Study On The Improvement Of Flavor Substances Of Vinasse Based Liquor By Lipase

Distillers'grain is a major by-product of liquor production,and is rich in organic components such as cellulose,protein,short-chain fatty acids,amino acids,and inorganic elements such as potassium and phosphorus.Distillers'grain is susceptible to mildew and perish,which brings huge environmental problems,and its resource utilization is of great significance.If the short-chain fatty acids in the liquor can be converted into ester flavors with aroma,the quality of the complex lees will be greatly improved,which will bring considerable economic benefits to the liquor business while solving the dilemma of disposal of lees.Yeast surface display technology is an immobilization method for displaying enzyme proteins on the surface of cells.The displaying enzyme could be obtained by simple cells collection while eliminating the process of protein separation and purification.Thus it has many advantages such as simple process,low cost and high catalytic efficiency.It shows good performance in the field of bio-transformation and manufacturing.The performance has been a research hotspot in the field of green bio-manufacturing in recent years.The previous research in this laboratory showed that Pichia pastoris based on this technology showed that Candida antarctica lipase B could catalyze the esterification of short-chain fatty acids.There is a certain potential for application in the study of aroma substances..In this paper,the research on the use of Luzhou-flavor liquor lees as the research object is to carry out the resource reuse research of lees based on yeast-catalyzed lipase-prepared lees.We first study the enzymatic treatment process at the laboratory level.First of all,the whole cell catalyst Pp-CALB independently developed by our laboratory was used to enzymatically treat the lees of lees,to establish a reliable reaction system and a method of steaming wine.Liquor ester flavor substances such as ethyl lactate are quantified.The study found that,after pasteurization,the diarrhea can eliminate the influence of bacteria on the synthesis of flavor esters.The contents of ethyl acetate and ethyl caproate were increased by nearly 40%compared with the unsterilized experimental group.Further,a single factor optimization experiment was carried out on the factors affecting the synthesis of flavor esters,such as the amount of Pp-CALB enzyme,the amount of edible alcohol,the reaction time and temperature,to obtain the better reaction conditions:the amount of edible alcohol 20%?w/w?,Pp-CALB enzyme addition amount 0.15%?w/w?,reaction temperature 25?,reaction time 5days,ethyl acetate content 1.60 g/L,ethyl caproate content 0.54 g/L,ethyl lactate content 0.91g/L,total ester content 3.05 g/L.On the basis of single factor optimization,L₉?3⁴?orthogonal experiment optimization was carried out to obtain the optimal treatment conditions:the addition of edible alcohol was 20%?w/w?,and the addition of Pp-CALB enzyme was 0.15%?w/w?1.The reaction temperature is 20?and the reaction time is 3 days.At this time,the ethyl acetate content was 3.17 g/L,the ethyl caproate content was 0.59 g/L,the ethyl lactate content was 0.76 g/L,the total ester content was 4.53 g/L,and the total ester content was higher than that after single factor optimization.Increase by nearly 50%.Based on the orthogonal experiment,the reaction system was preliminarily enlarged,and a small-scale experiment with a processing capacity of 1 kg was first carried out.The content of ethyl acetate,ethyl caproate,ethyl lactate and total esters were 3.44 g/L,0.85 g/L,0.70 g/L and 4.98 g/L in order,of which the main flavor of the liquor is acetic acid Ethyl acetate and ethyl caproate were 16.38 times and 16.67 times higher than those of the experimental group without Pp-CALB enzyme treatment,respectively.On this basis,we conducted a pilot test of300 kg in the winery.When the amount of CALB enzyme powder was 1 kg,the content of ethyl acetate,ethyl caproate,and ethyl lactate were 216.48 mg/L,752.95 mg/L and 163.64mg/L,respectively,showing good application potential.