A new option for the packaging of berries

A new option for berry containers

06/10/2015

At the time, more than 20 years ago, when Chilean berries began to position themselves in the international market, small semi-rigid plastic containers appeared that kept the lid and base together, which led to their being called clamshell or clam pots. They quickly became the ideal packaging - in the world and in Chile - to export raspberries, blueberries, blackberries and strawberries, among others. So much so that they are still the kings of the market. Until now, the only possible question is that, although there has been progress in technology to improve their safety and make them more environmentally friendly, for the most part they are manufactured from resins derived from petroleum, so once discarded remain in the environment for hundreds of years.

The impact on the environment is not minor. For example, in the 2014 year, 80.000 tons of blueberries were exported. Considering that a traditional plastic clamshell container contains 120 grams of fruit and weighs 16,45 grams, it was calculated that approximately 11.000 tons of plastic were necessary to package cranberries of Chilean origin for export only in that season. And since the pot has no other uses, it eventually becomes a polluting waste.

Precisely for this reason, in Chile, following the global trend of looking for more environmentally friendly products, several years ago, we began to look for formulas that allow us to have containers made from alternatives that are friendlier to the environment, but that maintain the characteristics of weight, transparency and innocuity. Precisely to this have focused on the Technological Development Unit (UDT) of the University of Concepción, where they have already developed biodegradable materials for the manufacture of packaging from natural products.

Johanna Castaño, PhD in Materials Sciences and who has been in charge of UDT research, says that the proposal to develop biodegradable thermoplastic containers for the fruit industry was born in the year 2009, product of the interest of the fruit export sector, which led them to participate and win a Fondef project to formulate a resin from polylactic acid obtained from products rich in starch such as corn, wheat and beet, among others, and which will have the thermal, mechanical and optical properties required to pack fruits.

"This acid has many equivalent and even better characteristics than many petroleum-based plastics, making it effective for a wide variety of uses.", comments Johanna Castaño.

They came up with a formulation that, according to the specialist, allows to obtain a clear and bright product such as polystyrene, resistant to moisture and grease, and has characteristics of taste and odor barrier similar to polyethylene terephthalate plastic, used for non-alcoholic beverages. It is also stable to ultraviolet light so it does not discolor and its flammability is very low.

In fact, the generation of different bioplastics has been developing for years in different parts of the world. However, its cost was still too high. However, the specialist explains that the production costs of different bioplastics have dropped considerably in relation to traditional plastics in recent years. This, together with the demand of demanding markets, has led to the development of biodegradable plastics, from PLA, thermoplastic starches, PHA (polyhydroxyalkanoates) and biodegradable polyesters.

This container degrades in conditions of compostability in a period of one to three years, depending on the conditions of temperature and humidity, among others.

The next step was to convert this new raw material into commercial packaging. In 2014, together with Petroquim, Ultrapac Sudamérica and Agrícola y gandera Río Cato, they won the Fondef project "Production and validation of biodegradable clamshell-type containers for the packaging and transportation of export fruits", which seeks the manufacture and validation of containers biodegradable for, mainly, the export of national blueberries.

The objective now is to manufacture the clamshells from the material generated in the first study, to pack in the order of 66 a thousand kilos of fruit; mainly blueberries, but also raspberries and strawberries. In December, they would begin exporting to the US. and then to some countries in Europe.

«The incorporation of additives and reinforcements to biomaterials allows us to obtain products with different mechanical, thermal and optical properties, according to the requirements of the final application. "We are also working to control the degradability of bioplastics, adapting it to the expected useful life of the final product.", says Castaño.

Source: Revista del Campo