Study Of Heat Induced Gel Rheological Properties Of Corn Germ Protein

Corn germ protein(CGP) has the highest amino acid score(AAS) in recular grains’ s, it contains seven essential amino acids, however,it has not been fully developed and utilized. This paper investigated the basic functional properties of CGP, intermolecular forces which affect the characteristics the form of CGP gel, and the effect phosphate on heat-induced CGP gelation properties, the objective to broaden its scope of application. The main contents are as follows: CGP(1) Conventional alkaline solubilizaatio and acid precipitation approach was applied to recover corn germ protein, followed by CGP basic functions measurement. The results showed that: the extracted protein content was of 56.42% by the Kjeldahl method, CGP solubility was of 0.1068 mg / mL by BCA, Ellman’s reagent colorimetric method showed disulfide bonds content in CGP was 72.82μM / g. The pH, temperature and time have an impacted on water holding capacity. In general, the water holding capacity of CGP increased with the increasing pH, temperature and time. This study also revealed that the higher the ratio of CGP / oil, the better the CGP oil holding capacity, but the oil holding properties of CGP was not sensitive to heat, continued heating would make it slowly declined.(2) Through pH adjustment and denaturing agents addition, combined with a dynamic shear rheometer analysis, the main molecular forces of heat-induced CGP gelation can be deduced. With the inclusion NaCl, Na2SO4, and NaSCN the impact on the heat-induced CGP gelation characteristics revealed that electrostatic interactions played a role on the formation of the CGP gel. We also found hydrophobic interaction was one of the main forces for heat-induced CGP gel formation by addition denaturant GuHCl, PG, and Urea. The use of 2-ME, NEM could destroy disulfide bonds the protein structure, which were identified as the main molecular driving forces promoting heat-induced CGP gel formation. Finally, reheating and recooling process revealed that hydrogen bonds played a more important role than hydrophobic interactions from gradually increased G’ during cooling and recooling.(3) We found the phosphates had an impact on heat-induced gelation properties of CGP. The results showed that a low concentration of sodium tripolyphosphate could improve heat-induced gelation properties of CGP, however, low concentrations of sodium hexametaphosphate had the opposite effect. Further studies indicated that the phosphate could also be added to vegetable protein, as a water holding agent, as well as a protein gelation promoting agent.