QUALITY ATTRIBUTES OF VALENCIA ORANGE FRUIT USING DIFFERENT EDIBLE COVERS

This study was aimed to determine the best treatment to control fruit rot, improve quality preservation, and increase storage life in Valencia orange. Fruits were treated with 1% clove oil, edible wax, a mixture of clove oil with wax or left as untreated control and stored at 7°C and 85% relative humidity. None of the treatments had a significant effect on pH, acidity or total soluble solids. Vitamin C content increased until 42 days storage and then decreased, but covers had no significant effect on it. The total phenolic compounds and antioxidant activity showed a decreasing trend during the storage period. Although clove oil treatment tended to accelerate water loss in comparison with the other treatments, however, differences were not significant at the end of the storage period. Application of clove oil inhibited growth of fungi on the fruits and application of a mixture of wax and clove oil provided the highest fruit firmness. This mixture also provided the highest glucose content in the edible tissue (P<0.05), whereas fructose, sucrose or total sugar were not affected by covers during storage. In conclusion, a mixture of wax and clove oil was the most effective cover (P<0.05) for preservation of fruit firmness, water content, prevention of decay or high glucose content after 3 months storage. Naringin and hesperidins decreased during storage, but application of covers only affected the amount of hesperidins.