Study On Processing Quality Of Blackened Jujube Wine

Blackened jujube is formed from red jujube by temperature-controlled wet curing.Take black date as raw material,through yeast fermentation and become a kind of date wine,called black date wine.In this project,the blackened jujube wine fermented with red jujube wine under the same conditions was compared with red jujube wine,the changes of alcohol degree,reducing sugar,total acid,5-HMF,c AMP,total flavonoids and polyphenols in the fermentation process were tracked and analyzed,and the antioxidant capacity,methanol,higher alcohols（isobutanol,isoamyl alcohol）,volatile component composition and relative content of blackened jujube wine and red jujube wine were compared,At the same time,the physicochemical properties,antioxidant capacity and volatile components of five kinds of blackened jujube wine（Ningyangdazao,Jinsixiaozao,Goutouzao,Muzao,Huizao）under the same conditions were compared and analyzed.The main results are as follows:（1）Study on physicochemical properties and antioxidant capacity of blackened jujube wine and red jujube wineThe results showed that the fermentation period and alcohol content of red jujube wine and blackened jujube wine were 11 d,13.4%vol and 16 d,12.9%vol,respectively.At the end of fermentation,the reducing sugar,polyphenols and total flavonoids in blackened jujube wine were significantly higher than those in red jujube wine.The total flavonoid and polyphenol contents of blackened jujube wine were 2.1 and 1.4 times higher than those of red jujube wine.Total acid,c AMP,methanol,higher alcohol（isobutanol,isoamyl alcohol）were lower than that of red date wine.Among them,c AMP in blackened jujube wine was only20.80% of that in red jujube wine.At the beginning of fermentation,the content of 5-HMF in blackened jujube wine was high,reaching 153.892 mg/L,but as the fermentation went on,the content was basically the same as that in red jujube wine on day 4.The results showed that the IC50 values of ABTS and DPPH were 0.531 g/m L and 0.417 g/m L,respectively,and the IC50 values of DPPH were 0.289 g/m L and 0.142 g/m L,respectively.The hydroxyl radical scavenging rates of blackened jujube wine and red jujube wine were 52.8% and 10.54%,respectively.The antioxidant capacity of blackened jujube wine was significantly higher than that of red jujube wine（P<0.05）.（2）Study on volatile components in fermentation of blackened jujube wine and red jujube wineThe main volatile components of red jujube wine and blackened jujube wine were determined by SPEM-GC/MS.The relative contents of alcohols,ketones and aldehydes in blackened jujube wine and red jujube wine were similar,while the proportion of esters in blackened jujube wine（19.23%）was significantly higher than that in red jujube wine（9.04%）.Among them,ethyl acetate in blackened jujube wine reached 7.26%,followed by the relative content of ethyl octanoate,ethyl decanoate,ethyl laurate and ethyl benzoate at a high level,while most of the esters in red jujube wine were below 1.00%,only isoamyl acetate,ethyl hexanoate and ethyl octanoate ranged from 1.12% to 1.55%.Moreover,the acid content of blackened jujube wine is lower than that of red jujube wine,which makes the overall aroma of blackened jujube wine rich and better typicality.（3）Study on physical and chemical properties and antioxidant capacity of different varieties of blackened jujube wineThe physical and chemical properties and antioxidant capacity of different varieties of blackened jujube wine were different during fermentation.The results showed that the fermentation period of the five jujube wines was 14～18 d,the alcohol content was12.3～14.7%vol,and the contents of reducing sugar and total acid were not different.At the beginning of fermentation,the contents of 5-HMF in different varieties of blackened jujube wine were different and high,but on the 4th day of fermentation,the contents of 5-HMF decreased rapidly to 3.00 mg/L and remained unchanged until the end of fermentation.The content of c AMP in different varieties of jujube wine was significantly different,among which,Goutouzao blackened jujube wine had the highest content（6.18 mg/L）,and Muzao blackened jujube wine had the lowest content（1.16 mg/L）.The contents of polyphenols and total flavonoids in Huizao blackened jujube wine were 1.89 mg/m L and 0.482 mg/m L,respectively.The antioxidant results showed that Ningyangdazao blackened jujube wine had the strongest scavenging ability of DPPH and ABTS,and the hydroxyl radical scavenging ability of gray jujube was the strongest.DPPH,ABTS and hydroxyl radical scavenging abilities of blackened jujube wine were the worst.The hydroxyl radical scavenging rate of Huizao blackened wine was the highest（58.28%）.The hydroxyl radical scavenging rate of Muzao blackened jujube wine was the lowest,only 27.02%.（4）Study on volatile components of different varieties of blackened jujube wineThe composition and content of volatile components in different varieties of blackened jujube wine are different.The results showed that there were 42 kinds of Ningyangdazao blackened jujube and blackened jujube wine,34 kinds of Goutouzao blackened jujube wine,41 kinds of Muzao blackened jujube wine,49 kinds of Jinsixiaozao blackened jujube wine and 42 kinds of Huizao blackened jujube wine.The alcohols（52.68%）in Ningyangdazao blackened jujube wine were the highest.In Goutouzao blackened jujube wine,esters（32.28%）accounted for the highest proportion;Aldehydes（18.62%）were the highest in Jinsixiaozao blackened jujube wine.The ketones in Ningyangdazao blackened jujube wine were the highest（9.88%）,and the ketones in Muzao blackened jujube wine,Jinsixiaozao blackened jujube wine and Huizao blackened jujube wine were all below 1.52%.No ketones were detected in Goutouzao blackened jujube wine.