Study And Analysis Of Flavor Substances In Monascus Submerged Fermentation

Monascus could produce not only edible pigments,polysaccharide,monacolin K,but also flavor substances.However,fungal toxin citrinin could also be produced during Monascus metabolism.In this paper,Monascus Z505 was selected as the starting strain.Cereals and other grain crops were used as raw materials to produce flavor substances by submerged fermentation.With pigment value,Monascus polysaccharide,citrinin and sensory evaluation as the main evaluation indexes,the fermentation process was optimized and the flavor components were analyzed by GC-MS.The paper provided a theoretical basis for the development of Monascus fermentation beverage.The conclusions are as follows:1.The fermentation characteristics of three Monascus strains(GN,H4000 and Z505)with strong aroma-producing abilities preserved in the laboratory were tested and compared.With the p H,pigments,polysaccharide,citrinin,sensory evaluation and fatty acid as evaluation indexes,it was found that the metabolism of Monascus GN was strong,and the contents of Monascus pigments(239.1 U/m L)and fatty acids(17.38mg/g)were relatively high,which was suitable for the study of high yield pigments and fatty acid.Monascus Z505 fermentation broth was the most harmonious with flowers and fruits with the highest content of polysaccharide(1.89 g/L)and the lowest amount of citrinin.And then,Monascus Z505 was selected for the development of Monascus fermented beverage.2.Monascus fermentation broth was treated by sample pretreatment methods such as dichloromethane liquid-liquid extraction,ethyl acetate liquid-liquid extraction,solid phase microextraction,and methyl sulfate method,respectively.The volatile flavor compounds in Monascus fermentation broth were detected by GC-MS.The liquid-liquid extraction method of ethyl acetate was found to be simple and its test results were accurate.Flavor compounds of phenylethanol,octanoic acid,ethyl linoleate,ethyl oleate and ethyl stearate were maily detected in the Monascus culture broth.3.It studied the effects of different raw materials on Monascus pigment,Monascus polysaccharide,citrinin,flavor components and sensory evaluation of monascus Z505 fermentation.Compared with rice,black rice,semen coicis,sweet potato powder and fresh sweet potatos,it was found that purple sweet potato powder has the best sensory evaluation with obvious floral and fruit aroma.The color value of monascus pigment was 19.74 U/m L and the crude polysaccharide of monascus was 5.84 g/L.The content of citricin was not detected.The main flavor components were phenylethanol,ethyl linoleate and ethyl oleate.4.The fermentation conditions were optimized by comparision of the flavoring substances produced by Monascus Z505.The optimum fermentation conditions were as follows: fermentation temperature was 20 ?,and fermentation time was 6 d.The contents of color value and crude polysaccharide were 42.15 U/m L and 5.87 g/L,respectively.The main flavor substances were composed of ethyl butyrate,butyl acetate,2-heptanone,2-nonone,phenylethanol,octanoic acid,ethyl linoleate and ethyl oleate.In comparation with the control,the content of pigments was improved by 64.97%.The flavor substance was more complex and more coordinated.