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Tyrosinase is the rate-limiting enzyme controlling the production of melanin, and tyrosinase inhibitors can regulate the overproduction of melanin by inhibiting tyrosinase activity, which is an effective method to treat...

In the present study, antioxidant activities and functional properties of cowhide collagen antioxidant peptides (CCAPs) with different molecular weight (MW) were investigated. The optimum preparation conditions of CCAPs were hydrolysis time of 1.53 hr, temperature of 54.9 °C, pH 7.38, and neutral enzyme to trypsin ratio of 0.048 g: 0.016 g according to single factor test and response surface methodology (RSM). Three fractions (CCAP‐I, CCAP‐II, and CCAP‐III) were obtained by ultrafiltration and lyophilization. Antioxidant activities revealed that CCAP‐III had high reducing power activity (0.323 ± 0.035) and scavenging effect on 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radicals (64.30 ± 5.99%), 2,2‐azino‐bis‐(3‐ethylbenzothiazoline)‐6‐sulfonic acid (ABTS) radicals (75.25 ± 3.14%), and hydroxyl radicals (68.26 ± 6.74%) compared to the other fractions. In addition, LC‐MS/MS analysis showed that Ala‐Gly‐Glu‐Arg, Gly‐Ile‐Ala‐Gly‐Glu‐Arg, Gly‐Pro‐Ala‐Gly‐Pro‐Ala‐Gly‐Pro‐Arg, Gly‐Val‐Val‐Gly‐Pro‐Glu‐Gly‐Ala‐Arg and Gly‐Phe‐Ser‐Gly‐Leu‐Asp‐Gly‐Ala‐Lys were the major peptides of CCAP‐III. CCAP‐III showed good hygroscopicity (HYG), water holding capacity (WHC), and oil holding capacity (OHC) when compared with CCAP‐I and CCAP‐II. However, CCAP‐II has great emulsifying properties, and CCAP‐I has excellent foaming properties. Therefore, CCAPs can be used as a promising source of functional peptides with antioxidant properties. Practical Application This study demonstrated the peptides of cowhide collagen has superior antioxidant and functional properties. This study provided a scientific basis for the preparation of antioxidant peptides from cowhide collagen.

Tea Polyphenols (TP) has received much attention for their excellent antioxidant and antibacterial activities. Some additives (such as sodium alginate and sodium pyrophosphate) have good hydrophobicity which have influence on the mechanical properties of food. The effect of TP on the antibacterial activity of collagen casing was investigated, the effect of addition of TP, sodium pyrophosphate and sodium alginate on mechanical properties including tensile force, tensile strength and elongation at break were also studied. Results from the single factor experiments demonstrated that TP showed strong antibacterial activities against Escherichia coli, Staphylococcus aureus and Salmonella according to the Minimum Inhibitory Concentration (MIC) and the inhibition zone method. Moreover, the mechanical properties of collagen casings were obviously influenced by the addition of TP and two food additives including sodium alginate and sodium pyrophosphate. This work would be useful for application of collagen casings with TP in food package to extend shelf-life of sausage during processing, transportation and storage.

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