Study On The Relationship Between The Changes Of Free Amino Acids And The Bacteria During The Fermentation Of Black Big Steamed Bread Starter

HD steamed buns fermention agent is an active bacterium agents that are used to ferment dough.Our previous study to determine the best strains proportion of HD steamed buns fermention agent: Saccharomyces cerevisiae: Lactobacillus paracasei: Lactobacillus acidophilus: Hanseula anomala = 4: 2: 6: 1 in the previous study.And analysis of the formation mechanism of main flavor substances when ferment the dough and during steaming buns.The purpose of this study is to analyze the change types and contents of free amino acids during dough fermentation,to study the relationship between the changes of free amino acids and microflora,so as to provide a theoretical basis for the promotion of HD steamed buns fermention agent.Firstly,ethanol ultrasonic extraction free amino acids method was optimized by single factor experiments.The extraction conditions are determined as follows: When the extract concentration is 70 %,extraction temperature of 50 ?,ultrasonic extraction time was 60 min,the best effect of amino acid extraction.This study detected and analyzed changes in free amino acids during the fementation of HD Steamed buns fermention agent fermented sourdough process by reversed-phase high performance liquid chromatography with pre-column derivatization(RP-HPLC)method of.Combining with the changes in the concentration of each strain from four strains sourdough,three strains sourdough,double strains sourdough,single strains sourdough,to determine the relationship changes of free amino acids and microflora during HD steamed buns fermention agent fermented sourdough process.The relationship among Glu,Saccharomyces cerevisiae and Lactobacillus paracasei : Y=10.88588X1-3.90086X2-62.64807;The relationship among Ile,Lactobacillus acidophilus and Lactobacillus paracasei :Y=6.97425X1+1.53185X2-6.79488X3-10.63443;The relationship between Asp with Hanseula anomala : Y=0.38168X+7.77677;The relationship between His with Hanseula anomala : Y=1.28099X-10.1081;The relationship among Thr,Lactobacillus acidophilus and Lactobacillus paracasei : Y=1.21815X1+0.86728X2-10.63443;The relationship among Val,Lactobacillus acidophilus and Lactobacillus paracasei : Y=4.98169X1-3.54689X2-13.60257;The relationship among Gly,Hanseula anomala and Lactobacillus paracasei : Y=2.85093X1-0.40464X2-18.86612;The relationship among Leu,Saccharomyces cerevisiae and Lactobacillus paracasei : Y=2.32319X1-0.75345X2-13.16971;The relationship among Phe,Lactobacillus acidophilus and Lactobacillus paracasei : Y=2.98157X1-0.40374X2-21.00367.Finally,the study on free amino acid were extracted and analyzed by reversedphase high performance liquid chromatography with pre-column derivatization method(RP-HPLC),were detected by 17 kinds of free amino acids in three kinds of steamed buns.And the total content of free amino acids in HD fermentation agent steamed buns for 37.0350 ?g/g;The active dry yeast steamed buns in the total free amino acid of 25.4039 ?g/g;The sourdough steamed buns in the total free amino acid is 36.4922 ?g/g.According to the flavor amino acid content classification comparison: HD fermentation agent steamed buns contains more sweet amino acids and aromatic amino acids,gives a unique flavor and sweet taste of buns.Therefore,HD fermentation agent steamed buns meets meet the needs of modern people in the nutrition and taste requirements.