Significance of Growth Rate, Acceptability of Fermented Milk and Release of Peptides by Lactic Cultures

Abstract

Ten lactic cultures (S. thermophilus MD2, S. thermophilus MD8, Lc. lactis 009, L. fermentum AI2, L. fermentum AI3, L. fermentum 138, L. plantarum AD29, L. rhamnosus NS4, L. rhamnosus NS6 and E. feacalis ND3) isolated from vegetables and fermented foods were evaluated for their potential to ferment milk, produce good quality curd and ability to release peptides in fermented milk. It was found that S. thermophilus MD8, S. thermophilus MD2 and L. rhamnosus NS6 were found to exhibit maximum growth rate (1.15, 0.98 and 0.49 respectively) and acid production rate (4.65, 5.14 and 5.59 respectively) in skimmed milk compared to other LAB. The curd/fermented milk prepared with S. thermophilus MD2, S. thermophilus MD8 and L. rhamnosus NS6  showed that the maximum acceptability as reflected by highest scores for overall acceptability i.e., 7.19, 7.07 and 7.04 respectively. Therefore, these three isolates were further studied for ACE (angiotensin-1 converting enzyme) inhibitory activity by spectrophotometric method and peptides released in milk medium after fermentation by RP-HPLC (reverse phase high performance liquid chromatography). L. rhamnosus NS6 exhibited relatively higher ACE inhibitory activity as well as released maximum peptides during RP-HPLC analysis than other two isolates. This reflects better acceptability and their application in preparation of acceptable quality fermented milk products.

Keywords:  Fermentation, growth rate, lactic acid bacteria (LAB), milk, sensory score

Cite this Article

M.R. Kathiriya, J.B. Prajapati, S. Hati  et al. Significance of growth rate, acceptability of fermented Milk and release of peptides by lactic cultures. Research & Reviews: Journal of Dairy Science and Technology. 2016; 5(1): 31–40p.