New method for quantitatively assessing susceptibility of citrus fruit to oleocellosis development and some factors that affect its expression

Abstract

Summary. A quantitative laboratory method for determining the susceptibility of citrus fruit to oleocellosis (rind oil damage) has been developed. This method allows the evaluation of various factors which govern the extent of rind oil damage to the rind. By using this method, it has been established that the development of oleocellosis symptoms was affected by temperature, with temperatures <10˚C reducing the rate of development of the disorder. Unfortunately, when the temperature was raised again after storage, oleocellosis development proceeded as normal. Other environmental factors such as oxygen and carbon dioxide concentrations were also shown to affect the rate and extent of colour development of the rind blemish. This method of determining sensitivity of citrus peel to rind oil also established that the degree of surface exposure to sunlight increased the rind’s susceptibility to the oil. The effects of different coatings and chemicals which may affect the toxicity of the rind oils were also investigated, with artificial wax coatings being shown to reduce oil damage by up to 35%. This finding indicates the importance of thorough wax application to fruit. The tape method of sensitivity testing, as illustrated in this paper, also demonstrates that variations in oleocellosis development are not only due to changes in the pressure required to break the oil glands but also the ability of the peel to tolerate the released oil.