Study On Fermentation Process Of Defatted Wheat Germ And The Biological Activity Of Its Extract

Wheat is one of the most extensive cultivated plants in the world.All over the world,there are about 35%～40%of the population eating wheat as staple food. Modern food science and nutrition have shown that wheat germ is not only rich in high-quality protein,fat,vitamins and minerals,but also contains some bioactive substances.Recent research demonstrated that the bioactive substances will increase obviously after fermentation.Otherwise,the research on fermentation with wheat germ is not many in China.And the main study is about fermentation food rather than bioactive substances.Because of the activity ofα-amylase in wheat germ is high similarly to barley,wheat germ have had generally exploitation value as fermented starting materials.Defatted wheat germ was used as raw material in this study,and a method of high performance liquid chromatogram for accurate fast inspection of the 2,6-DMBQ was established.Five Saccharomyces cerevisiae were screened to fermented defatted wheat germ and the fermentation conditions were optimized. Then the antioxidant activity,antibacterial activity,anti-tumor activity of fermentation products were studied.The main conclutions are presented as follows:1.A method of high performance liquid chromatogram method for accurate fast inspection of the 2,6-DMBQ was established.The high performance liquid chromatogram conditions were as follows:Agilent ODS2(250mm×4.6mm,5μm), Liquid phase was Methyl alcohol-Water whose volume ratio was 25:75,the flow rate was 1mL/min,Temperature:30℃,the detector was Ultraviolet detector,the wave length was 288nm.2.Took the defatted wheat germ as raw material,used the content of 2,6-DMBQ as evaluation index,screening five Saccharomyces cerevisiae to fermented wheat germ.They were high-activity Saccharomyces cerevisiae, thermostable Saccharomyces cerevisiae,yellow rice wine Saccharomyces cerevisiae,Beer Saccharomyces cerevisiae and grape wine Saccharomyces cerevisiae.We discovered the best Saccharomyces cerevisiae was Thermostable Saccharomyces cerevisiae.Carried on the fermented condition optimization such as the fermentation time,the addition of the wheat germ and the addition of the strain.the best Fermented condition is:wheat germ(w):water(v)=1:14,wheat germ(w):strain(w)=3:1,the fermented time is 36h,the fermentation temperature is at 30℃.3.The antioxidant activity tests of defatted wheat germ fermentation were studied,we studied the free radical scavenging effects of defatted wheat germ fermentation,such as DPPH Free Radical,hydroxyl radical,superoxide anion radical,and also studied a method for evaluating oxidation status of refrigerated cooked ground pork was established by synchronous fluorescence.The results showed that the defatted wheat germ fermentation had significant scavenging effect to DPPH free radical and hydroxyl radical,when the concentration was 1.0mg/mL,the clearance were respectively 82.9%,86%,the scavenging effect to superoxide anion radical and lipid inhibition were not significant,when the concentration was 1.0mg/mL,the clearance were respectively 38%,19%,the defatted wheat germ without fermentation had weak scavenging effect to all free radical except some activity to DPPH free radical.4.We studied the antibacterial activity of defatted wheat germ fermentation to eight pathogenic bacteria,used double-dilution method to analyze the minimum inhibitory concentration.Also we studied the stabilization of defatted wheat germ fermentation when it exposed to ultraviolet ray and high temperature.The results showed that the defatted wheat germ fermentation could inhibit escherichia coli, bacillus subtilis,and staphylococcus aureus efficiently,the minimum inhibitory concentration were respectively 12.5mg/mL,12.5mg/mL,50 mg/mL.Then the fermentation had no inhibition effect to mould and yeast.After the fermentation was exposed to ultraviolet ray and high temperature.The antibacterial activity reduced quickly.In 12h,the inhibition rate was increased by the time.5.The anticancer activities of the fermentation in vitro were analyzed with MTT method.We chose four tumor cell lines:A549,B16,SGC,Hela.The results showed that defatted wheat germ fermentation exhibited low anticancer activities in vitro,the maximal percentage inhibition was 40.5%,the inhibition of methanol extract was better than ethanol extract.And showed significant does-dependent response.Methanol extract and ethanol extract showed best inhibitory effect to B16.Defatted water extract had no inhibition to all tumor cell lines.There is no obvious difference between freeze dried product and spray dried product.