Author Kofi Owusu-Akyaw Oduro
Aloe,Postharvest losses are rampant due to lack of proper storage conditions and handling of the fresh food products, the perishable nature of fruits and vegetables makes their shelf life limited, respiration rate, ethylene production, and transpiration, edible coatings seem to extend the shelf life of products, type of packaging is made from various natural resources like polysaccharides, protein and lipid materials, moisture barriers, oxygen scavengers, ethylene scavengers, antimicrobial properties, methods of application of the edible coating on the food materials include dipping, spraying, brushing, layer by layer among others, there have been several verifications of the positive impact of edible coatings/films on pome fruits, citrus fruits, stone fruits, tropical and exotic fruits, berries, melon, and tomatoes. Postharvest losses which result in the degradation of quantity and quality of the fruits after harvest constitute a serious challenge, fresh food products are susceptible to dehydration, mechanical injury, environmental stress, pathological breakdown, and enzymatic attacks which lead to some nutritional, functional, and sensorial losses and production of off-flavor and also posing a level of threat in terms of possessing a level of toxicity, reduction of the edible quality of the food products due to biochemical changes, physiological aging and microbial infections during storage and transportation, gas composition greatly affects the shelf life of the products, an extension of the supply time of fruits and vegetables besides preserving their quality would have economic profits, fruits are either climacteric or un-climacteric. The latter cannot ripen once removed from the plant but the former can ripen after being picked and produce more ethylene which makes them more susceptible to spoilage, and inhibit the rate of deterioration of these fruits, there is a need to alter the gaseous environment or control it, for instance making use of packaging materials with low water vapor and oxygen permeability to reduce respiration but not a too low oxygenated environment which can lead to anaerobic respiration which can also produce off-flavors, an edible coating which can control and inhibit the deteriorative changes as well as increasing the shelf life of the products. Edible coating/films are a good candidate to help solve the cases of postharvest losses since it has mechanical, thermal, antimicrobial, and even antioxidant properties, Edible coating or films are biopolymers, that provide a barrier against moisture, gases, and solute movement, the edible coating is liquid form while the former usually forms a thin layer around the food product, significant decrease in weight loss and ripening rate, lower microbial growth and lower mass loss, Edible coatings/films helps to improve the appearance of horticultural produce by giving shine, hiding scars, suppressing decay and physiological disorder developments, edible coatings can be generally classified into three main groups; protein-based edible coatings, polysaccharide-based coatings and lipid-based coatings, active or functional compounds; antioxidants, antimicrobials, nutrients, vitamins, anti-browning agents, enzymes and probiotics that could be applied into coating matrix to help preserving products quality, dipping technique is by immersing the fresh food produce into the coating solution to allow complete wetting of the surface of the food material, Layer by layer method is based on alternate deposition of oppositely charged polyelectrolytes that result in a more effective control of the coating properties and functionality, Vacuum impregnation technique, food material is subjected to atmospheric restoration while it remains immersed in the coating solution under atmospheric pressure, Spraying method is more suitable for less viscous coating solutions which can be sprayed at high pressure, surface area of the liquid coating increase through the formation of droplets and distribution over the fruit surface, Benefits of edible coatings/films, moisture barrier, oxygen scavengers, ethylene scavenger, antimicrobial properties, anti-browning and antioxidant properties, texture modifiers for inhibition of physical damages, nutraceuticals for preservation of nutritional quality, improved shelf life, delayed loss of firmness and weight, less changes in colour, pH and Brix value, controlled rate of respiration, weight loss retention, delay in ripening index, firmness and weight loss retention, reduce the respiration rate, antimicrobial, prevention of fungal infection, some examples used in fresh fruits Guava, Mango, Tomatoes, Avocado, Barhi date, Strawberries, Apple, Citrus, Berries, Melon , pitaya , soursop , pineapple , papaya, banana, longan
