The Action of Lecithin and Calcium Dips in the Control of Bitter Pit in Apple Fruit1

Abstract

Addition of 1% lecithin (phosphatidyl choline) to 4% Ca dips increased internal CO 2 levels and decreased O 2 levels in fruit of apple ( Malus domestica Borkh.) stored at 3°C. This effect was greater than that found with lecithin alone. At 18°, respiration and ethylene production by the fruit were reduced slightly by Ca, but to a much greater extent by lecithin. A further reduction of the production of both gases was found with Ca and lecithin. The climacteric rise was also delayed by lecithin treatments. At 3°, ethylene production was both delayed and reduced by lecithin treatments, but no influence on CO 2 production was detected. Although differences in Ca concentration of the fruit caused by the addition of lecithin to Ca could not be detected when bulked samples of fruit were analysed, use of 45 Ca showed that both the initial rate of Ca uptake and the final Ca content of the fruit flesh after 6 weeks at 3° were increased by lecithin. The beneficial effects of lecithin plus Ca in bitter pit control probably result from rapid modification of gas exchange together with increased Ca uptake.