Quality Evaluation of Ready-to-Use Various Brown Rice (Oryza sativa) Powder Using Extrusion Process

Extrusion is a method for preparing ready-to-use rice powders that can help reduce cooking time. This study aimed to investigate the effects of extrusion on the physicochemical properties, antioxidant, and anti-calcium oxalate crystal formation activities of rice powder from eight brown rice varieties. The results showed that all eight rice samples had moisture contents of 6.55-7.32% and aw values of 0.43-0.49. Glutinous rice has a higher water absorption index and swelling power than non-glutinous rice. The analysis of the aroma values using PCA and k-means revealed that the samples could be divided into two major groups based on their rice aroma, group 1 (RD43, Hom Mali 105, and Hom Mali Daeng) and group 2 (Khiaw Ngoo, Riceberry, Luem Pua, RD6, and Kum Lanna). RD43, Hom Mali 105, and Hom Mali Daeng had high peak viscosities (102-126 cP) and high breakdown values (51-83 cP), indicating high swelling. Riceberry had low peak viscosity values (27 cP) but high setback viscosity values (26 cP), indicating a strong tendency to retrogradation. In terms of bioactivity, Colored rice varieties contain high levels of total monomeric anthocyanins and phenolic compounds and exhibit strong antioxidant activity. Colored rice and colored glutinous rice exhibited a high percentage inhibition of calcium oxalate crystal formation (40.03-58.71%). This study highlights the importance of extrusion processing methods in preserving the nutritional benefits of different brown rice powders, which can be used in the food industry to enhance the nutritional value of rice products.