Study On Brewing And Antioxidant Activity Of Mulberry-strawberry Wine

Mulberry is rich in nutrients and contains large amounts of substances withantioxidant activity, such as anthocyanin, Resveratrol, vitamin C, and vitamin B, whichare capable of many different kinds of roles in health care such as improving eyesight,prevent hardening of the arteries, anti-cancer and anti-aging. Strawberry is known as the"Queen of fruits", its nutritional value is very high, and is rich in vitamin C. People willnot get inflamed or catch cold even eat lots of strawberry. So strawberry is suitable forboth young and old to eat.With the improvement of people’s living standard, fruit wine has been given moreattention and love. Mulberry-strawberry wine which was fermented with mulberry andstrawberry together, not only solved the shortcomings of the two fruits which are difficultto preserve, but also met the demand of people for nutrition and health.Mulberry contains large amount of anthocyanin, which is the main substance withantioxidant activity. Anthocyanin mainly exist in the form of glycoside in nature, so thecontent of anthocyanin with form of glycoside was measured as a index in this experiment.Simultaneously we determine the total antioxidant capacity of mulberry-strawberry wine.Antioxidant exert antioxidant activity in the body is realized mainly by scavenging freeradicals, and hydroxyl radical is the main free radical of human body, so we text thehydroxyl radical scavenging ability of the mulberry-strawberry wine.Anthocyanin content in mulberry-strawberry wine is determined by pH-differentialmethod, specific methods of operation according to article “Optimization of analyticalcondition of determining anthocyanin content in blueberry wine by pH-differentialmethod”.The total antioxidant capacity of mulberry-strawberry wine was determined withPrussian blue method. The experimental procedure has some adjustments compared withthe steps of the article “The Optimization of Determination Method in Total AntioxidantCapacity and Total Polyphenol Which Applied to the Research of Brewing of BlueberryDry Red Wine”: The concentration of potassium ferricyanide was changed to0.1%, and the volume of it was changed to1mL. Simultaneously the water temperature was adjustedto55℃, water bath time must be changed to35min.Spectrophotometric method was used to determine the hydroxyl radical scavengingcapacity of wine in this experiment, Specific methods of operation in accordance witharticle in accordance with article named “Determination of hydroxyl radical in Fentonreaction by Spectrophotometry. There are some changes in the specific steps，for example,volume of FeSO4solution was changed to2.5mL, and we changed water bath of37℃toplaced it at room temperature. The result of experiment optimized has some improvement,but the main advantage is that we did not need to water bath, instead we just put it at roomtemperature for some time, so it is easier for us to operate.The aroma of strawberry wine is pleasant, while the taste and color was not verysatisfactory. Mulberry wine has good color and taste, but the advantage of aroma was notobvious. So the mulberries and strawberries was mixed to make mulberry-strawberry wine,so that they can complement each other. By measuring anthocyanin ofmulberry-strawberry wine during the brewing process and comparing the sensory index ofit, we know that, the color, aroma, taste and other sensory indicators ofmulberry-strawberry wine are good, and the loss of anthocyanin during fermentationprocess, so it was determined that the ratio of mulberries and strawberries was3:7.During the brewing process of Mulberry-strawberry wine, anthocyanin and otherphenolics were extracted at the beginning of fermentation. The antioxidant capacity andability to scavenge the hydroxyl radical of wine was also increasing. Three days later (thelength of time may change under different fermentation conditions), the anthocyanincontent of wine was decreased. At the same time, some other fat-soluble antioxidants wereextracted with the alcohol increasing, and the total antioxidant capacity and hydroxylradical scavenging capacity of wine increased a little. The total antioxidant ability andscavenging ability of Wine did not increase and had a slight decrease after leachingcompletely.The effect of aging conditions on the anthocyanin content and antioxidant capacity ofwine was biggest, so more suitable aging conditions should be explored, such as low temperature and avoiding light etc. The influence of dipping time was small, this showedthat, the antioxidants extracted was little after the third day. In addition, the affect of sulfurdioxide amount on the indexes was small.The wine taste better after a certain aging time, but the antioxidant capacity of winewill be greatly reduced with the aging time increasing, even if stored it without light and ata low temperature conditions. Therefore, it should be drinked as soon as possible ensurethat the wine taste good.