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The aim of this study was to determine the effect of enzymatic hydrolysis using different proteases (Alcalase® and papain) and hydrolysis period on antioxidative activities and amino acid profiles of hydrolysed chia peptides. The experiment has been carried out using 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 (pH 3.5, 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 protein content of 17.22% and was selected to further hydrolysed using Alcalase® and papain enzyme at different hydrolysis time. The degree of hydrolysis (DH), protein solubility and peptide content of the chia protein hydrolysates (CH) were observed. Alcalase®-CH and Papain-CH demonstrated the highest DH at 60 mins of hydrolysis with the value of 47.09% and 44.29%, respectively. The protein solubility and peptide content were directly proportional to the DH. The Alcalase®-CH hydrolysed at 60 mins exhibited the highest antioxidant activities as measured by DPPH, ABTS and FRAP assays with values of 35.46µM 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 and Papain-CH (37.25%,). The highest aromatic amino acid content also recorded by Alcalase®-CH (20.10%), whereas Papain-CH with the value of 15.54%. However, both CH exhibited higher hydrophilic and aromatic amino acid compared to DCF and CI. This result has proved that the enzymatic hydrolysis of CH using Alcalase® and papain improved the nutritional and antioxidant capabilities, thus potentially represent a naturally occurring antioxidant ingredient in the production of functional food and nutraceutical appliance with significant health benefits.

A natural isolate, Bacillus licheniformis KIBGE-IB3, was subjected to mutational analysis for the enhanced production of glucoamylase. Randomly generated mutants were initially screened for enzyme production and after secondary screening B. licheniformis KIBGE-IB3M67 demonstrated maximum glucoamylase production with improved starch saccharifying capability. Enzyme activity from KIBGE-IB3M67 reached up to 25 kU/mg by strain improvement, which was nearly twofold increase in enzyme production as compared to the parent strain. SEM revealed that raw potato starch is more profoundly hydrolyzed when treated with mutant glucoamylase. Successful mutation also reduced the fermentation time from 48 to 24 h for glucoamylase production, optimum fermentation pH and temperature slightly shifted from 7.0 (wild) to 7.5 (mutant), from 30 to 508C (wild), and from 20 to 558C (mutant), respectively. Reduction in fermentation time and enhanced starch saccharification ability makes this mutant (KIBGE-IB3M67) an attractive candidate for the production of glucoamylase at commercial level.

This study aims to determine the effects of various alkaline pHs on the nutritional and functional properties of protein isolated from defatted chia flour (DCF). The DCF isolated using alkali extraction method at pH 8.5, 10.0, and 12.0 were coded as CPI-8.5, CPI-10.0, and CPI-12.0, respectively. The highest extraction yield and protein recovery yield was demonstrated by CPI-12.0 (19.10 and 59.63%, respectively), with a total protein content of 74.53%, and glutelin showed the highest portion (79.95%). The CPI-12.0 also demonstrated the most elevated essential (36.87%), hydrophobic (33.81%), and aromatic (15.54%) amino acid content among other samples. The DCF exhibited the highest water (23.90 gg−1) and oil (8.23 gg−1) absorption capacity, whereas the CPI-8.5 showed the highest protein solubility (72.31%) at pH 11. DCF demonstrated the highest emulsifying capacity at pH 11 (82.13%), but the highest stability was shown at pH 5 (82.05%). Furthermore, CPI-12.0 at pH 11 shows the highest foaming capacity (83.16%) and stability (83.10%). Despite that, the CPI-10.0 manifested the highest antioxidant capacity (DPPH: 42.48%; ABTS: 66.23%; FRAP: 0.19), as well as ACE-I (35.67%). Overall, the extraction pH had significant effects in producing chia protein isolates (CPI) with improved nutritional and functional qualities.