Effect Of Superheated Steam On Quality Of Highland Barely Products

In recent years,with the in-depth research on the nutrition and physiological function of highland barley,the highland barley products have gradually attracted the attention of the majority of consumers.Highland barley is susceptible to microbial contamination during planting,harvesting,storage,processing,and transportation,which leads to a decline in the quality of highland barley and its products.The highland barley products will brown in a short time during storage.so it is necessary to sterilize and treat highland barley products with enzymes.Superheated steam treatment has the advantages of uniform heating,fast heating,less nutrition loss and high cleaning efficiency.Superheated steam has been widely used in the food processing industry.In this paper,the superheated steam is used as the heating medium.According to different processing requirements,the barley grains,barley rice and barley chips are superheated steam treated.So as to achieve the purpose of killing microorganisms and inhibiting enzyme activity.Meanwhile,the physicochemical properties and edible quality of barley and its products were systematically studied.It aims to provide theoretical basis and data support for the application of superheated steam in the food processing industry,to provide a new processing method for the enzyme killing and stony enzymes of cereals,and to provide a new heat treatment method for the sterilization and drying of cereals.The main conclusions of this study are as follows:(1)Superheated steam treatment can quickly kill the bacteria and mold on the surface of highland barley,in which the greater the velocity of superheated steam,the better the sterilization effect.The rapid killing effect of superheated steam on microorganisms is mainly concentrated in the first 120 s.After 120 s,the sterilization efficiency of superheated steam is reduced,and the phenomenon of towing exists.The higher the temperature of superheated steam,the more significant the sterilization effect.At 140? superheated steam treatment for 120 s,all the mildew on the surface of highland barley has been killed.The sterilization effect of superheated steam is not affected by the microorganism content on the surface of highland barley.(2)After superheated steam treatment,the moisture and 1000-grain weight of highland barley grain decreased significantly,and the fat binding state changed,but the effect on protein and ash content was small.The superheated steam treatment increased the particle size of the whole barley powder and significantly decreased the activities of amylase,polyphenol oxidase and peroxidase.The superheated steam treatment made the barley starch partially gelatinized,and the protein-protein and protein-starch aggregation and cross-linking reactions occurred.Superheated steam treatment can reduce the brightness and improve the gelatinization viscosity of the whole barley powder.(3)The optimal tempering condition of highland barley rice is 6% of water and 10 min of tempering time.The protein,fat,starch and ash content of highland barley rice changed significantly with the increase of the number of rice milling tracks.After superheated steam treatment,the peroxidase of the barley rice significantly decreased.Combined with the killing effect of superheated steam on microorganisms,the optimal treatment conditions were determined as 120? 3min(HBR-120(SS),140? 2min(HBR-140(SS)),160? 2min(HBR-160(SS)),180? 2min(HBR-180(SS))and 200? 2min(HBR-200(SS)).HBR-140(SS)highland barley rice has the longest maturation time,the largest water absorption and volume expansion rate,and the largest solid loss rate of highland barley rice at hbr-160(SS).The hardness and viscosity of highland barley rice increased significantly after superheated steam treatment,but there was no significant difference in other indexes.After superheated steam treatment,the color,water absorption and water solubility of highland barley rice flour changed significantly,and the L* value and water absorption index suddenly increased,while the b* value decreased.(4)According to the score of the shape and size of the highland barley flakes,the best processing conditions of the highland barley flakes are 25% of water conditioning,6h of tempering time and 0.07 mm of rolling distance.After the superheated steam treatment,the moisture content of highland barley decreased significantly.There was no significant difference in the contents of total starch,crude fat,crude protein and beta-glucan of highland barley flakes with the best parameters,HBS-160(SS)highland barley tablets have the highest soluble solid content and HBS-140(SS)highland barley tablets have the highest brightness.