COMPARATIVE STUDY OF ANTIOXIDANT ACTIVITIES, COSMECEUTICAL PROPERTIES AND PHENOLIC ACIDS COMPOSITION OF FERMENTED RICE BRAN AND COCONUT TESTA

Abstract

Malaysia produces large number of agro-industrial products annually including rice and coconut. Along with the production, rice bran and coconut testa are also abundantly generated as by-products. Solid state fermentation (SSF) is a simple biotechnological technique that has been employed for production of bioactive compounds. The use of SSF on agro-industrial by-products is economically viable and helps to reduce the environmental impact of the by-products disposal. In this present study, rice bran (RB), coconut testa (CT) and a combination of rice bran and coconut testa (RBCT) were fermented with single culture of Aspergillus oryzae and Rhizopus oligosporus. The effect of fungal SSF on the cosmeceutical-related activities and phenolic acid content of the fermented RB, CT and RBCT extracts was determined. The results showed that total phenolic content (TPC) as well as antioxidant activity measured using the ferric reducing ability of plasma (FRAP) of all substrates increased upon fermentation. Contrary to the TPC and FRAP assays results, the radical-scavenging activity of the fermented samples as measured by using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, were varied. Tyrosinase inhibition activity was found to be the highest in the extract of RB fermented with A. oryzae (56.18%) compared to other extracts. The same extract showed the highest elastase inhibition activity with a value of 60.27%. High performance liquid chromatography (HPLC) analyses showed ferulic, sinapic, caffeic and protocatechuic acids were significantly increased in RB fermented with A. oryzae. The results of this study suggest that fungal solid-state fermentation of rice bran may have the potential to be exploited in producing different types of active metabolites that are useful for cosmeceutical industries