Separation And Characterization Of Taro Protein

This investigation use taro as the material, by optimizing the process conditions to get optimum technological parameters for the preparation of taro protein isolated, according to Osborne fractionation method, albumin, globulin, gliadin and glutelin protein components were future fractioned from taro, on the basis, the physical and chemical properties of taro protein isolated and the molecular properties of the protein components have been characterised.1. The best extraction technology conditions for taro pro tein isolated: the extraction system of p H value is 10.00, the temperature is 40℃, liquid-to-solid ratio is 6 m L/g, acid sinking p H value is 4.90, the taro protein isolated yield was 1.33±0.020%, the purity was 84.67±0.011% under those conditions.2. IEF electrophoresis analysis shows that the taro protein isolated p I mainly concentrated in 6.73 and 5.21. SDS-PAGE analysis found that taro separated protein is mainly composed of four subunits, its relative molecular mass distributio n in 57 000, 46 300, 34 200 and 8 500 Da, adding mercaptoethanol open the disulfide bond increased new molecular weight stripe at about 23 100 Da. DSC analysis confirmed that the taro separated protein denaturation temperature was 71.3 ± 0.2 ℃, denaturation enthalpy ΔH is 1.550 J/g. Rheological analysis showed that p H and Na C l, KCl, Ca C l2, Mg C l2 concentration of taro has distinct effects on the taro protein isolated denaturation and aggregation.3. According to the method of Osborne, albumin, globulin, gliadin protein components were isolated, the relative contents were 43.38%, 3.97%, 2.99% and 43.38% respectively; p I were 5.04, 5.23, 6.67 and 6.76 respectively. SDS-PAGE analysis showed the relative molecular weight distribution at 57 900, 38 000, 32 900-58 400, 21 700-54 700 Da of the albumin, globulin, gliadin and gliadin protein components. DSC analysis confirmed that albumin, globulin, gliadin and glutelin denaturation temperature were 67.1 ℃, 70.1℃, 71.9℃ and 71.2℃ respectively, denaturation enthalpy ΔH respectively is 1.434 J/g, 1.455 J/g, 1.470 J/g and 1.511 J/g. Amino acid of the four kinds of protein components is relatively complete, rich in essential amino acids.4. Secondary structure analysis showed that albumin, globulin, gliadin and glutelin molecular structure difference is obvious. Four protein components in amide I region contains a lot of β-sheet and β-turn secondary structure and a small amount of α-helix and random coil structure. In addition to the α-helix secondary structure differences, albumin and gliadin β-turn and random coil number are comparable. But in the main chain conformation, glutelin and gliadin β-sheet and β-turn contents are higher than that of albumin and globulin, little content and random coil structure. This showed that the structure of glutelin and gliadin is stable, consistent with the DSC experiment conclusion.