Fermented tofu: Enhancement of keeping quality and sensorial properties

- Spoiled tofu population was characterized.
- A new way to produce tofu by LAB soymilk fermentation has been set up.
- The prevention of undesired microbial spoilage population has been optimized.
- The stability and the quality of the products were confirmed by challenge test.

In this study a new way to produce tofu by means of soymilk fermentation by specific lactic acid bacteria, Lactobacillus casei and Lactobacillus acidophilus alone or in combination, and subsequent precipitation has been developed, in order to prevent undesired microbial and chemical spoilage, as well as improve the stability and the quality of the product. In particular, the combination L. casei and L. acidophilus generated tofu having shelf life exceeding 20 days and able to prevent the growth of the spoilage strains inoculated. This fermented tofu was characterized by the production of antimicrobial molecules, such as acetic acid, limonene, 2-nonen-1-ol, 1-nonanol, 2(5H)-furanone, benzyl alcohol, phenylethyl alcohol and heptanoic acid. Depending on the Lactobacillus species used, the fermentation process generated different metabolites profiles and sensorial properties. Another promising properties conferred by the lactic acid bacteria fermentation was the inhibition of unsaturated fatty acids (UFAs) peroxidation or reduction of the aldehydes originated to their corresponding alcohols.