Study On The Flavor And Whipping Characteristics Of Oat Milk

With the popularity of vegetarianism and the improvement of health awareness,people have turned their attention from traditional milk to plant-based milk.Oat milk is the most popular plant-based milk in recent years,and the combination of oat milk and coffee is wellreceived by the public.However,oat milk has similar issues to traditional plant-based milk.there are adverse flavors such as grass and metal,which can affect the integration with coffee flavor.At the same time,oat milk generally has low protein content,which leads to its poor dispelling foam characteristics,then affect the fusion effect with coffee and reduce the drinking experience.In view of the above two problems,this topic explores the methods that can improve the flavor of oat milk and raise dispelling foam characteristics.First,different methods are used to pretreat oats,compare the flavor changes of oat flour before and after pretreatment,then study the flavor changes of oat milk caused by different pretreatment methods,and identify key flavor volatiles.Second,study the impact of different oat raw materials on the flavor of oat milk.Finally,the effects of enzyme type,addition amount,enzymolysis conditions and ingredients on the dispelling foam characteristics of oat milk were studied..This topic aims to provide new ideas and directions for optimizing oat milk flavor and improving dispelling foam characteristics.The main research contents are as follows:Firstly,the effects of different pre-treatment methods on the inactivation effect,color,and flavor of oat powder lipase were studied.The results showed that four pre-treatment methods(baking,atmospheric steam,high-pressure steam,and microwave)can significantly reduce the activity of lipase,and the baking method having the greatest effect on the color change of oat powder.Using Headspace solid-phase microextraction(HS-SPME)and Gas chromatography-mass spectrometry(GC-MS)to identify the volatile compounds of oat flour with different pre-treatments.Combined with thermal map analysis of the trend of volatile compounds,it was found that the content of aldehydes,alcohols,ketones,and heterocyclic compounds increased after pre-treatment,especially after baking,the volatile content of oat flour increased most significantly.These compounds are mostly oxidation decomposition products of oils and Maillard reaction products.The results of principal component analysis(PCA)showed that different pre-treatment oat flour can be well distinguished,esters and aromatic hydrocarbons are related to untreated flour,vanillin and triacetin which have the flavor of milky and fruity are related to high-pressure steam flour;heterocyclic compounds,alcohols,some ketones,and most aldehydes are related to baking flour;acids and olefins are related to atmospheric steam flour;2,3-octanedione,and(E)-cinnamaldehyde which have the flavor of fruit are related to microwave powder.High-pressure steam and microwave treatment promote the generation of pleasant volatiles.Secondly,the effects of different pre-treatment methods on the flavor of oat milk were studied.HS-SPME-GC-MS technology was used to qualitatively and quantitatively analyze the volatiles of oat milk with different pre-treatments.At the same time,Olfactory analysis(GC-O)and Aroma dilution analysis(AEDA)were used to determine the key flavor volatiles of oat milk with different pre-treatments.Volatiles with dilution factor(FD)greater than 4 were selected as the key flavor volatiles.The relationship between sensory properties and key flavor compounds was analyzed by Partial least squares(PLSR),and the results showed a positive correlation between vanillin and the milk aroma of high-pressure steam oat milk;3-(Methylthio)propanal,2-acetyl-1-pyrroline,2-ethyl-3,5-dimethylpyrazine,dihydro-5-pentyl-2(3H)furanone were positively correlated with the baking taste of roasted oat milk;Trans-4,5-epoxy-(E)-2-decene is positively correlated with the metallic taste of untreated milk;Hexanal and 2-and 3-methylbutyric acid are positively correlated with the grassy taste of untreated milk.In summary,untreated milk has more negative flavors such as grass and metal,while high-pressure steam oat milk has more milk aroma.Once again,the pretreatment method of high-pressure steam was selected to study the effect of different raw materials on the flavor of oat milk.The GC-MS results showed that the concentration of volatile compounds in the oat milk sourced from Europe was the highest,while the concentration of volatile compounds in the oat milk sourced from Australia was the lowest.The key flavor compounds in the oat milk sourced from Australia,which mainly impart the flavor of greasy and metallic,such as hexanal,2-pentylfuran,(E,E)-3,5-octadien-2-one,nonaldehyde,(E)-2-nonenal,(E)-2-decenal,(E,E)-2,4-decadienal,and dihydro-5-pentyl-2(3H)-furanone,were lower than those in the oat milk sourced from Europe and China.The content of vanillin,a key flavor volatile that produces a milky aroma,is 107% higher than that of domestic wheat,indicating that Australian wheat is superior to the other two and more suitable as a raw material for oat milk.Finally,by comparing the content of solids,the suitable range of the use of different amylases was determined.The effects of different amylase types and addition amount on the physicochemical properties,dispelling foam characteristics and microstructure of oat milk were studied,and the suitable amylase type and addition amount of oat milk were determined to be0.2% of medium-temperature amylase and 0.2% of high-temperature amylase.By comparing the effects of different types of proteases and enzymatic hydrolysis conditions on the protein content of oat milk,the suitable protease for enzymatic hydrolysis of oat milk was determined to be protein glutaminase(PG)enzyme.Then the effects of PG enzyme hydrolysis conditions on the physicochemical properties,dispelling foam characteristics and microstructure of oat milk were studied.The suitable addition amount of PG enzyme was 0.05%,and the suitable hydrolysis time was 45 minutes.Then,the effects of different ingredient addition on the dispelling foam characteristics of oat milk were compared.The results showed that the dispelling foam characteristics of oat milk were the best when adding 0.1% dipotassium phosphate,0.02% calcium carbonate,0.02% tricalcium phosphate,and 0.06% sodium chloride.