Evaluation of Antioxidant Capacity in Combined Green Tea (Camellia sinensis), Rosemary (Rosemarinus officinalis), and Mixed-tocopherol Extracts and its Application in Refined, Bleached, Deodorized (RBD) Palm Olein

Abstract

Utilizing natural antioxidants is a crucial method for controlling lipid oxidation in food, preventing deterioration and rancidity. Common natural antioxidants include green tea, rosemary, and tocopherol. Polyphenols in green tea and rosemary scavenge oxidation, inhibit free radical formation, and prevent lipid peroxidation. The phenolic compounds in tocopherol also contribute to antioxidant activity by donating phenolic hydrogen. Moreover, the combination of antioxidants were found to have interaction influenced by various bioactive compounds and results in novel physiological properties. This project aims to evaluate the effects of different ratios of antioxidant combinations (green tea-rosemary, green tea-mixed tocopherol, and rosemary-mixed-tocopherol) using DPPH (2,2-Diphenyl-1-picrylhydrazyl) and ABTS (2,2’-Azino-bis(ethylbenzothiazoline-6-sulphonic acid) diammonium salt) method. Results indicated that various ratios of combined antioxidant showing synergistic interactions (FIC50I<1), due to enhanced antioxidant mechanisms. The optimal ratios were applied to refined, bleached, and deodorized (RBD) palm olein, resulting in delayed lipid oxidation as evidenced by lower peroxide value (PV) and malondialdehyde (MDA) levels. From the result, it can be concluded that the utilization of natural combined antioxidants, particularly green tea-rosemary (6:4) and green tea-mixed-tocopherol (8:2) in RBD palm olein resulted in lower PV and TBARS value, especially in the initial cycles of frying.