Antioxidant activity of shelf stable herbal seasoning incorporated with pleurotus Sajor-Caju (Oyster mushroom) powder

Abstract

Pleurotus sajor-caju (oyster mushroom) has been consumed by people worldwide and they are known to produce different kinds of bioactive compounds. In this study, the methanolic extracts of herbal seasoning (HS) incorporated with Pleurotus sajor-caju (PSC) powder were evaluated for their antioxidant activity. A total of six different formulations with different levels of PSC powder at 0% (A), 20% (B), 40% (C), 60% (D), 80% (E) and 100% (F) to substitute coconut milk powder (CMP) were used in this study. The products were evaluated at the 0-month and 6-month of storage. HS (F) recorded the highest TPC (total polyphenol content) (1823.84±0.84 mg GAE/g), ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) (71%) and FRAP (Ferric Reducing Antioxidant Power) assays (60.52 mg AAE/g) at 0 month of the storage study. At the 6-month of storage study, the highest TPC, ABTS and FRAP assay were recorded in HS(F) (1539.23±0.61 mg GAE/g), (59%) and (27.51 mg AAE/g), respectively. HS(A), the control treatment recorded the lowest TPC, ABTS and FRAP assay at the 6-month of the storage study. The addition of PSC powder to replace CMP may influence the presence of bioactive compounds in HS. The reduction of antioxidant after 6 months of storage might be due to the instability of other antioxidant compounds such as carotenoids and phenols. In conclusion, after the 6-month of the storage study, this edible mushrooms still exert some antioxidative capacities thus potentially being expended as a natural antioxidant in thermally processed food products.