Characterization of free and insoluble-bound phenolics of chia (Salvia hispanica L.) seeds

The content, antioxidant activity and composition of free and bound phenolics from chia seeds were investigated. The free phenolics were extracted by using ethanol and methanol of analytical purity, 70% v/v ethanol and by 70% v/v methanol. The bound phenolics were extracted from seeds after alkaline hydrolysis was done. The phenolics content obtained by aqueous-alcoholic solutions was higher than the content obtained by using the pure alcoholic solution (for 20.8% by 70% methanol and 41.2% by 70% ethanol). The content of bound phenolics was 932 μg g−1. Among the identified phenolic compounds the apigenin 4'-O-glucoside was the most abundant, and among the acids, a rosmarinic was the most abundant in free phenolic extract and caffeic acid in bound. The correlation coefficients indicated the DPPH method and reducing power were more suitable for assessing the antioxidant activity than the FRAP method.