Abstract:To address quality issues such as stratification and sedimentation in walnut milk,cold-pressed walnut cakes were used as raw material to prepare walnut milk through enzymatic hydrolysis.The hydrolysis degree,sensory score,stratification index,and weighted scores served as evaluation indicators,while enzymatic hydrolysis time,solid-to-liquid ratio,enzymatic hydrolysis temperature,and enzyme addition amount were considered as investigation factors.The production process of preparing walnut milk through enzymatic hydrolysis was explored via single-factor and orthogonal experiments,and its quality characteristics were analyzed.The results indicated that alkaline protease combined with neutral protease exerted a relatively better effect on protein hydrolysis in walnut.Range analysis revealed that the order of influence of the factors was：solid-liquid ratio>enzymatic hydrolysis time>enzyme addition amount>enzymatic hydrolysis temperature.The orthogonal test obtained the optimal preparation process as follows：enzymatic hydrolysis time of 3.0 h,solid-to-liquid ratio of 1∶20（g/mL）,enzymatic hydrolysis temperature of 55 ℃,and enzyme addition amount of 0.5%.The protein content of enzymatically hydrolyzed walnut milk prepared through this process was （2.79±0.36） g/100 g,with（10.10±2.30）% of soluble solids,（1.05±0.05） g/100 g of fat content,and （0.09±0.01） g/100 g of ash content.The total number of colonies,coliform group,and Pb content all met the requirements of GB 7101—2022 'National Food Safety Standard for Beverages'.The rheological properties indicated that,with increasing shear rate,the viscosity of walnut milk decreased,exhibiting a shear thinning behavior.Meanwhile,with increasing temperature,when compared with commercially available walnut milk,the rheological properties of enzymatically hydrolyzed walnut milk displayed a significant trend of first decreasing and then increasing.In conclusion,alkaline protease combined with neutral protease effectively hydrolyzed the protein in walnut cakes,thereby reducing the stratification and sedimentation of walnut milk to a certain extent,albeit the resultant flavor warranted further improvement.