The effect of enzymatic hydrolysis on the antioxidant activities and amino acid profiles of defatted chia (Salvia hispanica L.) flour

The aim of this study was to determine the effect of enzymatic hydrolysis using differentproteases (Alcalase® and papain) and hydrolysis period on antioxidative activities andamino acid profiles of hydrolysed chia peptides. The experiment has been carried outusing a completely randomized block design. The protein from defatted chia flour (DCF)was first isolated using different extraction pH (pH 10; 11; 12) and precipitation pH (pH3.5, 4.0 and 4.5) to determine the highest protein isolated (CI) yield. The chia isolate (CI)extracted using the combination treatment (pH 12, 3.5) demonstrated the highest proteincontent of 17.22% and was selected to further hydrolysed using Alcalase® and papainenzyme at different hydrolysis time. The degree of hydrolysis (DH), protein solubility andpeptide content of the chia protein hydrolysates (CH) were observed. Alcalase®-CH andPapain-CH demonstrated the highest DH at 60 mins of hydrolysis with the value of47.09% and 44.29%, respectively. The protein solubility and peptide content were directlyproportional to the DH. The Alcalase®-CH hydrolysed at 60 mins exhibited the highestantioxidant activities as measured by DPPH, ABTS and FRAP assays with values of35.46µM AAE, 34.45µM TE and 23.11 µM FeSO4.7H2O E, respectively. The Alcalase®-CH demonstrated higher (p<0.05) hydrophobic amino acid (42.51%) compared to andPapain-CH (37.25%,). The highest aromatic amino acid content also recorded byAlcalase®-CH (20.10%), whereas Papain-CH with the value of 15.54%. However, bothCH exhibited higher hydrophilic and aromatic amino acid compared to DCF and CI. Thisresult has proved that the enzymatic hydrolysis of CH using Alcalase® and papainimproved the nutritional and antioxidant capabilities, thus potentially represent a naturallyoccurring antioxidant ingredient in the production of functional food and nutraceuticalappliance with significant health benefits.