Studies On Enzymatic Extraction Of Arabinoxylan From Maize Bran And Its Stability Improvement Of Myofibrillar Protein Of Bighead Carp

Fresh corn bran as a clean and easy obtained agricultural byproduct was an abundant resource for exploiting food components.The content of arabinoxylan was the highest in the nonstarch polysacchride of fresh corn bran.At present,there was little research on enzymic extraction and application of arabinoxylan from corn bran.In this research the fresh corn bran was used to extract arabinoxylan by combined-enzymes and the extraction process was optimized by response surface.The extract obtained under the optimum condition was fractional precipitated by ethyl alcohol,and the two components was added in myofibrillar protein of bighead carp to improve its stability.The main results of this study were as follows:?1?The arabinoxylan of fresh corn bran was extracted by combined-enzymes,and CCD test was use to design the response surface test.pH,solid to liquid ratio,extracting time,temperature and amount of enzymes were selected according to single factor experiment to do response surface analysis.The optimum condition was determined as follows,pH was 3.0,solid to liquid ratio was 1:30,the extraction time was 6 h,the extraction temperature was 35.0,and the enzyme amount was 920U/g.The verification test demonstated that the yield was 40.73±0.09%,AX content of the extract was 75.88±0.11%.This result was consistent with the predicted values.which showed that the results optimized by the response surface method were reasonable and practical.?2?The extract obtained under the optimum condition was precipitated by four concentration of ethanol,and four components were obtained,which were F₂₀,F₄₀,F₆₀and F₉₀.The monosaccharide composition of the four components were mainly xylose and arabinose,and part of mannose,galactose and glucose,and a small amount of rhamnose;The yield?which was 12.46±0.59%and 27.42±0.43%,respectively?,AX content?which was 76.83±0.11%and 78.87±0.11%,respectively?and total sugar content?which was 65.31±0.39?g/ml and 69.24±1.10?g/ml,respectively?of F₆₀0 and F₉₀0 were significantly higher than F₂₀0 and F₄₀?P<0.05?;Both the A/X?which was0.56±0.11 and 0.58±0.00?and Mw/Mn?which were 2.72±0.11 and 3.98±0.09,respectively?of F₆₀0 and F₉₀0 were significantly lower than those of F₂₀0 and F₄₀?P<0.05?.Uronic acid content of F₉₀0 was significantly higher than other components?P<0.05?,which was 11.53±0.34?g/ml.Uronic acid content of F₆₀0 and F₄₀0 was no significant difference?P>0.05?,but significantly lower than F₂₀?P<0.05?;The protein contents was no significant difference between the components?P<0.05?.Mw of F₆₀was 19.27±0.66×10⁴,which was significantly higher than F₂₀,F₄₀,F₉₀?P<0.05?,and Mw of F₉₀0 had no significant difference with F₂₀0 and F₄₀?P<0.05?.So F₆₀0 and F₉₀0 was selected to be applied in improving myofibrillar protein's stability.?3?F₆₀0 and F₉₀0 were added to myofibrillar protein of bighead carp,and the denaturation temperature of myofibrillar protein of bighead carp moved to higher temperature,and when F₆₀0 was added,the denaturation temperature moved to 46.41?and 67.39?,when F₉₀0 was added,the denaturation temperature moved to 46.28?and 68.22?.The solubility myofibrillar protein of bighead carp which was added to F₉₀0 increased the most.The emulsification and emulsification stability of the myofibrillar protein of bighead carp was significantly improved when was added to the sacchride?P<0.05?,among which,the myofibrillar protein of bighead carp which was added to F₆₀0 had the best emulsification ability,and the myofibrillar protein of bighead carp which was added to F₉₀0 had the strongest emulsification stability.The energy storage modulus of gel of the myofibrillar protein of bighead carp and saccride in the process of thermal gelation was changed,and the energy storage modulus of the gel was the highest,F₆₀0 was the second,the smallest trehalose,and F₆₀,F₉₀0 were greater than the blank.The gel properties of the gel changed,and hardness of the gel the gel which was added to F₉₀0 was the largest,and the elasticity of sucrose was the largest.To sum up,the addition of AX of corn bran can improve the stability of myofibrillar protein of bighead carp.This subject could provide theoretical foundation for the comprehensive utilization of by-products of corn deep-processing and a new idea for aquatic products processing.