Research On Tofu Of Coagulant And Preservation

Tofu is a traditional Chinese soybean food, Which is extremely popular for people allover the world because of its rich nutrition and special medicinal and health care functions.Traditional Tofu mainly includes Marinated Tofu, Plaster tofu, and lactone tofu, Each ofwhich has unique flavor and characteristics. However, tofu industry development was limitedbecause of its single taste and short shelf life. To overcome this shortage, Ningxia soybeantaken as raw material were researched in this paper. The optimal formula of composite curingagent and the optimum process conditions were selected. And comprehensive preservation oftofu was processed with streptococcus element (Nisin). The results are as follows:1. Composite curing agent: Compounded with lactone, calcium sulfate, magnesiumchloride, The effect of concerting single and composite curing agent on tofu yield werestudied through the single factor and compound experiment, Orthogonal and verificationexperiments were also conducted. The best composition of various of curing agent wasidentified: lactone, calcium sulfate, magnesium chloride are0.3%,0.15%,0.15%.Respectively, The best process condition parameters: composite coagulant dosage is0.6%, thesolidification temperature is85℃, solidification time is30min. The formulation and processparameters are feasible through testing. Composite curing agent was superior to single curingagent on the production, quality of tofu, taste, flavor and sensory evaluation.2. Tofu shelf-life: The suitable concentration of Nisin adding and soaking concentrationwere determined through single factor experiment. Three methods for sterilization namedmicrowave sterilization, high pressure sterilization and high temperature sterilization werecompared. The results show that high pressure sterilization effect is the best, but it affect thecolour and lustre of tofu.The effect of microwave sterilization on the colour and lustre of tofuwas not big, But obviously not as good as high temperature sterilization. Better experimentalresults were showed with high-temperature sterilization in the temperature of90~95℃and30min. Comprehensive preservation technology to deal with tofu was adopted. The qualityguarantee period of the tofu was extended to2weeks through adding0.8g/kg nisin, Which isbiological preservative antistaling agent, in the process of tofu production, soaking the beancurd products with concentration of1.5%nisin, sterilizing with the temperature90~95℃for 30min, and cooling rapidly by water and cold storage with the temperature range of0~4℃.