| As the new protein resource, the special nutritional and biological function ofbuckwheat protein are already paid attention by domestic food industry. The deepdevelopment of buckwheat resource is limited as few studies on the extracting process of buckwheatprotein, isolation, physico-chemical and functional properties of protein fractions. In thispaper, using F. esculentum Moench as raw material, the extracting process of crude proteinand the physico-chemical and functional properties of protein fractions were studied.Effects of protein fractions on color and texture properties of the sausage were primarilydiscussed. The main results were showed as follows:1. The optimization of extracting process of F. esculentum Moench crude proteinDifferences of extracting condition and rate of F. esculentum Moench crude proteinby alkali method and enzymatic method were compared. The results showed that theoptimum conditions for alkali extraction were as follows: pH=10.0, temperature 50℃, theratio of stuff to water 1:5, extracting time 80min, when the extraction rate of protein was83.6％and purity of product was 74.5％. The optimum conditions for enzymaticextraction were as follows: pH 10.0, temperature 40℃, the ratio of stuff to water 1:10,dosage of alcalase 0.2％, hydrolyzing time 50min, when the extraction rate of protein was88.7％and purity of product was 72.5％.2. The physico-chemical properties analysis of F. esculentum Moench protein fractionsAlbumin, globuline, prolamin, glutein were obtained by multiplestep extractionmethod and their physico-chemical properties were compared. The protein compositiondistribution of albumin, globuline, prolamin, glutein was 21.91％, 19.36％, 2.26％,19.95％, the isoelectric point was pH4.40, 5.00, 4.80, 4.60, the denaturation temperatureof the powder was 79.39℃, 70.36℃, 80.04℃, 83.09℃and that of the dilute solution was88.38℃, 75.42℃, 75.85℃, 102.13℃, respectively. The main color of albumin, globuline,prolamin was white, somewhat yellow and that of glutein was red. The essential aminoacid was abundant in albumin, globuline, glutein. The F. esculentum Moench has highcontent of Fe in albumin, Zn in prolamin, Mg in globuline, and very low content of Pb, Sn,As in each protein fractions. SDS-PAGE spectrum of albumin was mainly composed offive bands with molecular weight of 36.8kDa, 29.0 kDa, 24.3kDa, 22.4kDa, 21.1kDa, thatof globuline was mainly composed of three bands with molecular weight of 57.9kDa,32.7kDa, 19.2kDa, that of prolamin was mainly composed of four bands with molecularweight of 28.4kDa, 23.3kDa, 21.6kDa, 17.7kDa and that of glutein was mainly composed of three bands with molecular weight of 63.9kDa, 47.5kDa, 38.2kDa.3. The functional properties evaluation of F. esculentum Moench protein fractionsComparing with those of F. esculentum Moench crude protein and soybean protein,water-holding ability, fat-holding ability, solubility, emulsifying property, foamingproperty of F. esculentum Moench protein fractions were studied, pH value andtemperature had a great influence on solubility of protein tested and crude protein had thebest solubility at different experimental conditions. The protein concentration, pH valueand temperature had a great effect on FC and FS of protein tested. Globuline and gluteinhad better FC and FS at different experimental conditions, pH value and sucroseconcentration had a great influence on EC and ES of soybean protein, while the proteinconcentration, NaCl concentration had a great effect on albumin. Glutein had preferableEC and ES at different experimental conditions. The WA of albumin was obviously betterthan that of other protein tested, while the FA of crude protein was the best.4. Effects of protein fractions on color and texture properties of the sausageAdding some albumin and glutein in sterilized sausage. F. esculentum Moench crudeprotein and soybean protein were contrasts. The results showed that the adding amount ofprotein tested could increase the yield of sterilized sausage and the crude protein had themost prominent influence in four protein tested. The adding amount of protein tested alsohad influence on the colour of sterilized sausage and the glutein had the greatest effect infour protein tested. The texture property of sterilized sausage could be significantlyimproved due to the addition of protein tested. When the adding amount of albumin,crude protein or soybean protein was 2％～3％, the hardness, springness and cohesivenessof sausage were better. When the adding amount of glutein was 3％～4％, the textureproperties were all satisfactory.
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