Effects Of Oat Raw Materials And Heat Treatment On The Stability Of High-protein Oat Milk

Oats have high nutritional value and unique flavor,and are ideal raw materials for preparing plant-based cereal beverages.However,this type of beverage is prone to instability problems such as droplet flocculation,protein precipitation,and fat floating during the actual production and storage process,which seriously affects the sensory quality and shelf life of the product.Based on this,based on the preliminary research in the laboratory,this project collected and screened representative oat raw materials at home and abroad,and explored the effects and laws of oat raw materials,grain enzyme inactivation methods and heat sterilization processes on the stability and nutritional quality of high-protein oat milk.By adjusting raw materials and processing technology,reducing the application of exogenous food emulsifiers,thickeners,etc.,provides a theoretical basis for the self-stabilization of the natural oat milk system.The main research contents and conclusions are as follows:(1)Collect 11 representative oat raw materials from home and abroad,and use cluster analysis to screen out 5 oat raw materials through nutritional quality indicators such as fat and protein content,and study the effects of different raw materials on the stability and nutritional quality of oat milk.The results show that the stability of emulsions made from different oat materials is different.Under the oat milk preparation technology used in this research,the stability of oat milk made from 5 oat raw materials is from high to low: Pinyan No.1> Baiyan No.2> Dingyou No.10> Bayou No.1 >Omai.The oat milk produced by Pinyan No.1 has the highest viscosity and the smallest average particle size(5.09 μm).The oat milk produced by four domestic oat varieties such as Dingyou 10 has a higher protein content of ～3g/100 m L,which is better than the samples produced by Australian wheat.In addition,studies have found that the protein and β-glucan content in oat milk is directly proportional to the content in the grains;the protein content of oat grains has a strong correlation with the emulsion stability.Pinyan No.1,Dingyou No.10,and Baiyan No.2 oatmeal raw materials can be used as suitable raw materials for making oat milk.(2)Using blanching,frying and microwave treatment to inactivate enzymes in oat grains,to study the effects of different enzyme inactivation methods on the residual lipase activity,total phenol content,and gelatinization characteristics of oat grains,as well as the stability and nutrition of oat milk The impact of quality.The results show that different methods of enzyme inactivation can significantly reduce the residual lipase activity and total phenol content of oats(p<0.05);but with frying and microwave inactivation of enzymes,the oat emulsion drops have a high degree of aggregation and the system is seriously destabilized;The blanching treatment(100℃,3 min)can increase the viscosity of oat milk,which is beneficial to improve the stability of the system.The average particle size of the emulsion is 5.23 μm,which is better than the other two enzyme inactivation methods,and the sugar content,protein content and other nutrients are retained The rate is higher.Therefore,blanching the raw materials to kill enzymes is more conducive to maintaining the quality of oat milk than frying and microwave inactivating enzymes.(3)The effects of pasteurization and ultra-high temperature instant sterilization(UHT)on the stability of oat milk were compared.The results showed that pasteurization(100℃,15 min)had little effect on the stability of oat milk,and the centrifugal precipitation rate was 7.39 %.UHT sterilization(115/125/137°C,10 s),the degree of protein denaturation is serious,a large number of aggregates are formed,and the stability of oat milk is reduced;for the oat milk samples treated with different UHT conditions,the oats treated at 115°C for 10 s The milk precipitation rate is the highest(28.07 %),and the sensory quality is poor.SDS-PAGE was used to analyze the composition of protein subunits in different samples and the migration laws of different parts in the emulsion.It was found that the protein in the emulsion after UHT treatment mainly migrated to the sedimentation layer,and the aggregates in the sediment were mainly oat globulin through disulfide.Bonding connection formation,mainly including α-globulin(20-25 kDa)and β-globulin(30-36 kDa)and a small amount of oat albumin(5 kDa).