Reduced protein carbonylation of cube steak and catfish fillet using antioxidative coatings containing cheddar whey, casein hydrolyzate and oolong tea extract

Authors: MUKHERJEE, DIPALOKE - Mississippi State University; HAQUE, ZAHUR - 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: Mukherjee, D., Haque, Z. 2016. Reduced protein carbonylation of cube steak and catfish fillet using antioxidative coatings containing cheddar whey, casein hydrolyzate and oolong tea extract. Annals Food Science and Technology. 17(2):529-536.

Interpretive Summary: This study compared three whey based edible coatings in the protection against protein oxidation of catfish fillet and cubed beefsteak. Three coatings were prepared by adding casein hydrolysate (CH), Chinese oolong extract (OTE) or both into Cheddar whey base solution. After storage of coated samples at 40 C for 1, 3, 5, 7 days, the carbonyl content (CC) which is the indicator of the degree of protein oxidation was measured. The results showed the coating with both CH and OTE possessed the highest anti-oxidative effects and substantially reduced the protein oxidation compared with the control in both tested samples.

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.