The barrier properties of packaging containers against air and other volatile gases are crucial for the preservation of nutrient composition and sensory quality. Comparing various fruit juice packaging containers proves that the oxygen permeability of the container directly affects the browning of fruit juice and the preservation of vitamin C; Metal cans, glass bottles, aluminum foil adhesive layers, and paper boxes with low oxygen permeability have better preservation of vitamin C, and iron cans are also preferred.  

The reduction effect of tin on the inner wall of tinplate will react with the oxygen remaining in the container during filling, reducing the opportunity for food components to be oxidized. The reducing effect of tin has a good preservation effect on the flavor and color of light fruits and juices. Therefore, juice cans packaged in unpainted iron cans have better nutrient preservation than juice cans packaged in other materials, with slight brown changes and better tolerance for flavor quality. As a result, the storage period is extended.  

Food is packaged in tin cans made of tinplate. Except for a few light colored fruit and juice cans, most empty cans with internal paint are used to improve the corrosion resistance of the container; Due to the electrochemical effect of metals, a small amount of iron will dissolve from canned food that has been painted during storage. It exists in the form of divalent iron in sealed canned food and is easily absorbed by the human body, with a content of approximately 1 to 10 ppm. For fruit and vegetable products, the iron content of the material itself is not high. For iron can products, with a beverage can of 350 ml per can and an iron content of 5 ppm, each can can can provide 1.75mg of iron, which is about one tenth of the daily intake of 18mg for the human body.

If the above-mentioned fruit and vegetable juice beverage cans contain abundant vitamin C, iron is more easily absorbed. Therefore, iron canned food and beverages are a good source of iron, and their significance in providing nutrients to iron canned food is even more profound. Due to these properties, tin cans provide a sealed system that completely isolates environmental elements in addition to heat. They prevent food from deteriorating due to light, oxygen, and moisture, and do not fade due to fragrance or environmental odor contamination. The stability of food storage is better than other packaging materials, and the retention rate of vitamin C and nutrients is also good.