Evaluation of waxes to replace polyethylene waxes.
Kritzinger M., Kruger F. J., Bezuidenhout M.
Author Affiliation: Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200, South Africa.
: 111-114
Abstract : In order to identify a suitable natural wax to replace polyethylene wax, the ITSC is in the process of evaluating alternative fruit coatings. As part of a study aimed at characterising the postharvest ailments of 'Heidi', the physiological effects of specific classes of coatings on the physiology of 'Heidi' mangoes were investigated during the 1996 season. Based on the results obtained in the latter investigation and the results from the study conducted by Kremer-Köhne and Duvenhage (1996) for the South African Avocado Growers' Association, three coatings were selected for evaluation during the 1996-97 mango season. The first two, Stafresh and Tropical Fruit Coating, are primarily Carnauba based while the third, an experimental coating distributed by Avima, is mineral based. TAG wax was used as polyethylene control while the possibility of exporting unwaxed fruit was also investigated. Because of its sensitivity, 'Heidi' fruit were used for the trials. The fruit were treated and stored under simulated export conditions and a range of physiological and pathological parameters were used to evaluate the fruit. The results indicated that South African Mango producers should not export fruit without an appropriate coating. Of the alternative coatings evaluated, the Avima experimental formulation rendered results that were most comparable with those attained with TAG. We are, however, doubtful as to the European Community (EC) acceptance of the mineral base claim of this wax. Of the other natural waxes, Stafresh achieved the best results and we recommend that this wax should be used if the EC starts enforcing Directive 95/2EC on coatings. Fortunately, the EC has granted South African mango producers a non specified grace period. This study is being continued using additional natural waxes and custom waxes formulated in the laboratory specifically for mangoes.