Effect of the Ratio of Amylose to Amylopectin in Brown Rice Compound Powder on the Quality and Structure of Extruded Instant Porridge

Brown rice is a nutritious whole grain food,but poor palatability,cooking quality and digestibility prevent it from becoming a mainstream table food. In order to improve its edible quality,the raw material characteristics of brown rice composite powder with different amylose to amylopectin ratios(0.176,0.196,0.216,0.236,0.256,0.276)and their effects on gelatinization,rehydration quality,texture and structure of extruded instant porridge were analyzed,the optimum amylose to amylopectin ratio for making brown rice extruded instant porridge raw material composite powder was explored in this paper. The results showed that with the increase of amylose to amylopectin ratio,the gelatinization temperature and peak temperature of brown rice compound powder increased,and the smoothness and tightness of cross-section of extruded instant porridge rice grain increased. When the amylose to amylopectin ratio was 0.256,the cross-section structure of the extruded instant porridge rice grain was the most uniform and compact,and the rehydration time reached 12.6 min. The loss rate of the solid content of the rice soup and the radial expansion rate were the smallest(0.153 g,2.282%). The hardness,gumminess and chewiness were significantly higher than the starch straight/branched ratio of 0.276,reached 3323.85 g,1242.76 g and 744.73 g. From this point of view,the amylose to amylopectin ratio of 0.256 in the brown rice compound powder was a preferred ratio for making the extruded instant porridge.