Novel moisture-regulating plastic packaging – with deliquescent salts in the polymer matrix – for suppressing condensation formation in packaged, moisture-sensitive products such as mushrooms and strawberries

Workgroup: Packaging materials

Scientific Partners and Guidance:
Fraunhofer INstitute for Process Engineering and Packaging IVV, Mr. S. Sängerlaub / Mr. M. Linke

IGF: 17609 N
Financing: BMWi
Duration: 2012-2015

International studies have shown that up to a third of agricultural products spoil before they reach the consumer due to incorrect post-harvest handling. There are further losses whilst the products are being stored by consumers. A key reason is often the high relative humidity in the packaging and the condensation of water. This arises in fresh products due to respiration and transpiration process and exacerbates the microbial spoiling.

It is desirable to have a packaging that either suppresses the formation of condensation or actively absorbs condensation that forms on the product or packaging material, without drying out the packaged goods.

The objective of the ReguPack project is to develop moisture-regulating packaging systems for products that rapidly spoil such as fruit berries and mushrooms. These costly products are particularly sensitive to moisture and only keep for a few days. It would be attractive for both retailers and consumers if the storage life could be prolonged.

In order to regulate the moisture, toxicologically harmless, deliquescent salts are directly incorporated into the packaging materials. They absorb any water that is produced within the packaging. For mushrooms and strawberries a relative humidity between 90% and 95% is optimal. In order to maintain the relative humidity in the packaging within a defined range, specific salts must be chosen. In order to adjust the water absorption capacity and kinetics, a variety of parameters can be varied such as the salt concentration, grain size, polymer matrix, and also process engineering steps during the manufacture of the packaging material.

The joint project is being undertaken by the Fraunhofer Institute for Process Engineering and Packaging IVV, which has expertise in packaging systems, and the Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V. (ATB), which has expertise in fresh products.

The development of a novel moisture-regulating packaging material, which hitherto has not been available in the marketplace, will improve the competitiveness of SMEs by allowing them to serve specially adapted solutions for niche markets.



The IGF project presented here by the Research Association of the Industrial Association for Food Technology and Packaging (IVLV e.V.) is funded by the Federal Ministry for Economic Affairs and Climate Action via the AiF as part of the program for the promotion of industrial community research (IGF) based on a decision of the German Bundestag.