Effects of 2′-fucosyllactose on the viability of starter cultures and Bifidobacterium strains of human origin in yogurt during refrigerated storage

Abstract: 2′-Fucosyllactose (2′-FL) is postulated to provide health benefits and promote the growth of probiotics. This work was undertaken to study the effects of 2′-FL on the viability of starter cultures and Bifidobacterium strains of human origin in yogurt during refrigerated storage. Yogurts were produced containing 2′-FL (0 or 2 g/L) and Bifidobacterium strains of human origin (Bifidobacterium longum subsp. longum BB536 or Bifidobacterium longum subsp. infantis ATCC 15697) at a concentration of at least 10⁹ CFU/mL. All yogurts were stored at 4°C for 5 weeks. Results showed that 2′-FL was stable in yogurts for at least 5 weeks of cold storage, and the addition of 2′-FL did not significantly alter yogurt fermentation parameters, associated metabolites, and the viability of mixed yogurt starter cultures and Bifidobacterium strains (p > 0.05). The addition of bifidobacteria had a negative impact (p < 0.05) on the survival rate of starter cultures, Streptococcus thermophilus and Lactobacillus delbureckii subsp. bulgaricus. Meanwhile, it is difficult to maintain a high survival rate of bifidobacteria in final yogurt products, and the addition of 2′-FL could not enhance the viability of bifidobacteria. B. longum BB536 survived at a level higher than 10⁶ CFU/g for 28 days, while B. infantis ATCC15697 maintained this level for only 7 days. In summary, this study has shown the impact of 2′-FL and bifidobacterial species on yogurt properties, and results suggest that it is promising to use 2′-FL in yogurt products as a prebiotic. Practical Application: Yogurt is known for its beneficial effects on human health and nutrition. This study reported the production of symbiotic yogurt containing bifidobacteria and 2′-fucosyllactose (2′-FL) as a functional food for specified health uses. The viability of yogurt starter cultures and probiotic bifidobacterial strains was analyzed in this study. Moreover, this research demonstrated that 2′-FL could be added to yogurt without affecting the characteristics of yogurt significantly.