Post harvest Management of Horticultural Crops (2+1)

Fruit coating

How fruit coating works?

• Fruit coating results in the restriction of the gas exchange between the fruit and surrounding atmosphere. This causes a builds up of CO2 and a depletion of O2 with in the fruit, thus causing an effect similar to CAS (controlled atmosphere storage).
• If surface coatings and their concentration are not selected properly, the respiratory gas exchange through fruit skins is excessively impaired leading to development of off-odours and off-flavours. Over waxing also results in abnormal ripening and softening that affects the marketing of such fruits.
• Fruit coatings can be formulated from different materials including lipid, resins, polysaccharides, proteins, and synthetic polymers. Most coatings are a composite of more than one film with the addition of low molecular weight molecules such as polyols, that serve as plastisizers (increase the plasticity or fluidity of the material). Otherwise, coatings can be too brittle and will flake or crack on the coated product. Surfactants, antifoaming agents, and emulsifiers are also often used in coatings.