| Tamarind has the name of "Oriental God tree",in which tamarind polysaccharide is the most studied and most in-depth part at home and abroad,and many research results have been widely used in production,and the waste of tamarind seed after polysaccharide extraction is often discarded or used as fertilizer,greatly reducing the comprehensive utilization value of tamarind.In this paper,the extraction technology of protein from the waste of tamarind polysaccharide was studied,and its structure and functional characteristics were studied respectively,and the development and utilization of tamarind seed protein was fully explored.There is a great relationship between protein extraction rate and protein extraction method.At present,no scholar has used alkali soluble acid precipitation method to extract protein from tamarind seed kernel.In this experiment,the extraction process of TSG is to combine traditional alkali soluble acid precipitation method with ultrasonic method,so that the extraction rate of protein is greatly improved.At the same time,Osborn method is used to extract tamarind seed kernel albumin,salt soluble globulin,gliadin and glutenin After extraction,the globulin extracted by alkali dissolution and acid precipitation was purified by dextran G-50 gel chromatography,which improved and improved the quality and purity of protein products.The single factor tests of the ratio of material to liquid,p H,temperature and time of extraction were carried out.The optimum technological parameters of TSG preparation were as follows: ratio of material to liquid(g/m L)1:40,p H 12.5,temperature 65.0?,extraction time 90 min,250 W ultrasound for 1 h,acid precipitation p H 4.6,under these conditions,the protein extraction rate was 68.43±0.87%(w:w).The purified TSG prepared by alkali dissolution and acid assisted extraction was purified by dextran G-50 gel chromatography,and the purity was 77.88 + 1.63%(w:w).The content of albumin,salt soluble globulin,gliadin and glutenin in tamarind seeds were.68.43±0.87%(w:w),3.18±0.54%(w:w),1.31±0.56%(w:w),0.44±0.23%(w:w),15.31±0.72%(w:w).The molecular weight and structure of TSG were determined.The molecular weight of TSG was mainly distributed between 10 k Da and 70 k Da,and the content of subunits was high at 13.83 k Da and 35.34 k Da.The content of free sulfhydryl group and disulfide bond were33.97±2.94 ?mol/g and 44.08±3.79 ?mol/g,The secondary structure and tertiary structure of protein were studied by FTIR and circular dichroism,The relative content of secondary structure was measured and calculated,It was found that in TSG,?-helix accounted for27.36±0.40%,?-fold 26.67±0.24%,?-corner 32.16±0.32%,irregular curl 13.81±0.19%,The tertiary structure is ?/? type protein..15 kinds of amino acids were detected in the purified protein by amino acid analyzer.There are 7 kinds of essential amino acids,accounting for45.85% of the total amino acids,among which 16.08% is isoleucine,10.88% is phenylalanine and 9.11% is histidine..The results of TSG functional analysis showed that at p H 2.5,the foaming ability and foaming stability of TSG were 1.35 times higher than those of SPI,while in other p H environments,the foaming,foaming and emulsifying stability of TSG were not as good as SPI,but the solubility and emulsification were better than SPI.In order to utilize TSG more effectively and rationally,the antioxidant capacity of the protein was explored.The results of in vitro experiments showed that the free radical scavenging capacity of the protein to ABTS and DPPH was good,which was 92.57% and 99.32% at 10 mg/m L,5.64 and 3.26 mg/m L for IC50,395.29 ?mol/L for FRAP at 10 mg/m L The IC50 value of inhibition rate of lipid peroxidation was 12.84 mg/mL,and TSG had good antioxidant capacity. |
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