Biodegradable films and bags with rice straw extract are developed as alternatives to plastic packaging

VALENCIA, 24 Aug. (EUROPA PRESS) -

A team from the Polytechnic University of Valencia (UPV) is working on the development of new biodegradable materials that guarantee the preservation of food and extend its useful life, as an alternative to traditional plastic containers. Among their results in the laboratory, they have developed biodegradable films for the preservation of pork meat and single-dose bags of sunflower oil made with extracts of rice straw.

From the academic institution they emphasize that the food packaging sector is one of the largest consumers of non-degradable plastic; Its use makes it possible to guarantee the correct conservation of food, extend its useful life and reduce losses throughout the food chain. But, they also cause "an important problem of environmental pollution."

To face this challenge, in addition to promoting responsible consumption and recycling, a solution is to replace conventional plastic containers with biodegradable materials, which can be composted together with food waste. In addition, the incorporation of active compounds in the packaging material can provide it with additional properties, such as a high antioxidant and/or antimicrobial capacity. And this favors, precisely, that packaged foods are better preserved and their useful life is longer, reducing the environmental impact of traditional packaging.

Within this field, a team from the Institute of Food Engineering for Development of the UPV, led by Dr. Amparo Chiralt, is studying how different compounds of natural origin, with proven antioxidant and antimicrobial activity, can be incorporated into biodegradable polymer matrices with hydrophilic (such as starch) and hydrophobic (such as biodegradable polyesters) nature to obtain active materials for packaging. To ensure the preservative function of the material, these compounds must be released into the food in a controlled manner, acting against potentially present microorganisms or interfering with oxidative processes.

The UPV research group is using phenolic acids, present in many vegetables, with antimicrobial, antioxidant and other health-promoting activities, in the design of active biodegradable materials for food packaging. In their studies, they have verified that the type of polymer (hydrophilic or hydrophobic) significantly affects the release and effectiveness of active compounds in contact with aqueous foods, which are the most sensitive to microbial spoilage.

They have also verified that biodegradable polyesters, with low affinity with water, do not effectively release the active compounds; and that hydrophilic polymers release active compounds effectively, when hydrated with food contact, but, with hydration, they lose adequate barrier capacity and mechanical resistance.

Obtaining biodegradable multilayer films with an active layer for food contact is a solution to promote sustainable and ecological food packaging, combining hydrophilic and hydrophobic biopolymers. Different works by the group show the effectiveness of laminating biodegradable films with complementary properties, with phenolic acids or plant extracts rich in these compounds, with high antioxidant and antimicrobial capacity.

Among other results, the materials developed from the UPV laboratories have made it possible to extend the useful life of the pork packaged in these laminates, with a high level of conservation of quality parameters and microbiological safety. They have also developed single-dose bags with active extracts obtained from rice straw for packaging unsaturated oils, such as sunflower oil, which allow them to be protected from oxidative processes.

These results "demonstrate that biodegradable polymers have a high potential for obtaining sustainable and ecological solutions for food packaging, also using agri-food waste as a source of active compounds or reinforcing materials (celluloses) to improve their functionality and competitiveness in the market", emphasize those responsible for the work.

However, he points out, a "great pending challenge" is increasing its production and reducing the cost, and adapting its properties to the requirements of food packaging, which are very different for the different types of food, depending on its composition and sensitivity to deterioration.