Production of functional Ash Reshteh containing rice resistance starch type III

Unlike the traditional processing methods, whose goal is to increase the digestibility of food, the recent trend of food processing containing starch has gradually changed to design foods with low glycemic index. The aim of this study was to investigate the simultaneous effect of ultrasound/microwave processes on the production of resistant starch type 3 (RS3) in rice and subsequently the production of Reshteh Ashi containing different levels of RS3. The produced starch was evaluated in terms of microstructure and crystal structure, and the rheological characteristics of Reshteh Ashi were analyzed. The results showed that at the 95% confidence level, the linear effect of both the ultrasonic power and microwave power variables, as well as the two-way interaction of ultrasonic power and microwave power, had a significant effect on the amount of RS3 in different samples (p<0.05). The amount of RS3 in different treatments of rice starch varied from 31.65 to 64.29%. The SEM studies showed that the starch granules had polyhedral or irregular shapes with a size in the range of 2.2-9.8 µm and an amorphous structure was formed by increasing the power of the two devices and subsequently increasing the amount of RS3 production. The application of ultrasound/microwave treatment led to the creation of new peaks and changes in the intensity of the peaks in the XRD spectrum. Alveograph results of Reshteh Ashi samples showed a significant change in the indices, including maximum overpressure, average abscissa to rupture, swelling index, area under the curve, configuration ratio and elasticity index. The results of this research showed that the use of resistant rice starch at the level of 10% can improve the technological characteristics of Reshteh Ashi in terms of textural characteristics, and as a result, the enrichment of Reshteh Ashi at the level of 10% RS3 is recommended.