Evaluation of Technological Attributes of Lactococcus lactis Cultures for Preparation of Dahi and Misti Dahi (Sweetened Dahi)

Abstract

Background: Dahi and Misti dahi are traditional Indian fermented milk products. The present study was aimed to evaluate the technological attributes of selected six Lactococcus lactis cultures namely NCDC 193, 125, 128, 94, 97 and 314 for preparation of Dahi and Misti dahi. Methods: Six Lactococcus lactis were collected and tested for acidification profile as well as growth rate was also determined in milk with (15%) and without sucrose. Their flavor producing ability, proteolytic ability by OPA method and antimicrobial activity against four spoilage causing microorganisms (Escherichia coli NCDC 134, Staphylococcus aureus NCDC 109, Micrococcus luteus NCDC 131 and Pseudomonas fluorescenes NCDC 316) were evaluated. Result: All the six cultures were able to grow and produce acidity in milk containing 15% sucrose and similar acidification profile as well as growth rate (K) were found in milk without sucrose. Cultures NCDC 193, 128 and 125 were found to produce flavoring compound (diacetyl). Proteolytic activity of the selected cultures ranged between 0.17 to 0.41 mg/mL of Leucine. Among six cultures three Lactococcus lactis cultures NCDC 314, 94 and 97 have shown zone of inhibition against all four test organisms.