Modulation of Antioxidant Capacity, Nutritional Composition, Probiotic Viability After Digestion and Sensory Attributes of Plant-Based Beverages Through Lactic Acid Fermentation

Fermented plant-based beverages are renowned due to their health benefits and sustainability. This study focuses on developing fermented local beverages from rice, carob, and tiger nuts. The fermentation process with four different commercial starters of lactic acid bacteria was optimized based on pH drop and colony counts at 37 °C and the supplementation with 7.5-15 g glucose/100 mL. Analyses of antioxidant capacity, phytochemical profile, proximate composition and sensory attributes were conducted, along with studies on the gastrointestinal survival of probiotics. Total polyphenols levels and antioxidant capacity followed the order: carob > tiger nut > rice (159.8-218.9 > 34.1-127.9 > 7.2-17.5 mg GAE/L for total polyphenols; 4461.9-15,111.6 > 2916.8-7897.3 > 1845.7-6103.5 µM Trolox/L for ORAC; and 2057.7-4235.3 > 318.9-876.7 > n.d.-239.7 µM Trolox/L for TEAC, respectively). The VEGE061 consortium showed the best results for the majority of parameters analyzed, influencing fat content and fatty acid profiles and increasing monounsaturated fatty acids in tiger nuts while promoting saturated fatty acids in rice beverages. Simulated in vitro digestion significantly reduced probiotic content in tiger nuts, carob, and, to a lesser extent, rice beverages. The beverages showed good sensory attributes, with tiger nut developing lactic and floral notes, carob achieving a balanced aroma profile with VEGE061, and rice displaying pleasant sensory qualities with VEGE033 and VEGE061 consortia. Further research is needed to explore optimal conditions for scaling up the process and strategies to improve probiotic delivery, aiming to increase post-digestion survival. This approach could promote the development of healthy and sustainable food alternatives.