“结皮”的英语？

要不时地搅拌牛奶蛋糊，防止其表面结皮。Stir the custard occasionally to prevent a skin forming.乳胶使用后应密封存放,防止乳胶表面结皮造成浪费.Pls seal up after use it to avoid freezing.牛奶结皮了.The milk has skinned over....