This study provides an overview of the factors that influence the effect of fermentation on the antioxidant
activity and the mechanisms that augment antioxidative activities in fermented plant-based foods. The
ability of fermentation to improve antioxidant activity is primarily due to an increase in the amount of
phenolic compounds and flavonoids during fermentation, which is the result of a microbial hydrolysis
reaction. Moreover, fermentation induces the structural breakdown of plant cell walls, leading to the liberation
or synthesis of various antioxidant compounds. These antioxidant compounds can act as free radical
terminators, metal chelators, singlet oxygen quenchers, or hydrogen donors to radicals. The
production of protease, a-amylase and some other enzymes can be influenced by fermentation that
may have metal ion chelation activity. Because the mechanisms that affect antioxidant activity during
fermentation are extremely varied, further investigation is needed to establish the precise mechanisms
for these processes.