Influence Of Technic Conditionson On The Fermented Soy-milk Quality

Lactic acid bacteria (LAB) fermented products is one of the most popular health foods around the world. As a kind of the fermented products, fermented soy-milk(FSM) was more nutritious than yogurt. The starter culture's domestication, technic conditions and nutrient components was the research focus in the field. It is difficult to find the products of FSM in the market. Like traditional yoghurt, the FSM's state should always be liquid or curd, its volume should also be large. It should storage under cold temperature and in short shelf life(about fifteen days). It would turn bad easily. Its transport is inconvenient, and the sell field was limited. Its physical and chemical properties such as acidity and thickness would be influenced by the starter culture and its fermenting mechanism during the processing of the FSM,and so on. Its quality of the FSM is often not so steady. Not so many people familiar to these products. The typical odor would be removed in the FSM after drying ,in order to adapt the internal and international market. The forma and flavor can change with the different tastes, and made the products' diversity come true. At the same time , it is without question that it would add new light to the soybean industry's deep processing when the solid FSM being successfully developed in our country.The key that the FSM was dried lies in: First, keep various kinds of nutritional labeling in the FSM as much as possible; Second, after drying the LAB among the FSM have high survival rate and high fermentative activity; Third, the FSM after drying should also have good better quick solution. Around above-mentioned three goal, the influence on the quality of the FSM by the condition of concentrating, drying and nutrient fortifying were studied, in order to offer scientific basis for the thing that the industrialization of the solid FSM was produced.It is the key craft link that the FSM be concentrated to prepare solid FSM. Different methods such as centrifugal separation, vacuum concentrate, decompression filtration and membrane separation were adopt to concentrate the FSM. The results indicated that, when membrane separation be adopted, the ratio of LAB being withhold was up to 99.5%, the nutritive value of the FSM and activation of the LAB among it could be kept well.Drying of the FSM is very important during the processing. Four different desiccation methods, including freeze-drying, atmospheric drying, modified-atmosphere drying and vacuum drying, was used to investigate for their influence on the quality of FSM. The results showed that all FSM powder had live LAB and could be used as starter culture in the production of fermented soy-milk. The freeze-dried powder has the highest survival rate of LAB , up to 45.43%; its nutrition component were very close to those before drying. When it was inoculated into raw milk, its inoculating amount was low (only 1%), but LAB among the FSM had the stronger activity and hightest viable count ,shortest fermenting time and best sensory quality. Those drying with protectant had better quality than without protectant.Adding protectant into FSM is a effective means to enhance the survival rate and fermenting activity of LAB during freeze-drying. Six different protectants, including sucrose, Maize starch, malt polysaccharide, skimmed milk power, glucose, lactoseand etc, were used to investigate for their protective effects on the FSM. These protectants were added into the FSM before freeze-drying, in a proportion of 10%. The index were mensurated such as LAB's survival rate, fermentive activity, drying time and etc. The results showed that the drying time of the FSM with sucrose, malt polysaccharide and skimmed milk power had been shortened and the survival rate of LAB in it was higher. The result of fermentive trial showed that the FSM powder had quick solution, LAB among them could rejuvenate rapidly and produce acid quickly after inoculation. Compared with that before drying its fermenting time had a little shorten. The product 's acidity at the end-point was rising. There was no difference in the color, aroma, flavor and organize state than before drying.The influence on the FSM was studied by adding flavonids in folium ginkgo after sterilization. The results showed, along with bigger flavonids in folium ginkgo added into FSM, LAB among them had been accelerated, the viable count of LAB increased obviously. It's better to add the flavonids in folium ginkgo before sterilization than after sterilization. The optium amount of flavonids in folium ginkgo was 2.5%.Furthmore, the result of trial showed, added lactic calcium into FSM, the sensory quality of the product had no difference more than former. The viable count of LAB among them increased with the bigger amount of lactic calcium. Compared with the...