The Preparation And Stabilization Mechanism Of Cashew-Based Milk

Plant-based milk are popular among consumers because they are lactose-and cholesterol-free,non-dietary restricted,and environmentally friendly.However,plant-based milk,especially nuts-based milk,often faces stability challenges during storage.As a typical representative of nuts,cashew nuts are among the most consumed nuts in the world and owns high nutritional value.Cashew nut protein limits its application in plant-based milk systems due to its poor solubility.Enzymatic hydrolysis is recognized as a method that can improve the physicochemical properties of proteins,while protein hydrolysates have a wide range of applications in improving the physical and oxidative stability of emulsion.In this paper,we investigated the effect of enzymatic modification on the physical and oxidative stability of cashew-based milk and its mechanism of action,and also developed a prediction model for consumer preference of plant-based milk to investigate the effect of enzymatic modification on the sensory of cashew-based milk.The main research contents are as follows:Firstly,the enzyme types were screened for the neutral conditions required for cashew-based milk production,and the results showed that the stability of cashew-based milk prepared by bromelain was the best,so bromelain was selected for the subsequent experiments.The effects of enzymatic time and the enzyme concentrations on the functional properties,physical stability and oxidative stability of cashew-based milk were further investigated,and the visual stability and microstructure of cashew milk after 14 days of storage were examined.The results showed that cashew-based milk prepared under moderate hydrolysis(60 min,600 U/g)not only had the maximum protein solubility(41.36±2.14%),but also smaller particle size(490.37±6.79 nm),largerζ-potential(-29.47±0.62 m V)and more uniform particle distribution could be observed.At the same time,enzymatic hydrolysis could favor improving the oxidative stability of cashew-based milk,which peroxide value and thiobarbituric acid reactive substances were declined by 90%and 60%after 14 days storage in comparison with the control,respectively.In addition,no precipitation was observed in moderately hydrolyzed cashew milk after 14 days of storage,and minimal aggregation was shown in optical and laser confocal microscopy images.This suggests that moderate hydrolysis can improve the physical and oxidative stability of cashew-based milk.Then,the mechanism of action of enzymatic modification to improve the stability of cashew-based milk was investigated.The changes of cashew protein molecular weight and protein structure in cashew-based milk before and after enzymatic modification were determined.The results showed that large molecular weight cashew protein was generated into small molecule peptides by enzymatic hydrolysis.Moderate hydrolysis resulted in a gradual increase in the proportion ofα-helical structure and a gradual decrease in the proportion ofβ-folded structure of cashew protein.The content of free sulfhydryl groups in cashew-based milk prepared under moderate hydrolysis conditions(60 min,600 U/g)was 1-fold larger than that in cashew-based milk without enzymatic modification.Correlation analysis showed that the changes in physical and oxidative stability of cashew-based milk before and after enzymatic digestion were highly correlated with the changes in solubility and secondary structure of cashew protein,and the correlation coefficients with cashew-based milk stability from largest to smallest was protein solubility>α-helix>β-fold>free sulfhydryl content>β-turn>irregular curl.A cashew-based milk simulation system was also constructed to verify the role of cashew protein in the change of cashew-based milk stability before and after enzymatic digestion and to exclude the interference of other components.The results showed that the simulated system prepared from the protein extracted from cashew milk prepared by moderate hydrolysis(60 min,600 U/g)had the best physical and oxidative stability.Finally,the effect of the enzymatic hydrolysis on the flavor and consumer preference of cashew-based milk was investigated by developing a prediction model for the preference of dairy products.24 kinds of commercially available dairy products were selected and a dairy product consumer preference prediction model was developed by three intelligent detection techniques,namely,electronic nose,electronic tongue and colorimeter,in order to predict the consumer preference of cashew-based milk quickly and objectively,and finally the model was validated by cashew-based milk.The results showed that the fusion of the three intelligent detection techniques could predict the appearance,smell,taste and overall preference of dairy products well(R~2>0.8,RMSE<0.5).The cashew-based milk before and after enzymatic digestion did not differ significantly in each consumer preference and predicted well after substitution into the prediction model(R~2>0.86,RMSE<0.05).In conclusion,this paper mainly focuses on cashew protein in cashew-based milk to investigate the effects of enzymatic modification on the physical and oxidative stability of cashew-based milk,and to elucidate the improvement and mechanism of action of enzymatic modification on the stability of cashew-based milk by changing the solubility and protein structure of cashew protein.Finally,a consumer prediction model of dairy products was constructed by three intelligent detection techniques,which showed that moderate enzymatic modification did not negatively affect the sensory of cashew-based milk.This paper provides a new idea and scientific basis for the preparation of green and non-additive self-stabilized cashew milk.