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Synergistic influence of extrusion conditions and whey protein isolate (WPI) incorporation on glycemic response and physicochemical characteristics of rice starch was studied. Box-Behnken Design was used to evaluate effect of process variables (rice starch:WPI ratio; feed moisture and barrel temperature) on quality characteristics of resistant starch-rich, low GI extruded snacks (RSLG-E). Optimum conditions for development of RSLG-E were WPI:18.30 %, feed moisture:20 % and barrel temperature:120 °C. FTIR spectroscopy showed maximum peaks at 1615 cm -1 and 1540 cm -1 corresponding to presence of amide group; however, such band was absent in control. Thermal analysis indicated significantly higher transition temperatures in RSLG-E than control. Expansion ratio (3.79 ± 0.17) and overall acceptability (4.48 ± 0.05) were found to be significantly lower in RSLG-E. In vitro digestibility indicated significantly lower very rapidly digestible starch (2.08 ± 0.03 %) and rapidly digestible starch (68.49 ± 1.07 %) in RSLG-E than control. Digestible starch (86.85 ± 0.97 %), starch hydrolysis rate (58.72 ± 0.97 %) and slowly digestible starch (72.61 ± 0.82 %) were lower in control., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study aimed at optimizing process protocols for development of low glycemic index (GI) rice flour (LGIRF) by employing enzymatic hydrolysis method using central composite rotatable design (CCRD). LGIRF was evaluated for pasting, farinographic, spectroscopic and microbiological attributes. Independent variables for optimization included concentrations of α-amylase (0.02-0.12 %), glucoamylase (0.02-0.24 %), as well as the incubation temperature (55-80°C). Resistant starch (RS), glycemic index (GI) and glycemic load (GL) were investigated as response variables. The optimum conditions for development of LGIRF with better quality were- α-amylase concentration of 0.040 %, glucoamylase concentration of 0.070 % and an incubation temperature of 60 °C. The results of mineral analysis revealed significantly (p < 0.05) lower levels of boron, potassium, zinc, phosphorus, magnesium, and manganese in LGIRF, while iron and copper were significantly higher. The viscosity profile as evident from pasting profile and farinographic characteristics of LGIRF were significantly (p < 0.05) lower than native rice flour. 1 H NMR and 13 C NMR spectroscopic studies showed an increase in flexible starch segments and a decrease in amorphous portion of starch LGIRF, along with chemical shift alterations in carbons 1 and 4. Free fatty acids and total plate count were significantly (p < 0.05) higher in LGIRF although was within limits., Competing Interests: Declaration of competing interest None of the authors report any conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study investigated physicochemical, glycemic index, pasting and microstructural properties of low glycemic index rice flour (LGIRF) stored in two different packaging materials (low density polyethylene-LDPE and metalized polyester-Met-PE) under accelerated storage conditions (38 ± 2 °C and 90-92% RH) for three months. The different properties were evaluated after every one month. Protein, fat, fibre and carbohydrate content decreased slightly while, water activity, moisture and ash of both control and LGIRF increased significantly with storage (P < 0.05). Total starch, in vitro glycemic index and glycemic load were higher in control and decreased during storage (P < 0.05). However, resistant starch, total sugars, reducing sugars and degree of sweetness in LGIRF exhibited higher, although non-significant variation relative to control during storage. Pasting properties revealed that peak and breakdown viscosities decreased while final and setback viscosities increased during storage (P < 0.05) however holding viscosity and pasting temperature exhibited non-significant variation (P > 0.05). Further, all pasting properties were significantly higher in control except pasting temperature (P < 0.05). All farinographic properties exhibited non-significant difference during storage and were significantly higher in control. Overall, while comparing LDPE and MeT-PE samples non-significant variation was observed in all properties. Microstructural studies showed that integrity of starch granules in LGIRF samples were least altered during storage., (Copyright © 2020 Elsevier B.V. All rights reserved.)