Study On The Processing Technology Of High Yield Bean Curd Stick

Bean curd stick made from soybean is a traditional and popular food in China due to plentiful nutritious, easy storage and convenience to eat. In order to increase yield, toughness and protect color, some producers add the contrabands of non-chemical raw material during processing, for example Diaobai Kuai, Borax Urotropine, which bring great harm to the health of the people. In this project Heilongjiang soybean used as materials, studied soybean protein extraction, picking membrane technology and choice additives, optimized processing technology and parameters so as to increasing product yield and improving sensory quality, and guaranteeing food safety. Main research and results were list as follows.1. The research of the relation of soaking factor to protein extraction rate showed that protein extraction rate was increase with temperature increase when soaking temperature was below 40℃. Conversely, the protein extraction rate decrease with temperature increase soaking temperature was over 40℃. The protein extraction rate was small when pH value was near to 4.0, and increase with pH value was over pH value. Ultrasound treatment could increase the protein extraction rate.2. Through three factor orthogonal test and variance analysis, e.g. soaking temperature, pH value and ultrasound treatment time, the factor order of effect protein extraction rate was obtained. The order from main to subordination was: ultrasound treatment time> soaking temperature>pH value. The optimum combination was that the water pH value of soybeans by 7.0, water temperature 40℃, Ultrasonic extraction time of 20min. On this condition, soybean protein extraction rate reached to 84.8%.3. Picking membrane technology was influenced by soybean milk concentration, depth, and temperature and pH value. Bean curd stick yield was 53.0% when the on the soybean milk was concentration 3.00°Be, depth 2.0cm, temperature 90℃and pH value. Bean curd stick yield was significantly affected by adding compound additives. Bean curd stick yield reached to 62.2% while adding the optimized compound with 0.20% sodium trimetaphosphate, 400U/kg MTG and 0.30% sodium alginate.4. The depth of soybean milk during picking membrane process affected the color of bean curd stick. The product exhibited favorable color when keep a certain depth of soybean milk of 2 cm.