Casein hydrolysate augments antimicrobial and antioxidative efficacy of cheddar whey based edible coating of retail-cut beefsteak

Authors: HAQUE, ZAHUR - Mississippi State University; ZHANG, YAN - Mississippi State University; MUKHERJEE, DIPALOKE - Mississippi State University

Submitted to: Annals Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2016
Publication Date: 12/16/2016
Citation: Haque, Z., Zhang, Y., Mukherjee, D. 2016. Casein hydrolysate augments antimicrobial and antioxidative efficacy of cheddar whey based edible coating of retail-cut beefsteak. Annals Food Science and Technology. 17(2):468-477.

Interpretive Summary: Hydrolysis of casein with chymotrypsin results in the formation of polypeptides (casein hydrolysate, CH) with hydrophobic aromatic amino acid on one end of the chain due to enzymatic specificity. The resultant CH is putatively to be anti-oxidative due to its chemical structure. The current study investigated the antibacterial effect of CH in beef steak and its antioxidant potential as a constituent of Cheddar whey based edible coating mix. The resulted demonstrated that even at lowest concentration range (0.15-0.2%), CH reduced coliform number by 100,000 times when applied to beef steak. In another two antioxidant assays, CH showed strong capacity. The current study showed the potential for the beneficial use of CH in muscle foods during retail-cut processing and display.

Technical Abstract: Hydrolysis of casein using chymotrypsin results in the formation of polypeptides (casein hydrolyzate, CH) with a hydrophobic aromatic amino acid on one end of the chain because the enzyme selectively cleaves the adjacent peptide-bond. Due to resonance of the aromatic micro-domain, thiols become redox-sensitive and actively participate in electron transfer. These types of amphipathic peptides also tend to be membrane-lytic. The two prong approach of this investigation was to, (1) assess antibacterial effect of the CH in beef steak, and (2), to determine its antioxidative efficacy as a constituent of Cheddar whey based edible coating mix. Coliform growth, using shoulder-cut beefsteaks as model, showed a significant (P<0.05) five log reduction to log CFU<1 even at its lowest concentration range (0.15-0.2 %) (w/v). Radical quenching ability reflected by increasedn time required for maximal alkoxyl- and peroxyl-radical accumulation in reaction mixtures without and with CH, by in vitro pyrolysis of 2, 2’-Azo-bis (2-amidinopropane), was six minutes even at its lowest trace concentration (0.1 %, w/v) indicating dramatic enhancement of long-term antioxidative persistence. At the same concentration, CH augmented 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging efficacy of the film by 28%. The study showed the potential for beneficial use of CH in dramatically enhancing efficacy of WPC based edible coatings to reduce microbial and oxidative degradation of muscle foods during retail-cut processing and display.