Abstract
Instant rice porridge produced through cooking, drying and a series of other processes possesses inferior sensory quality which is related to the gelatinization and retrogradation of rice starch. The effects of different enzyme treatments including α-amylase, β-amylase and neutral protease and different drying methods including hot air drying, freeze drying and freeze-hot air drying on gelatinization and retrogradation of instant rice porridge were investigated in this work utilizing rapid viscosity analyzer (RVA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). As for enzyme treatments, rice porridge treated by α-amylase demonstrated the lowest viscosity value and the greatest porosity which suggested that α-amylase exceeded other two enzymes in maintaining gelatinization, inhibiting retrogradation and facilitating rehydration of instant rice porridge. For different drying methods, it was found that freeze drying was most advantageous to maintain gelatinization with the lowest viscosity and the greatest porosity. This study is especially helpful to gain initial insight into the development of instant rice porridge processing technology.
