Aroma Analysis Of Sesame Flavor Liquor By Key Microorganism

The typical sesame flavor in the sesame flavor liquor is mainly generated fromcomplex effect of mixed microbes and Maillard reaction during the fermentativeprocess. However, the effect of single microbial specie on specific aroma components inthe sesame flavor liquor has not been clearly at present. In this paper, basic screeningmedium was obtained from single factor experiment and orthogonal experiment throughthe enzymolysis of feedstock (wheat germ and bran), which could be used as the matrixfor studying aroma components of sesame flavor from single microbe. Results showedthat the moisture content of wheat germ and bran after drying measured was7.05%and11.7%, respectively. These basic screening mediums prepared from the proportion ofwheat germ and bran (1:1), and material to water (1:7), with the addition (400u/g) ofacid protease, saccharifying enzyme and xylanase for hydrolyzing8h, respectively,contained rich reducing sugar and amino nitrogen. It could supply the need of microbesfor their growth and metabolism. Simultaneously, these small molecule componentsaccumulated as the precursors to generate aroma materials, favoring the production ofaroma components.The growth curve of bacteria and yeast was determined using the colorimetricmethod, which showed the highest growth rate of them was achieved at8h and20h,respectively, providing the theory reference for inoculation time, addition dosage andfermentative time in the follow-up fermentation process. To observe morphology andcolony morphology of microorganism is attributed to understand the physiologicalcharacteristics of microorganisms. Several aspects, such as the thermostability ofBacillus faciliating the metabolic role of thermophilic protease, high esterification ofyeast, and fungis as main fermenting microbes own high saccharifying power andprotein resolution. It can not only provide theoretical guidance for the microbial aromaproducing mechanism in the later fermentation, but has a preliminary understanding tothe liquor aroma components regulated by microbes. Reducing sugar content in theliquid after fermentation decreased25mg/g than that of initial condition, while thecontent of free nitrogen was increased from3to3.5～5mg/g.The single strain of bacteria, yeasts and molds was fermented in correspondingbasic screening medium, and the aroma components in fermentation liquid fractionwere detected by GC-MS. Compared to the aroma components in the control, it showed that the bacteria mainly produced pyrazine and higher fatty acids, yeast mainlyproduced ester like ethyl acetate and ethyl hexanoate, and the fungi fermentationgenerated more phenols, aldehydes and ketones compounds. The presence of thesecomponents enriched aroma of sesame flavor liquor, demonstrating the importantfunction of aroma components Study on the main aroma components by single species,and the regulation of the proportion of microbes could improve the flavor aroma ofsesame flavor liquor and further enhanced the stability of liquor quality. When themicrobes producing aroma obviously were mixed to cultivate, and ferment, thecomposition and quantity of aroma components would change accordingly, whichprovides the theoretical foundation for the production of sesame flavor liquor.