Effect Of Microwave Irradiation On Storage Stability And Quality Of Whole Wheat Flour

Whole wheat flour is a main form of whole grain food.Compared with ordinary flour,whole wheat flour is more balanced in nutrition due to the introduction of bran and wheat germ,but it also introduces more lipids(mainly in wheat germ),microorganisms(mainly in wheat bran)and enzymes with high activity.This series of changes caused by the degradation of lipids makes the storage time of whole wheat flour far lower than ordinary flour.At the same time,in the production of whole wheat flour,the mixing of bran also brings in more microorganisms,biological toxins(such as DON,etc.),and chemical contaminants(such as pesticide residues),which makes the eating safety of whole wheat flour more affected.Therefore,it is of great significance to adopt appropriate technical means to improve the stability of whole wheat flour and extend the shelf life,while also ensuring the quality of whole wheat flour.In the early stage of this experiment,the whole wheat flour was treated with different microwave power and different microwave time to compare and analyze the basic indicators of whole wheat flour under different microwave conditions,and the use of rheological fermentation instrument to study the different microwave conditions on whole wheat flour dough.The influence of the rheological fermentation characteristics of the whole wheat flour was analyzed,and the changes of the total number of colonies,fatty acid value and steamed bread quality during the storage of whole wheat flour were analyzed,the wheat grains were peeled and grinded to different degrees using the milling equipment.A series of physical and chemical indicators of whole wheat flour,such as pasting characteristics and physical and chemical indicators of whole wheat steamed bread specific volume,color difference,etc,to study the effect of peeling rate on the quality of whole wheat flour and determine the best milling time after 20 s of wheat grain milling treatment.The whole wheat flour obtained by milling was processed under different microwave conditions,and the parameters of flour quality,fatty acid value,gelatinization characteristics,rheological fermentation characteristics and browning were measured to study its storage stability for whole wheat flour.The main conclusions of the subject research are as follows1.The effect of microwave irradiation on the storage stability and quality of whole wheat flour by direct grindingWith the increase of microwave power and the extension of processing time,the increase rate of fatty acid value and aerobic plate count of whole wheat flour was inhibited;the content of wet gluten and the stability time increased first and then decreased;the maximum height of the gas release curve(H’m)and the gas total volume(R1)increased gradually,and the gas retention volume(R2)increased first and then decreased,and fermentation performance was improved;ratio of steamed bread Volume and comprehensive scores increased first and then decreased.When the microwave processing power is 400 W and the processing time is 120 s,it is good for the storage of whole wheat flour,and it can improve the flour properties,rheological fermentation characteristics and the quality of steamed bread.2.Effects of debranning treatment on the quality of whole wheat flour and steamed breadIncreasing of debranning process time improved debranning degrees and decreased the contents of pesticide residues,deoxynivalenol and sand.The precision and lightness of whole wheat flour were increased gradually.The dry and wet gluten contents of whole wheat flour were gradually reduced with the increasing of debranning process time,which were superior to common wheat flour.The weakness decreased roughly.The gas production and holding capacity of dough were first increased and reached the maximum when the debranning process time was 15 min,then decreased.The viscosity of pasting properties of whole wheat flour wereincreased roughly.The lightness and specific volumeof steamed bread were increased gradually and its sensory score was higher than that of the control,especially when the debranning process time was 15 min.In summary,the debranningprocess improved the quality of whole wheat flourand steamed bread to a certain extent.The safety parameters and qualityproperties of whole wheat flour and its steamed bread were in an optimal state when the time of debranning treatment was 15min.3.The effect of microwave treatment of wheat grains on the storage stability and quality of whole wheat flour(milling rate is 4.51%)Whole wheat flour was prepared by microwave-treating wheat grains after 20 s of milling.The experimental results showed that:with the increase of microwave power or the extension of microwave time,the fatty acid value was significantly inhibited;moderate microwave treatment(microwave power≤400 W,(Irradiation time≤120 s)the increase of wet gluten content in whole wheat flour;can increase the flour stability time of flour,reduce the weakening degree,increase the peak viscosity and rejuvenation value of batter;adversely affect the rheological fermentation characteristics;the color of the film after microwave treatment.The improvement and the browning rate have been reduced,indicating that moderate microwave treatment has a certain effect of inhibiting browning.4.The effect of microwave treatment on the storage stability of whole wheat flour produced by two processing techniquesWith the increase of microwave power and the extension of processing time,the fatty acid value of whole wheat flour produced by these two processing processes showed a significant downward trend.The fatty acid value of whole wheat flour without microwave irradiation has exceeded that of whole wheat flour in 16 weeks The industry standard(LS/T3244-2015),the fatty acid value of whole wheat flour in the direct grinding method under microwave irradiation(800 w 120 s)reached 106.59 mg KOH/100g in sixteen weeks,and the removal of 4.51%cortex under microwave irradiation 800 w 120 s The fatty acid value of whole wheat flour is only 66.39 mg KOH/100g in sixteen weeks.