INSTEAD of discarding the waste leftover from turning tomatoes into juice or sauce, these by-products could find new life as a protective coating in food cans. Scientists have developed a natural material that could be used to replace the coatings currently used inside these containers, which can contain Bisphenol A (BPA).


Identified as an endocrine disruptor with adverse effects on fertility, but also as a risk factor for diabetes, Bisphenol A has been under scrutiny for many years.

Synthesized at the end of the 19th century by chemists looking for a synthetic substitute for female hormones, this chemical compound was rediscovered in the 1950s when industrialists began to assemble compounds to make plastics and resins.

BPA was finally banned in 2010 in the manufacture of baby bottles, and then in 2015 for food containers. A 2008 study showed that in 2003-4, BPA was detected in over 92 percent of persons in a US data set.

One of the most common ways that individuals in the West are exposed to BPA is via food containers. Since BPA has been banned in Europe, manufacturers have sometimes replaced it with other Bisphenols, notably S and F, which may also be potentially harmful.

In response to this issue, a group of scientists from university research centers in Seville and Malaga in Spain, and Genoa in Italy, have found a way to replace the lining inside cans, potentially containing Bisphenol A, with another material made from tomato waste.

In the cans, this protective lining creates a barrier with the food. It is thus easy to understand how BPA can end up being found in food. Researchers have developed a "recipe" using all the waste from tomato processing, like skin, seeds and stalks.

This tomato pomace was first dried in the sun and then in the oven, before being reduced to a powder to be mixed with a sodium hydroxide solution.

The last manufacturing steps give rise to a waxy material that is mixed with an ethyl alcohol solution in order to be applied as a lacquer coating, adhering perfectly to the metal and preventing it from oxidizing.

Published in the Journal of Cleaner Production, the findings of this research now need to be built on by testing this new natural material in real-world conditions, with real cans.
This will give the scientists a better understanding of whether their discovery can be used to make food containers a healthier environment for human health.