Growth and viability of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in traditional yoghurt enriched by honey and whey protein concentrate

Document Type: Full paper (Original article)

Authors

1 Ph.D. Student in Biology, Department of Food Chemistry and Microbiology, School of Applied Medical Sciences Prijedor, Republic of Srpska, Bosnia and Herzegovina

2 Department of Food Chemistry and Microbiology, School of Applied Medical Sciences Prijedor, Republic of Srpska, Bosnia and Herzegovina

3 MP Lab, Belgrade, Serbia

4 Department of Food Preservation Technology, Faculty of Technology, University of Novi Sad, Novi Sad, Serbia

5 Ph.D. Student in Biology, Department of Food Preservation Technology, Faculty of Technology, University of Novi Sad, Novi Sad, Serbia

Abstract

The ability of whey protein concentrate (WPC) (1% w/v) and/or honey (2% and 4% w⁄v) to improve lactic acid bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) growth and viability in yoghurt during a 21 day period of storage was investigated. Another focus of this study was to examine fermentation kinetics and post-acidification rates through pH and lactic acid content measurements over the 21 day period. The addition of WPC and acacia honey accelerated fermentation and improved lactic acid bacteria (LAB) growth over the 21 days, but honey proportion did not significantly affect the viability of LAB.
Moreover, adding honey and WPC did not support the overproduction of lactic acid, which positively influenced yoghurt stability during the 21 day storage period.

Keywords