Study On The Microorganism Flora And Flavor Compounds From Vinasse Fish

This paper was consisted of four parts of studies on vinasse fish. (1) Improvement of the processing technology to produce the vinasse fish with best quality and flavor. The results were showed as followings: the optimal salting technology was 8% of salt dosage,salting at 10℃for 24 h ; the optimal drying technology was the lowest speed of the fan, drying at 40℃for 8h; the optimal fermentation technology was 1% of fermentation dosage,aerobic fermentation for 40h,anaerobic fermentation for 48 h. In the addition, the sterilization temperature and time were optimized based on evaluation of 10 sensory staffs on both quality and flavor of variety of the vinasse mugil cephalus. We found that the optimal sterilizating technology was sterilization at 95℃for 10 min. Under the optimal processing technology, the vinasse mugil cephalus with best quality and flavor was produced; (2) Isolation, purification and identification of the microorganism in the process of the fermentation of the vinasse mugil cephalus. Under the optimal processing technology condictions, the microorganism from the fermentation of vinasse mugil cephalus were isolated and purified by Selective Agar and identified by the form observation, physiological and biochemical, PCR technology and Microbial Automatic Identification System on the strains. We found that Bacillus subtilis,Pseudomonas,Lactic acid bacteria and Yeasts were the dominant microorganism in the proces of the fermentation of Vinasse mugil cephalus. The Bacillus subtilis was the dominant microorganism in the early and mid fermentation stage. The Pseudomonas and the Lactic acid bacteria were the dominant microorganism in the later fermentation stage. The Yeast was the microorganism in the whole fermentation stage. The proteolytie and lipolytie activities of the dominant strains by the special Media were studied. It was showed that Bacillus,Pseudomonas,Lactic acid bacteria were of the function of Proteolytie activity, and Yeasts were of the funcation of lipolytie activity; (3) On the detection and analysis of nonvolatile compounds from the fermentation of vinasse mugil cephalus by conventional chemistry and GC analysis, we found the following variation of the compounds: decrease of the NaCl; increase of the total sugar, the reducing sugars, and the organic acids; decrease of crude protein and Salt-soluble protein; decrease of the amino nitrogen after prior increase; decrease of fat and increase of FAA. The content of the nonvolatile compounds were in dynamic equilibrium during the later fermentation stage. This result indicates that quality of vinasse is stable after 88h of fermentation. In the addition, the analysis was made on the correlations between the nonvolatile compounds and the dominant microorganism by SPSS sofeware. It was found that Bacillus were significantly and positively correlated with the content of the amino nitrogen, and Pseudomonas and Yeasts were significantly and positively correlated with the content of the FAA, which theoretically explain Bacillus were of the proteolytie activity and could degrade protein into the amino nitrogen, Pseudomonas and Yeasts were of the lipolytie activity and could degrade FAT into FAA. This was correspond with the result of the proteolytie and lipolytie activities; (4) The volatile flavor compounds from the fermentation of vinasse mugil cephalus were isolated by solid phase micro extraction and analysed by GC-MS. 42 volatile flavor compounds were identified, of which, 15 of them from original material, 10 of them from the 40 h fermentation of vinasse mugil cephalus, 25 of them from the 88 h fermentation of vinasse mugil cephalus. The main volatile flavor compounds from 88h of fermation were identified as carboxylic acids, ketones and Esters, the content of which accounted for 88.8% in all the volatile flavor compounds. They made great contribution to the flavor of vinasse mugil cephalus.