In-vitro antioxidant and antibacterial properties of fermentatively and enzymatically prepared chicken liver protein hydrolysates

Protein hydrolysates were prepared from chicken liver using fermentation and enzymatic hydrolysis. The lactic acid bacteria Pediococcus acidilactici NCIM5368 was employed in the fermentation process and a commercial protease (Alcalase® 2.5) was used in enzymatic hydrolysis. Chicken liver hydrolysates prepared by fermentation (FCLH) and enzymatic hydrolysis (ECLH) revealed appreciable amounts of protein [55.85 and 61.34 %; on dry weight basis, respectively]. Fermentation and enzymatic hydrolysis resulted in 14.3 and 26.12 % of degree of hydrolysis. Total antioxidant activity, reducing power, scavenging of superoxide, 2- diphenyl-1-picrylhydrazyl (DPPH) and 2, 2-azino-bis-3-ethyl-benzthiazoline-6-sulphonic acid (ABTS) radicals were determined for both FCLH & ECLH. FCLH & ECLH showed total antioxidant activity of 0.99 and 1.13 μg AAE mg−1 proteins, respectively; while, they scavenged 96.14 and 92.76 % of DPPH radicals respectively. FCLH showed higher ABTS radical scavenging activity (32.16 %) than ECLH (19.29 %). Superoxide anion scavenging activity of FCLH & ECLH were found to be 95.02 & 88.94 %, respectively. Residues obtained after both treatments also exhibited antioxidant activities. FCLH reported highest antagonistic activity against Listeria monocytogenes (30 mm); while, ECLH showed antibacterial activity only against Micrococcus luteus (12 mm). Both hydrolysates have the potential to be a protein rich ingredient for use in formulated foods and possible help in reduction of oxidative stress.