Physicochemical And Functional Properties Of Dehulled And Defatted Flours And Proteins From Different Legumes

Legume was well known as high protein, starch, fiber, low fat, rich in minerals andvitamins, has special physiological active substances and medicinal value. Protein is animportant component in the legumes, which properties affect the development and utilizationof legume resources. Therefore, it is necessary to study the physicochemical and functionalproperties of legume flour and its protein to provide theoretical basis and guidance on theexploitation and utilization of legume. In this paper, big white kidney bean, light speckledkidney bean, small white kidney bean, cowpea, mung bean, small red bean, lentil, and pea hadbeen selected as the specimens to systematically analyze the physicochemical and functionalproperties of defatted legume flours and proteins, as well as the impact of glycosylationmodification on tne properties of legume proteins. The main conclusions are as follows:Compared with soybean flour, defatted legume flour had higher bulk density, waterabsorbing index and gelation capacity, and lower water solubility index, water-absorbingcapability and oil-absorbing ability. Legume flour was significantly different from soybeanflour in foaming capacity and stability, and did not revealed significant differences inemulsification and emulsion stability. Significant differences in physicochemical andfunctional properties of legume flour were also observed. Big white kidney bean exhibitedhigher water-absorbing index, oil-absorbing ability, emulsion stability and lower bulk density.Small white kidney bean displayed higher water-absorbing capability, emulsification, foamingcapacity and foaming stability. Pea flour exhibited higher gelation and foaming capacity butlower emulsion stability.The legume protein content in the range of20.74%to27.77%, globulin and albumin asthe main storage protein content were higher. Isoelectric point of legume proteins wasbetween pH4to pH5. The protein that was extracted with the alkali soluble acid sinkingmethod has high purity. Protein subunits and molecular weight distribution of differentlegume genera has significant difference. Compared with soybean protein pea, lentil, mungbean and cowpea protein has better foaming ability, legume protein foaming stability washigh. Legume flour was significantly different (P<0.05) in foaming capacity, and did not revealed significant differences (P<0.05) in emulsification. With the increase of proteinconcentration, emulsion stability was decreased. The least gelation capacity of light speckledkidney bean protein was lowest, at10%, pea protein was highest. Under the least gelationcapacity, Phaseolus and Lentils varieties protein gel strength was high, different legumeprotein gel viscosity index was significantly different (P<0.05).After the glucose modification, legume protein subunit bands were obviously offset andhysteresis. With the extension of reaction time, legume protein grafting degree increased.When the glycosylation reaction conditions was3%protein concentration and95℃, exceptthe mung bean and pea protein, the other legume protein has highest grafting degree. With theincrease of reaction temperature and protein concentration, the browning degree of proteinenhanced. When protein concentration of5%, at95℃, the browning degree is most serious.After the glucose modification, the solubility of legume protein near the isoelectric point haveobvious improve, light speckled kidney bean protein solubility was best.