Characterization of native lactic acid bacteria from traditionally fermented chhurpi of Sikkim Himalayan region for the production of chhurpi cheese with enhanced antioxidant effect

Abstract

Lactic acid bacteria (LAB) were isolated and characterized from chhurpi, a traditionally produced cheese product of Sikkim Himalaya. Enterococcus durans was the most dominant LAB making up 34% of the identified LAB, followed by Lactobacillus delbrueckii (25%). Chhurpi was produced using milk curdling LAB strains followed by simulated in vitro gastrointestinal digestion of chhurpi. Evaluation of protein hydrolysis and antioxidant activity was performed. Chhurpi produced using Lactobacillus delbrueckii WS4 had a relatively higher yield (10.4%), protein hydrolysis, and antioxidant activity as compared to other starter strains (P < 0.05). Gastrointestinal digestion of chhurpi increased the antioxidant activity, with the highest activity observed for gastrointestinal digests of chhurpi produced by using Lb. delbrueckii WS4. The EC50 for DPPH radical scavenging activity of chhurpi produced by using Lb. delbrueckii WS4 was observed to decrease significantly (from 239.16 to 48.87 mg sample/ml) after digestion with pepsin and pancreatin (P < 0.05). Protein hydrolysis and antioxidant activity in whey were comparable to that of chhurpi, indicating the potential of using the chhurpi whey to develop nutraceuticals. This is the first report on evaluating the antioxidant activity of chhurpi produced using defined LAB strains and the effect of gastrointestinal digestion on chhurpi functionality.