Effects Of Heat Moisture Treatment On Highland Barley-Wheat Dough And Dried Noodles

People pay more and more attention to healthy eating habits,because the incidence of cardiovascular diseases,diabetes,chronic intestinal diseases and obesity is gradually increasing.Highland barley has unique nutritional value,but its application in flour products is limited due to the lack of gluten protein.At present,studies have proven that adding heat moisture treated flour or starch could improve the quality of flour products.However,these studies do not explain how heat moisture treated flour or starch affects dough and flour products.At present,the research object of heat moisture treatment is still mainly the influence on the properties of starch,but the influence on the properties of flour is not well understood.Therefore,this study firstly investigated the effect of heat moisture treatment with different temperature and moisture content on highland barley flour,then three kinds of heat moisture treated highland barley flour and wheat flour are mixed to make compounded dough.Finally,we studied the effect of heat moisture treated highland barley flour on the quality of dried noodles.This study modified native highland barley flour by heat moisture treatment at different temperatures(90,110,and 130°C)and moisture contents(15%,25%,and35%).The effects of the treatment on the pasting,thermal,rheological,structural,and morphological properties of the native and heat moisture treated highland barley flour were evaluated.The results showed that heat moisture treatment at 90°C and 25%moisture content induced the highest pasting viscosity(5147 c Pa)and final viscosity(5384 c Pa).In all conditions heat moisture treatment increased gelatinization temperature,but decreased gelatinization enthalpy(0.43 J/g)in the heat moisture treated highland barley flour compared with that in the native highland barley flour.The highland barley flour treated at 15% moisture content had a higher storage modulus and loss modulus than native highland barley flour,indicating that heat moisture treatment(moisture content,15%,25%,and 35%)favored the strengthening of the highland barley flour gels.X-ray diffraction and Fourier-transform infrared spectroscopy results showed that heat moisture treated highland barley flour retained the characteristics of an A-type crystal structure with an increased orderly structure of starch,while the relative crystallinity could be increased from 28.52% to 41.32%.The aggregation of starch granules and the denaturation of proteins were observed after heat moisture treatment,with additional breakage of the starch granule surface as the moisture content increased.Heat moisture treatment could increase the resistant starch content from 24.77% to 33.40%,but it also led to an increase in the rapidly digestible starch content to 85.30% with the increase in moisture content and heating temperature.These results might promote the application of heat moisture treatment technology in modifying highland barley flour.Nature highland barley flour and three different heat moisture treatment strengths of highland barley flour were mixed with wheat flour in different proportions to study the characteristics of the compounded dough.The results showed that the water absorption of the dough increased,the degree of softening increased and the farinograph quality number decreased with the increase of highland barley flour addition.The heat moisture treated highland barley flour can improve the tensile resistance of the compound dough,and the tensile resistance can reach up to 665 BU.The tensile elongation of the compound dough showed a gradual decrease.Adding highland barley flour treated at 90℃ and 15% moisture content has the least negative effect on compound dough.When highland barley flour was added at 12.5%,the dynamic rheological properties of the compound dough were closer to wheat dough compared to nature highland barley flour.Textural and stress relaxation results showed that the highland barley flour increased the hardness and decreased the elasticity of the compound dough,which required more stress to compress the dough.Moist heat treatment of barley flour could absorb more water inside the compound dough,which changed the moisture distribution of the dough,resulting in the inability to form a good gluten network structure,making the relative content of free sulfhydryl groups and the surface hydrophobicity of proteins increase.On the whole,highland barley flour with low heat moisture treatment strength has less deterioration for the dough at the same barley flour addition.On the basis of the above study,we selected the highland barley flour which was heated at 90 ℃ and 15% to be compounded with wheat flour to make dried noodles.The TPA results showed that the hardness of the noodles with the addition of highland barley flour fluctuated in the range of 4978.12-5082.26 g,which was closer to that of wheat noodles.The dried noodles with the addition of heat moisture treatment had a greater breaking force compared with the control group.The noodles treated with heat moisture treated highland barley flour had greater breaking force and lower flexibility compared to the control group.The final sensory evaluation showed that the noodles with the addition of heat moisture treated barley flour were preferred.