Design and Optimization of Edible Coating and Osmotic Dehydration Processes for the Development of High-value Fruits and Vegetables with Extended Shelf-life

Berries and mushrooms are some of the most important traditional Mediterranean products that are characterized by high nutritional value and beneficial properties for the human body. Mushrooms are popular for their texture and taste but also for their chemical and medicinal properties. Although they have beneficial properties for human health, the shelf-life of fresh produce is very limited. In addition, sea buckthorn (Hippophae rhamnoides) berry is valued for its high nutrient density, providing high amounts of vitamin C, vitamin E, carotenoids, oils rich in unsaturated fats, etc. However, these berries are fragile and delicate and have a short shelf-life. The aim of the present study was the design and development of new berry and mushroom products, which are characterized by prolonged shelf-life without the addition of chemical preservatives, high nutritional value with low salt and sugar levels, and increased seasonal availability. The design and development of these products was based on the optimization of osmotic dehydration process and the application of edible coatings, using alternative agents. Various osmotic agents, such as glycerol, natural pectins or fruit juices were examined as alternatives to the conventional ones, with the aim to reduce salt and sugar levels in final products. Osmotic dehydration process was further optimized in terms of several parameters (immersion time, temperature, osmotic agent concentration, product to solution ratio). Dehydrated products were then coated using alternative agents, such as chitosan and aloe vera. The dehydrated and coated products were evaluated for their quality and sensory properties, during storage in controlled conditions. The examined alternative osmotic agents had significant effect to the water loss and water activity of the selected products and led to products with advanced characteristics. The use of alternative agents during edible coating application also led to the increase of products’ shelf-life and the enhancement of their nutritional value.