| Poria cocos(P.cocos),a kind of traditional edible and medicative fungi,has enjoyed a great fame at home and abroad.P.cocos has a great deal of bioactive effects,such as invigorating spleen,tranquilization,decreasing blood glucose,inhibiting the growth of the bacteria and fighting against cancer.In this paper,the wheat was fermented by P.Cocos through solid-state fermentation and the changes of key enzyme activities and various nutrient components were continuously detected during the fermentation process.And the effects of extract from fermentation product(FPE)on the liver and antioxidation capacity in mice were evaluated.PCR-DGGE technology and traditional isolation and culture methods were used to explore the effects of FPE on the intestinal flora of mice,and whether FPE would affect the proliferation of Bifidobacterium and Lactobacillus in vitro was verified.The aim of this study was to provide a theoretical basis for the development of P.cocos fermentation products.1.The changes of key enzyme activity and various nutrient components during the solid-fermentation processWheat was fermented by P.cocos at 26℃.The changes of key enzyme activities of P.cocos mycelium and nutrient composition of fermentation products during fermentation process were investigated.The results showed that in the process of fermnentation,the activity of amylase was increased to the highest value of 494.2 U·mL-1 on 20 d,and after that it remained fairly stable.The highest xylanase activity value of 1073.2 U·mL-1 was obtained on 20 d with a slight decrease later.Cellulase activity was increased with time and was increased to 1280.5 U·mL-1 on 40 d.Through comparing with the control group of sterilization,we found that total sugar content was decreased significantly and down about 45.2%on 25 d,but the reducing sugar content increased from 0.389%to 27.40%.Furthermore,content of total triterpenoids and water-solubility triterpenoids increased gradually as the fermentation time rise and obtained the highest value of 1.6 mg/g and 0.12 mg/g respectively on 25 d.The content of nutrients in fermentation products remained in a relatively stable state after 25 d fermentation in general,which showed that the optimum cycle of the fermentation was about 25 d.Through comparing the volatile substances of wheat with product fermented for 25 d,we found that the numbers and content of volatile substances in fermentation products have been increased.And specifically,the relative content of aldehydes and alkenes increased while the alkanes decreased and there were some new compounds appeared in the fermentation products,which demonstrate that the volatile components of wheat may influenced by fermentation.2.The effects of extract from solid-fermentation products of P.cocos on liver function and antioxidation in miceWistar mice were used as the animal model to study the effect of extract from fermentation product on liver function and antioxidation.The mice were administrated for 4 consecutive weeks.The mice in experimental group and control group were administrated with FPE and normal saline(NS)respectively and the body weight of both were 320.31±5.89 g and 320.65±10.13 g.There was no significant difference of the body weight between the two groups which indicated that FPE had no impact on the diet of mice.At the same time,FPE had no significant effect on the content of alanine transaminase(ALT),aspartate transaminase(AST),alkaline phosphatase(ALP),albumin(ALB)in serum(P>0.05),suggesting that the FPE would not damage the liver function in mice.In comparison to control animals(1.4±0.14 mM),mice in experimental group(2.0±0.22 mM)showed increased total antioxidant capacity(TAS)(P>0.05).The activity of superoxide dismutase(SOD)in the experimental group was improved very significantly(P<0.01)which were 129.98±4.60 U/mL and 111.55±5.16 U/mL respectively in experimental group and control group.Those results suggested that the FPE could enhance the antioxidant capacity in mice.3.The effect of extract from solid-fermentation products on intestinal flora in micePCR-DGGE technology and traditional isolation and culture methods were used to explore the effects of FPE(0.5g/mL)on the intestinal flora of mice.According the results of the colony count of Lactobacillus,Bifidobacterium,Enterobacteria and Enterococcus in mice fecal,the number of Lactobacillus and Bifidobacterium in experimental group was both significantly improved(P<0.05).In addition,the results of PCR-DGGE showed that the amount of dominant bands of mice intestinal flora were similar in control group and experimental group which were 18 and 16 respectively.Nine major bands which had great changes were further eluted from gel,reamplified and sequenced.The results demonstrate that the bacterial phylotypes were closely related to the Bacteroidetes,Proteobacteria and Firmicute.FPE could promote the growth of probiotics,such as Lactobacillus johnsonii and Lactobacillus reuteri,reduce the amount of pathogenic bacteria,such as Clostridium bifermentan.All those results showed that FPE had a certain effect on the intestinal flora in mice.4.The vitro validation test of the effect on the proliferation of the Bifidobacterium and Lactobacillus with the extract from solid-fermentation productsThe effect on the proliferation of the Bifidobacterium and Lactobacillus with the extract from the solid-fermentation products(FPE)was also tested in vitro experiments to verify its effects,the results demonstrated FPE could be as a kind of bifidus factor to promote the proliferation of Bifidobacterium.Compared with other bifidus factors,such as isomalto oligosaccharides and fructo oligosaccharides,FPE could significantly promote the growth of Bifidobacterium(P<0.01).High concentration of FPE would inhibit the proliferation of the Bifidobacterium and Lactobacillus.The best added concentration of FPE should be from 2.5%to 5%.The absorbance of culture liquid containing FPE was higher than the control groups(P<0.01),Therefore,the extract can be used as a prebiotic to promote the growth of Bifidobacterium and Lactobacillus. |
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