Research Of Development In New Type Oat Yogurt And Its By-products

Oat（Arena sativa L.）is one of the eight major food crops and one of the best full-price nutritional cereals.It is rich in protein,dietary fiber,essential fatty acids,minerals,vitamins,as well as bioactive compounds such as polyphenols and flavonoids.Oat and its products showed multiple bioactivities including reducing cholesterol,controlling weight,lowering blood sugar,lowering blood lipids,and improving human immunity.In this study,oats were used as the main raw material to produce oat milk through baking,gelatinization,and enzymatic hydrolysis.Through inoculation of lactic acid,the oat milk was then fermented into oats yogurt.Furthermore,the by-product that filtered out during oat milk processing was dried and combined with chickpea flour to develop a high-protein and high-fiber biscuit.The optimum production process and formula of oat milk,oat yogurt and oat milk by-product biscuit were determined by single factor and orthogonal test.The physicochemical properties,nutritional value,and sensory characteristics of these three products were analyzed and the results were shown as follows:1.Optimization of oat milk processing:（1）Based on sensory evaluation,the pretreatment of oat seed was determined.（2）Based on sensory evaluation and total solid content,the optimum ratio of material to liquid of oat milk.（3）Based on the reducing sugar content,sugar content,polypeptide content and DPPH free radical scavenging rate,the optimal enzymatic hydrolysis process of oat milk was determined asα-Amylase addition 0.24%,enzymolysis temperature 70℃,enzymolysis time60min,saccharifying enzyme addition 0.12%,enzymolysis temperature 60℃,enzymolysis time 70 min,complex protease（papain:flavor protease=1:1）addition 0.28%,enzymolysis temperature 55℃,enzymolysis time 120min.（4）The protein content in oat milk is1.25g/100g,the fat content is 1.04g/100g,the sugar content is 14.1°BX,the reducing sugar content is 31.27mg/m L,the p H is 6.8,and the content of total amino acids is 1.85g/100g.2.Development of oat yogurt and quality evaluation:（1）Through single factor and orthogonal experiment,the optimal processing process of oat yogurt was determined as follows:the ratio between oat milk and reconstituted milk was1:1,addition of lactic acid was 0.2%,fermentation time was 8 hours,and the fermentation temperature was 40℃.（2）Every 100g of oat yogurt contains 2.07g of protein and 1.6g fat,7.05gβ-Dextran,2.79g total amino acid,4.27×10⁶CFU/m L total lactic acid bacteria,68 of acidity,and 4.21 of p H.There was no pathogenic bacteria were detected.Texture analysis showed that there was no significant difference in elasticity and cohesion between oat yogurt and Mengniu flavor yogurt,and the hardness and chewability of oat yogurt were significantly higher than Mengniu flavor yogurt.（3）The total flavonoid content of oat yogurt is 29mg/g,and the total phenol content is 24mg/g.The ABTS free radical scavenging rate and DPPH free radical scavenging rate of oat yogurt were significantly higher than those of Mengniu-flavored yogurt.（4）The volatile compounds of oat yogurt were determined by GC/MS and a total of 65 volatile flavor compounds were detected,including 16 acids,16aldehydes,13 ketones,10 alcohols,4 lactones,3 esters and 3 other compounds.The proportion of acid compounds is the highest,especially the content of n-octanoic acid with fruit aroma was the highest.Various volatile components work together to provide oatmeal yogurt unique flavor.3.Application of oat milk by-products（OMB）---development of OMB biscuits enriched with chickpea flour（1）Based on sensory test and hardness analysis,the processing process of oatmeal chickpea biscuit was determined through single factor experiment and orthogonal test:22.59g/100g chickpea powder,3.61g/100g milk powder,21.08g/100g artificial sweetener,15.06g/100g butter,baking in the oven at 150℃for 7-10 min,and then baking at 50℃for another 30min after cooling.（2）The color and texture analysis showed that the oat residue chickpea biscuit was brighter than the wheat flour biscuit,with L^*=52.56,a^*=7.50,b^*=39.3.The protein content of biscuit dough is positively correlated with its hardness.（3）OMB biscuit（100g）contained 7.79g of protein,14.18g of fat,16.69g of carbohydrate compounds,16.69g of dietary fiber,54.72mg ofβ-glucan,and its caloric value was 376.84kcal.Compared with wheat biscuits,the protein content of OMB biscuits was higher while the carbohydrate content and calories were lower.OMB biscuits were rich in dietary fiber,which was more nutritious and healthy.（4）The total flavone content of OMB biscuits was 74mg/g,and the total phenol content was 122mg/g.The ABTS free radical scavenging rate,DPPH free radical scavenging rate,and hydroxyl free radical scavenging rate of OMB biscuits were significantly higher than those of wheat biscuits made under the same process.In conclusion,the new oat yogurt developed in this study has a delicate taste,rich nutrition and a unique flavor.By-product oatmeal residue chickpea bean cookie with complete pattern,rich aroma,has a certain nutritional value.This study can enrich the types of multigrain yogurt products,improve the comprehensive utilization rate of oats,and provide some reference for the development of oat products.