RESUMEN
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.
RESUMEN
Proteolytic and/or lipolytic lactic acid bacteria (LAB) were isolated from visceral wastes of different fresh water fishes. LAB count was found to be highest in case of visceral wastes of Mrigal (5.88 log cfu/g) and lowest in that of tilapia (4.22 log cfu/g). Morphological, biochemical and molecular characterization of the selected LAB isolates were carried out. Two isolates FJ1 (E. faecalis NCIM5367) and LP3 (P. acidilactici NCIM5368) showed both proteolytic and lipolytic properties. All the six native isolates selected for characterization showed antagonistic properties against several human pathogens. All the native isolates were sensitive to antibiotics cephalothin and clindamycin; and, resistant to cotrimoxazole and vancomycin. Considering individually, P. acidilactici FM37, P. acidilactici MW2 and E. faecalis FD3 were sensitive to erythromycin. The two strains FJ1 (E. faecalis NCIM 5367) and LP3 (P. acidilactici NCIM 5368) that had both proteolytic and lipolytic properties have the potential for application in fermentative recovery of lipids and proteins from fish processing wastes.