Study On Extracting Techniques Of Leaf Protein From Alfalfa And Its Comprehensive Processing Techniques

The extracting techniques of leaf protein from alfalfa(Medicago sativa L.) and its comprehensive processing techniques is reached. The following results are gained through this research.1 The best harvest time for alfalfa (variety is Algonquin) is at the beginning of flowering season when extracting leaf protein from alfalfa. At this time alfalfa's biomass and the crude protein content achieves the optimal coupling exactly. The yield rate of leaf protein is 4.49%. The crude protein content is 60.55%.2 The study on two or three stubbles of alfalfa indicates that alfalfa should be processed early after harvested as soon as possible in order to reduce the storage time. The longer the laying aside time is, the lower the yield rate of leaf protein. The yield rate of leaf protein varies apparently with the laying aside time. The harvested alfalfa should be deposited in shade and not beyond three days.3 Though all those processing methods of direct heating, heating with acidlizing, heating with alkalizing, acid extracting, alkali extracting, the direct heating has been eventually chosen in this study. The optimal technical processing is : material→cleaning→cutting up→refining (the ratio of materials and water is 1 to 3, adding 0.20% sodium chloride to water), pressing(the layers of filtration is 2)→heating(85℃ for 7 minutes) →cooling, centrifugal casting ,depositing→concretion of leaf protein→drying→leaf protein of alfalfa .4 In order to gain the white leaf protein, two steps of separation by heating should be carried on. The heating temperature is 40℃ or beyond it in the first time, and when the temperature reaches up to 85℃ in the second time, the white leaf protein may obtain.5 The quality of leaf protein from freezing vacuum drying is better than that from constant temperature dry, which protein loss can be decreased 2% approximately.6 We use the fuzzy recognition method and the amino acid ratio correlates method to evaluate the quality of nutrition. According to the two methods, the leaf protein nutritional value is high. It can draw close to egg protein (standard protein) 0.72 ~ 0.83, with SRC (amino acid ratio coefficient minute) 80 ~ 82. The function characteristic of leaf protein from alfalfa is good which may substitute the soybean albumen to apply in food.In addition, this experiment is also carried on the nutrition piece trial manufacturing to the alfalfa leaf albumen, the side product has been conducted preliminarily to its deep utilizing, which enhances the alfalfa latent nutritional value and the economical additional value, and promotes alfalfa industrial production development.