Evaluation of biological activities and stability of thai organic riceberry broken rice extracts for the anti-aging cosmetology

Abstract

Objective: Thai organic Riceberry rice, deep purple rice, has been known to have the wide variety of nutritional benefits. However, broken rice which accounted for 20-30% of the yield, was sold at a very low price. This study aimed to optimize the extracting procedure and evaluate the biological activities of Thai organic Riceberry broken rice extracts for anti-aging cosmetology as well as to investigate the stability profile of the extract. Methods: The extracting procedure, of which deionized water served as a solvent, was varied by spray-drying temperature (150 and 170°C) and pH value (2.0 and 5.5). Antioxidant effects of the obtained extracts were evaluated through 2,2-Diphenyl-1-picrylhydrazyl, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid, linoleic acid peroxidation, and ferric reducing antioxidant power assays. Furthermore, the anti-tyrosinase effect was studied through the L-tyrosine pathway. The total phenolic content (TPC) of each extract was evaluated by Folin–ciocalteu’s method. The extract, presenting the greatest activity, was then selected for investigating its stability under various storage conditions. Results: Four Riceberry rice extracts presented noticeable antioxidant and anti-tyrosinase effect. The extract, derived from a spray-drying temperature of 150°C and a pH value of 2.0, exhibited the highest effects with the highest TPC (27.08 ± 0.67 mg Gallic acid/g extract). This extract also presented a good stability profile. However, this extract should be stored in a high-temperature condition (45°C) to prevent degradation. Conclusion: The aqueous extracts of Thai organic Riceberry broken rice could be a promising agent for further developing into anti-aging cosmetology.