Extraction,Isolation,Structure Characterization And Emulsifying Properties Of Salt Soluble Protein From Peony(paeonia Suffruticosa Andr.)Seed

The yield of peony seed protein was growing,and it had not been effectively used.In this paper,peony seed was used as the raw material.After the oil was removed,four kinds of protein components were isolated from peony seed.The structural characterization of the four protein components was determined.The partial physicochemical properties and functional properties of the extracted salt soluble protein were analyzed.PH value was used to modify the emulsifying properties of salt soluble protein.The conclusion in this study could be refered theoretically for the extraction and utilization of salt soluble peony seed protein.The main researches were as follows:(1)According to Osborne classification,the protein of peony seed defatted powder was separated and graded.The results showed that the proportion of albumin,globulin,prolamin and glutenin in peony seed defatted powder were 69.68︰7.27︰ 3.50︰19.56.Through the amino acid analysis of four protein components of peony seed,the total amino acid content of albumin was highest,44.90%,and globulin,prolamin,glutenin were 27.30%,26.10%,23.30%,respectively.From the intrinsic fluorescence,the tryptophan residues of globulin,prolamin and glutenin than albumin.The analysis of the infrared spectroscopy,Amides Ⅰshowed that the albumin had more beta-folding structures.Globulin contained more beta-folding,beta-angle and random curl,which was close to the two level structure of soybean protein.Prolamin and glutenin had more beta-angle.The four components had different protein subunits.The two bands with the deepest color of more than 116 kD were the main components of the albumin.Globulin had a unique band in 14.4kD~18.4kD.The band of prolamin 35kD~45kD was clear and clear.Glutenin had the only band in greater than116 kD.Through the four components of the structure characteristics and combined with scanning electron microscopy.It could be concluded that the difference of the four protein components are separated completely and are differences in the properties.(2)On the basis of single factor experiment,the optimum extraction process of salt solution was obtained by response surface test.The extraction time was 69 min,the extraction temperature was 40 degrees,the ratio of material to liquid was 1:20,and the concentration of NaCl was 1.03mol/L.The extraction process parameters were improved to verify the test.Theaverage protein extraction rate of peony seed was 23.49%,and the 78.30% of protein was effectively extracted from the peony seed.The physical and chemical properties and functional properties of the optimized separation protein of peony seed were measured.The content of amino acids was as high as 71.75%.The essential amino acid was deficient in lysine.It was rich in glutamic acid and aspartic acid.It had good hydration property.NSI was64.12%.Water absorbability was 3.63g/g.The contact angle of the three phase was 36.45 degrees.The scanning electron microscope had more tiny pores.It also had good surface properties.The emulsifying activity index was 53.49g/m2.The emulsification stability index was 26.32 min.The foaming ability was 54.50%.The stability of the blister was 21.83%.(3)The emulsifying properties of salt soluble protein were determined by different pH value.The peony seed protein emulsion was at pH 8.The stability of emulsification and emulsification was the highest,which was 85.27% and 90.74%.When the emulsion was pH2~5,the Pickering emulsion was formed.The thermal stability and particle size of the emulsion were significantly increased,and the color of the emulsion was changed.The emulsion was pH8~10,and the O/W type emulsion was formed.The more the emulsion was neutral,the lower the emulsification ability and the stability of the emulsion,the smaller the particle size of the emulsion and the darker the color of the emulsion.Under the neutral condition of the emulsion,the particle size was larger and the stability was low.