Study On The Effect Of Pretreatment On Triticale Bran And Its Effect On The Quality Of Dough

Triticale bran,a by-product of the milling process of triticale（X Triticosecale Wittmack）,is rich in dietary fibre,protein,pigments and other nutrients.However,the addition of bran in food processing often leads to the deterioration of product quality,so its utilization rate is still at a low level.Therefore,it is necessary to pretreat triticale bran,improve its nutritional composition and processing properties,in order to improve the utilization rate of triticale bran.In this study,eight pretreatment methods were used to pretreat triticale bran,and the changes of properties of triticale bran after pretreatment were explored.On this basis,the pretreated triticale bran was added back to triticale flour,and reconstituted into triticale whole-wheat flour（TWWF）to investigate the effect of the pretreated bran on the processing properties of TWWF and the quality properties of triticale whole-wheat bread（TWWB）.The main research results are as follows:Firstly,the effects of pretreatment methods on the functional components of triticale bran were studied.Water-extractable arabinoxylan（WEAX）content increased by 118.97%after solid-state fermentation,WEAX andβ-glucan contents increased by 5.81 times and 1.00 times after enzymolysis,respectively.The phytic acid and glutathione contents were reduced after all pretreatments,and the phytic acid degradation was the most significant after enzymolysis,while the glutathione content was the lowest after high-pressure steaming pretreatment.After pretreatment,the starch of triticale bran was partially gelatinized,and the crystallinity and gelatinization enthalpy were both reduced,with the most significant reduction in both after high-pressure steaming,by 33.39%and 60.29%respectively.After enzymolysis,the water holding capacity,oil holding capacity and swelling force of triticale bran decreased,while the water solubility index increased.Enzymolysis and solid-state fermentation increased the total phenolic content of the free extract of triticale bran and its DPPH and ABTS radical scavenging capacity,and enzymolysis pretreatment showed the highest retention（84.79%）of anthocyanin.Secondly,the effects of pretreatment methods on the properties of triticale bran protein were studied.After enzymolysis,the contents of albumin,free polypeptide,free amino acid and essential amino acid in triticale bran were increased by 13.32%,61.17%,13.92%and73.72%,respectively.All pretreatments reduced the proportion of high molecular weight proteins and polypeptide.The release rate,hydrolysis degree and digestibility of in vitro digestion of triticale bran protein were significantly increased after enzymolysis treatment,which were increased by 31.73%,22.28%and 26.30%,respectively,after digestion termination.In conclusion,the protein properties of triticale bran was significantly improved after enzymolysis.In addition,the effects of pretreatment methods on the lipid stability of triticale bran were studied.After high-pressure steaming and solid-state fermentation,the fatty acid value decreased by 21.61%and 20.33%,respectively.After steaming treatment,the peroxidase value,lipase and peroxidase were all low to undetected levels,the activity of lipoxygenase was the lowest after high-pressure steaming,and only 20.09%remained.The contents of saturated and monounsaturated fatty acids increased by 21.97%and 27.74%,respectively,and the content of polyunsaturated fatty acids decreased by 15.72%after enzymolysis,and a higher levels of 2-pentylfuran was detected in the volatile compounds.In conclusion,high-pressure steaming had the most significant stabilizing effect on lipid of triticale bran.Then,the effects of bran pretreatment methods on the properties of TWWF and triticale whole-wheat dough（TWWD）were studied.After solid-state fermentation,the gluten performance index of TWWF increased from 0.259 to 0.289,and the breakdown value of starch gelatinization decreased by 22.26%.The development time of TWWD was shortened from 6.30 min to 2.37 min,the stability time was increased from 8.80 min to 10.12 min,and the weakening degree was significantly reduced.The storage modulus（G’）and loss modulus（G"）of TWWD increased,and the loss tangent（tanδ）decreased,which enhanced the elasticity of TWWD.The fermentation tolerance of TWWD was enhanced,the gas retention capacity was increased by 14.13%,the proportion of A₂₂ was significantly increased,and the distribution of water was improved in favor of the enhancement of gluten network structure.In conclusion,the processing properties of TWWD were significantly enhanced after solid-state fermentation of triticale bran.In addition,the effects of bran pretreatment methods on the gluten protein properties of TWWD were studied.The addition of triticale bran resulted in an increase in albumin and globulin and a decrease in glutenin macropolymers（GMP）of TWWD.After solid-state fermentation,the SDS soluble protein of TWWD decreased significantly,the GMP content increased from 5.47%to 6.78%,the weight loss rate and free amino group decreased by 11.35%and 40.35%,respectively.With the decrease of hydrophobic interaction,hydrogen bond and disulfide bond were increased by 23.71%and 61.86%,respectively,and the contents ofα-helix andβ-sheet conformation of stable gluten protein structure were increased,indicating that the gluten network structure of TWWD was significantly enhanced after solid-state fermentation of triticale bran.Finally,the effects of bran pretreatment methods on the quality of TWWB were studied.After different pretreatment,the quality of TWWB was improved,and the improvement effect of solid-state fermentation was the most significant,with the specific volume increased by20.60%,hardness and chewability decreased,porosity decreased by 26.07%,and cell density increased significantly.