Opaque
In addition to the deterioration of food, 光也会引起蛋白质和氨基酸的变化. 暴露在光线下时，维生素 C 更容易与其他食物成分发生反应, 造成大量损失. 根据研究分析, 透明玻璃瓶牛奶中维生素C的损失是 14 比深色瓶装牛奶高出几倍. 光照也会使牛奶产生氧化气味, as well as the decomposition of nuclide and methionine, which will result in the loss of nutritional value. The opacity of tinplate makes the preservation rate of vitamin C the highest.
Good sealing
The barrier of packaging containers to air and other volatile gases is very important for the preservation of nutritional components and sensory quality. The comparison of various juice packaging containers shows that the oxygen permeability of the container directly affects the browning of juice and the preservation of vitamin C; the metal cans, glass bottles, aluminum foil laminations and cartons with low oxygen permeability have better preservation of vitamin C, among which the iron cans are the best.
锡的还原
马口铁内表面的锡会在灌装时与容器内残留的氧气发生反应，减少食品配料氧化的机会. 锡的还原作用对淡味水果和果汁的风味和色泽有很好的保鲜作用. 所以, 不涂铁罐的果汁罐比其他包装材料的果汁罐营养保存更好. 褐色变化轻微, 风味品质可接受性好, 并延长储存期.
