Investigation On Fermentation Technology Of Pear Wine

The country is a big country in the production of pears,and the area and output of pear cultivation rank first in the world.However,the rate of deep processing of pear fruit in China is low,and most of them are mainly fresh food.In order to rationally develop and utilize pear resources and improve their economic benefits,it is necessary to carry out deep processing of pear fruit products.The pear fruit is tender and fragrant,juicy and sweet,and is suitable for brewing fruit wine.In this paper,the pear fruit varieties suitable for brewing pear wine were screened.The brewing process of snow pear was studied.The effects of fermentation conditions on the higher alcohol production of pear wine were studied.The bio-acidification of snow pear wine was studied.The main findings are as follows:（1）Screening of pear fruit varieties suitable for brewing pear wine.Pear wine is made from snow pear,yellow crown pear,south fruit pear,pear pear,Fengshui pear and banana pear.Twenty indicators including physical and chemical indicators,organic acid content and antioxidant content of six kinds of pear wine were determined.Descriptive statistical analysis,principal component and cluster analysis were used to evaluate the quality of pear wine.The evaluation results show that Nanguo Pear is most suitable for making pear wine,while Huangguan pear is not suitable for processing pear wine.（2）Research on the conventional brewing process of Snowflake Liquor.The effects of fermentation temperature,initial sugar content,inoculum size,pH and SO₂concentration on the conventional fermentation of Snowberry wine were studied and the process optimization was carried out.The suitable fermentation process for snow pear wine is:initial sugar degree 21°Brix,inoculum volume 5%,initial pH 5.0,fermentation temperature 20°C,SO₂ addition amount 60 mg/L,fermentation time 7d.Under this condition,the brewed rosewood wine has an alcohol content of 10.7%.The organic acids in the snow pear wine are mainly malic acid,acetic acid,citric acid and succinic acid.（3）The effect of fermentation conditions on the production of higher alcohol in snow pear wine.The higher alcohol content in fruit wine is an important flavor substance of fruit wine.Too high or low alcohol content has a negative impact on the sensory evaluation of fruit wine.The higher alcohol content of the snowflake wine using the conventional brewing process was 324.22 mg/L.The higher alcohols in the snow wine mainly include:isoamyl alcohol,isobutanol,n-propanol,β-phenylethanol,and the isoamyl alcohol content accounts for about the higher alcohol.The total amount of the four higher alcohols accounted for 62.17%total amount higher alcohols in the snow pear wine.The fermentation temperature had a great influence on the higher alcohol content of snow pear wine.With the increase of fermentation temperature,the higher alcohol content of snow pear wine increased significantly.The choice of ammonium phosphate,ammonium chloride,ammonium sulfate,diammonium hydrogen phosphate and ammonium hydrogencarbonate for the addition of nitrogen source to snow pear wine reduced the higher alcohol content of snow pear wine,and the effect of diammonium phosphate was the best.The optimum addition amount of diammonium hydrogen phosphate was 0.2 g/L.After optimization by orthogonal experiment,the optimal fermentation conditions for low-yield high-alcohol snow pear wine were:（NH₄）₂HPO₃ addition amount 0.2g/L,fermentation temperature 15°C,initial fermentation pH4.0,fermentation time 7d,inoculum volume 7%.The higher alcohol content of the brewed snow pear wine was significantly reduced to 110.58 mg/L.Compared with the snow pear wine brewed by the conventional process,the taste of the taste has been obviously improved,the bitter taste was almost disappeared,and the aroma was more coordinated.（4）Study on biological acidification of snow pear wine.Due to the low acidity of the raw materials of the snow pear fruit,the snow pear wine brewed by the conventional process has low acidity,light taste and insufficient aroma.The snow pear wine brewed by chemical acidification has a single taste and uncoordinated taste.Therefore,the research on biological acidification of snow pear wine has been explored.A lactic acid bacteria suitable for the bio-acidification of snowflake pear wine was selected from 11 strains of lactic acid bacteria:Lactobacillus plantarum 1101.The optimal fermentation process of acid-increasing snow pear wine was as follows:5%of the inoculum was used to inoculate Lactobacillus plantarum 1101 into the snowflake wine with 15 g/L glucose,and the fermentation was allowed to stand at 30°C for 7d in a constant temperature incubator.The total acid of snowflake pear wine increased from 3.01 g/L to 6.57 g/L,and the malic acid in wine decreased from 1.24 g/L to 0.54 g/L;the content of ester aroma was significantly increased.After the lactic acid fermentation of the snowflake pear wine,the aroma quality of the snow pear wine was obviously improved.In addition,the sensory quality of the snow pear wine was obviously improved,the taste was mellow and the aroma was more intense.