Research On Technology, Quality And Clarification Technology Of Cold-crushed Apple Pulp Fermented Wine

Apple is one of the popular fruits in China for its fresh taste,high nutritional value and relatively cheap price,and has a broad market prospect.In recent years,cider is getting more and more attention in pace with the increase of people’s health conscious,and cider production provides a new idea and new development direction for apple industry diversification.Compared with the foreign countries,there was a late start for China’s cider brewing industry,and no apple varieties for cider brewing,no yeast species for cider fermentation,and no mature cider brewing technology in China.Although the rapid development in recent years,as a new industry of China’s fruit wine brewing,apple cider industry still needs deep exploration in its processing and fermentative strain.Different from the traditional apple juice fermentation,this fermented experiment was doing with cold crash apple pulp using Shaanxi red Fuji and Granny Smith as raw materials.The selection of fermentative strain,processing parameters,co-fermentation ratio in two kinds apple pulp,quality analysis,and clarifying technology for apple sider were researched.The main results are as follows:1.The optimal fermentation conditions(initial sugar content 18%,SY yeast inoculum 0.1 g/L,and temperature 20℃)for apple sider with cold crash apple pulp fermented was obtained through single factor and response surface experiments after the detection of sugar content,alcohol content,pH value and total acid in different yeast fermentation cycles and the final index analysis.Compared to fermented cider with apple juice,the residual sugar(7.5±0.46 g/L pulp,7.3±0.31 g/L juice)and the alcohol content(7.8±0.1%,8.0±0.1%)of pulp fermented cider was no significant difference.However,the nutrient content of pulp fermented cider was higher than fermented cider with apple juice,such as total phenol(74.99±1.23 g/L pulp,47.50±2.20 g/L juice)and organic acid(5.33±0.01 mg/mL pulp,5.01±0.03 mg/mL juice).2.There was no significant difference in residual sugar(7.5±0.46 g/L pulp,7.3±0.31 g/L juice)and the alcohol content(7.8±0.1%,8.0±0.1%)between mixed apple pulp(the ratio of Granny Smith apple:red Fuji apple was 1:1,1:2,1:3,1:4(V/V)respectively)fermented cider and Fuji apple pulp fermented cider.The addition of Granny Smith apple had no significant effect on the fermentation rate,and with highly yeast stability.By comparing the nutrient composition and aroma analysis of fermented cider with acid adjusting,we found that the acidity(100%)increasing(66±0.31>58±0.23>44±0.11>39±0.18>33±0.33)with Granny Smith apple ratio(1:1,1:2,1:3,1:4,0:1(V/V))increases,while the total phenol content(87.3±0.11>83.7±0.30>79.7±0.24>75.7±0.61>68.5±0.43 mg/100mL)increasing as Granny Smith apple ratio increases.And the antioxidant activity of cider increased with the increase of Granny Smith apple addition ratio,and the color value of cider decreased which indicating sider’s browning was not easy.The organic acid content(8.28±0.03>6.99±0.10>6.23±0.06>5.62±0.03>5.33±0.01 mg/mL)increased with the increase of Granny Smith apple proportion,malic acid showed the largest change,followed by tartaric acid and lactic acid,and the content of succinic acid was basically unchanged among all of organic acid.There were 42 species of fragrant substances in mixed apple pulp fermented cider,including the 19 kinds of ester substances,11 kinds of alcohols,9 kinds of low-level fatty acid and 3 kinds of aldehydes and ketones.The main different fragrant substances between different fermented sider with different proportion of Granny Smith apple to adjust acidity was in esters,but other fragrant substances(such as aldehydes and ketones,low-level fatty acids and alcohols)were no significant difference basically.The important aroma substance in mixed fermentation cider was lauric acid ethyl ester,while the isobutanol and iso-amyl alcohol was mainly alcohols and acetic acid was mainly lower fatty acid in mixed fermentation cider.The optimal ratio of Granny Smith apple pulp to red Fuji apple pulp was 1:1(V/V)for mixed fermentation sider.3.The single factor experiment was done to choose the best clarifying agent using diatomite,bentonite,gelatin,chitosan as clarifying agent,and the bentonite was found has best clarifying effect on apple cider with the best light transmittance of 78.1%.The optimal clarifying conditions(bentonite added quantity of 6 g/L,clarify time of 6 d,temperature of 4℃)were got through the response surface experiments.There was no significant change of nutritional composition in apple cider before and after the clarification,no significant difference was discerned with e-nose detection.So,the clarify conditions were available for apple cider.4.According to the national standard,the quality of fermented fruit liquor obtained from this test is basically in line with the standard requirements,and all of them are dry fruit wine.