Study On The Brewing Technology Of Cucurbita Moschata And Change Of Aroma Components

Cucurbita moschata,an annual tendril-bearing trailing plant,which belongs to the family Cucurbitaceae of the genus Cucurbita.There is much Cucurbita moschata in China and it distributes in Yunnan Province,Fujian Province,Jiangshu Province,Zhejiang Province,Hubei Province,Hennan Province,Hebei Province,Shanxi Province,Liaoning Province.e tal.It is rich in nutritious substance and contains many kinds of physiologically active factor.Adopting Cucurbita moschata as material to produce fermented wine can solve the problem of Cucurbita moschata overstock,open up new field for our Country's pumpkin resource utilization,enrich the wine species of market,so it will have a broad market prospect,get remarkable economic benefit.This paper focuses on processing pumpkin wine of high quality,several aspects were studied mainly in this paper.It included brewing adaptability of pumpkin juice,the effect of mixed enzymes on extracting pumpkin juice,the technology of main fermentation,analysis of aroma components of pumpkin juice and pumpkin wine.The main studies and results in the paper are mentioned as follows:1.Pumpkin slice was heat by four methods,the steam-heating method can increase the productive rate of juice and the soluble solid materials,which is better than the others.The experimental results showed that the extraction results with steam-heating method were that the productive rate of juice was 71.05%,the soluble solid materials.was 6.9%.2.Cloudy pumpkin juice was extracted from pumpkin pulp by filtration with two layers nylon gauze of 60 mesh,after filtration the total sugar,reducing sugar content and starch content is changed largely,which is that the network structure formed with pectin,crude fiber material etc of pumpkin pulp hampered some nutrients'filtration.In cloudy pumpkin juice,the total sugar content is 30.74g/L,the reducing sugar content is 9.04g/L,the total acidity is 1.27g/L,the starch content is 13.65g/L.3.The mixed enzymatic liquefaction conditions should be performed in 50℃for 3h at pH4.6, the experiment separately studied the influence of pectinase concentration,cellulose concentration and glucoamylase concentration on the productive rate of juice and the soluble solid materials.The results showed that the ratio of pectinase 0.08%,cellulase 1.0%and glucoamylase 0.25%were optimal through L₉(3⁴) orthogonal test on the basis of single factor tests of pectinase,cellulase and glucoamylase.Through orthogonal test,the productive rate of juice was 87.6%,reducing sugar was 39.7g/L.Mixed enzymatic liquefaction method was a better one,because of its higher productive rate of juice and soluble solid materials.The nutrients of pumpkin juice were little influenced because enzymatic liquefaction temperature was lower.The extract sliquefied by mixed enzymes was light yellow and delicate fragrance smell.4.Through comparison of.different fermentation methods,cloudy clarified juice fermented wine produces high alcohol concentration,the sensory quality of raw wine is good,which is better than fermentation with peels and clarified juice fermentation.So we adopt the cloudy juice fermentation as the fermentation mode.5.With study on the processing technology of pumpkin fermented wine,the thesis makes a systematic research on the basic factors of fermentation,it shows that the cloudy pumpkin juice with total sugar 17%-21%can produce alcohol content 9.8%-12.3%after 5 days fermentation,the surplus total sugar of original wine is under 4g/L,the optimum temperature of fermentation is between 20-25℃,the optimum loading capacity of can is 80%.Through the studied of dominant fermentation conditions orthogonal experiment,it shows that the wine fermented by angle yeast has the best total sensory quality,not only its aroma of wine is happy and aroma of fruit is obvious,but also its taste is harmony.The study shows that the circle of main fermentation is 6 days,the optimal inoculation volume 7%,the optimal total acidity is 7g/L,the amount of sulfur dioxide is 75mg/L.6.In pumpkin juice,aroma components which could be distinguished were 49 and 37 kinds in the original pumpkin juice and pumpkin juice with mixed enzyme treatment respectively,12 kinds aroma components were the similar between them,which are 1-Pentanol,acetoin,cis-3-Hexen-1-ol, n-hexanal,4-hydroxy-2-methylacetophenone and so on.Total amount of similar components covered respectively 9.92%of original pumpkin juice and 13.24%of pumpkin juice with mixed enzyme treatment..7.Aroma components which could be distinguished were 37,37 and 40 kinds in the pumpkin juice with mixed enzyme treatment,original pumpkin wine and pumpkin wine with stored 3 months respectively.Comparison the aroma components of pumpkin juice with the mixed enzyme treatment, original pumpkin wine and pumpkin wine with stored 3 months,5 kinds aroma components is similar, they are 1-pentanol,acetoin,4-hydroxy-2-methylacetophenone,nerolidol and hexadecanoic acid, methyl ester,total amount of similar components covered 3.26%,26.27%22.93%respectively; Comparison the aroma components of pumpkin juice with the mixed enzyme treatment and original pumpkin wine,8 kinds aroma components is similar,they are 1-pentanol,acetoin, 4-hydroxy-2-methylacetophenone,nerolidol,hexadecanoic acid,methyl ester,dodecanoic acid, pentadecanoic acid and phthalic acid,diisobutyl ester,total amount of similar components covered 22.67%and 29.04%respectively;Comparison the aroma components of original pumpkin wine and pumpkin wine with stored 3 months,27 kinds aroma components is similar,in addition to 5 kinds aroma components among the pumpkin juice with the mixed enzyme treatment,original pumpkin wine and pumpkin wine with stored 3 months,they are acetic acid,2-methyl-1-Propanol,propylene glycol,ethyl Acetate,2,3-butanediol,3-ethoxy-1-propanol and so on,total amount of similar components covered 85.44%and 92.28%respectively,18 kinds aroma components,the relative content of 18 kinds aroma components decreased,9 kinds increased in 3 months stored.