Effect of enzymatic hydrolysis on digestibility and morpho-structural properties of hydrothermally pre-treated red rice starch

Improving physicochemical and nutritional attributes of rice starch through green modification techniques

Rice, has long been an inseparable part of the human diet all over the world. As one of the most rapidly growing crops, rice has played a key role in securing the food chain of low-income food-deficit countries. Starch is the main component in rice granules which other than its nutritional essence, plays a key role in defining the physicochemical attributes of rice-based products. However, rice starch suffers from weak techno-functional characteristics (e.g., retrogradability of pastes, opacity of gels, and low shear/temperature resistibility. Green modification techniques (i.e. Non-thermal methods, Novel thermal (e.g., microwave, and ohmic heating) and enzymatic approaches) were shown to be potent tools in modifying rice starch characteristics without the exertion of unfavorable chemical reagents. This study corroborated the potential of green techniques for rice starch modification and provided deep insight for their further application instead of unsafe chemical methods.

Effect of osmotic pressure and simultaneous heat-moisture phosphorylation treatments on the physicochemical properties of mung bean, water caltrop, and corn starches

This study aimed to investigate the physicochemical properties of modified starch prepared through the simultaneous heat-moisture and phosphorylation treatment (HMPT) and osmotic pressure treatment (OPT) for water caltrop starch (WCS), mung bean starch (MBS), and amylose-rich corn starch (CS) for different time periods. Furthermore, variations in starch content [amylose and resistant starch (RS)], swelling powder (SP), water solubility index (WSI), crystallinity, thermal properties, gelatinization enthalpy (ΔH), and glycemic index (GI) were examined. This study demonstrates that neither HMPT nor OPT resulted in a significant increase in the resistant starch (RS) content, whereas all samples succeeded in heat-treating at 105 °C for another 10 min exhibited a significant increase in RS content compared to their native counterparts. Moreover, the gelatinization temperatures of the three starches increased (To, Tp, and Tc), whereas their gelatinization enthalpy (ΔH) and pasting viscosity decreased. In particular, the GI of all three modified starches subjected to HMPT or OPT showed a decreasing trend with modification time, with OPT exhibiting the best effect. Therefore, appropriate modification through HMPT or OPT is a viable approach to develop MBS, WCS, and CS as processed foods with low GI requirements, which exceptionally may be suitable for canned foods, noodles, and bakery products.

Modulation of the properties of starch gels by a one-step extrusion modification method based on Ca2+-citric acid synergistic crosslinking

Citric acid (CA) is a green and safe food-grade crosslinking agent for starch, but its high crosslinking temperature limits its application. In this study, a "one-step" extrusion modification method based on Ca2+-esterification synergistic crosslinking was proposed for the preparation of high gel performance crosslinked starch at low temperatures (90 °C). The linear and nonlinear rheological properties of crosslinked starch were comprehensively characterized, and the enhancement effect of synergistic crosslinking reactions on starch gel properties was quantitatively studied. The results show that the elastic modulus of the synergistically crosslinked starch (SC-0.5Ca2+, G' = 3116 ± 36) was significantly increased by 879 % compared to the elastic modulus of starch without synergistically crosslinked modification (SC, G' = 318 ± 9). The elastic modulus of starch gels can be adjusted by changing the ion concentration. Nonlinear rheological Lissajous curve analysis results show that the synergistic crosslinked gel system has a stronger anti-deformation ability. In addition, the honeycomb porous structure and smaller pore size distribution of the synergistic crosslinked gels were characterized using scanning SEM. The XPS, FTIR and XRD results suggest that the synergistic crosslinking enhancement effect may involve various molecular forces such as electrostatic attraction, hydrogen bonding and ester bonding.

Enhancement of Starch Gel Properties Using Ionic Synergistic Multiple Crosslinking Extrusion Modification

Crosslinking is a promising method to modulate the gel properties of food-grade starch gels. Still, the poor crosslinking effect of a single type of crosslinker limits the application of this method in starch gel modification. In this study, an Ca2+ synergistic multiple crosslinking modification method was proposed to prepare crosslinked starches with good gel properties and setting. The rheological properties of the samples were tested. The modified sample (SC-Ca-N3, G' = 1347 ± 27) showed a 79% improvement compared to the starch without synergistic crosslinking modification (SC-N, G' = 752 ± 6). The elastic modulus of starch gels can be adjusted by changing the degree of the crosslinking reaction. The results of nonlinear rheological Lissajous curve analysis showed that the synergistically crosslinked gel system strongly resisted deformation. In addition, the microstructure of the modified samples was characterized using scanning electron microscopy. The XPS, FTIR, and XRD results indicated that multiple molecular forces participate in the synergistic crosslinking reaction.

Development and applications of enzymatic modified starch with high water solubility providing a continuous supply of glucose

Amylopectin clusters (APCs) are produced by cyclodextrin glucanotransferase (EC 2.4.1.19). Their solubility rate in aqueous solution was found to be 16.7 %. The weight-average molecular weight of APCs is ∼105 Da, as determined by multiangle laser light scattering analysis. Side chain length analysis indicated that the relative proportions of side chains with a degree of polymerization in the ranges of 2-8 and 25-50 decreased and increased, respectively, during preparation of APCs. In the exercise experiment, the blood glucose level of rats was higher in the APC-treated group than in the groups treated with commercial carbohydrate supplement (CCD) and glucose. In the forced swimming test, the swimming time in the APC and CCD groups increased by 22.6 % and 31.1 %, respectively, compared with the glucose administration group. The insulin levels were also similar between the APC and CCD groups. However, the glycogen levels in the liver and muscles of mice were significantly higher in the APC group than control group. These results suggest that APCs could potentially enhance endurance when added to sports drinks.