Preparation of an In Vitro Low‐Digestible Rice Starch by Addition of Grass Carp Protein Hydrolysates and Its Possible Mechanisms

Abstract

Starch‐containing foods with a high glycemic index and deficiency protein cannot meet the consumers’ proactive demand. Thus, the objective of this work is to test the effect of the presence of grass carp protein hydrolysates (GCPHs) on the digestive and structural properties of pristine rice starch (PRS) during the treatment of high pressure homogenization in combination with spray‐drying (HPH‐SP), and its possible mechanisms. The results show that, when the mass ratio of PRS: GCPHs increases from 100:0 to 100:15 during HPH‐SP treatment, the presence of GCPHs significantly increases the contents of slowly digestible starch (SDS) from 7.8 to 23.0%, and resistant starch (RS) from 10.7 to 25.3% in PRS‐GCPHs complexes after gelatinization, respectively. Structures based on SEM, XRD, ATR‐FTIR, and SAXS show that, compared to HPH‐SP treatment alone, HPH‐SP treatment in the presence of GCPHs can remarkably destroy crystallinity, shorten branch chain content, lower the IR ratio of 1045/1022 cm−1, bragg spacing and lamellar peak intensity of PRS, and strengthen rigidity of PRS‐GCPHs complexes granules, which can play a significant role in increasing the contents of SDS and RS. Moreover, gelatinized PRS‐GCPHs rapidly assembles and aggregates to form more space hindrance and inhibit amylase close to leaching amylose, chained, or even branched amylopectin, which can be also attributed to the increased contents of SDS and RS authenticated by the observations of RVA, AFM, and representative images. These findings suggest that the presence of GCPHs during HPH‐SP treatment can be potently employed for preparing in vitro low digestible starch.

Starch-based food matrices containing protein: Recent understanding of morphology, structure, and properties

“…Atomic force microscopy (AFM) can be used to reveal nanoscale structural features of samples, which are considerably smaller than those observable by CLSM (Niu et al, 2017;Xiao, Niu, Wu, Li, & He, 2019;Xiao & Zhong, 2017). AFM studies have demonstrated that the number and height of protrusions on the surfaces of starch-protein hydrolysate mixtures were significantly altered, compared to those of starch-only samples, suggesting that protein hydrolysates can affect the aggregation of amylose and amylopectin on a nanoscale (Kong et al, 2016;Niu et al, 2017;Xiao et al, 2019;Xiao & Zhong, 2017).…”

“…starch granule-channel proteins and starch granule-surface proteins) might be involved in the formation of crystalline structures or that the operative extraction methods partially destroyed starch crystallites J o u r n a l P r e -p r o o f 29 (Hu et al, 2017;Zhan et al, 2020). Moreover, processing operations can influence the multi-scale structures of starch-protein systems, possibly by promoting interactions between starches and proteins which lead to specific structures (Chen, Luo, et al, 2019;Chi, Li, Zhang, Chen, & Li, 2018;Li et al, 2018;Qiu et al, 2015;Xiao et al, 2019). For instance, starches (corn and potato) complexed with soybean peptide, subjected to HMT, have been reported to display higher relative crystallinity than their non-HMT counterparts, which was attributed to interactions between starch chains and side-chain groups in the soybean peptide during HMT (Chen, Luo, et al, 2019).…”

“…Zhu, Wen, Li, & Zhao, 2013;Xiao et al, 2019;Zhang et al, 2019). Thus, the presence of proteins or protein hydrolysates can be seen to inhibit starch retrogradation.…”

Structural and functional characteristics of Japonica rice starches with different amylose contents

“…The ATR-FTIR spectra of starches were measured using a Nicolet iS50 FTIR spectroscopy (Thermo Scientific, Waltham, MA, USA) with a built-in diamond attenuated total reflection (ATR). The spectral region of 1200-800 cm −1 was deconvoluted with a half-band width and enhancement factor of 19 cm −1 and 1.9, respectively (Xiao et al, 2019).…”

Effect of Homogenization Modified Rice Protein on the Pasting Properties of Rice Starch

“…Previous studies have shown that higher soluble protein had greater influence on the gelatinization properties of starch [ 16 ]. It is also indicated that small molecular weight proteins had a stronger effect on the inhibition of starch retrogradation or digestibility than large molecular weight proteins [ 17 , 18 ]. Therefore, it is feasible to regulate the physico-chemical properties of starch-based food products by changing the properties of protein.…”