Research And Development Of Plant-based Coffee Foaming Milk

Fancy coffee,such as cappuccino and mocha,originated in Italy and is popular among young consumers because it is filled with whipped milk foam.In recent years,due to lactose intolerance in some parts of the population,as well as the pursuit of a healthy diet and increasing environmental concerns,plant-based coffee foaming milk has emerged.However,the foaming capacity and foaming properties of plant-based coffee foaming milk on the market are significantly lower than that of milk coffee foaming milk,and the product quality needs to be further improved.In this paper,soybean,chickpea and oat,three plant protein raw materials with good thermal stability and compatibility with coffee flavor,were selected to prepare coffee special foaming milk.The foaming properties and other properties related to foaming were discussed,and the influencing factors of foaming properties were analyzed and improved,so that the foam texture,taste and foaming properties were comparable to milk.It provides a theoretical basis for the further development and application of plant-based coffee foaming milk.The main research results are as follows:Firstly,six common plant protein raw materials including soybean,chickpea,pea,oat,radix sinian and pumpkin seeds were selected from beans,cereals and nuts to prepare plant protein milk.The thermal stability of Radix Sinian and pumpkin seed milk was compared,and it was found that the the thermal setting time was less than 30 s,and the thermal stability was poor.Four other plant protein milk with good thermal stability were mixed with coffee to evaluate the flavor compatibility.It was found that the flavor of soybean milk,chickpea milk and oat milk mixed with coffee was more harmonious,suitable for further study.Heat coagulation timeSubsequently,the foaming capacity and stability,foam structure and size,foam flow properties,adsorption components and drainage kinetics of soybean milk,chickpea milk and oat milk were investigated from three aspects of foaming properties,mechanism and application.It was found that the foaming properties were soybean milk,chickpea milk and oat milk from the largest to the smallest,but the foam stability was in the opposite order.Vegetable protein milk foams had different flow and wall adhesion characteristics.Soybean milk had the highest initial flow velocity and wall adhesion,while oat milk had the lowest wall adhesion,and its final foam outflow percentage was 94.50%.The mean diameter of soybean milk foam was the largest,while the liquid film thickness of oat milk foam was the largest.Protein and lipid components had different adsorption behaviors at the gas-liquid interface.The former was positive adsorption and decreased the surface tension,while the latter was negative adsorption and increased the surface tension.The contents of soybean 11 S protein B-peptide chain,chickpea legumin β subunit and oat 12 S protein β subunit were higher in foam liquid membrane,and the proportion of phospholipids in liquid membrane lipids was higher.Three kinds of vegetable protein emulsion foam liquid film showed different drainage characteristics.Then,the effects of protein and fat contents on the foaming properties of plant-based coffee foam were investigated from foaming capacity,foaming stability,fluidity,microstructure,average diameter of foam and liquid film thickness,and the foaming properties of plant-based coffee foam were improved by enzymolysis and adding auxiliary components.It was found that when protein levels fell below 3%,the increase of protein content was beneficial to the foaming properties of soybean milk and the foaming stability of three plant milk,but not conducive to the foaming properties of chickpea milk and oat milk.The fluidity of soybean milk and chickpea milk foam decreased with the increase of protein content.When the protein concentration was higher,the foam size was smaller,the liquid film thickness was larger,and the foam distribution was tighter.The addition of fat in the condition of high protein content was conducive to the fluidity of the foam,and the foam was not easy to stick to the wall.Increased fat content was generally not conducive to foaming and foam stability.Enzymatic hydrolysis of protein was beneficial to foaming properties and foaming fluidity of soy milk,but the foam stability will be greatly reduced.The addition of food grade surfactant or stabilizer could improve the foaming properties and enhance the stability of the system.Finally,the optimal conditions of soybean milk,chickpea milk and oat milk were determined,and the optimal p H values were 7.0,7.0 and 7.4,respectively.The optimum bubbling temperatures were 55℃,55℃ and 50℃,respectively.The best brewing time was 60 s.The three kinds of plant-based coffee foaming milk made by ourselves had improved the texture and taste of the foam to a certain extent,and the foaming properties had also been improved,and the overall acceptability was good when consumed with coffee.