| Hull-less barley(HB)is the traditional staple food in the Tibetan Plateau and widely planted in China as a coarse cereals,which play an important role in the life of Tibetan.In recent years,with the development of research and further processing of HB,the consumption of highland barley was increasing year by year due to the nutrition and health functions.However,there are some problems such as low flour yield,serious loss of nutrition,and poor palatability due to the restriction of traditional milling process.High activities of lipase and peroxidase in HB are easy to lead to hydrolysis and oxidation of the product fat in the storage,resulting in rancidity and reducing the shelf life.Besides,hull-less barley flour can only be used with wheat flour at a lower proportion due to its protein can not form the gluten network alone,which weakens the nutritional value and application.Based on the above practical and scientific problems in HB processing,this study started with the HB milling and high ratio HB noodle making,mainly carried out the HB classified milling and it is associated with the stabilization technology,the evaluation of storage performance of stabilized HB flour,the research of new conditioning technology,the research of the processing and quality improvement mechanism of high ratio HB noodles.The objective of this study was to explore the new path of HB processing and utilization.Main conclusions are as follows:(1)Moderate processing of hull-less barley flour(BF)could be realized by the HB classified milling(HB-CM)process which organically integrated grinding,roller milling,and pearling system.Pearling process improved the characteristics of HB flour and the quality of noodles contained 50% HB flour.With 20% pearling,the highest yield and ?-glucan content of HB flour(78.56% and 6.42%,respectively)were obtained in HB-CM.Noodles prepared with HB flour(20% pearling)exhibited better texture and sensory properties.Both HB-CM and stone milling(HB-SM)improved the yield and ?-glucan content in HB flour.However,HB-CM could make the damaged starch reducing by 47.8% compared with HB-SM.(2)The inactivation rate of lipase and lipoxygenase in HB reached 80% and 100% respectively treated with stir-frying,microwave,atmospheric steam,and superheated steam.The optimal tempering moisture of the four types of stabilization method was 20%,24%,20%,and 16%,respectively,the temperature/power was 180?,700 W,300?,100?,and the treatment time was 20 min,120 s,30 s,60 min.Besides,stir-frying and microwave treatment increased the ash content in HB flour,and atmospheric steam treatment reduced the flour yield.The content of total phenols and unsaturated fatty acids in HB would reduce by stabilizing treatment.(3)Water content is a key factor affecting the storage properties of HB flour.The rates of enzymatic hydrolysis and oxidation were the lowest during storage when the moisture content was 8%.During 120 days of accelerated storage,the stabilized flour had no obvious rancid except for the control.The hydrolysis and oxidation rate of lipids were different depending on different stabilization methods.The hydrolysis rate in descending order was that control,microwave,frying,atmospheric steam,superheated steam,and the oxidation rate was that control,microwave,frying,atmospheric steam,superheated steam.The content of total phenol and unsaturated fatty acid in HB flour also decreased during storage.(4)The effects of shallow tempering on enzyme inactivation of HB under stabilization were studied to improve the efficiency of enzyme deactivation.The results showed that shallow tempering could effectively reduce the moisture and tempering time.The tempering moisture in stir-frying,microwave,steam,and superheated steam treatment separately reduced from 20%,24%,20%,16% to 16%,20%,16%,12%,and tempering time reduced from 8h to 2-3h.The stabilization treatment time of microwave and atmospheric steam increased from 120 s and 60 min to 150 s and 70 min respectively to achieve the same enzyme inactivation,but there was no change in treatment time of stir-frying and superheated steam.The gelatinization degree of HB flour treated by atmospheric steam decreased from 41.96% to 36.38% under the shallow tempering.The stabilization with both balanced and shallow tempering reduced the content of anthocyanin in HB flour,but there was no significant difference between the two methods.(5)The effects and mechanism of different dough mixing methods on the quality of high proportion HB noodles(50% HB flour)were investigated.It found that the quality of HB noodles obtained by DC-M method was the best by comparing three mixing methods F-M,DS-M,and DC-M.The improvement mechanism was revealed by the results of water distribution and microstructure in noodle dough.The results showed that the HB flour and wheat flour could well combined with water respectively under the DC-M method,which may reduce the competition between dietary fiber and wheat gluten protein for water absorption,and weakened the damage of crude fiber to gluten network,thus obtaining a more uniform and denser network structure in which the starch granules were wrapped tightly.The DCM method may enhance the protein network structure inside the noodle,which might be related to the better tensile and cooking properties of the noodle. |
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