Previously, we have shown that seven different snail proteins for antimicrobial activity, among them, a protein extract from terrestrial snail Cryptozona bistrialis inhibited the growth of pathogenic bacteria and fungi. In the present study, we hydrolysed C. bistrialis protein extract to identify peptides exhibiting the antimicrobial and antioxidant activities. The tissues of the land snail C. bistrialis was homogenized and digested with three different enzymes: papain, trypsin and pepsin. During enzyme hydrolysis the degree of hydrolysis and percentage of peptide bond breakage was calculated. Among the protein hydrolysates by the three enzymes, the papain-digested hydrolysate of C. bistrialis showed highest degree of hydrolysis and significant antimicrobial activity. Based on these results papain digestion was selected for further studies. The papain-digested protein hydrolysate showed maximum 73 % DPPH radical scavenging and 70 % ABTS radical scavenging activities. Ferric reducing antioxidant power was increased when increasing the concentration of the protein hydrolysate of C. bistrialis.
Key words: Cryptozona bistrialis, Antimicrobial activity, antioxidant activity, enzyme digestion, protein hydrolysate.
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