Abstract:

In this study, the nutritional properties (mainly free amino acids), staling characteristics and volatile flavor
compound characteristics of natural yeast sourdough bread were analyzed by TA, DSC, HPLC and SPME-GC-MS
techniques, respectively. Compared with the common yeast bread, natural yeast fermentation significantly increased the
content of 12 kinds of amino acids in bread including valine, methionine, phenylalanine, isoleucine, leucine, lysine and
other essential amino acids. Meanwhile, natural yeast fermentation reduced the hardness and aging enthalpy of bread during
storage, delaying the staling of bread. Moreover, natural yeast fermentation enhanced the volatile flavor compounds of bread
by forming the new flavor compounds, D-limonene, 3,7-dimethyl-1-octanol and 2-methyl-1-decanol, while the relative
amount of each group of flavor compounds was changed. Furthermore, natural yeast fermentation improved the overall
acceptability of bread and obtained higher sensory evaluation scores.

Key words: natural yeast sourdough bread, free amino acids, staling properties, volatile flavor compounds