Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 1st International Congress on Bioactive Compounds and 2nd International Workshop on Bioactive Compounds - Vol. 1 - 2018

Phenolic antioxidants are well recognized for their potential in counteracting several chronic ailments related to oxidative stress such as cardiovascular diseases and certain types of cancer. Like other plant foods, legumes are rich sources of phenolic compounds. Furthermore, chickpeas have a high potential to become more popular among the general population, but the literature to support their benefits to health are still scarce. Therefore, as a first-level screening, a simplex-centroid mixture design with three solvents (x1=water; x2=acetone and x3=methanol), binary and ternary mixtures as well as their aleatory combination was applied to investigate the recovery of soluble phenolics from chickpea. A surface response and contour plot of the quadratic model was generated. Total phenolic contents (TPC) was the independent variable. The equation representing model (74.12x1+29.71x2+21.01x3-95.56x1x2-62.52x1x3) indicates no interaction between acetone and methanol (p>0.05). The coefficient of determination (R2 = 0.9833) obtained by analysis of variance (ANOVA) indicate that 98% of data fitted the model. F calculated values (63.3) were higher than that of F tabulated (3.52), hence the models can be used to predict TPC. The extracts obtained during optimization showed TPC ranging from 18.7 to 74.3 mg gallic acid equivalents/100 g. Extracts obtained with aqueous extraction showed higher TPC but did not render extracts with higher antiradical activity towards ABTS radical cation (352.6 µmol trolox equivalents/100 g). In contrast, binary or ternary mixtures of water with organic solvents (acetone and/or methanol) showed up to 93% higher antioxidant potential. Extracts obtained upon water/methanol (1:1, v/v) extraction presented the greatest antiradical activity (680.8 µmol trolox equivalents/100 g). Non-phenolic compounds (e.g. protein and sugar components) may react with Folin-Ciocalteu reagent, which is used to estimate the TPC. Furthermore, phenolics from the crude chickpea extracts are mainly glycosylated, thus having higher affinity for polar solvents. In addition, structural differences play an importante role in the bioactivity food phenolics and, in general, aglycones show higher antiradical activity than their respective conjugates. Therefore, considering the results of this contribution, TPC estimation may not be the best index to screen the ideal condition to recover phenolic antioxidants, especially for feedstocks with high protein and sugar components.