Edible coating application for lightly processed Fruits and vegetables

1.      Mandarins

Mandarins are coated with a composite film containing hydroxypropyl methyl cellulose (HPMC) and lipids (Beewax, carnauba wax or shellac) at 20% and 60% were studied by Perez Gago et al in 2002. These researchers found that when higher HPMC formulation were used, there was increase in internal CO2, a decrease in internal O2 and build up of internal ethanol production and lower weight loss were observed in fruits coated with higher concentration of lipids (60% beewax), making this formulation more appropriate for extending the postharvest shelf life of mandarins.

2.      Oranges

Oranges coated with commercial polysaccharide or shellac, beewax or TAL Pro-Long- based coatings exhibit higher concentration of flavor characteristic aroma volatile

3.      Apples

Apple is a popular and commercially important  item for fresh cut products  However, Fresh cut apples tend to brown rapidly, losing weight and firmness and are prone to microbial growth, which is conducive to undesirable change in flavor, textural loss of nutrients . Coating apple slices with carbohydrate/ lipid bilayer film reduces water loss during storage between 12 to 14 times when compared to the water loss suffered by uncoated apples slices in similar storage condition .The use of edible coating as carriers of additives for fresh apples preservation may be found in the incorporation of organic acids, such as malic and lactic acids, into coating formulations as antimicrobial agents without adversely impacting the sensory properties of whole apples  . The shelf life quality of freshly harvested Golden Delicious apples coated with three individually developed lipids/ hydrocolloids coatings was assessed throughout refrigerated storage. The apples were monitored for 8 weeks. The coating resulted in low internal O2 and least loss of fruit firmness when compared with non-coated apple group

4.      Grapes

A novel EC based on Aloe vera gel is used as a means of preservation to maintain the quality and safety of Crimson seedless table grapes during cold storage and subsequent shelf life. Uncoated clusters showed a rapid deterioration as compared to compared to coated because Aloe vera gel coating is simple and non contaminating treatment, maintained the functional properties during post harvest storage of table grapes 

5.      Carrots

Surface white discoloration on peeled carrots during storage affects their quality and storage life. White discoloration of surface is the result of both physical and physiological responses to wounding. The physical response is irreversible surface dehydration of outer layer . This physiological resonse is the formation of lignin , an irreversible components of color change  White flush (due to surface dehydration can be controlled with hygroscopic coatings e.g. polyhydric alcohols and salt solution.. A cellulose based coating called Natureseal, significantly reduced white blush on peeled carrots for up to 1 month at 4 C. The edible cellulose based coating on sensory, microbiological and chemical quality of mini peeled carrots was studied during storage at 2C. Carrots treated with edible coating had reduced levels of white surface discoloration and higher sensory scores, fresh carrot aroma, fresh flavor and overall acceptability than non coated carrots .