What is tinplate?

Tinplate is an iron sheet with a layer of tin on its surface, which is not easy to rust. It is also called tinned iron. This coated steel plate has been called "tinplate" for a long time in China. Some people think it is called "tinplate" because tinplate used to make cans is imported from Macao (the English name Macao can be pronounced "tin plate"). There are other sayings. For example, China used to use this tinplate to make kerosene lamp caps, which were shaped like tinplates, so they were called "tinplates". The name "tinplate" is not exact, so it was renamed as tinplate at the China tinplate conference in 1973, and the name "tinplate" was no longer used in official documents.

Declaration of origin

Tinplate originated in Bohemia (now Czechoslovakia). This area is rich in metals since ancient times, with advanced technology, and knows how to use water power to engage in machine manufacturing. Tinplate production began in14th century. After the First World War, the armies of various countries produced a large number of iron containers (cans), which have continued to this day.

industrial development

/kloc-in the 0/7th century, Britain, France and Sweden all wanted to establish their own tinplate industry, but they needed a lot of money. So it has never been developed. It was not until 18 1 1 Brian Jintang and John Hall started tinplate canned food that tinplate manufacturing industry developed on a large scale. Today, the world produces about 250,000 tons of tin every year, of which more than one third is used to make tinplates, and most of them are used in canned food industry.

Characteristic advantage

opaque

Light can not only cause food deterioration, but also cause changes in protein and amino acids. However, after being exposed to light, vitamin C is more likely to interact with other food ingredients, causing a lot of losses. According to research and analysis, the loss of vitamin C in transparent glass bottle milk is 14 times higher than that in dark bottle milk. Light will also make milk produce oxidation odor, and nuclides and methionine will be cracked, thus losing nutritional value. The opaque tin can makes the preservation rate of vitamin C the highest.

Good sealing performance

The barrier of packaging containers to air and other volatile gases is very important for preserving nutrition and sensory quality. Comparing various fruit juice packaging containers, it is proved that the oxygen permeability of containers directly affects the browning of fruit juice and the preservation of vitamin C. Metal cans, glass bottles, laminated aluminum foils and cartons with low oxygen permeability can better preserve vitamin C, among which iron cans are the best.

Reduction of tin

Tin in the inner wall of tinplate will react with the residual oxygen in the container during filling, reducing the chance of oxidation of food components. The reduction of tin has a good preservation effect on the flavor and color of light-colored fruits and juices. Therefore, canned fruit juice packed in unpainted tin cans has better nutrition preservation, slight browning, better flavor quality acceptability and longer shelf life than canned fruit juice packed in other packaging materials.