| A novel bioactive peptide derived from Chinese rice wine(millet) was investigated. The Chinese rice wine was ultrafiltrated analysis and then condensed. It was fractionated by gradient elution using ethanol from macroporous adsorption resin(MAR DA201-C), and then further fractionated on Sephadex G-15 and preparative RP-HPLC. The bioactive peptide identification was accomplished with LC/ESI-MS and Protein/Peptide Editor program. The results show that the ultrafiltration has a slightly infulunce on radical scavenging capacity and oxidation resistance ability of millet wine. Four fractions with different polar peptides and different average hydrophobic value were obtained by gradient elution using ethanol from MAR DA201-C. The peptide with the higher cholesterol micelle solubility inhibition rate and free radical scavenging activity was found in 75% ethanol fraction. There were four major peptide peaks monitored at 220 nm with Sephadex G-15 for further fractionation; the bioactive peptide was obtained in Peak B. Ten main peaks in the elution profile of fractions from preparative HPLC-RP column, and the peptide with the highest cholesterol micelle solubility inhibition rate and higher free radical scavenging activity was found in Peak p6. The amino acid sequence of the peptide was identified as CGSP(Cys-Gly-Ser-Pro). The oligopeptide content in aging millet wine and market millet wine was studied by the gel chromatography preliminary. The result shows that: the oligopeptide content in aging rice wine increased with the aging time, the market oligopeptide content in rice wine compared with aging wine, the oligopeptide content in market rice wine is relatively less than in aging rice wine.In the study, the oligopeptide content of the raw materials(millet and wheat-qu) of rice wine(millet) brewing was studied and the different processing methods of millet about the oligopeptide were analyzed. The results shows that the oligopeptide content in millet after soaking were similar with the original, and the oligopeptide content after cooking in millet was slightly higher than after soaking. The oligopeptide content of millet after cooking and the microwave processing is 7.21 mg/g, and slightly higher than that of millet after cooking and the roasted processing. And the wheat-qu was made using single strain of Aspergillus rhizopus, two strains Rhizopus oryzae and Aspergillus niger, and traditional wheat-qu. The saccharifying ability, liquefying power, fermentation ability, and protein decomposition ability were determinated and compared. the results shows that saccharifying ability, liquefying power, and protein decomposition ability of the two strains wheat-qu were 990 mg/gh, 5.3 g/gh, 40.6 μg/gh, respectively. And the oligopeptide contents in three of wheat-qu were 1.24%, 2.63% and 1.85%, respectively. And the content had a direct relationship with the protein enzymes contant in wheat-qu.The factors that influence the oligopeptide content in the fermented mash were experimentally studied in the brewing process. And the fermentation temperature, initial p H of water, fermentation time, leaching time and adding amount of wheat-qu and yeast were discussed. And the optimization method of response surface was also used. And the results shows that the optimal fermentation conditions for leaching time was 30.7 h, the adding amount of yeast was 5.86‰, initial p H of water was 6.3, fermentation temperature was 32 ℃. And the average oligopeptide content of three times of fermentation experiments under this condition was 4.12 mg/m L. And the results also showed that leaching time and initial p H of water were interaction significantly, adding amount of yeast and temperature has significant interaction. |
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