3.3.1. Total phenolic content
Phenolics are major functional compounds in natural plants due to their redox properties, which perform important functions by absorbing and neutralizing free radicals, quenching singlet and triplet oxygen as well as by decomposing peroxides (Pietta, 2000). Total phenolic content of four TK groups increased rapidly after 1 week and then slowly until 16 weeks (Fig. 3a) Throughout the fermentation period, 1:1 TK and 1:1 TK-L showed higher total phenolic content than 1:0.5 TK and 1:0.5 TK-L. In comparison of TK with TK-L, TK-L showed higher phenolic content than TK.