Development of lotus seed-based vegan yogurt: fermentation optimization, quality evaluation and analysis of key bioactive alkaloids

Introduction Lotus seed is a nutritious and functional food material, yet its utilization in plant-based fermented products remains underdeveloped. This study aimed to develop a novel plant-based yogurt using lotus seeds as the primary raw material, and to systematically optimize the probiotic strain combination and fermentation process to improve product quality and functionality. Methods The optimal lactic acid bacteria strain combination and key fermentation parameters (temperature, time, glucose addition, and inoculum size) were determined through single-factor experiments and response surface methodology. Results The optimal strain combination was Lactobacillus delbrueckii subsp. bulgaricus, Lactiplantibacillus plantarum , and Streptococcus thermophilus at a ratio of 1:2:1. The optimized product, fermented at 38 °C for 7.5 h with 12.2% glucose and a 3.7% inoculum, exhibited high water-holding capacity (68.57%) and favorable sensory acceptance (80.9 points). The yogurt presented a uniform white color, smooth texture, and characteristic lotus seed aroma. Nutritional analysis showed significantly lower fat and calorie content, along with higher dietary fiber, compared to conventional dairy yogurt. Microstructural observations indicated that fermentation promoted the formation of a uniform and compact gel network, enhancing texture and stability. Notably, fermentation effectively preserved key bioactive alkaloids from lotus seeds, including neferine and nuciferine. Discussion This study successfully developed a plant-based yogurt from lotus seeds with desirable physicochemical, sensory, and nutritional properties. The optimized fermentation process also retained important bioactive compounds, offering a theoretical basis and practical guidance for the value-added utilization of lotus seeds and the development of functional plant-based fermented foods with potential health benefits.