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Tomato Skin – A Natural Lining for Metal Cans
- 03 February 2014
The packaging industry is under pressure to improve its environmental performance and become more competitive. In addition, food packaging safety has come under more scrutiny. An innovative EU-funded project has addressed all three of these objectives at once, with a straightforward yet potentially revolutionary solution using tomato skins.
The BIOCOPAC project developed a novel bio-lacquer for metal food packaging designed to meet current demand for sustainable production and safety. The project team expects their innovation will increase the competitiveness of the EU's metal cans industry, cut unnecessary waste and better protect consumers.
The natural lacquer was developed from tomato skins, a by-product that food processors often treat as waste. The lacquer can be applied to the internal and external surfaces of cans used for foodstuffs.
Metal packaging is often coated to protect the contents from the metal itself which, for example, can lead to discolouration in some dark-coloured fruits, or to protect the metal from acidic products such as soft drinks.
Three challenges for Europe
From the very beginning, the BIOCOPAC team sought to address three key challenges facing Europe: unnecessary waste, consumer safety and industrial competitiveness. The project has made important steps forward in all three areas.
"With regards to the environmental challenge, the development of new food contact packaging bio-lacquers from the by-products of tomato processing will promote the exploitation of waste by reusing it," explains project coordinator Angela Montanari of Stazione Sperimentale per L'industria delle Conserve Alimentari in Italy. "The bio-lacquer will increase the sustainability of metal cans, promoting their recyclability and decreasing the environmental impact of packaging and waste."
Food safety was another key priority. Natural bio-lacquers designed specifically for food contact packaging should help ensure that there is no chance that food will be contaminated by the migration of synthetic substances from the packaging to the product. The innovation is expected to provide can manufacturers with an environmentally friendly solution they can offer to food processors worldwide.
"In the past few years, growing demand for environmentally friendly products has encouraged the development of the biopolymer and bioplastics sectors," says Montanari.
She says the BIOCOPAC solution will provide packagers with an alternative to Bisphenol A, a carbon-based compound used to coat many food and beverage cans. Bisphenol A has come under public scrutiny over claims it affects health.
The new BIOCOPAC lacquer will also be trademarked, making its use immediately recognisable to consumers.
Good use of waste
BIOCOPAC's research began with an analysis of tomato waste, and continued with the development of an experimental method of extracting cutin (a waxy 'polymer') from tomato peel.
"We then studied different formulations of bio-lacquers suitable for metallic materials," says Montanari.
Extracting raw cutin from tomato peel proved highly successful in terms of yield and applicability on an industrial scale. Different formulations of lacquer containing from 10 % to 100 % cutin were prepared and studied to find the ideal formulation for the final bio-lacquer.
"The more promising formulations were then applied to different metallic substrates – tin plate, tin-free steel and aluminium," continues Montanari. "Properties such as the degree of curing, appearance and sterilisation resistance were measured."
From the initial lacquered sheets, the team was able to produce two- and three-piece cans, crown corks and caps. In every case, the lacquer demonstrated an excellent performance, she says.
As a result of this research, the partners plan to file for two patents to be registered. One will cover the extraction method for cutin from tomato peel – a method that will probably be developed on an industrial scale – while the other will cover the formulation of the bio-lacquer.
"This experience has been wonderful," says Montanari. "It has given me the possibility to work in the EU with European partners in a very professional way, and at the international level. Moreover, this project has provided me with an opportunity to see and understand that collaboration between industries and research centres can lead to positive results, even in low-technology sectors such as metallic packaging."
Source: Envirocentre.ie - Tomato Skin – A Natural Lining for Metal Cans
