Influence of Lactobacillus plantarum WCFS1 on post-acidification, metabolite formation and survival of starter bacteria in set-yoghurt

• Published in: Food microbiology 2016-10, Vol.59, p.14-22
• Main Authors: Settachaimongkon, Sarn, van Valenberg, Hein J.F., Gazi, Inge, Nout, M.J. Robert, van Hooijdonk, Toon C.M., Zwietering, Marcel H., Smid, Eddy J.
• Format: Article
• Language: English
• Subjects: Bacteria; Dairy; Fermentation; Fermented milk; Food Microbiology; Hydrogen-Ion Concentration; Lactic acid bacteria; Lactobacillus delbrueckii; Lactobacillus delbrueckii - metabolism; Lactobacillus plantarum; Lactobacillus plantarum - drug effects; Lactobacillus plantarum - growth & development; Lactobacillus plantarum - metabolism; Metabolites; Metabolomics; Milk; Probiotics; Sodium Chloride - pharmacology; Starters; Stress response; Stress, Physiological; Survival; Yoghurt; Yogurt - analysis; Yogurt - microbiology
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2016.04.008

The objectives of this study were to evaluate the growth and survival of the model probiotic strain Lactobacillus plantarum WCFS1 in co-culture with traditional yoghurt starters and to investigate the impact of preculturing on their survival and metabolite formation in set-yoghurt. L. plantarum WCFS1 was precultured under sublethal stress conditions (combinations of elevated NaCl and low pH) in a batch fermentor before inoculation in milk. Adaptive responses of L. plantarum WCFS1 were evaluated by monitoring bacterial population dynamics, milk acidification and changes in volatile and non-volatile metabolite profiles of set-yoghurt. The results demonstrated that sublethal preculturing did not significantly affect survival of L. plantarum WCFS1. On the other hand, incorporation of sublethally precultured L. plantarum WCFS1 significantly impaired the survival of Lactobacillus delbrueckii subsp. bulgaricus which consequently reduced the post-acidification of yoghurt during refrigerated storage. A complementary metabolomics approach using headspace SPME-GC/MS and 1H NMR combined with multivariate statistical analysis revealed substantial impact of sublethally precultured L. plantarum WCFS1 on the metabolite profiles of set-yoghurt. This study provides insight in the technological implications of non-dairy model probiotic strain L. plantarum WCFS1, such as its good stability in fermented milk and the inhibitory effect on post-acidification. •The model probiotic Lactobacillus plantarum WCFS1 was co-cultivated in yoghurt.•LP-WCFS1 was precultured under elevated NaCl and low pH stress conditions.•Technological implication of LP-WCFS1 and its stress-adapted cells was evaluated.•Incorporation of stress-adapted LP-WCFS1 influenced post-acidification in yoghurt.•Incorporation of stress-adapted LP-WCFS1 influenced the metabolome of yoghurt.