Study On The Development And Storage Stability Of Apple Soymilk

Apple,as a kind of fruit rich in polyphenol compounds,is deeply loved by people.Soymilk,as one of my country’s traditional drinks,have the reputation of "plant milk".Both apple and soymilk have good nutritional value.But due to the excessive protein content in soymilk,and the low p H of the turbid apple juice,which is easy to leads to the instability of the formulated soymilk drinks.There have few reports on the development of apple soymilk beverage.Therefore,in this study,apple juice and soymilk were used as raw materials,combined with the nutrition and flavor characteristics of apple and soymilk,to study the apple soymilk.By studying the ratio of raw materials,the influence of the p H of the cloudy apple juice,the high-pressure homogenization conditions,and the selection and optimization of stabilizers,an apple soymilk beverage with unique taste and high stability was developed.Then the apple soymilk beverage was stored at 4℃,and its instability process,the changes in physical and chemical indicators,nutrients,and sensory characteristics,were analyzed during storage times.After that,the main reasons for the instability of apple soymilk during storage were discussed.Finally,the molecular mechanism instability of apple soymilk was further analyzed through research the glycinin(7S)and β-conglycinin(11S)interacted with the characteristic phenolic compounds(gallic acid,epicatechin,and chlorogenic acid)of apple juice.The main conclusions were as follows:1.In this study,through single factor,orthogonal experiment and response surface analysis,the best formula of apple soy milk beverage was apple soymilk volume ratio 1: 1,the addition of citric acid,sweetener,gellan gum,pectin,and CMC were 0.4 g/L,1.5 g/L,0.62 g/L,0.60 g/L,0.37 g/L,respectively.Through further research on the stability of apple soy milk beverage,it was found that the stability of apple soymilk beverage was the best when the p H of the apple juice was 5.5.In addition,by changing the homogenization pressure and the number of homogenization,it was found that the apple soymilk obtained had the best edible quality when the pressure and number of homogenization was 20 MPa and 2 times.2.The shelf life of apple soymilk was nine days when stored at 4°C.During the shelf life of apple soymilk,the particle size increased,the stability decreased,and the flavor changed little.In the later period of storage,the particle size decreased and the stability increased due to the action of microorganisms.The main reason for the instability of apple soymilk during storage may be that the soymilk protein in soybeans interacted with the polyphenols in the cloudy apple juice and then resulting in changes in the charging properties and stability coefficients of the juice.Finally,it causing the cloud-like particle system to continuously aggregate and further settle under the action of gravity.3.Gallic acid,epicatechin and chlorogenic acid can interact with glycinin(7S)andβ-conglycinin(11S).Under the condition of 298 K,gallic acid,epicatechin and chlorogenic acid could form a complex with glycinin(7S)and β-conglycinin(11S),which increased the particle size of the solution and decreased its stability.However,under the condition of 368 K,gallic acid cannot inhibit the thermal denaturation of glycinin(7S),but the formation of epicatechin and chlorogenic acid complex could effectively inhibit glycinin(7S)and β-conglycinin(11S)heat accumulation.These results showed that the three polyphenols could inhibit the thermal denaturation of β-conglycinin(11S).It may be because gallic acid only binds to glycinin(7S)and β-conglycinin(11S)on the surface of the protein,but forms a more stable complex conformation with 11 S.On the other hand,Epicatechin and chlorogenic acid form hydrogen bonds and hydrophobic interactions with 7S and 11 S.