Background: Contamination of the skin of fruits and vegetables is responsible for increases the possibilities of the spoilage. Edible coatings with antimicrobial agents can extend the shelf life of fruits and vegetables.
Methodology:Edible coating agents (pectin and chitosan) individual or mixed with emulsions of lemon grass and thyme oils were prepared at different concentrations, and were evaluated for their antimicrobial activity, and used for coating orange fruits (Washington Navel Orange), which stored at 10°C and 95% relative humidity for 90 days. Changes in weight loss, firmness, Decay rate, respiration rate, pH, total soluble solids (T.S.S.), Titratable acidity, chlorophyll and carotenoids, ascorbic Acid (AsA) and microbial load were determined.
Results: Coating solutions containing emulsion enhanced chemical and microbial properties of fruits. Weight loss was decreases compared to uncoated samples (25 vs 3%), Control treatment fruits without coating showed higher decay ratereaching 15% after 90 days of storage. Coating the fruits with pectin or chitosan and their emulsion with lemon grass oil reduced the decay rate to the level of 3% to 6%.Firmness value was improved in the treated samples. Orange fruits coated with the chitosan or chitosan /emulsion recorded the lowest respiration rate (10.3 to 10.44 mgCO2 /kg. h) at the endof cold storage. Coating the fruit with pectin or chitosan emulsion reduced the losses of ascorbic acid (vitamin C) to about 34%.
Conclusion: chitosan-pectin / emulsion coating increased the shelf life and enhanced different properties of orange fruits.