Bionanocomposite Soy Protein Coating to Extend Shelf-Life of Avocados

Food waste extends further than simply the loss of food, which amounts to nearly 1.3 billion tons of food globally every year. In the US alone, food that will eventually be wasted is grown on enough land to feed the world’s hungry twice over, demands 25% of freshwater supply, and releases 135 million tons of greenhouse gases every year. With rising population and resource strain, there is an inevitable need for innovative, green, and sustainable solutions that extend beyond short term solutions like landfilling and conversion of food waste into animal feed.

Among all foods, fruits and vegetables suffer the highest categories of losses with 50-60% of produce discarded to landfills. Existing commercial solutions that extend the shelf-life of fresh produce involve primarily wax coatings combined with chemical fungicides; however, these technologies are associated with human health and environmental concerns. Currently, there is a lack of optimal alternative edible coatings for perishable foods, particularly relevant for high value produce items with low shelf-life like avocados (~3 days). Here, we developed cellulose nanocrystal (CNC) soy protein nanocomposite coating to extend the shelf-life of avocados, which are considered a high-value agriculture product. The coated avocados resulted in more than 25% reduction in weight loss over 10 days and maintained more than 90% fruit over 7 days. Nearly double the shelf-life was achieved while maintaining high fruit firmness, low weight loss, and intact fruit structure with minimal browning. Increased improvement in avocado preservation and quality was attributed to the incorporation of CNC in the coating, resulting in enhanced moisture retention, better adhesion properties, and greater mechanical robustness. This study provides further insight on the smart utilization of low-cost materials, like soy and CNC, as protective coatings to extend the shelf-life of fruits and vegetables, thus, mitigating food waste economically and sustainably.