Opacity
In addition to causing the deterioration of food, light can also cause changes in proteins and amino acids. And vitamin C is more likely to interact with other food ingredients when exposed to light, resulting in a large loss. According to research and analysis, the loss of vitamin C of milk in transparent glass bottles is 14 times higher than that of milk in dark bottles. Light will also cause milk to produce oxidative odor, and the cracking of radionuclides and methionine will lead to loss of nutritional value. The opaqueness of the tinplate allows the highest retention rate of vitamin C.
good sealing
The barrier properties of packaging containers to air and other volatile gases are very important for the preservation of nutritional content and sensory quality. Comparison of various juice packaging containers proves that the oxygen transmission rate of the container directly affects the browning of the juice and the preservation of vitamin C; the preservation of vitamin C in metal cans, glass bottles and aluminum foil glued layers and cartons with low oxygen transmission rate Better, among them, tin cans are the best.
reduction of tin
The tin on the inner wall of the tinplate will interact with the oxygen remaining in the container during filling, reducing the chance of the food ingredients being oxidized. The reduction effect of tin has a good preservation effect on the flavor and color of light-colored fruits and juices. Therefore, the juice cans packed in unpainted iron cans have better nutritional preservation and slight browning than those packed with other packaging materials. The acceptance of the flavor quality is better, and the shelf life is thus extended.