Effect of sodium 2‐phenylphenate applied in wax coatings on appearance of injuries in citrus fruit

摘要

AbstractCitrus fruits were treated with wax coatings containing sodium 2‐phenylphenate tetrahydrate (SOPP) and stored at 10 °C. No injuries appeared during 30 days' storage in Valencia oranges sprayed with waxes containing up to 4.75 of SOPP, or during 70 days' storage in Shamouti oranges and in grapefruit dipped in waxes containing up to 2.16 of SOPP. In Shamouti oranges and grapefruit dipped in waxes containing 3.1 to 3.88 of SOPP, injuries appeared at the beginning of storage. In non‐injured fruits, the amounts of SOPP applied by waxing did not exceed 74.7 μg/cm2of the fruit surface and the 2‐phenylphenol (OPP) residues in the fruits did not exceed 36.8 parts/million; in injured fruits the amounts of SOPP applied varied between 105.1 and 211.3 μg/cm2and the OPP residues between 41.5 and 123.6 parts/million. In non‐injured fruit the amount of wax applied did not exceed 3.46 μl/cm2; in injured fruits the figure varied between 3.19 and 6.2 μg/cm2, suggesting that the wax coating concentrates at some places on the peel, causing injuries to the fruit. In injured grapefruit 7.93 μl/cm2of wax was found on the injured part of the peel, and 3.21 μl/cm2on the non‐injured part, so that 124.6 μg of SOPP/cm2corresponding to 61.6 parts/million of OPP in the fruit was applied to the fruit without