Pg. 23-27 The Refinement of the Promising Low pH ”Acid B” Post-Harvest Treatment

The promising results attained with the “Acid B” treatment during the 1999-2000-season, warranted further refinement of the application protocol, especially in terms of acid concentration and time exposure specifications. During the first trial conducted during the 2000/2001 season, “Acid B” was applied at different concentrations, ranging from 80 to 225 ml/l, for exposure times differing between 10 and 120s. Undesirable off-tastes were found to develop when dipped for longer than 10 seconds regardless of the concentration. Optimum product in terms of taste and colour was obtained between 166 – 170 ml/I for 10s. In terms of taste, the sensory panel found the 10s 170 ml/l treatment to be acceptable when compared to the SO₂ treated fruit. However, some panellists still recorded a slight burning sensation on the tongue. It was encouraging to note that the optimal “Acid B” treatments had lower fungal infection rates than the SO₂ treatment. The combination of the “Acid B” treatment with controlled and modified atmosphere was also investigated. Unfortunately, all the treatments developed unacceptable off-tastes and a high incidence of fungal infection occurred. The use of cocktail mixtures of “Acid B” and other food additives were also investigated. The combination of citric acid and “Acid B” showed promise, but requires further refinement. Semi-commercial trials are to be launched during the coming season.