Enzyme membrane reactor in isolation of antioxidative peptides from oil industry waste: A comparison with non-peptidic antioxidants

Edible oil industries suffer from the problem of seed meal utilization, which is recognized as a byproduct of edible oil. Present work has investigated production of peptide antioxidants, from oil seed meals to meet the increasing crave for natural antioxidants in food and pharmaceutical industries. Metalloendopeptidase 'Protease A Amano 2G' (Aspergillus oryzae) was used to hydrolyze seed protein isolate in enzyme membrane reactor (EMR) and protein hydrolysate was sequentially fractionated by ultrafiltration to obtain potential peptide fraction. Degree of hydrolysis was varied within enzyme to substrate ratio 0.1-2 g/100 g and hydrolysis time 10-60 min to maximize peptide yield and antioxidant activity of peptides in vitro. Controlled hydrolysis with enzyme dose of 2 g/100 g, exhibited peptide yield of 4.60 +/- 0.08 mg/100 mg meal protein in membrane reactor (DH 30.7%) and 4.23 +/- 0.22 mg/100 mg meal protein in batch mode of hydrolysis (DH 29.3%). Antioxidant potential of peptide fractions were compared with commercial non-peptidic antioxidants and major findings confirm superior activity for protein fragments (IC50-0.062 mg/mL) as compared to protein isolate (IC50-0.038 mg/mL), with enhanced product stability by preventing oxidative deterioration. Results substantiate the prospect of EMR in obtaining peptides from edible oil industry waste, having comparable antioxidative potential with commercial non-peptidic antioxidants. (C) 2012 Elsevier Ltd. All rights reserved.