Tailoring the physico-chemical properties and VOCs of pea-based fermented beverages through Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus fermentation

This study aims at investigating the fermentative performances of Lactobacillus delbrueckii subsp. bulgaricus (Ldb), Streptococcus thermophilus (St) when used individually or in a blend on pea emulsion-based beverages. Microbial growth, physico-chemical properties (rheology, water molecular mobility, colour) and the volatile profile were investigated during or after fermentation guided by two selected strain (St 5149, Ldb 2214) and their blend. The results showed that strains St 5149 and the blend were able to grow in the pea protein emulsion beverage more quickly and with a shorter Lag phase (0.29-0.58 h) and to promote a faster gelation kinetic than Ldb 2214, as showed by impedometric and rheological analyses during fermentation. Water molecular mobility of the fermented systems measured by 1H NMR was also impacted by the different LAB strains, with a reduction in the amount of unbound water for sample fermented with St 5149. These differences, however, did not influence the colour parameters of the fermented beverage which had L* between 12.16 and 13.56, a* between 15.15 and 15.92, b* between 21.09 and 22.87. Notably, the aromatic profile of the fermented pea beverages suggested that selected LAB strains, particularly when used in a blend, effectively reduced the off-flavor notes associated with pea protein isolates. The results show that the selected LAB strains are able to positively impact the physicochemical properties of pea fermented beverages and will pose the fundamental knowledge for the development of innovative, sustainable products alternative to both dairy and soy-based fermented products.