SUSAMPACK

Summary:

Microbial infection of fresh produce is a critical issue throughout the postharvest supply chain, from harvesting to transformation, trade, and final sale. This fact contributes to this kind of products, in their raw state or in a minimally processed form, have the highest wastage rates among all types of foods, which is becoming a serious economic and environmental issue. Moreover, according to national studies conducted in EU countries, fruit and vegetables contribute to almost 50% of the food waste generated by households. The generation of avoidable waste is a consequence of the behavioural choices of the consumers such as poor purchase planning, but there are several other factors that might relate to the waste levels generated from the consumption of fresh fruit and vegetables, such as the package properties.
Packaging is one of the key elements for preserving quality, extending shelf life, and ensuring microbial safety of fresh and minimally processed produce. One of the major developments in packaging technology for fresh and minimally processed produce is antimicrobial packaging based on the release of antimicrobial compounds from the package into the head space of the packaged item. However, most active packaging systems are based on the deliberately addition of agents in polymeric matrices and their release by diffusion without or with scarce control. On top of that, the incorporation of the active agents is inefficient when these molecules are volatile or labile.
This project seeks to make advances in the development of antimicrobial food packaging by using dynamic polymers that include effective triggering mechanisms for the smart release of the molecules. Imine and acetal click chemistry can be employed for the stabilization of antimicrobial volatiles in polymeric structures having reactive functional groups by means of reversible covalent grafting. The bonds created by imines and acetals are covalent and thus, robust but can be hydrolysed under mild acidic conditions and temperature. The reversibility of imines and acetals allows the development of more efficient stimuli-responsive sustained-release systems for diverse industrial applications including active packaging of foods. The target of this project is to develop sustainable antimicrobial stimuli-response devices for the preservation of packaged postharvest products, fresh and minimally processed fruits that can respond to microbiological deterioration. This work will contribute to the design of more efficient antimicrobial devices for food packaging applications based on the click and green chemistry of imines and acetals and their reversibility, in combination with the use of polymers obtained from food waste and by-products of the agro-industry and naturally-occurring antifungal volatiles mostly found in essential oils. The devices will act inside a package being capable of stabilizing the antimicrobial volatile until a change in the conditions of the environment surrounding the packaged food (pH, temperature) provokes the cleavage of the reversible covalent bond and the release of the antimicrobial. The efficiency of the devices will be assayed through shelf-life extension studies of packaged food, moreover, their validation as food contact materials and environmental impact will be evaluated.