| Until now,wheat bran, by-products of bulk grain processing, its development and utilization are rare, generally be used as feed ingredients. Wheat bran contains a type of plant secondary metabolites with extensive bioactivities which were termed as phenolics. The phenolics content is rich in the wheat bran. Meanwhilephenolics own the ability to improve human body physiology. While But it didn’t get a good processing application. In this study,we used the screened strains which can produce ferulic acid esterase to ferment wheat bran to release the bran bound form of phenolics and analyzed its oxidation resistance. Our research achievements on the one hand, is beneficial to gain more phenolic acid, on the other hand for bran value-added utilization of agricultural and sideline products as well as the medicinal functions such as main research direction of the development to provide effective way. The results are as follows: 1. Selection and identification of ferulic acid esterase producing strains:Using GAR plate screening and Oxford cup test to isolate strains producing ferulic acid esterase.Subsequently, individual characteristics of morphology, colony and ITS sequence analysis were performed. Finally, we obtained three strains with strong ability to produce ferulic acid esterase. They all belong to Aspergillus: No.6 Aspergillus(Aspergillus clavatus), No.1 black orange bacteriostatic bubble sheng Aspergillus(Aspergillus awamori), No.8 meters 3 Aspergillus oryzae, Aspergillus oryzae) respectively.Further, we analyzed and compared these three strains abilities on enzyme activity, total phenolic acid and ferulic acid release quantity. 2. Using strain fermentation in the bran to compare various enzyme activity, total phenolic acid and ferulic acid release quantityThe methods of spectrophotometric and HPLC were adopted to evaluate the enzyme acitivity of ferulic acid esterase, cellulase and xylanase strains abilities and release quantity of total phenolic acid and ferulic acid in bran fermented by these three strains. The results suggested that total phenolic acid and ferulic acid release quantityhas difference even though in the same conditions. Additonally, With the extension of time, the enzyme of all strains tended to elevate first and subsequently decline. The strain No.6 blue smoke ’s ferulic acid esterase, cellulase and xylanase enzyme activity are superior relative to the No.1 black orange bacteriostatic and No.8 meters 3 strains in fermented wheat bran. In 4thd,these three kinds of enzyme activity of No.6 reached their peak. Meanwhile, the ability to yield total phenolic acids was also stonger than others as the amounts of released total phenolic acids was increased by 6.6 times in the fermented wheat bran of No.6 strain, of which ferulic acid occupied 0.697%, enhancd by 0.22% related to the raw wheat ferulic acid. The released total phenolic acids also improved inbran fermented by other two strains. 3. Produce ferulic acid esterase strains fermented bran extract in vitro oxidation resistance changeThe oxidation resistance of(DPPH and ABTS, FRAP metal chelating ability) ferulic acid esterase produce by the screened out strains in liquid fermented wheat bran extraction were analyzed to evaluate the differentiation of various strains fermentation ability. The results showed that DPPH radical scavenging ability, ABTS +. removal ability, FRAP antioxidant capacity and metal chelating ability of bran fermented by three strains respectively would increases as the increase of wheat gluten concentration, moreover, 4 kinds of antioxidant capacity of the wheat bran fermented by No.6 were stronger than the wheat bran fermented by No. 1 black orange bacteriostatic and 8 meters 3. Compared with existing antioxidants VC and butylated hydroxytoluene,as well as the unfermented wheat bran, antioxidant capacity was dramatically enhanced. Electron microscope scanning structure of fermented wheat bran found that the microorganism fermentation can cause changes in the structure of wheat bran, qualitative crosslinking structure became loose, specific surface area increased, the crosslinking structure fractured, the smooth medial surface appear uneven marks and holes, all these resulted in release of bioactive substances and improvement of the total phenol and the content of ferulic acid in the fermented wheat gluten, finally, enhanced its antioxidant capacity. So that changes in the structure of fermented wheat bran is primary reason for the increase of the phenolic acids. |
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