The Research On Fermentation Process Of Mulberry Jiaosu And Biotransformation Of Anthocyanins

The edible jiaosu is a product,containing specific bioactive ingredients,which is produced from animals,plants and fungus by microbial fermentation(T/CBFIA08001-2016).The mulberry is one of the medicine food homology foods,which had many biological activites,such as anti-oxidation,anti-aging,lowering blood fat and so on.In this research,the fermentation process,biochemical index,antioxidant activity and anthocyanin bioconversion of jiaosu from dry mulberry were investigated.The main results are as follows:(1)The optimal fermentation process of mulberry jiaosu was investigated by the single factor and orthogonal experiments and Lactobacillus plantarum was was selected as the fermentation strain.Firstly the dry mulberry,water and concentrated apple juice were mixed at a mass ratio of 1:8:1,then the mixture was pasteurized for 30 min under 60 °C.Finally,3% Lactobacillus plantarum was added to ferment at a constant temperature of 30°C for 15 days.(2)The biochemical indicators of mulberry jiaosu in the fermentation process were measured.The results showed that the pH of fermentation broth changed from 4.47 ± 0.04 to 3.49 ± 0.03,the concentration of glucose was reduced from 47.22 ± 0.08 mg/m L to 9.73 ± 0.07 mg/m L and the concentration of fructose was reduced from 105.82 ± 0.13 mg/m L to 29.41 ± 0.10 mg/m L by fermentation.The content of lactic acid and acetic acid in the fermentation broth increased continuously during the fermentation process,and their concentrations respectively were 9.81 ± 0.07 mg/m L and 2.91 ± 0.02 mg/m L after 15 days.In addition,the fermentation liquid also contained citric acid,succinic acid,malic acid,pyruvic acid,isovaleric acid and so on.(3)The antioxidant activity of mulberry jiaosu during fermentation was analyzed by antioxidant assays in vitro.The results showed that the content of total phenolics and flavonoids,DPPH radical scavenging capacity,hydroxyl radical scavenging rate and oxygen radical absorbance capacity(ORAC)showed a positive correlation during the fermentation process.They rapidly rose at earlier fermentation period,then decreased slightly.Finally,they kept stable with a better oxidation resistance.But the content of anthocyanin was continuously reduced during the fermentation,and there was negative correlation with other indexes.(4)The biotransformation of anthocyanin during the fermentation was discussed.The results showed that the content of protocatechuic acid,one of the transformation products,increased with the decrease of anthocyanin.The liquid chromatography mass spectrometry(HPLC-Q-TOF-MS)was applied to analyze the conversion products of mulberry anthocyanins.It was conjectured that phenolic acids,which contained protocatechuic acid and 8 other phenolic acids,were the biotransformation products of anthocyanin,In this research,a short-term and high-efficiency fermentation process of mulberry jiaosu was investigated.It was comfirmed that there were 9 phenolic acid conversion products by exploring the biotransformation of anthocyanin,which investigated partial biological activity of mulberry jiaosu and provided the reference for industrial production and development of health care products for mulberry jiaosu.