Studies On Technics Of Leguminous Pastures Leaf Protein Concentrations Extraction By Alkaline Extraction And Acid Precipitation

The purpose of this investigation was to extract and evaluate leaf protein concentrates(LPC) of alfalfa,white clover and chinese milkvetch in system.It involved there parts:the best harvest time for alfalfa,white clover and chinese milkvetch; the most suitable process conditions for extracting LPC from alfalfa,white clover and chinese milkvetch by alkaline extraction and acid precipitation;evaluation of LPC.Based on the study, Legume leaf protein concentrate as a new protein resource will play an important role in easeing the shortage of protein.1. The output and quliaty of Legumes are affected by location growth period and so on.The test compared the component of alfalfa,white clover and chinese milkvetch at the different period including vegetation stage,early budding stage.fully budding stage,early blooming stage,fully blooming stage,podding stage. The result showed that the best harvest times of alfalfa, white clover and chinese milkvetch as raw materials for LPC were early blooming stage,fully budding stage,between fully budding stage and early blooming stage.2. Alfalfa,white clover and chinese milkvetch are protein-rich perennial legumious plant, which have the basic condition of raw materials for LPC. The extraction process was optimized by single factor and orthogonal experiments, and the most suitable process conditions for extracting LPC were determined as follows:Alfalfa:the ratio of liquid and material 32:1,strring time1.5min,alkali extraction pH10,alkali extraction timel5min,acid precipitation pH2.7,acid precipitation time29min,contrifugal speed4500r/min,centrifugal time25min.Based on above-mentioned conditions,the rate of Alfalfa LCP was 56.38%,the content of coarse protein in extracted material was 57.55%.White clover:the ratio of liquid and material 24:1,strring time1.1min,alkali extraction pH10,alkali extraction timel9min,acid precipitation pH4,acid precipitation time28min,contrifugal speed4000r/min,centrifugal time25min.Based on above-mentioned conditions,the rate of White clover LCP was 60.54%,the content of coarse protein in extracted material was 56.59%. Chinese milkvetch:the ratio of liquid and material 31:1,strring time2min,alkali extraction pH9.7,alkali extraction time15min,acid precipitation pH3.8,acid precipitation time21min,contrifugal speed4000r/min,centrifugal time30min.Based on above-mentioned conditions,the rate of Chinese milkvetch LCP was 58.51%,the content of coarse protein in extracted material was 49.17%.3. LPC of alfalfa,white clover and chinese milkvetch were prepared by alkali extraction and acid precipitation according to test 2.Their protein properties were detemined and compared with SPI.Both of them had similar foaming stability, the latter had better water bonding capacity,emulsifying capacity and emulsion stability,foaming capacity than the former, but the former remarkably excelled in oil bonding capacity.