Effect of Lactobacillus rhamnosus on Physicochemical Properties of Fermented Plant-Based Raw Materials

Texture and flavor are currently the main challenges in the development of plant-based dairy alternatives. To overcome them, the potential of microorganisms for fermentation of plant-based raw materials is generating great interest in the food industry. This study examines the effect of Lactobacillus rhamnosus, LGG^® (LGG^® is a trademark of Chr. Hansen A/S) on the physicochemical properties of fermented soy, oat, and coconut. LGG^® was combined with different lactic acid bacteria (LAB) strains and Bifidobacterium, BB-12^® (BB-12^® is a trademark of Chr. Hansen A/S). Acidification, titratable acidity, and growth of LGG^® and BB-12^® were evaluated. Oscillation and flow tests were performed to analyze the rheological properties of fermented samples. Acids, carbohydrates, and volatile organic compounds in fermented samples were identified, and a sensory evaluation with a trained panel was conducted. LGG^® reduced fermentation time in all three bases. LGG^® and BB-12^® grew in all fermented raw materials above 10⁷ CFU/g. LGG^® had no significant effect on rheological behavior of the samples. Acetoin levels increased and acetaldehyde content decreased in the presence of LGG^® in all three bases. Diacetyl levels increased in fermented oat and coconut samples when LGG^® was combined with YOFLEX^® YF-L01 and NU-TRISH^® BY-01 (YOFLEX^® and NU-TRISH^® are trademarks of Chr. Hansen A/S). In all fermented oat samples, LGG^® significantly enhanced fermented flavor notes, such as sourness, lemon, and fruity taste, which in turn led to reduced perception of the attributes related to the base. In fermented coconut samples, gel firmness perception was significantly improved in the presence of LGG^®. These findings suggest supplementation of LAB cultures with LGG^® to improve fermentation time and sensory perception of fermented plant-based products.