Fermentation with a Multi-Strain to Enhance the Flavor of Hongjun Tofu, a Chinese Fermented Okara Food

Multi-strain fermentation has a better effect on the flavor of fermented foods than single strain. Meanwhile, the traditional HongJun tofu was fermented with a single fungal strain, Neurospora crassa, giving it a single flavor — mushroomy, and a bland taste with only a slight aftertaste of sweetness. Adding probiotics can enhance the flavor of fermented food. In this study, multi-strains (Lactiplantibacillus plantarum or/and Meyerozyma guilliermondii) were co-fermented with N. crassa to improve the flavor of HongJun tofu. L. plantarum is a probiotic that adds to the pleasant flavor of HongJun tofu. M. guilliermondii is an ester-producing non-brewer’s yeast. Therefore, co-fermentation of L. plantarum and M. guilliermondii with N. crassa resulted in significantly lower relative aroma activity values for odor of beans (aldehydes). Meanwhile, the main flavor compounds retained were fruity, mushroomy, floral, and nutty flavors, with a reduction of bitterness, an increase in freshness, and a richer taste without sourness. Results indicated that L. plantarum and M. guilliermondii synergistically worked, and their simultaneous use did not result in flavor deterioration. Every played an advantageous role in adding pleasing flavors to HongJun tofu. This work provides a reference method for improving the flavor of HongJun tofu and facilitated its commercial production.