Study On Extraction Of A.Caroliniana Willd And Nutritional Value Evaluation

A.caroliniana Willd is annual small form floating aquatic ferns,widely distributed in tropical and subtropical freshwater ecosystem. A.caroliniana Willd has strong ability of nitrogen fixation and high protein content.In this paper,the extracting process,the best decoloration and fishy odor elimination condition,the nutritional value,functional properties of leaf protein of A.caroliniana Willd all had been studied,which could provide scientific foundation for A.caroliniana Willd utilizing.The main resultes were described as follow:1.The thermal method,acid and alkali method, acidified thermal method,alkalized thermal method for extracting leaf proteins from A.caroliniana Willd were observed comparatively. The results showed that the best method was acidified thermal method and the optimal technical processing was:A.caroliniana Willd→cleaning,refining(the ratio of material and water:1:3,refining time:4min)→filtering(four gauzes)→green juice→flocculation(heating temperature65℃,for 5 min,pH 3)→cooling,centrifugal(4000r·min^-1,10min)→cencretion of leaf protein→freeze-drying→leaf protein of A.caroliniana Willd. The extracting and yield rate of LPC was 33.28% and1.34% in this process condition.2. This paper showed that different conditions influenced the decoloration and fishy odor elimination of the leaf protein of A.caroliniana Willd. Under the condition of using80% acetone and anhydrous ethanol mixed solution(1:1) as soaking extractant,the optimal operating conditions were determined by orthogonal experiment. The optimal conditions were:solid / liquid ratio of 1:8 and soaking at 70℃for 4h with 3 stages. The extracting rate of chlorophyll was 4.58% in this best process condition,and the color was shallow white,the fishy odor was few.3.Using Amino acids automatic analyzer tested the Amino acid contents of the leaf protein of A.caroliniana Willd. The kinds of Amino acid were complete,the EAA 7,the NEAA 10. The total ratio of Amino acid was 41.38%,The ratio of EAA contents to total amino acid contents was 42.18,The ratio of EAA contents to NEAA contents was 0.72,higher than the WHO/FAO stander 40%,0.6 respectively. The similarity scale of leaf protein of A.caroliniana Willd to egg protein was 0.81,the SRC was 81.87.4.The leaf protein of A.caroliniana Willd has good dissolubility,water binding capacity,oil-absorbing capacity,oam ability and foam stability,mulsibility and emulsion stability. The oil-absorbing capacity and emulsibility and emulsion stability is similar to the soybean protein,so the leaf protein of A.caroliniana Willd can be used into the foods industry instead of soybean protein.