Effect of Soluble Sugar and Free Amino Acid Content in Old Dough Fermented by Lactic Acid Bacteria

[Objective]The research aimed at study effect of soluble sugar and free amino acid content in old dough fermented by lactic acid bacteria and yeast. [Method]Soluble sugar and free amino acid content was determined by HPLC. [Result]At the beginning of fermentation,lactic acid makes the soluble sugar content of the old dough decreased faster,but will increase its content in the later period,and it will increase the free amino acids content during fermentation of the old dough. Wherein Lactobacillus mindensis Z4 promote soluble sugar metabolism most obvious,San Francisco lactobacillus S8 can contribute to increase the content of maltose and reduced glucose content,San Francisco lactobacillus and Lactobacillus brevis free amino acids content more obvious. [Conclusion]Impact of different lactic acid bacteria to soluble sugar and free amino acids metabolize of the old dough is different,ultimately it will have an impact on the quality of Chinese steam bread.