Study On The Quality Evaluation Of Pit Mud Used For The Production Ofchinese Sesame-flavor Liquor

The quality of pit muds is an important factor affecting the flavor of Chinese liquor,its quality evaluation is of great significance in fermentation process of Chinese liquor.So the sesame-flavor liquor pit muds were selected as experimental samples,their comprehensive comparison and analysis of the quality were given as follows:The physical and chemical index analysis of pit muds found that except for moisture,the pH and the content of humus,effective phosphorus,effective potassium,ammonia nitrogen in the degraded were lower than normal and high-quality pit mud;The relationship between pH and other factors is the highest,which is the major factor in the degradation of pit mud.Compared with the esters produced from normal and high-quality pit,the difference of the trace compounds from degraded pit revealed that the original liquor had a higher ethyl lactate,lower ethyl caproate and the proportions of ethyl lactate,ethyl caproate,ethyl acetate and ethyl butyrate were less uniform.Though the content of caproic acid is higher in the acid compounds,the content of alcohol was lower in the alcohol compounds.In addition,the content of alcohol compounds except n-propanol produced from normal pit was lower than that from high-quality pit.25 PLFAs were detected in different grades of pit mud.The dominant fatty acids in the high-quality and normal pit mud only showed differences in the types,but the fatty acid content in the degraded pit mud was generally lower than the others,some of the characteristic fatty acids existed in the normal pit mud were not detected.Analysis of pit microorganism by bacterial primers found that the highest similarity of all sequencing bands were belong to 21 genuses,3 phylums including Firmicutes,Bacteroidetes and Proteobacteria.Among them,Syntrophomonasand Lactobacillus is most obvious in degraded pit mud.Weis sella,Anaerobranca,Tetragenococcus,Ruminococcus were the dominant genuse in normal pit mud and the superior genuse of high-quality pit mud were Clostridium,Tanticharoeni,Pseudomonas,Azotobacter and Lacibacte.The Clostridium class primers were used to analyze the microorganisms of the mud.The highest similar of all sequencing bands belonged to the Clostridium class,a total of 11 genera.Based on the comprehensive DGGE pattern and strain sequencing results,it was found that the Bacteria and Clostridium bacteria in high-quality pit mud had the highest diversity and evenness,followed by normal pit mud,the degraded was the worst.Except for moisture,Analysis of physical and chemical Indicators in the process of new pit mud cultivation suggested that they had a same trend in thecontent of ammonia nitrogen,effective phosphorus,effective potassium,humus and pH,which decreased at the earlier and then increased until to stable status.Analysis of pit microorganism by bacterial primers found that the highest similarity of all sequencing bands belonged to 5 phylums including Firmicutes,Bacteroidetes,Proteobacteria,Actinobacteria,Synergistetes.At the genus level,Lactobacillus,Welchella Acinetobacter,Chryseobacterium,Empedobacter,Corynebacterium,Leucobacte,Prevotella,Desulfotomaculum,Porphyromonadaceae,Comamonas were the dominant microorganisms at the initialperiod of pit mud culture、...