Trametes versicolor mycelium fermenting whole kidney beans into tempeh-like product

This research explored the feasibility of using Trametes versicolor mycelium as a culture for fermenting kidney beans into tempeh-like products within 5 days, with citric acid (0, 3, and 6%, w/w; dry bean basis) applied as an abiotic stressor to enhance bioactive compound synthesis. The results showed that T. versicolor effectively colonized the bean surfaces, forming mycelial networks that bind the beans into semi-solid blocks. The fermented samples exhibited comparable springiness (0.44-0.64), cohesiveness (0.24-0.31), and resilience (0.13-0.17) values as conventional tempeh samples fermented with Rhizopus oligosporus. Notably, the total terpenoid content on day 5 increased to 78.8 and 73.1 mg linalool equivalent/g dry matter in samples fermented with 6 and 3% citric acid, respectively, significantly higher than the sample fermented without citric acid (54.6 mg/g). These results demonstrate that citric acid-induced abiotic stress enhanced the terpenoid accumulation by up to 44%. This proof-of-concept study suggested that T. versicolor mycelium could ferment kidney beans into tempeh-like products with acceptable visual and textural properties, promising for developing innovative plant-based fermented whole foods.