Effect of sterilization methods on quality and storage characteristics of tofu fermented by lactic acid bacteria

This study examined the effects of pasteurization (PAS), ultrasonic sterilization (ULS), and microwave sterilization (MWS) on the quality and storage characteristics of brine-fermented tofu (BFT) and fermented tofu (FT). Comparative analysis revealed that MWS had a negligible detrimental effect on the structural integrity and organoleptic properties of BFT and FT, while effectively maintaining its water-holding capacity (WHC) and exhibiting the least impact on its texture. In contrast, PAS and ULS increased hardness and chewiness significantly ( P < 0.05), but ULS also enhanced the brightness of tofu. Throughout the storage period, the WHC, elasticity, and sensory properties of tofu generally decreased, whereas the hardness and chewiness increased. PAS-BFT and MWS-FT maintained sensory quality for the longest periods of 14 and 12 days respectively, and could be decomposed to more small molecule peptides within 0–8 days and 0–6 days, which are more easily to be absorbed by the body. The findings discovered that MWS is the most suitable method for sterilization of tofu, with superior capability in maintaining the quality, extending shelf life, and improving digestibility of tofu. • Microwave sterilization (MWS) was less destructive to the structure of tofu. • Pasteurization (PAS) and ultrasonic sterilization (ULS) reduced the WHC. • The microstructure of fermented tofu (FT) was better than brine fermented tofu (BFT). • The best sterilization method for BFT and FT were PAS and MWS, respectively.