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Study On Preparation Of Freeze-Dried Powder Of Low-alcohol Cider And Optimization Of Its Fermentation Process

Posted on:2015-07-21Degree:MasterType:Thesis
Country:ChinaCandidate:N HuFull Text:PDF
GTID:2371330491453624Subject:Engineering
Abstract/Summary:PDF Full Text Request
Apple cider in the beverage market in China still belongs to the emerging products.With the advantage of low alcohol,rich of liquor fragrant,special aroma of apple,low-alcohol apple cider is popular,which is widely suit for people of all ages,every job and all kinds of occasions.It has a great market potential.Therefore,the optimization of low-alcohol cider is significant on the basis of previous research.Firstly,we saved yeast strains with vacuum freeze-drying method.This study concentrated on to gain the two different composite cryoprotectants against the two strains.The yeast powder,with high survival rate and strong ferment activity,could be able to direct production,which could be use in industry and have an application prospect.Then,analyzing yeast strains,ferment material,ferment method and the optimization of ferment process,which aimed to gain a better brewing process and parameters.Also,consumers would rather to choose it because of its flavor and taste.Thus,the study mainly gained the produce and preserve methods of ferment yeast powder for the fermentation of apple cider,which posses high survival ratio and ferment activity based on vacuum freeze-drying method.Also,we optimized and established the best production for low-alcohol and made an evaluation of aroma compounds.The results of this paper are as follows:1、This paper selected cryoprotectants of the two strains and optimized their preservation methods.The results showed that:0.9%NaCl as blank control,We verified 10 single cryoprotectants,in which obtained a composite cryoprotectant proportion that ensure high survival ratio.Based on it,fermentation activity of the two strains have been done by Duiham tube,results indicated that the two strains could finished their fermentation in two days after inoculation with great ferment activity.2、Picked pH、titratable acid、reducing sugar、alcohol degree as the main parameters to evaluate a optimal ferment method to brewing low-alcohol apple cider.Compared two fermenting methods,sequential fermentation and mixed fermentation,analysis their influence to key parameters of low-alcoholic apple cider.The results showed that:Sequential fermentation method is suit for a low alcohol degree and leads to a fruity liquor,mellow cider and suitable indicators by inoculation of Pichia 24 h after accessing saccharomyces cerevisiae fermentation.By this method,the quality of apple cider is better than normal fermentation.3.Using optimal-D-mixture to screen the variety of three apple materials,which are Huangjinshuai,Fuji,Qinguan.Picked alcohol degree as response value.And the experiment was designed and processed by Design Expert 7.0,a proper proportion was found.The results showed that Huangjinshuai to fuji is 0.715 to 0.285.According to the proportion,the alcohol degree is 5.42.It can meet great demands of consumers.4.Single factor experiment used brewing temperature,soluble solid,pH,yeast content as four factors,according to the contribution to the cider alcohol degree,selecting brewing’temperature,soluble solid,inoculum volume for process optimization.By the response surface method,Design-Expert 7.0 was used to design Box-Behnken experiment and follows the optimum parameters:brewing temperature was 24℃,soluble solid was 17 Brix,two yeast species amounts were 7%,respectively.Under this condition,the alcohol degree was 2.6 with desirability model.5.The aroma composition of cider was analyzed followed by process optimum experiment.These components were enriched with solid phase micro-extraction method(SPME)and detected by gas chromatography mass spectrometry(GC/MS).57 components were found,mainly acids,esters and aroma components composed of ethyl acetate,ethyl caprylate,ethyl hexanoate,propiolic acid,acetic acid,3-methyl-1-butyl alcohol,phenylethyl alcohol,eugenol,2,4-double(1,1-2 methyl ethyl)-phenol.Additional,little ketones and a oxime material were also discovered.The results showed that:Using sequential fermentation and the two yeast strains to ferment low-alcohol cider,there are kinds of aroma compounds and the cider is rich for pleasing flavor,which can satisfy consumers greatly.
Keywords/Search Tags:Low-alcoholic apple cider, Fermentation method, Process optimization, Aroma compounds, Yeast powder
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