A new pre-gelatinized starch preparing by gelatinization and spray drying of rice starch with hydrocolloids

A new pre-gelatinized starch preparing by gelatinization and spray drying of rice starch with hydrocolloids

Carbohydrate Polymers 229 (2020) 115485 Contents lists available at ScienceDirect Carbohydrate Polymers journal homepage: www.elsevier.com/locate/ca...

2MB Sizes 6 Downloads 119 Views

Carbohydrate Polymers 229 (2020) 115485

Contents lists available at ScienceDirect

Carbohydrate Polymers journal homepage: www.elsevier.com/locate/carbpol

A new pre-gelatinized starch preparing by gelatinization and spray drying of rice starch with hydrocolloids

T



Xiao-hong Hea, Wen Xiab, Rui-yun Chena, Tao-tao Daia, Shun-jing Luoa, Jun Chena, , ⁎ Cheng-mei Liua, 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: Rice starch Hydrocolloids Spray drying Pre-gelatinized starch Cold paste viscosity

Rice starch with hydrocolloids (pectin, xanthan gum, sodium alginate or ι-carrageenan) was gelatinized and subsequently spray dried to prepare pre-gelatinized rice starch (PRS) with hydrocolloids (PRS-H). The PRS-H displayed concave granular shape with amorphous structure, indicating rice starch in PRS-H was completely gelatinized. Cold paste viscosity of PRS-H was enhanced in comparison with that of PRS. Especially, xanthan and ι-carrageenan increased cold paste viscosity of PRS-H more than pectin and alginate did. Cold paste viscosity of physically mixed PRS and hydrocolloids (PRS+H), and flow behavior of hydrocolloids themselves as well as gelatinized starch-hydrocolloids without spray drying (GRS-H) indicated interactions existed between starch and hydrocolloids during the preparation. Swelling power, water solubility index, and dynamic viscoelastic properties of PRS-H were also adjusted by different hydrocolloids. These results showed that premixing hydrocolloids with starch before gelatinization in method of spray drying would be a suitable methodology for manufacture PRS with altered properties.

1. Introduction Starch is a type of carbohydrate biosynthesized in higher plants, and it plays an important role in providing energy for humans and animals as the main component of substantial food products (Tetlow, 2010). Besides, starch has also been extensively used as gelling agent, thickener, stabilizer in food industry (Li et al., 2018). However, native starch has some drawbacks in application. For instance, it is water insoluble if not gelatinized, thus not possessing satisfied properties for producing some heat sensitive foods (e.g. those containing colorants, spices, flavoring agents, vitamins and bioactive compounds) or foods processed at low temperature (e.g. instant puddings, cold desserts, baby foods) (Hedayati, Shahidi, Koocheki, Farahnaky, & Majzoobi, 2016). Pre-gelatinized starch (PGS) is a physically modified starch which has ability to absorb water and swell in cold water to promote the viscosity as well as achieve desirable paste and thickening properties (Din, Xiong, & Fei, 2015; Nakorn, Tongdang, & Sirivongpaisal, 2009). The common and available techniques to manufacture PGS are drum drying, extrusion and spray drying (Borries-Medrano, JaimeFonseca, Aguilar-Méndez, & García-Cruz, 2018; Majzoobi et al., 2010; Singh, Kaur, & McCarthy, 2007). The drum drying and extrusion ⁎

changed the product into a flaky and cylindrical thread, respectively, hence extra procedures (such as pulverizing and sieving) were required to obtain a powder product. Compared to drum drying and extrusion technology, spray drying is a more convenient method to produce PGS, where PGS could be rapidly converted into powder substances (Gharsallaoui, Roudaut, Chambin, Voilley, & Saurel, 2007). Previous studies have shown that spray dried rice starch exhibited exceptional flowability and superior ability to swell (Laovachirasuwan, Peerapattana, Srijesdaruk, Chitropas, & Otsuka, 2010; Mitrevej, Sinchaipanid, & Faroongsarng, 2008). In pursuit of the widened application of PGS in food industry, modifying properties of PGS by other food components (sugar, salt and organic acids, etc.) has gained attention in recent years. For example, Hedayati, Majzoobi, Shahidi, Koocheki, and Farahnaky (2016) and Hedayati, Shahidi, Koocheki, Farahnaky, and Majzoobi (2016) showed that CaCl2, glucose and sucrose increased cold paste viscosity and mechanical properties of PGS. Majzoobi, Kaveh, Blanchard, and Farahnaky (2015) and Majzoobi, Kaveh, Farahnaky, and Blanchard (2015) suggested that acetic acid and ascorbic acid affected cold water viscosity, texture and syneresis of PGS. Hydrocolloids could be also applied to alter and adjust properties of PGS. Russ, Zielbauer, Ghebremedhin, and

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.carbpol.2019.115485 Received 7 June 2019; Received in revised form 14 October 2019; Accepted 15 October 2019 Available online 16 October 2019 0144-8617/ © 2019 Elsevier Ltd. All rights reserved.

Carbohydrate Polymers 229 (2020) 115485

X.-h. He, et al.

Vilgis (2016) reported that xanthan gum and ι-carrageenan boosted the mechanical behavior of pre-gelatinized tapioca starch pastes. κ-carrageenan was found to significantly increase the viscosity and elastic moduli of pre-gelatinized maize starch at 60 °C (Chaudemanche & Budtova, 2008). In aforementioned investigations, hydrocolloids were mixed with the prepared PGS. However, in the practical application, purchasers tend to use the final PGS without extra procedures even a simple mix, producer of PGS was thus required to add hydrocolloids into PGS during the preparation. Additionally, it was reported that hydrocolloids could affect gelatinization of starch via manners such as altering starch granules swelling and leaching, interacting with starch polymer molecules and associating swollen granules (Bemiller, 2011). Adding hydrocolloids before gelatinization may change the properties of PGS differently from physically mixing hydrocolloids with the prepared PGS. To the best of our knowledge, few experiment has been so far carried out in modifying properties of PGS by premixing starch with hydrocolloids, gelatinization, then spray drying. Also, there was little information about modifying pre-gelatinized rice starch by hydrocolloids, despite that rice starch was a very common raw material of PGS. The objective of the work was to prepare a new pre-gelatinized starch through gelatinization and spray drying of rice starch with hydrocolloids. Considering that types of hydrocolloids would differently affect the gelatinization of starch, four common hydrocolloids including pectin, xanthan gum, sodium alginate and ι-carrageenan were used. The information from this research provided a methodology to manufacture PGS with altered properties, which would help in developing PGS and starch-hydrocolloid based food products.

The corresponding PRS-H (PRS-pectin, PRS-xanthan, PRS-alginate, PRS-ι-carrageenan) were obtained as a dry powder using a high-performance glass cyclone. After gelatinizing with deionized water, rice starch was spray dried to prepare PRS.

2.3. Scanning electron microscopy (SEM) The morphology of samples was observed using SEM (Quanta-200, FEI Company, Netherlands). The samples were mounted on an aluminum stub using double-sided stick tape, and sputter coated with a thin film of gold. The shape and morphology characteristics were examined at ×2000 magnifications with an accelerating voltage of 5 kV voltage (Hu et al., 2018).

2.4. X-ray diffraction (XRD) analysis The amorphous/crystalline structure of samples was characterized by an X-ray diffractometer (D8 Advance, Germany) operated at 40 kV and 30 mA with Cu Kα radiation (Ye et al., 2016). The samples were scanned over the range of 5° to 40° diffraction angle (2θ) with a step size of 0.02° (2θ) and counting time of 0.2 s/step.

2.5. Cold paste viscosity The Rapid Visco Analyzer (TecMaster, Perten Instruments, Warriewood, Australia) was used to determine cold paste viscosity following the method of Majzoobi, Kaveh, and Farahnaky (2016). Weighted amounts of PRS or PRS-H was added into a glass bottle, and deionized water was added to prepare 10% w/w suspensions. The PRS and PRS-H were stirred using a magnetic stirrer at ambient temperature for 30 min. Subsequently, aliquots (28 g) of each paste was straightly weighed in an aluminum canister and run in the RVA instrument. The procedure used to determine cold paste viscosity was described as follows: the temperature of the RVA was set at a constant temperature (25 °C), and the experiment was continued for 15 min. The paddle speed was 960 rpm for the first 10 s, and 160 rpm for the remainder of the experiment. The viscosity changes of PRS and PRS-H over time at a constant temperature were obtained and analyzed. Additionally, the mixture of hydrocolloids and PRS (PRS+H), which had the same ratio of starch to hydrocolloids as PRS-H, was prepared to compare cold paste viscosity with PRS-H. Hydrocolloids (5 wt.% on a PRS basis) were dissolved in deionized water, and PRS was added to form 10% w/w suspensions. Afterwards, the samples were stirred using a magnetic stirrer at ambient temperature for 30 min. The determination of cold paste viscosity of PRS+H (PRS + pectin, PRS + xanthan, PRS + alginate, PRS+ι-carrageenan) was the same as that of PRS-H as mentioned above.

2. Materials and methods 2.1. Materials Rice starch (S7260, moisture 10.34%, lipids 0.01%, protein 0.62%, ash 0.34% and amylose 24.23%), pectin (P9135, degree of methylation 67.09% and galacturonic acid content 81.23%), xanthan gum (G1253, from Xanthomonas campestris, molecular weight ≈ 2000 kDa) and ιcarrageenan (commercial grade, C1138, Lot # SLBB2304 V) were purchased from Sigma-Aldrich (Shanghai, China). Sodium alginate was provided by the National Institute for the Control of Pharmaceutical and Biological Products (Beijing, China), and it was purified to determine molecular weight of 30.0 kDa and molar ratio of mannuronate (M) to guluronate (G) 15:85 according to our previous method (Liu, He et al., 2017). 2.2. Preparation of PRS and PRS-H 1.5 g of hydrocolloids (pectin, xanthan gum, sodium alginate and ιcarrageenan) were respectively dissolved into deionized water (1 L) to obtain corresponding hydrocolloids solution. Then, 30 g rice starch was added, and the resulting slurry was homogenized by stirring (at a speed of 250 rpm) for 2 h at ambient temperature. Subsequently, the uniform starch-hydrocolloids slurry was heated up to 95 °C in a thermostatic magnetic stirring water bath and kept for 30 min accompanying with constant stirring at 250 rpm. In order to minimize the evaporation of water during the process of gelatinization, the beakers were covered with three layers of preservative films. Same dry base content of starch was gelatinized with deionized water to prepare the blank sample. Gelatinized rice starch or gelatinized rice starch-hydrocolloids (starch-pectin, starch-xanthan, starch-alginate, and starch-ι-carrageenan) were spray dried using a Büchi B-290 Mini-Spray Dryer (Büchi Labortechnik, Switzerland) according to the method described by Russ et al. (2016). The samples were pumped via a peristaltic pump at a rate of 0.3 L/h to a two-fluid nozzle (0.7 mm nozzle tip diameter), and atomized with the compressed air flow (flow rate = 667 L/h). The inlet drying temperature was 200 °C, and the aspirator rate was set to 100%.

2.6. Swelling power (SP) and water solubility index (WSI) Swelling power (SP) and water solubility index (WSI) were determined according to previous studies with slight modifications (Li & Yeh, 2001; Majzoobi, Kaveh, Blanchard et al., 2015). Briefly, weighted samples (W0) were suspended in deionized water to prepare slurry with 2% dry matter (w/w) and gently stirred for 30 min in thermostatic magnetic stirring water bath at 25 °C. Then, the slurry was centrifuged at 4000 rpm for 12 min. The supernatant was poured out carefully and collected, and weight of residue (W1) was recorded. Subsequently, the supernatant was dried to constant weight (W2) in an air oven at 105 °C. WSI and SP were calculated according to Eqs. (1) and (2), respectively.

2

WSI(%) = [W2/W0] × 100

(1)

SP(g/g) = W1/[W0 × (100%-WSI)]

(2)

Carbohydrate Polymers 229 (2020) 115485

X.-h. He, et al.

noticed that the granule integrity of original corn starch was remained upon heating the mixture of xanthan gum and starch (at a ratio of 1:9) to 95 °C. However, it was observed that PRS-H also displayed red blood cells-like morphology, as shown in the representative micrograph of PRS-xanthan (Fig. 1C), which was similar with the morphology of PRS. This result may be because the low ratio (1:20, w/w) of hydrocolloids to starch used during preparing PRS-H was not enough to change the morphology of starch granule.

2.7. Rheological measurements 2.7.1. Steady shear rheology of hydrocolloids and gelatinized rice starchhydrocolloids without spray drying (GRS-H) Hydrocolloids solution (0.15% w/v) were prepared by completely dissolving 0.375 g hydrocolloids in 250 mL deionized water with gentle stirring at room temperature, and then centrifuged (3000 rpm, 10 min) to devoid of entrapped air bubbles. The gelatinized rice starch (GRS) or gelatinized rice starch-hydrocolloids without spray drying (GRS-H) were prepared as described in Section 2.2. According to the procedure used by Liang, Wang, Chen, Liu, and Liu (2015), the steady shear rheological measurements of hydrocolloids, GRS and GRS-H were determined by Rheometer MCR302 (Anton Paar, Austria), equipped with a concentric cylinder measuring system CC27 (SN 36390). The samples were sheared from 0.01 to 100 s−1 at temperature of 25 ± 0.1 °C to determine the flow behavior.

3.2. XRD analysis Some researchers implied that crystalline properties of starch could be affected by the presence of hydrocolloids (Chaisawang & Suphantharika, 2006; Kim & Yoo, 2011; Torres, Moreira, Chenlo, & Morel, 2013). Therefore, X-ray diffractograms were performed to investigate the crystalline packing arrangements of native starch, PRS and PRS-H, and the results were presented in Fig. 2. Native rice starch was typical A-type X-ray pattern which exhibited strong peaks at about 15°, 17°, 18°, and 23°, as generally reported for cereal starch (Kim et al., 2013; Li et al., 2013). The diffraction pattern of PRS was different from native starch, and all peaks almost disappeared, indicating that crystalline structure of native starch after gelatinization and spray drying was completely destroyed. Likewise, all PRS-H were non-crystalline structure, and similar XRD patterns with PRS were observed. PGS reported in previous literature existed in the form of complete (Nakorn et al., 2009) and partial gelatinization (Tpr et al., 2018). Based on the result of morphology and XRD, it could be inferred that rice starch in PRS-H were completely gelatinized, and hydrocolloids seemed to have no observable influence on gelatinzation of starch in our method. Therefore, other properties of PRS-H in the follow have been conducted.

2.7.2. Oscillatory rheological measurements of PRS and PRS-H The 10% w/w PRS and PRS-H pastes obtained from the measurements of cold paste viscosity were used for the determination of the viscoelastic properties, which were analyzed at 25 °C using a MCR302 Rheometer (Anton Paar, Austria). A stainless steel cone-plate geometry with 40 mm diameter and 1° cone angle was equipped which was at a gap size of 0.102 mm. Sample pastes were loaded onto rheometer plates, and the surplus samples were trimmed off with a spatula. All samples were allowed to condition at 25 °C for 2 min before the tests. During the determination, edge of the gap was covered by a thin layer of low-density silicon oil (dimethylpolysiloxane, 50 cP viscosity) to minimize evaporation. For amplitude sweep tests, the strain γ ranged from 0.01% to 100% at a constant ω of 10 rad/s. The determined parameters were limiting value of strain (γl), storage and loss moduli at LVE (G'LVE and G"LVE) and corresponding moduli at flow point (Gf, G' = G"). Frequency sweeps experiments were investigated over a range of 0.1–10 Hz at a constant deformation (0.5% strain) within the linear viscoelastic (LVE) region of all samples (Liu et al., 2016).

3.3. Cold paste viscosity of PRS-H and PRS+H For the perspective of PGS, cold paste property was the most prominent peculiarity due to the ability of increasing viscosity at ambient temperature. Cold paste viscosity of PRS and PRS-H during the whole process of constant shearing in RVA was displayed in Fig. 3A. The cold paste viscosity of PRS at the end of the determination was 1758 cP, which was higher than that of drum-dried pre-gelatinized corn starch (1132 cP) and wheat starch (1392 cP) as published (Majzoobi, Kaveh, Farahnaky et al., 2015; Majzoobi et al., 2016). The differences in cold paste viscosity were presumably due to the source of starch and the method for production of pre-gelatinized starch. PRS-H pastes exhibited different viscosity depending on the hydrocolloids, and viscosity was increased at varying levels in comparison with PRS. The viscosity of PRS-xanthan, PRS-ι-carrageenan, PRS-alginate and PRS-pectin at the end of the determination were 2922 cP, 2684 cP, 2077 cP, 1955 cP, respectively. The percentage contributions of xanthan gum, ι-carrageenan, sodium alginate and pectin to increase the viscosity were 66.21%, 52.64%, 18.14% and 11.21%, respectively. In comparison with pectin and sodium alginate, xanthan and ι-carrageenan contributed to obtain superior thickening properties. Meanwhile, it was observed that viscosity changes were slight in the whole process of constant shearing, implying that PRS and PRS-H were endowed with shearing stability. Despite that both PRS and PRS-H were shear resistant, PRS-H may have greater potential for application in products such as instant puddings, pie fillings, and baby foods which need to be processed at low temperature for thickening. The higher cold paste viscosity than PRS could lower the cost of products. The PRS and hydrocolloids were also mixed to prepare PRS+H, and cold paste viscosity of PRS-H was further compared with that of PRS +H. It was observed that cold paste viscosity of PRS+H was likewise enhanced according to hydrocolloids (Fig. 3B). The viscosity of PRS + xanthan, PRS+ι-carrageenan, PRS + alginate and PRS + pectin at the end of the determination was 2239 cP, 2337 cP, 2190 cP and

2.8. Statistical analysis The data obtained were analyzed by one-way analysis of variance (ANOVA), expressed as mean ± standard deviations and compared by Duncan’s multiple test (p < 0.05). The statistical analysis of the data was performed using the SPSS (version 16.0, Chicago, United States). 3. Results and discussion 3.1. Morphology Native starch, PRS and PRS-H were examined through SEM to investigate the morphology changes after treatment. It was found that PRS and PRS-H showed considerable disparities in shape and surface morphology with native starch as revealed in Fig. 1. Native rice starch was polyhedral shape and plump granules with relatively narrow and well-distributed size (Fig. 1A), which was consistent with the previous research reporting the morphological structure of rice starch (Bhat & Riar, 2016; Cai et al., 2015; Zhu et al., 2017). The shape of PRS became elliptical accompanying with some big size and severe folds or wrinkle shrinkage occurred on granular surface (Fig. 1B), which was analogous to the appearance of red blood cells. This result was similar to spray dried glutinous rice starch as published by Laovachirasuwan et al. (2010). Hydrocolloids were reported to be able to restrict granule swelling and starch polymer molecules leaching during gelatinization (Bemiller, 2011), thus the morphology of starch granule would be affected. Nagano, Tamaki, and Funami (2008) observed that maize starch granules were volumetrically compressed after starch (5% w/w) heated in 0.5% (w/w) guar gum. Zhang, Gu, Zhu, and Hong (2018) also 3

Carbohydrate Polymers 229 (2020) 115485

X.-h. He, et al.

Fig. 1. SEM images of (A) native starch, (B) PRS, and (C) PRS-xanthan. Magnification was 2000×.

was determined as shown in Fig. 4A. For both GRS and GRS-H, apparent viscosity was decreased as shear rate increased, showing shear-thinning behavior of pseudo-plastic fluid. Low apparent viscosity was observed in terms of GRS, and viscosity of GRS-H was increased especially at initial shear rate, which was varied with hydrocolloids. Starch-xanthan and starch-ι-carrageenan possessed higher apparent viscosity than starch-alginate and starch-pectin. In order to better illustrate the interactions between starch and hydrocolloids, the apparent viscosityshear rate curves for hydrocolloids were depicted in Fig. 4B. All hydrocolloids behaved low apparent viscosity (less than 0.35 Pa.s) at concentrations of 0.15% (w/v). Apparent viscosity of xanthan gum was higher than that of ι-carrageenan, sodium alginate and pectin at analyzed shear rate range. In addition, sodium alginate and pectin at low concentration exhibited almost Newtonian fluid, which was similar to the results of Marcotte, Taherian Hoshahili, and Ramaswamy (2001) and Rezende, Bártolo, Mendes, and Filho (2010). Comparing Fig. 4A and B, it was found that the increase of viscosity was not a superposition of viscosity for GRS and hydrocolloids, but a significant viscosity enhancement phenomenon, implying the presence of interactions or crosslinking between starch and hydrocolloids as suggested by Qiu et al. (2015). Differential apparent viscosity of GRS-H was observed, and the sequence of apparent viscosity was similar to that of cold paste viscosity for PRS-H. The results proved above speculation that differences in cold paste viscosity of PRS-H were assigned to interactions between starch and different hydrocolloids.

Fig. 2. X-ray diffraction patterns of native rice starch, PRS and PRS-H.

1876 cP, respectively. It was also noted that viscosities of PRS + xanthan, PRS+ι-carrageenan, and PRS + pectin were correspondingly lower than those of PRS-xanthan, PRS-ι-carrageenan and PRS-pectin, but PRS + alginate showed higher viscosity than PRS-alginate. From these results, it was speculated that interactions between starch and hydrocolloids were probably occurred at the procedure of gelatinization during preparing PRS-H, thus leading to difference of viscosities between PRS-H and PRS+H, as well as different viscosities of PRS-Hs.

3.5. Swelling power (SP) and water solubility index (WSI) of PRS-H Swelling power and water solubility index were another vital property of PGS. The results of SP and WSI of native starch, PRS and PRS-H weredisplayed in Figure 5. Native rice starch was marginally swollen, and the SP value was 2.94 g/g. SP of PRS changed and increased 4.33 times at ambient temperature. For PRS, granules presented a weak structure with complete loss of crystalline as X-ray diffraction pattern (Fig. 2) displayed, which facilitated the entrance of water

3.4. Flow properties of hydrocolloids and GRS-H The interactions between starch and hydrocolloids could be embodied in flow behavior of gelatinized starch/hydrocolloid systems (Korus, Juszczak, Witczak, & Achremowicz, 2004; Qiu et al., 2015). Therefore, steady shear viscosity of GRS-H as a function of shear rate 4

Carbohydrate Polymers 229 (2020) 115485

X.-h. He, et al.

Fig. 3. Cold paste viscosity of (A) PRS-H and (B) PRS+H.

Fig. 4. Viscous flow curves of (A) GRS-H and (B) hydrocolloids at 25 °C.

reported by Liu, Chen et al. (2017) and Majzoobi, Kaveh, Farahnaky et al. (2015). The presence of granule structure was probably accountable for this result, since Hedayati, Majzoobi et al. (2016) and Li et al. (2014) illustrated that granular cold-water swelling starch was more prone to absorb water molecules than those PGS with destroyed granule structure. The WSI of native starch was 1.97%, and those of PRS, PRS-xanthan, PRS-ι-carrageenan, PRS-alginate, PRS-pectin were 9.37%, 10.20%, 12.90%, 13.22% and 13.38%, respectively (Fig. 5). Theoretically, the WSI of PRS-H should be 14.37% if hydrocolloids were fully dissolved. The lower WSI in the actual test indicated that the dissolution of polymer molecules was restricted, probably because interactions between starch and hydrocolloids reduced the dissolution of polymer molecules at different level. 3.6. Dynamic rheological properties Fig. 5. Swelling power (SP) and water solubility index (WSI) of PRS and PRS-H.

Small amplitude oscillatory shear analysis could provide information about the three-dimensional network structures of PRS-H in a nondestructive way (Yousefi & Razavi, 2015).

molecules with ease and swelling (Fu, Wang, Li, & Adhikari, 2012). The SP of PRS-H was increased at different level in comparison to PRS. The values of PRS-pectin, PRS-alginate, PRS-ι-carrageenan and PRS-xanthan were enhanced progressively. It was also observed that the sequence of SP values was identical with that of cold paste viscosity. Absorbing water and swelling of starch granules were reckoned to be related to the viscosity in RVA tests as demonstrated by large quantities of researches (Alamri, Hussain, Mohamed, Abdo Qasem, & Ibraheem, 2016; Li et al., 2014). In addition, SP values of PRS and PRS-H in this study were relatively higher than that of extrusion-cooked and drum-dried PGS as

3.6.1. Amplitude sweep The amplitude sweep tests were used to define the linear viscoelastic (LVE) region where the strain response was proportional to the applied stress (Chen et al., 2018). In the present case, the extent of the LVE region of samples quantified under amplitude sweeps at a constant ω of 10 rad/s was shown in Fig. 6A. The LVE region of the samples was in the strain range of 0.01–1.65%, which was appropriate for all samples. The limiting value of strain (γL) of PRS paste was around 3.84%. However, incorporating hydrocolloids changed this parameter. Values 5

Carbohydrate Polymers 229 (2020) 115485

X.-h. He, et al.

Fig. 6. Dynamic rheological properties of PRS and PRS-H at 25 °C. (A) Linear viscoelastic regions of samples, open-storage moduli (G'), closed-loss moduli (G"). (B) Variation of G' and G" with frequency for samples, open-storage moduli (G'), closed-loss moduli (G"). (C) Variation of tan δ with frequency for samples. □ - PRS-Xan, ○ - PRS-ι-carrageenan, ltri; - PRS-pectin, star;- PRS, ◊ - PRS-alginate. Reported results correspond to mean ± standard deviation. Different letters within the same column indicate significant differences (p < 0.05). Table 1 The rheological parameters of PRS and PRS-Ha. Samples

G' LVE (Pa)

G" LVE (Pa)

γL (%)

PRS PRS-pectin PRS-xanthan PRS-alginate PRS-ι-carrageenan

336.87 346.67 760.31 282.08 494.97

53.95 ± 0.92 61.10 ± 0.85 114.90 ± 1.84 74.55 ± 1.34 102.00 ± 1.41

3.84 2.41 1.65 3.75 6.25

± ± ± ± ±

0.18 8.02 3.27 0.12 2.78

± ± ± ± ±

Gf (Pa) 0.15 0.15 0.03 0.04 0.02

142.91 135.39 306.10 118.53 179.17

G'0.1Hz ± ± ± ± ±

0.00 0.62 3.10 1.19 0.83

307.72 330.64 673.63 250.13 433.22

G'10Hz ± ± ± ± ±

2.13 2.29 4.67 4.62 8.50

468.84 ± 2.12 499.31 ± 5.16 1003.69 ± 9.94 420.28 ± 4.89 701.94 ± 7.76

Parameters in the LVE region determined by amplitude sweep tests: G'LVE and G"LVE - storage moduli and loss moduli; γL-limiting value of strain; Gf - modulus at flow point. G'0.1Hz - storage moduli at 0.1 Hz of frequency sweep tests; G'10Hz - storage moduli at 10 Hz of frequency sweep tests. a Reported results correspond to mean ± standard deviation.

of γL were about 2.41%, 1.65%, 3.75%, 6.25% for PRS-pectin, PRSxanthan, PRS-alginate and PRS-ι-carrageenan, respectively (Table 1). The γL reflects the deformability of the samples, and is also a criterion of the degree to withstand mechanical stress without structural damage (Precha-Atsawanan, Uttapap, & Sagis, 2018). The bigger value of γL, the higher stress that causes this strain was, which indicated superior spreadable character and stronger ability to protect the pastes from destroying during processing. PRS-ι-carrageenan with high γL may be suitable for spreading in foods such as pastries and salad dressings. Moreover, storage moduli (G'LVE) were higher than loss moduli (G"LVE) of all samples in the LVE region, indicating network structure and viscoelastic gel-like behavior. Meanwhile, moduli of PRS-H were altered according to the incorporating hydrocolloids as summarized in Table 1. Compared to PRS, G'LVE and moduli at flow point (Gf) of PRSxanthan and PRS-ι-carrageenan were enhanced, but those of PRS-alginate were decreased. Russ et al. (2016) also reported that different

hydrocolloids could change viscoelastic moduli of pre-gelatinized tapioca starch, even an inversion of viscoelastic properties could be induced. G"LVE representing viscous behavior arranged in turns: PRSxanthan > PRS-ι-carrageenan > PRS-alginate > PRS-pectin > PRS, which showed same sequence as cold paste viscosity and swelling power.

3.6.2. Frequency sweep The mechanical spectra of G' and G" of PRS and PRS-H as a function of frequency (Hz) were presented in Fig. 6B. Both moduli were increased along with frequency. For all samples, G' was higher than G", and no intersection occurred between G' and G". Hence, PRS and PRS-H exhibited gel-like property and recoverable deformations under the measured frequency sweep range. The presence of hydrocolloids changed dynamic moduli. Compared to PRS, G'0.1Hz and G'10Hz of PRSxanthan, PRS-ι-carrageenan and PRS-pectin were elevated, but those of 6

Carbohydrate Polymers 229 (2020) 115485

X.-h. He, et al.

PRS-alginate were lowered (Table 1). The change trend of G'0.1Hz and G'10Hz of PRS-H behaved similar with that of G'LVE in amplitude sweep test. The building up of gel network and moduli were affected by the arrangement way of continuous amylose phase and swollen granules in the starch systems (Singh, Singh, Kaur, Sodhi, & Singh Gill, 2003). Incorporating hydrocolloids has altered cold paste viscosity and hydration properties of PRS owing to interacting with starch in different ways, so hydrocolloids interwining starch molecules and swollen granules or embedding in starch phase would also change the network arrangement of pastes, thus PRS-H revealing distinguishable viscoelasticity. Loss tangent (tan δ, ratio of G" to G') is another dynamic rheological indicator to reflect viscoelastic behavior. Values of tan δ < 1 and tan δ > 1 illustrate predominantly elastic and viscous behaviors, respectively (Yousefi & Razavi, 2015). As presented in Fig. 6C, tan δ of all samples were less than 0.35 over the whole frequency range, suggesting that all pastes were more elastic than viscous. Meanwhile, the values of tan δ were changed in varying degrees owing to incorporating hydrocolloids. Samples had low tan δ values at low frequency, but showed different performance at high frequency (i.e fast displacements). The PRS paste behaved dependent on changing frequency, and a less frequency dependent deformation behavior was achieved for PRS-xanthan and PRS-ι-carrageenan. On the contrary, PRS-alginate and PRS-pectin still displayed apparent frequency dependence. All these variations of parameters demonstrated that PGS with desired mechanical properties could be tuned by selecting and incorporating different hydrocolloids in preparation, hereby suitably applying for specific products.

Macromolecules, 92, 637–644. Borries-Medrano, E. V., Jaime-Fonseca, M. R., Aguilar-Méndez, M. A., & García-Cruz, H. I. (2018). Addition of galactomannans and citric acid in corn starch processed by extrusion: Retrogradation and resistant starch studies. Food Hydrocolloids, 83, 485–496. Cai, J. M., Man, J. M., Huang, J., Liu, Q. Q., Wei, W. X., & Wei, C. X. (2015). Relationship between structure and functional properties of normal rice starches with different amylose contents. Carbohydrate Polymers, 125, 35–44. Chaisawang, M., & Suphantharika, M. (2006). Pasting and rheological properties of native and anionic tapioca starches as modified by guar gum and xanthan gum. Food Hydrocolloids, 20(5), 641–649. Chaudemanche, C., & Budtova, T. (2008). Mixtures of pregelatinised maize starch and κcarrageenan: Compatibility, rheology and gelation. Carbohydrate Polymers, 72(4), 579–589. Chen, L., Tian, Y. Q., Bai, Y. X., Wang, J. P., Jiao, A. Q., & Jin, Z. Y. (2018). Effect of frying on the pasting and rheological properties of normal maize starch. Food Hydrocolloids, 77, 85–95. Din, Z. U., Xiong, H. G., & Fei, P. (2015). Physical and chemical modification of starches a review. Critical Reviews in Food Science and Nutrition, 57(12), 2691–2705. Fu, Z. Q., Wang, L. J., Li, D., & Adhikari, B. (2012). Effects of partial gelatinization on structure and thermal properties of corn starch after spray drying. Carbohydrate Polymers, 88(4), 1319–1325. Gharsallaoui, A., Roudaut, G., Chambin, O., Voilley, A., & Saurel, R. (2007). Applications of spray-drying in microencapsulation of food ingredients: An overview. Food Research International, 40(9), 1107–1121. Hedayati, S., Majzoobi, M., Shahidi, F., Koocheki, A., & Farahnaky, A. (2016). Effects of NaCl and CaCl2 on physicochemical properties of pregelatinized and granular coldwater swelling corn starches. Food Chemistry, 213, 602–608. Hedayati, S., Shahidi, F., Koocheki, A., Farahnaky, A., & Majzoobi, M. (2016). Physical properties of pregelatinized and granular cold water swelling maize starches at different pH values. International Journal of Biological Macromolecules, 91, 730–735. Hedayati, S., Shahidi, F., Koocheki, A., Farahnaky, A., & Majzoobi, M. (2016). Comparing the effects of sucrose and glucose on functional properties of pregelatinized maize starch. International Journal of Biological Macromolecules, 88, 499–504. Hu, X. T., Guo, B. Z., Liu, C. M., Yan, X. Y., Chen, J., Luo, S. J., et al. (2018). Modification of potato starch by using superheated steam. Carbohydrate Polymers, 198, 375–384. Kim, B. S., Kim, H. S., Hong, J. S., Huber, K. C., Shim, J. H., & Yoo, S. H. (2013). Effects of amylosucrase treatment on molecular structure and digestion resistance of pre-gelatinised rice and barley starches. Food Chemistry, 138(2), 966–975. Kim, W. W., & Yoo, B. (2011). Rheological and thermal effects of galactomannan addition to acorn starch paste. LWT-Food Science and Technology, 44(3), 759–764. Korus, J., Juszczak, L., Witczak, M., & Achremowicz, B. (2004). Influence of selected hydrocolloids on triticale starch rheological properties. International Journal of Food Science & Technology, 39(6), 641–652. Laovachirasuwan, P., Peerapattana, J., Srijesdaruk, V., Chitropas, P., & Otsuka, M. (2010). The physicochemical properties of a spray dried glutinous rice starch biopolymer. Colloids & Surfaces B Biointerfaces, 78(1), 30–35. Li, J. Y., & Yeh, A. I. (2001). Relationships between thermal, rheological characteristics and swelling power for various starches. Journal of Food Engineering, 50(3), 141–148. Li, W. H., Cao, F., Fan, J., Ouyang, S. H., Luo, Q. G., Zheng, J. M., et al. (2014). Physically modified common buckwheat starch and their physicochemical and structural properties. Food Hydrocolloids, 40(10), 237–244. Li, W. H., Shan, Y. L., Xiao, X. L., Luo, Q. G., Zheng, J. M., Ouyang, S., et al. (2013). Physicochemical properties of A-and B-starch granules isolated from hard red and soft red winter wheat. Journal of Agricultural and Food Chemistry, 61(26), 6477–6484. Li, Y. T., Wang, R. S., Liang, R. H., Chen, J., He, X. H., Chen, R. Y., et al. (2018). Dynamic high-pressure microfluidization assisting octenyl succinic anhydride modification of rice starch. Carbohydrate Polymers, 193, 336–342. Liang, R. H., Wang, L. H., Chen, J., Liu, W., & Liu, C. M. (2015). Alkylated pectin: Synthesis, characterization, viscosity and emulsifying properties. Food Hydrocolloids, 50, 65–73. Liu, C. M., He, X. H., Liang, R. H., Liu, W., Guo, W. L., & Chen, J. (2017). Relating physicochemical properties of alginate-HMP complexes to their performance as drug delivery systems. Journal of Biomaterials Science Polymer Edition, 28(18), 2242–2254. Liu, C. M., Liang, R. H., Dai, T. T., Ye, J. P., Zeng, Z. C., Luo, S. J., et al. (2016). Effect of dynamic high pressure microfluidization modified insoluble dietary fiber on gelatinization and rheology of rice starch. Food Hydrocolloids, 57, 55–61. Liu, Y. F., Chen, J., Luo, S. J., Li, C., Ye, J. P., Liu, C., et al. (2017). Physicochemical and structural properties of pregelatinized starch prepared by improved extrusion cooking technology. Carbohydrate Polymers, 175, 265–272. Majzoobi, M., Kaveh, Z., Blanchard, C. L., & Farahnaky, A. (2015). Physical properties of pregelatinized and granular cold water swelling maize starches in presence of acetic acid. Food Hydrocolloids, 51, 375–382. Majzoobi, M., Kaveh, Z., & Farahnaky, A. (2016). Effect of acetic acid on physical properties of pregelatinized wheat and corn starch gels. Food Chemistry, 196, 720–725. Majzoobi, M., Kaveh, Z., Farahnaky, A., & Blanchard, C. L. (2015). Physicochemical properties of pregelatinized wheat and corn starches in the presence of different concentrations of L-ascorbic acid. Starch-Stärke, 67(3-4), 303–310. Majzoobi, M., Radi, M., Farahnaky, A., Jamalian, J., Tongtang, T., & Mesbahi, G. (2010). Physicochemical properties of pre-gelatinized wheat starch produced by a twin drum drier. Journal of Agricultural Science & Technology, 13(2), 193–202. Marcotte, M., Taherian Hoshahili, A. R., & Ramaswamy, H. S. (2001). Rheological properties of selected hydrocolloids as a function of concentration and temperature. Food Research International, 34(8), 695–703. Mitrevej, A., Sinchaipanid, N., & Faroongsarng, D. (2008). Spray-dried rice starch: Comparative evaluation of direct compression fillers. Drug Development

4. Conclusion A new pre-gelatinized starch (named PRS-H) has been produced by gelatinizing starch with hydrocolloids and subsequently spray drying. Incorporating hydrocolloids induced significant increase in cold paste viscosity. The way to prepare PRS-H was able to obtain pre-gelatinized starch with better thickening properties than directly mixing PRS and hydrocolloids, especially in regard to xanthan gum and ι-carrageenan. Differences in cold paste viscosity of PRS-H were assigned to interactions between starch and hydrocolloids. The swelling power of PRS-H was enhanced, which behaved similar sequence with cold paste viscosity. Moreover, viscoelastic properties of PRS could be tuned by incorporating different hydrocolloids to obtain pastes with appropriate spreadability and mechanical properties. Therefore, the results of this research could provide guidance for food manufacturers to choose hydrocolloid for producing PGS with desirable pastes, so as to achieve better application in foods such as instant puddings, pie fillings, baby foods and pastries dressings, which need to be processed at low temperature for thickening or spreadable properties. 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 (31571875, 31660488, and 31601397), Outstanding Youth Talents in Jiangxi Province (20171BCB23026), and Postgraduate Innovative Funds of Nanchang University (CX2017133). References Alamri, M., Hussain, S., Mohamed, A., Abdo Qasem, A. A., & Ibraheem, M. (2016). A study on the effect of black cumin extract on the swelling power, textural, and pasting properties of different starches. Starch-Stärke, 68(11–12), 1233–1243. Bemiller, J. N. (2011). Pasting, paste, and gel properties of starch–hydrocolloid combinations. Carbohydrate Polymers, 86(2), 386–423. Bhat, F. M., & Riar, C. S. (2016). Effect of amylose, particle size & morphology on the functionality of starches of traditional rice cultivars. International Journal of Biological

7

Carbohydrate Polymers 229 (2020) 115485

X.-h. He, et al.

thermal and rheological properties of starches from different botanical sources. Food Chemistry, 81(2), 219–231. Tetlow, I. J. (2010). Starch biosynthesis in developing seeds. Seed Science Research, 21(1), 5–32. Torres, M. D., Moreira, R., Chenlo, F., & Morel, M. H. (2013). Effect of water and guar gum content on thermal properties of chestnut flour and its starch. Food Hydrocolloids, 33(2), 192–198. Tpr, D. S., Cml, F., Demiate, I. M., Li, X. H., Garcia, E. L., Jane, J. L., et al. (2018). Spraydrying and extrusion processes: Effects on morphology and physicochemical characteristics of starches isolated from Peruvian carrot and cassava. International Journal of Biological Macromolecules, 118, 1346–1353. Ye, J. P., Hu, X. T., Zhang, F., Fang, C., Liu, C. M., & Luo, S. J. (2016). Freeze-thaw stability of rice starch modified by improved extrusion cooking technology. Carbohydrate Polymers, 151, 113–118. 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. Zhang, Y. Y., Gu, Z. B., Zhu, L., & Hong, Y. (2018). Comparative study on the interaction between native corn starch and different hydrocolloids during gelatinization. International Journal of Biological Macromolecules, 116, 136–143. Zhu, D. W., Zhang, H. C., Guo, B. W., Xu, K., Dai, Q. G., Wei, C. X., et al. (2017). Physicochemical properties of indica-japonica hybrid rice starch from Chinese varieties. Food Hydrocolloids, 63, 356–363.

Communications, 22(7), 587–594. Nagano, T., Tamaki, E., & Funami, T. (2008). Influence of guar gum on granule morphologies and rheological properties of maize starch. Carbohydrate Polymers, 72(1), 95–101. Nakorn, K. N., Tongdang, T., & Sirivongpaisal, P. (2009). Crystallinity and rheological properties of pregelatinized rice starches differing in amylose content. Starch-Stärke, 61(2), 101–108. Precha-Atsawanan, S., Uttapap, D., & Sagis, L. M. C. (2018). Linear and nonlinear rheological behavior of native and debranched waxy rice starch gels. Food Hydrocolloids, 85, 1–9. Qiu, S., Yadav, M. P., Chen, H., Liu, Y., Tatsumi, E., & Yin, L. J. (2015). Effects of corn fiber gum (CFG) on the pasting and thermal behaviors of maize starch. Carbohydrate Polymers, 115(115), 246–252. Rezende, R. A., Bártolo, P. J., Mendes, A., & Filho, R. M. (2010). Rheological behavior of alginate solutions for biomanufacturing. Journal of Applied Polymer Science, 113(6), 3866–3871. Russ, N., Zielbauer, B. I., Ghebremedhin, M., & Vilgis, T. A. (2016). Pre-gelatinized tapioca starch and its mixtures with xanthan gum and ι-carrageenan. Food Hydrocolloids, 56, 180–188. 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. Singh, N., Singh, J., Kaur, L., Singh Sodhi, N., & Singh Gill, B. (2003). Morphological,

8