Effects of Hydrothermal and Microwave Dual Treatment and Zein on the Enzymolysis of High Amylose Corn Starch

Resistant starch (RS) type 2-high-amylose corn starch (HACS) was subjected to simultaneous hydrothermal (25% moisture content, 90 °C for 12 h) and microwave (35% moisture content, 40 W/g microwaving for 4 min) treatment and zein (at a zein to treated starch ratio of 1:5, 50 °C for 1 h) to improve its resistance to enzymolysis. Scanning electron microscopy (SEM) highlighted the aggregation and adhesion of the composite. The average particle size of the composite (27.65 μm) was exceeded that of both the HACS (12.52 μm) and the hydrothermal and microwave treated HACS (hydro-micro-HACS) (12.68 μm). The X-ray diffraction results revealed that the hydro-micro-HACS and composite remained B-type, while their crystallinity significantly decreased to 16.98% and 12.11%, respectively. The viscosity of the hydro-micro-HACS and composite at 50 °C was 25.41% and 35.36% lower than that of HACS. The differential scanning calorimetry (DSC) results demonstrated that the composite displayed a new endothermic peak at 95.79 °C, while the weight loss rate and decomposition temperature were 7.61% and 2.39% lower than HACS, respectively. The RS content in HACS, the hydro-micro-HACS, and composite was 47.12%, 57.28%, and 62.74%, respectively. In conclusion, hydrothermal and microwave treatment combined with zein provide an efficient physical strategy to enhance the RS type 2-HACS.

The Effect of Mocaf Substitution on Crispness and Organoleptic Quality of Milk Sticks

Milk sticks are one of the dairy products that are served in the form of snacks. One of the ingredients added in making milk sticks is wheat flour which has a high amylose content. It causes the resulting milk sticks to be less crunchy. It is necessary to substitute flour with low amylose content, namely mocaf (Modified Cassava Flour). This research objective was to determine the effect of mocaf on the level of crispness and organoleptic quality of milk sticks. Milk sticks was made in animal science laboratory UNISKA Kediri by adding different percentage of flour: P0 (100% wheat flour), P1 (90% wheat flour and 10% mocaf), P2 (80% wheat flour and 20% mocaf), P3 (70% wheat flour and 30% mocaf), and P4 (60% wheat flour and 40% mocaf) in six replications. This research using completely randomized design (CRD). These results indicated that the substitution of mocaf in the manufacture of milk sticks could reduce the moisture content of the milk sticks so that the substitution of mocaf could increase the crispness. The organoleptic assessment was carried out on the parameters of color, taste, and crispness. There were no significant differences between the color and taste parameters, while the crispness showed that P0 was not significantly different from P1, but it was significantly different from P2, P3, and P4.

High Resistant Starch Rice: Variation in Starch Related SNPs, and Functional, and Sensory Properties

Human diets containing greater resistant starch (RS) are associated with superior glycemic control. Although high amylose rice has higher RS (29 g/kg to 44 g/kg) than lower amylose content varieties, sensory and processing properties associated with RS have not been evaluated. This study used variants of Waxy and starch synthase II a (SSIIa) genes to divide high amylose (256 g/kg to 284 g/kg) varieties into three haplotypes to examine their effects on RS, RVA parameters, and 14 cooked rice texture properties. RVA characteristics were influenced by both genes with peak and hotpaste viscosity differentiating the three haplotypes. Setback from hotpaste viscosity was the only RVA parameter correlated with RS content across three haplotypes (r = −0.76 to −0.93). Cooked rice texture attributes were impacted more by Waxy than by SSIIa with initial starch coating, roughness, and intact particles differentiating the three haplotypes. Pairwise correlation (r = 0.46) and PCA analyses suggested that roughness was the only texture attribute associated with RS content; while protein content influenced roughness (r = 0.49) and stickiness between grains (r = 0.45). In conclusion, variation exists among genetic haplotypes with high RS for sensory traits that will appeal to diverse consumers across the globe with limited concern for negatively affecting grain processing quality.

Inhibitory Effect of Ascorbic Acid on in vitro Enzymatic Digestion of Raw and Cooked Starches

Ascorbic acid, also known as vitamin C, was previously reported to inhibit the activity of pancreatic α-amylase, the primary digestive enzyme for starch. A major implication of such inhibition is a slowed rate of starch digestion into glucose, which thereby reduces postprandial hyperglycemia. The aim of this study was to explore the inhibitory effects of ascorbic acid at various concentrations on the in vitro digestion of high amylose maize starch (HAMS) and potato starch (PS) in both raw and cooked conditions. Resistant starch (RS) content, defined as the starch that remained after 4 h of simulated in vitro enzymatic digestion, was measured for the starch samples. Upon the addition of ascorbic acid, the RS contents increased in both raw and cooked starches. Cooking significantly reduced the RS contents as compared to raw starches, and less increase in RS was observed with the addition of ascorbic acid. The inhibitory effect of ascorbic acid on the digestion of raw starches showed a dose-dependent trend until it reached the maximum extent of inhibition. At the concentrations of 12.5 and 18.75 mg/mL, ascorbic acid exhibited the most potent inhibitory effect on the in vitro starch digestion in raw and cooked conditions, respectively. Overall, our results strongly indicate that ascorbic acid may function as a glycemic modulatory agent beyond other important functions, and its effects persist upon cooking with certain concentrations applied.