Study On The Key Processing Technology Of Noodles With A High Highland Barley Flour Content

Highland barley,rich in?-glucan and other functional ingredients,is a high-quality and healthy food raw material with balanced nutrition.However,due to the lack of gluten protein in the highland barley flour,it is difficult to form the dough,which limits its application in noodle products.In order to prepare the noodles with high highland barley flour content,based on selecting the variety of wheat flour and vital wheat gluten suitable for the processing of highland barley noodles,the addition of gluten and pre-gelatinized starch were optimized,and thus the formula of noodles containing 51%highland barley flour was determined;and then the drying process conditions suitable were optimized.The main content and results of this study were summarized as follows:?1?Taking resistance to extension as the key parameters,the improvement of different wheat flour and vital wheat gluten on the processing quality of dough sheet were analyzed,and the core indexes of selecting the variety wheat flour and vital wheat gluten using for processing the noodles with high highland barley flour content were defined.Furthermore,to determine the reasons for the difference in improvement,the contents of GMP and free sulfhydryl groups,the microstructure and water distribution in the dough sheet were measured.The results showed that the wheat flour of F2 and the vital wheat gluten of G1 had the best improvement on the resistance to extension of dough sheets.The correlation coefficients between the gluten index and dry gluten content of wheat flour and resistance to extension of dough sheet were 0.929 and 0.983,respectively.The correlation coefficients between the gluten index,water absorption of vital wheat gluten and resistance to extension of dough sheet were 0.997 and 0.998,respectively.When wheat flour was F2 and vital wheat gluten was G1,the resistance to extension,GMP content and PMV of dough sheets were the highest,the content of free sulfhydryl group was the lowest,and the structure of gluten network distributed most uniformly and densely.Therefore,the wheat flour of F2 and the vital wheat gluten of G1 were the best ingredients for making highland barley noodles.Gluten index or dry gluten content can be used as the core index for selecting wheat flour,and gluten index or water absorption can be used as the core index for selecting vital wheat gluten.The differences in the contents of GMP and free sulfhydryl group and gluten network structure in dough sheets lead to the difference of resistance to extension of dough sheet.?2?The effects of the addition of vital wheat gluten and pre-gelatinized starch on the processing quality were determined by analyzing the texture property of dough sheet,and the mechanism was studied by measuring the physicochemical properties of mixed flour and the water distribution of dough sheet.Furthermore,the superiority of the formula obtaining by texture analysis of dough sheet was verified,by analyzing the noodle quality.The results showed that the resistance to extension of dough sheet increased with the increase of the addition of vital wheat gluten,and adding 8%vital wheat gluten could make resistance to extension higher than 300 g.The adhesiveness of dough sheet increased with the increase of the addition of pre-gelatinized starch,and only adding 1%pre-gelatinized starch could make the adhesiveness less than 600g?sec.When the addition of vital wheat gluten increased from 3%to 9%,the WAI of mixed flour increased by 9.60%,and the tightly bound water(A₂₁)increased by 0.57%.When the addition of pre-gelatinized starch increased from 1%to 5%,the viscosity at ambient temperature of the mixed flour increased significantly,and the tightly bound water(A₂₁)increased by 0.38%.Compared with adding 6%vital wheat gluten,the springiness of cooked noodles decreased significantly when adding 9%vital wheat gluten,and other indexes did not change significantly.The noodles with 1%pre-gelatinized starch showed the lowest cooking loss and the highest chewiness and hardness.Therefore,the optimum addition of vital wheat gluten and pre-gelatinized starch was 8%and 1%,respectively.Excessive addition of vital wheat gluten had limited improvement on noodle quality,while excessive addition of pre-gelatinized starch led to the degradation of noodle quality.?3?The temperature and relative humidity of each stage during the drying process of highland barley noodles were settled,and the moisture content and drying rate of noodles under different drying processes were measured,as well as the mechanical properties of dry noodles and cooking quality of cooked noodles were measured.Moreover,LF-NMR was used to determine the water migration of noodles under different drying conditions.The results showed that the moisture content of noodles decreased with the increase of drying temperature and increased with the increase of relative humidity.The drying rate decreased with the increase of relative humidity during first 80 min,and increased with the increase of relative humidity after 80min.The drying temperature only has a significant effect on the drying rate during first 70 min.The cooking loss of noodles decreased significantly with the increase of relative humidity and increased with the increase of drying temperature.When the drying process was T3M2?the temperature,relative humidity and time of drying in three stages:pre-drying stage,30?,85%,35 min;main drying stage:40?,80%,35 min;50?,75%,35 min;60?,70%,45 min;final drying stage:35?,65%,20 min;25?,60%,20 min?,the elastic modulus and fracture stress of dry noodles were the highest.During the drying process,T₂₂,T₂₃ and A₂₂ gradually decreased.Relative humidity and drying temperature had significant effects on T₂₂after 40 min and 50 min,respectively,but they had little effect on T₂₃.In addition,high drying temperature resulted in a low A₂₂ and high A₂₃;high relative humidity resulted in a high A₂₂2 and low A₂₃.Therefore,during the drying process,the relative humidity had a greater effect on the drying rate of highland barley noodles than temperature,and the optimal drying process was T3M2.Moreover,the effect of relative humidity on T₂₂ was greater than that of temperature,and the effect of temperature and relative humidity on A₂₂ and A₂₃3 showed and opposite trend.