The Effect Of Fermentation On The Contents Of Functional Compositions In Mulberry

Mulberry, the fruit of Morus alba L., has abundant nutritional ingredient and active constituents, such as resveratrol, polydatin, anthocyanins, procyanidine and organic selenium, for what it is used as both food and drug. Mulberry has long been used as a tonic medicine in Traditional Chinese Medicine. It possesses the functions of helping produce saliva and slake thirst, nourishing blood, expelling wind-damp, alleviating hangover, etc. and is used to treat diabetes, liver and kidney deficiency, insomnia and tinnitus, constipation, premature graying hair, neurasthenia, and so on. The physiological studies on mulberry showed that treatment with mulberry can decrease blood sugar and lipids, prevent cardiovascular diseases, display anti-aging effect, and improve eyesight.This article reviewed the progress in the studies on chemical components and pharmacological activities of mulberry, then developed a new processing method on mulberry fruit, making mulberry rice wine by fermenting dry powder of mulberry together with sweet rice. Traditional brewing process for rice wine was adopted to produce in these studies, in which sweet rice was used as carbon source for fermenting mulberry powder, and the changes of the contents of the functional constituents in mulberry, including anthocyanins, procyanidine, resveratrol, and polydatin, were monitored during fermentation.DNS method was employed to quantify the contents of reducing sugar, density flask method for alcohol level, pH-differential method for anthocyanidin, UV spectrophotometry for proanthocyanidin, HPLC for resveratrol and polydatin. All these quantitative methods were validated for the applicability on samples including mulberry. The results from methodological evaluation showed these methods had good properties in linearity, precision, and repeatability. The accuracy of the UV spectrophotometry for determining procyanidine, while the recovery rates of the methods for measuring reducing sugar, resveratrol, and polydatin were87%,90%, and93%, respectively. So, the quantitative results for sugar, resveratrol, and polydatin should be divides by the corresponding recovery rates to give the true contents of these composites..Two steps were exerted in producing mulberry rice wine, including saccharification of sweet rice and addition of mulberry powder followed by fermentation. The fermentation liquors were sampled at the day of0,1,2,4,6,8, for measuring the content of reducing sugar, anthocyanidin, proanthocyanidin, resveratrol, polydatin and alcohol level, pH value. The result showed that, during the fermentation process, the pH value of fermentation liquor did not changed significantly, while the contents of anthocyanin, resveratrol, and polydatin decreased gradually and eventually stabilized at60μg/mL,1.0μg/mL and0.35μg/mL, respectively, accompanied by the decrease of reducing sugar content and the increase of alcohol content. On the contrary, the content of procyanidine increased in the process of fermentation and eventually stabilized at3.25mg/mL.