ratios of absorbance bands at 1047 and 1022 cm−1 from deconvoluted FTIR spectra have been employed for investigation of starch structure on a short-range molecular level, which refers to the structural order of starch chains near the granule surface (i.e. short-range ordered structure) (Sevenou, Hill, Farhat, & Mitchell, 2002; van Soest, Tournois, de Wit, & Vliegenthart, 1995). As displayed in Fig. 5, ISM treatment evidently weakened the intensity of peak around 1047 cm−1, despite of similar spectra patterns for all samples. It was demonstrated that ISM treatment disrupted the short-range ordered structure of potato starch. The ratio of 1047 cm−1/1022 cm−1 for PS was 0.999, and that of ISMPS30 declined by 30.13%. A more notable reduction of 35.54%, 41.64%, and 56.56% was calculated for ISM-PS60, ISM-PS90, and ISMPS120, respectively. The decrease in the ratios of 1047 cm−1/ 1022 cm−1 for ISM-PS was possibly related to dissociation and disruption of double helices in crystalline region (Hu et al., 2018), which was in accordance with the results of loss crystallinity obtained from XRD analysis. The destroyed long and short-range molecular structure confirmed that ISM treatment brought about structural disturbance for PS, which was prone to alter physicochemical properties of PS.

3.4. Long-range crystalline properties X-ray diffraction analysis was performed to investigate long-range crystalline structure of starch, and the results were presented in Fig. 4. Unlike native potato starch with characteristic B-type diffraction peaks at 5.6, 15.1, 17.2, 19.8, 22.2, 24.0 (2θ) (Varatharajan et al., 2011), PS 5

Innovative Food Science and Emerging Technologies 60 (2020) 102278

X.-h. He, et al.

Fig. 6. Pasting properties of PS and ISM-PS.

ISM-PS90, and ISM-PS120 were 2.69%, 16.42%, 32.07%, and 52.76%, respectively. DSC measurements confirmed that starch gelatinization was accountable for the destroyed PS granule observed using SEM, disrupted crystalline analyzed by XRD, and dissociated helical structures determined by FTIR, and the pressure level acted as an important factor in ISM induced starch gelatinization. Given that degree of gelatinization for PS were arbitrarily adjusted by employment of ISM pressure, ISM technology might achieve desirable properties of PS to allow wider applications in food and non-food industries.

Fig. 5. Deconvoluted FTIR spectra from 1200 to 800 cm−1 wavenumbers and the 1047 cm−1/1022 cm−1 ratios of PS and ISM-PS. Means in the same line with different letters are significantly different (p < 0.05).

3.6. Thermal properties analysis The thermal properties of potato starch were significantly affected by ISM treatment, and the gelatinization transition temperatures (To, Tp, and Tc), gelatinization enthalpy (ΔH) and degree of gelatinization (DG) of PS and ISM-PS were listed in Table 1. PS demonstrated an endothermic transition associated with gelatinization at temperatures ranging from 56.81 to 64.73 °C, which was lower than the values of native potato starch (58.45 to 66.63 °C, data not shown). It may be ascribed to the destabilized crystalline structure of potato starch after freeze-drying, as suggested by Zhang et al. (2014). To, Tp, and Tc were significantly decreased (p < 0.05) after ISM treatment at 30 and 60 MPa, and subsequently showed an upward tendency with the increase of pressure from 90 to 120 MPa. Weak internal structural organization for intact ISM-PS30 and ISM-PS60 granules facilitated hydration between starch and water molecules, leading to a decline in To, Tp and Tc. When PS was imposed on higher ISM pressure, in addition to melting unstable crystals, an annealing stage for ISM-PS might occur to form more perfect crystal as speculated by Li et al. (2015), which lead to reversed and subsequently elevated transition temperature of ISMPS90 and ISM-PS120. Besides, the higher To, Tp and Tc of ISM-PS120 may be attributed to the more stable crystals remaining in compact small granules than the initially molten ones. The gelatinization enthalpy (ΔH) is the thermal energy required for melting the ordered helical structures and crystal packing in starch granules (Kim, Kim, Choi, Park, & Moon, 2016). ISM treatment progressively reduced the ΔH of PS with the increase of pressure (Table 1), which was indicative of substantial disruption and melting down of starch crystals. Meanwhile, appreciable increase in degree of gelatinization (DG) was noticed for ISM-PS, and DG of ISM-PS30, ISM-PS60,

3.7. Pasting properties Pasting parameters of PS and ISM-PS determined using RVA were summarized in Table 2, and the representative curves were shown in Fig. 6. ISM treatment affected the pasting properties of potato starch effectively, and the influence was dependent on pressure. It was noticed that PV, TV and BD were firstly increased and subsequently decreased, and ISM-PS60 exhibited maximal values in those parameters, which conformed to the changes of “Thermal Properties”. These variations in pasting parameters were probably ascribed to the alteration of granular structure and transformation of crystalline structure (Katopo, Song, & Jane, 2002). The starch granules rub against each other under stirring in RVA, and continually uptake water and swell upon heating with simultaneous leaching of amylose, which leads to the rise of viscosity (Ma, Zhu, & Wang, 2019). PV is an indicator of early and rapid swelling of starch granules, which is affected by granule swelling and frictions between swollen granules (Qiu et al., 2016). Different degrees of gelatinization owing to ISM treatment endowed ISM-PS with unequal extent of structural compactness and amount of residual granule starch for swelling, which brought about differences in PV. Intact starch granules of ISM-PS30 and ISM-PS60 with disturbed crystalline arrangement were susceptible to swell and leak amylose, thus exhibiting increased PV. Whereas, in relation to ISM-PS30 and ISM-PS60, destructive granules of ISM-PS90 and ISM-PS120 weakened the ability to absorb water and

Table 2 Pasting properties of PS and ISM-PS.a Samples

Peak viscosity (cp)

Trough viscosity (cp)

Breakdown (cp)

Final viscosity (cp)

Setback (cp)

PS ISM-PS30 ISM-PS60 ISM-PS90 ISM-PS120

3094.00 3630.00 4130.67 3235.00 3027.67

1124.33 1454.00 1529.67 1524.00 1469.67

1969.67 2176.00 2601.00 1711.00 1558.00

1400.33 1780.00 1847.33 1893.00 1855.33

276.00 326.00 317.67 369.00 385.67

a

± ± ± ± ±

19.00d 10.44b 38.76a 11.27c 21.45d

± ± ± ± ±

9.07d 10.15b 5.13a 5.20a 1.53c

± ± ± ± ±

21.57c 15.10b 43.27a 9.54d 21.66e

± ± ± ± ±

9.71d 6.56c 5.69b 11.13a 8.14b

Reported results correspond to mean ± standard deviation. Different letters within the same column indicate significant differences (p < 0.05). 6

± ± ± ± ±

5.29d 4.36c 7.51c 7.81b 8.39a

Innovative Food Science and Emerging Technologies 60 (2020) 102278

X.-h. He, et al.

swell, leading to a subsequent decrease in PV. Lower PV of ISM-PS120 was also attributed to residual compact crystalline structure and less effective frictions (Molavi, Razavi, & Farhoosh, 2018). BD indicated the degree of disintegration during continuously shearing at holding temperature (95 °C) (Pongsawatmanit, Temsiripong, & Suwonsichon, 2007). Promoted swelling and pasting of ISM-PS30 and ISM-PS60 facilitated the disintegration of starch granules, thus increasing BD value. In contrast, less swollen granules to rupture for ISM-PS90 and ISMPS120 induced a significant decrease in BD value. After cooling, shortterm retrogradation was occurred owing to reassociation of amylose molecules, and subsequently holding at 50 °C made viscosity of pastes elevate to develop the FV. SB is expressed by FV subtracting TV (Zaidul, Yamauchi, Kim, Hashimoto, & Noda, 2007). It was found that SB of ISM-PS was gradually increased in comparison with PS. The elevated SB was probably attributed to an increase in effective concentration of starch molecules for retrogradation owing to ISM treatment. ISM-PS with characteristic of higher tendency towards retrogradation may be appropriate and beneficial to produce some kinds of pasta like Chinese rice vermicelli strands and Japanese “harusame” noodles (Karim, Norziah, & Seow, 2000). 3.8. Dynamic rheological properties Rheological studies can provide knowledge to describe and predict the structural changes of foods during processing, and dynamic rheological measurements are often used to investigate the viscoelastic behavior of samples (Yousefi & Razavi, 2015). A dynamic frequency sweep range from 0.1 to 10 Hz was employed to investigate the mechanical spectra of moduli about PS and ISM-PS (Fig. 7A), and the parameters of G΄ and tan δ values at frequency of 0.1 and 10 Hz were listed in Table 3. In all cases, storage moduli (G′) were significantly higher than loss moduli (G″) in the assayed frequency range. Both moduli showed a frequency dependence, indicating a typical weak gellike structure with viscoelastic nature. Analyzing the effect of ISM treatment, it was found that G′ of ISM-PS were increased regardless of ISM pressure, which indicated that ISM treatment promoted the formation of more mechanical rigid PS gels (Cappa, Barbosa-Cánovas, Lucisano, & Mariotti, 2016). However, G′ of ISM-PS showed tendency to ascend from 30 to 90 MPa, and then turned downward trend after increasing pressure to 120 MPa. For example, G′0.1Hz (storage modulus at 0.1 Hz) was increased from 25.27 Pa to 39.65, 43.90, and 61.60 Pa for ISM-PS30, ISM-PS60, and ISM-PS90, respectively, and subsequently decreased to 39.50 Pa for ISM-PS120. G′10Hz (storage modulus at 10 Hz) behaved similar change tendency with G′0.1Hz as ISM pressure increased (Table 3). Commonly, starch pastes are considered as composite systems, which consist of swollen granules and fragments embedded in a three-dimensional network of aggregated amylose molecules (Ahmad & Williams, 2001). In regard to ISM-PS treated below 90 MPa, expanded granules with disordered internal structure was probably beneficial for the interactions or cross-linking between swollen granules and amylose chains of starch after pasting, leading to more junction zones and structured network system. Whereas, seriously interrupted starch of ISM-PS120 impeded alignment of starch chains and weakened formation of gel network, thus performing subsequently declined moduli. Loss tangent (tan δ) values represents the ratio of G″ and G′, which is also used to evaluate rheological changes from gel formation, and a lower value indicates more elastic behavior (Pongsawatmanit, Temsiripong, Ikeda, & Nishinari, 2006). As presented in Fig. 7B and Table 3, tan δ behaved opposite performance with G′. As ISM pressure increased, tan δ was firstly decreased and then increased, and the value of ISM-PS90 was the lowest. At frequency of 0.1 Hz, the value of tan δ for PS was 0.280, and those of ISM-PS30, ISM-PS60, ISM-PS90, and ISM-PS120 were 0.235, 0.218, 0.168, and 0.209, respectively. Overall, the tan δ values of ISM-PS were lower than that of PS, indicating an increase in relative elastic contribution to pastes and less liquid-like structure. These results implied that ISM treatment reinforced the

Fig. 7. Dynamical moduli (A) and loss tangent (B) of PS and ISM-PS determined by dynamic viscoelasticity measurement.

network structure and improved stability of starch pastes towards mechanical processing, and the mechanical rigidity of PS pastes was determined by ISM pressure. Adjustable and enhanced elasticity of ISM-PS indicated that modified PS might be applied in jelly-like food products and desserts that need to retain ingredients in a fixed position or a behavior close to solid at rest (Yousefi & Razavi, 2015). 4. Conclusions In the present study, an improved device named “industry-scale microfluidizer (ISM)” was applied to treat potato starch. ISM treatment effectively modified potato starch, causing the disorganization of structure and alteration of thermal, pasting and rheological properties. Starch gelatinization was induced by ISM treatment. The degree of structural disruption and gelatinization could be regulated by changing ISM pressure, and a more severe structure destruction and higher degree of gelatinization was observed at high pressure level. Adjustable viscosity, increased retrogradation tendency and improved mechanical rigidity of potato starch was provided by ISM treatment, which was of particular interest for some food uses. These results suggested that ISM might be an effective industrial technique to develop PS with desired properties. CRediT authorship contribution statement Xiao-hong He: Methodology, Investigation, Writing - original 7

Innovative Food Science and Emerging Technologies 60 (2020) 102278

X.-h. He, et al.

Table 3 Dynamic rheological parameters (G′, G″ and tan δ) of PS and ISM-PS.a Samples

G′0.1Hz (Pa)

G″0.1

PS ISM-PS30 ISM-PS60 ISM-PS90 ISM-PS120

25.27 39.65 43.90 61.60 39.50

7.01 ± 0.14c 9.30 ± 0.04b 9.55 ± 0.35b 10.35 ± 0.07a 8.25 ± 0.06c

± ± ± ± ±

0.81c 2.89b 2.97b 0.28a 0.84b

Hz

(Pa)

tan δ0.1Hz 0.280 0.235 0.218 0.168 0.209

± ± ± ± ±

G′10 0.010a 0.018b 0.007bc 0.001d 0.003c

Hz

(Pa)

66.92 ± 1.17d 92.5 ± 2.40bc 97.85 ± 4.45b 119.10 ± 1.26a 85.21 ± 4.51c

G″10

Hz

26.32 32.60 33.10 34.15 29.50

(Pa)

± ± ± ± ±

0.25d 0.14b 0.42b 0.21a 0.42c

tan δ10Hz 0.395 0.352 0.338 0.286 0.346

± ± ± ± ±

0.007a 0.011b 0.011b 0.002c 0.013b

a Reported results correspond to mean ± standard deviation. Different letters within the same column indicate significant differences (p < 0.05). G′0.1Hz, G″0.1 Hz and tan δ0.1Hz were values of storage modulus, loss modulus, and loss tangent at 0.1 Hz during frequency sweep, respectively. G′10 Hz, G″10 Hz and tan δ10Hz were values of storage modulus, loss modulus, and loss tangent at 10 Hz during frequency sweep, respectively.

draft.Shun-jing Luo: Visualization, Resources.Ming-shun Chen: Investigation, Validation.Wen Xia: Formal analysis, Visualization.Jun Chen: Conceptualization, Methodology, Writing - review & editing.Cheng-mei Liu: Supervision, Funding acquisition.

foodhyd.2015.10.002. Karim, A. A., Norziah, M. H., & Seow, C. C. (2000). Methods for the study of starch retrogradation. Food Chemistry, 71(1), 9–36. https://doi.org/10.1016/S03088146(00)00130-8. Kasemwong, K., Ruktanonchai, U. R., Srinuanchai, W., Itthisoponkul, T., & Sriroth, K. (2011). Effect of high-pressure microfluidization on the structure of cassava starch granule. Starch-Stärke, 63(3), 160–170. https://doi.org/10.1002/star.201000123. Katopo, H., Song, Y., & Jane, J. L. (2002). Effect and mechanism of ultrahigh hydrostatic pressure on the structure and properties of starches. Carbohydrate Polymers, 47(3), 233–244. https://doi.org/10.1016/S0144-8617(01)00168-0. Kim, J. H., Kim, H. R., Choi, S. J., Park, C. S., & Moon, T. W. (2016). Production of an in vitro low-digestible starch via hydrothermal treatment of amylosucrase-modified normal and waxy rice starches and its structural roperties. Journal of Agricultural & Food Chemistry, 64(24), 5045–5052. https://doi.org/10.1021/acs.jafc.6b01055. Li, W. H., Tian, X. L., Liu, L. P., Wang, P., Wu, G. L., Zheng, J. M., ... Zhang, G. Q. (2015). High pressure induced gelatinization of red adzuki bean starch and its effects on starch physicochemical and structural properties. Food Hydrocolloids, 45, 132–139. https://doi.org/10.1016/j.foodhyd.2014.11.013. Li, W. H., Zhang, F. S., Liu, P. L., Bai, Y. F., Guo, L., & Shen, Q. (2011). Effect of high hydrostatic pressure on physicochemical, thermal and morphological properties of mung bean (Vigna radiata L.) starch. Journal of Food Engineering, 103(4), 388–393. https://doi.org/10.1016/j.jfoodeng.2010.11.008. Li, Y. T., Wang, R. S., Liang, R. H., Chen, J., He, X. H., Chen, R. Y., ... Liu, C. M. (2018). Dynamic high-pressure microfluidization assisting octenyl succinic anhydride modification of rice starch. Carbohydrate Polymers, 193, 336–342. https://doi.org/10. 1016/j.carbpol.2018.03.103. Liu, C., Wang, S. J., Chang, X. D., & Wang, S. (2015). Structural and functional properties of starches from Chinese chestnuts. Food Hydrocolloids, 43, 568–576. https://doi.org/ 10.1016/j.foodhyd.2014.07.014. Liu, C. M., Liang, R. H., Dai, T. T., Ye, J. P., Zeng, Z. C., Luo, S. J., & Chen, J. (2016). Effect of dynamic high pressure microfluidization modified insoluble dietary fiber on gelatinization and rheology of rice starch. Food Hydrocolloids, 57, 55–61. https://doi. org/10.1016/j.foodhyd.2016.01.015. Liu, W., Liu, J. H., Liu, C. M., Zhong, Y. J., Liu, W. L., & Wan, J. (2009). Activation and conformational changes of mushroom polyphenoloxidase by high pressure microfluidization treatment. Innovative Food Science & Emerging Technologies, 10(2), 142–147. https://doi.org/10.1016/j.ifset.2008.11.009. Liu, Y. F., Chen, J., Wu, J. Y., Luo, S. J., Chen, R. Y., Liu, C. M., & Gilbert, R. G. (2019). Modification of retrogradation property of rice starch by improved extrusion cooking technology. Carbohydrate Polymers, 213, 192–198. https://doi.org/10.1016/j. carbpol.2019.02.089. Luo, S. J., Chen, R. Y., Huang, L., Liang, R. H., Liu, C. M., & Chen, J. (2017). Investigation on the influence of pectin structures on the pasting properties of rice starch by multiple regression. Food Hydrocolloids, 63, 580–584. https://doi.org/10.1016/j. foodhyd.2016.10.016. Ma, S. P., Zhu, P. L., & Wang, M. C. (2019). Effects of konjac glucomannan on pasting and rheological properties of corn starch. Food Hydrocolloids, 89, 234–240. https://doi. org/10.1016/j.foodhyd.2018.10.045. Molavi, H., Razavi, S. M. A., & Farhoosh, R. (2018). Impact of hydrothermal modifications on the physicochemical, morphology, crystallinity, pasting and thermal properties of acorn starch. Food Chemistry, 245, 385–393. https://doi.org/10.1016/j.foodchem. 2017.10.117. Monroy, Y., Rivero, S., & García, M. A. (2018). Microstructural and techno-functional properties of cassava starch modified by ultrasound. Ultrasonics Sonochemistry, 42, 795–804. https://doi.org/10.1016/j.ultsonch.2017.12.048. Pongsawatmanit, R., Temsiripong, T., Ikeda, S., & Nishinari, K. (2006). Influence of tamarind seed xyloglucan on rheological properties and thermal stability of tapioca starch. Journal of Food Engineering, 77(1), 41–50. https://doi.org/10.1016/j.jfoodeng. 2005.06.017. Pongsawatmanit, R., Temsiripong, T., & Suwonsichon, T. (2007). Thermal and rheological properties of tapioca starch and xyloglucan mixtures in the presence of sucrose. Food Research International, 40(2), 239–248. https://doi.org/10.1016/j.foodres.2006. 10.013. Qiu, S., Yadav, M. P., Liu, Y., Chen, H., Tatsumi, E., & Yin, L. J. (2016). Effects of corn fiber gum with different molecular weights on the gelatinization behaviors of corn and wheat starch. Food Hydrocolloids, 53, 180–186. https://doi.org/10.1016/j. foodhyd.2015.01.034. Sevenou, O., Hill, S. E., Farhat, I. A., & Mitchell, J. R. (2002). Organisation of the external region of the starch granule as determined by infrared spectroscopy. International

Acknowledgments The authors would like to thank the Centre of Analysis and Testing of Nanchang University and State Key Laboratory of Food Science and Technology for their expert technical assistance. This study was supported financially by the National Natural Science Foundation of China (Nr 31660488 and 31601397), Research Program of State Key Laboratory of Food Science and Technology, Nanchang University (Project No. SKLF-ZZA-201908 and SKLF-ZZB-201922), and Postgraduate Innovative Funds of Nanchang University (CX2016212). Declaration of competing interest The authors declare no conflict of interest. References Ahmad, F. B., & Williams, P. A. (2001). Effect of galactomannans on the thermal and rheological properties of sago starch. Journal of Agricultural and Food Chemistry, 3(49), 1578–1586. https://doi.org/10.1021/jf000744w. Ahmed, J., Thomas, L., Arfat, Y. A., & Joseph, A. (2018). Rheological, structural and functional properties of high-pressure treated quinoa starch in dispersions. Carbohydrate Polymers, 197, 649–657. https://doi.org/10.1016/j.carbpol.2018.05. 081. Ahmed, J., Thomas, L., Taher, A., & Joseph, A. (2016). Impact of high pressure treatment on functional, rheological, pasting, and structural properties of lentil starch dispersions. Carbohydrate Polymers, 152, 639–647. https://doi.org/10.1016/j.carbpol.2016. 07.008. Ashogbon, A. O., & Akintayo, E. T. (2014). Recent trend in the physical and chemical modification of starches from different botanical sources: A review. Starch-Stärke, 66(1–2), 41–57. https://doi.org/10.1002/star.201300106. Asmeda, R., Noorlaila, A., & Norziah, M. H. (2016). Relationships of damaged starch granules and particle size distribution with pasting and thermal profiles of milled MR263 rice flour. Food Chemistry, 191, 45–51. https://doi.org/10.1016/j.foodchem. 2018.07.202. Cappa, C., Barbosa-Cánovas, G. V., Lucisano, M., & Mariotti, M. (2016). Effect of high pressure processing on the baking aptitude of corn starch and rice flour. LWT, 73, 20–27. https://doi.org/10.1016/j.lwt.2016.05.028. Castanha, N., da Matta Junior, M. D., & Augusto, P. E. D. (2017). Potato starch modification using the ozone technology. Food Hydrocolloids, 66, 343–356. https://doi. org/10.1016/j.foodhyd.2016.12.001. Chen, J., Liang, R. H., Liu, W., Liu, C. M., Li, T., Tu, Z. C., & Wan, J. (2012). Degradation of high-methoxyl pectin by dynamic high pressure microfluidization and its mechanism. Food Hydrocolloids, 28(1), 121–129. https://doi.org/10.1016/j.foodhyd. 2011.12.018. Chen, Z., Schols, H. A., & Voragen, A. G. J. (2010). Physicochemical properties of starches obtained from three varieties of Chinese sweet potatoes. Journal of Food Science, 68(2), 431–437. https://doi.org/10.1111/j.1365-2621.2003.tb05690.x. Choi, H. S., Kim, H. S., Park, C. S., Kim, B. Y., & Baik, M. Y. (2009). Ultra high pressure (UHP)-assisted acetylation of corn starch. Carbohydrate Polymers, 78(4), 862–868. https://doi.org/10.1016/j.carbpol.2009.07.005. Hu, X. T., Guo, B. Z., Liu, C. M., Yan, X. Y., Chen, J., Luo, S. J., ... Wu, J. Y. (2018). Modification of potato starch by using superheated steam. Carbohydrate Polymers, 198, 375–384. https://doi.org/10.1016/j.carbpol.2018.06.110. Huang, T. T., Zhou, D. N., Jin, Z. Y., Xu, X. M., & Chen, H. Q. (2016). Effect of repeated heat-moisture treatments on digestibility, physicochemical and structural properties of sweet potato starch. Food Hydrocolloids, 54, 202–210. https://doi.org/10.1016/j.

8

Innovative Food Science and Emerging Technologies 60 (2020) 102278

X.-h. He, et al.

Wang, C., Tang, C. H., Fu, X., Huang, Q., & Zhang, B. (2016). Granular size of potato starch affects structural properties, octenylsuccinic anhydride modification and flowability. Food Chemistry, 212, 453–459. https://doi.org/10.1016/j.foodchem. 2016.06.006. Wang, J. R., Zhu, H. P., Li, S., Wang, S. J., Wang, S., & Copeland, L. (2017). Insights into structure and function of high pressure-modified starches with different crystalline polymorphs. International Journal of Biological Macromolecules, 102, 414–424. https:// doi.org/10.1016/j.ijbiomac.2017.04.042. Wang, X. M., Zhu, X. M., Zhang, N. H., Tu, Z. C., Wang, H., Liu, G. X., & Ye, Y. H. (2018). Morphological and structural characteristics of rice amylose by dynamic high-pressure microfluidization modification. Journal of Food Processing and Preservation, 42(10), e13764. https://doi.org/10.1111/jfpp.13764. Yousefi, A. R., & Razavi, S. M. A. (2015). Dynamic rheological properties of wheat starch gels as affected by chemical modification and concentration. Starch-Stärke, 67(7–8), 567–576. https://doi.org/10.1002/star.201500005. Yusuph, M., Tester, R. F., Ansell, R., & Snape, C. E. (2003). Composition and properties of starches extracted from tubers of different potato varieties grown under the same environmental conditions. Food Chemistry, 82(2), 283–289. https://doi.org/10.1016/ S0308-8146(02)00549-6. Zaidul, I. S. M., Yamauchi, H., Kim, S. J., Hashimoto, N., & Noda, T. (2007). RVA study of mixtures of wheat flour and potato starches with different phosphorus contents. Food Chemistry, 102(4), 1105–1111. https://doi.org/10.1016/j.foodchem.2006.06.056. Zhang, B., Wang, K., Hasjim, J., Li, E., Flanagan, B. M., Gidley, M. J., & Dhital, S. (2014). Freeze-drying changes the structure and digestibility of B-polymorphic starche. Journal of Agricultural and Food Chemistry, 62(7), 1482–1491. https://doi.org/10. 1021/jf405196m. Zhou, D. N., Zhang, B., Chen, B., & Chen, H. Q. (2017). Effects of oligosaccharides on pasting, thermal and rheological properties of sweet potato starch. Food Chemistry, 230, 516–523. https://doi.org/10.1016/j.foodchem.2017.03.088.

Journal of Biological Macromolecules, 31(1), 79–85. https://doi.org/10.1016/S01418130(02)00067-3. Singh, J., Kaur, L., & Mccarthy, O. J. (2007). Factors influencing the physico-chemical, morphological, thermal and rheological properties of some chemically modified starches for food applications—A review. Food Hydrocolloids, 21(1), 1–22. https:// doi.org/10.1016/j.foodhyd.2006.02.006. Singh, N., Singh, J., Kaur, L., Sodhi, N. S., & Gill, B. S. (2003). Morphological, thermal and rheological properties of starches from different botanical sources. Food Chemistry, 81(2), 219–231. https://doi.org/10.1016/S0308-8146(02)00416-8. Tester, R. F. (1997). Properties of damaged starch granules: Composition and swelling properties of maize, rice, pea and potato starch fractions in water at various temperatures. Food Hydrocolloids, 11(3), 293–301. https://doi.org/10.1016/S0268-005X (97)80059-8. Tu, Z. C., Yin, Y. B., Wang, H., Liu, G. X., Chen, L. L., Zhang, P., ... Zhang, L. (2013). Effect of dynamic high-pressure microfluidization on the morphology characteristics and physicochemical properties of maize amylose. Starch-Stärke, 65(5–6), 390–397. https://doi.org/10.1002/star.201200120. van Soest, J. J. G., Tournois, H., de Wit, D., & Vliegenthart, J. F. G. (1995). Short-range structure in (partially) crystalline potato starch determined with attenuated total reflectance Fourier-transform IR spectroscopy. Carbohydrate Research, 279, 201–214. https://doi.org/10.1016/0008-6215(95)00270-7. Varatharajan, V., Hoover, R., Li, J. H., Vasanthan, T., Nantanga, K. K. M., Seetharaman, K., ... Chibbar, R. N. (2011). Impact of structural changes due to heat-moisture treatment at different temperatures on the susceptibility of normal and waxy potato starches towards hydrolysis by porcine pancreatic alpha amylase. Food Research International, 44(9), 2594–2606. https://doi.org/10.1016/j.foodres.2011.04.050. Wang, B., Li, D., Wang, L. J., Chiu, Y. L., Chen, X. D., & Mao, Z. H. (2008). Effect of highpressure homogenization on the structure and thermal properties of maize starch. Journal of Food Engineering, 87(3), 436–444. https://doi.org/10.1016/j.jfoodeng. 2007.12.027.

9