45F-3 |
Effects of ethephon and aminoethoxyvinylglycine on the carbohydrate and acid contents of 'Scarletspur Delicious' apples (Malus domestica Borkh.) |
S. R. DRAKE1, D. C. Elfving2, T. A. Eisele3, M. A. Drake4, S. L. Drake4, and D. B. Visser. (1) USDA-ARS-Tree Fruit Research Lab., 1104 N. Western Ave., Wenatchee, WA 98801-1230, (2) Tree Fruit Research Lab., Washington State Univ., 1100 N. Western Ave., Wenatchee, WA 98801-1230, (3) Tree Top, Inc., 220 E. Second Ave., PO Box 248, Selah, WA 98942-0248, (4) Dept. of Food Science, North Carolina State Univ., Schaub Hall, Box 7624, Raleigh, NC 27695-7624 Fresh market apples continue to be a popular consumer product. To maximize apple quality pre-harvest treatments to accelerate or retard ripening are often applied. Actual control over the ripening process would be a useful tool to maximize quality and consumer acceptance. Ethephon (ETH, EthrelŽ) stimulates ripening in apples while aminoethoxyvinylglycine (AVG, ReTainŽ) prevents ethylene biosynthesis in apple fruits and retards ripening. The objective of this study was to determine if these two bioregulators could beneficially affect carbohydrate and acid content of 'Scarletspur Delicious' apples. This study was conducted over two crop seasons using mature 'Scarletspur Delicious' apple trees on MM.111 rootstocks. In year 1, apple trees were sprayed at one or two weeks before harvest with 150 or 300 ppm ETH. In year 2, similar plots were sprayed four weeks before harvest with 125 ppm AVG. Some of these trees were then treated one or two weeks before harvest with either 150 or 300 ppm ETH. Untreated trees served as controls. In the first year, any application of ETH alone increased the total content of sugars (total carbohydrates plus sucrose) in fresh apples, but reduced the amount of fructose present. Sorbitol was increased at both 150 and 300 ppm, but only if ETH was applied 2 weeks before harvest. Total acidity and the levels of both quinic and malic acids were reduced by ETH. In year 2, AVG alone reduced the amounts of total carbohydrates, sucrose and citric acid. Combinations of AVG and ETH increased total carbohydrates, reduced fructose, reduced total acidity and reduced the amounts of quinic, malic, shikimic and citric acids. Combining AVG with ETH permitted the delay of harvest with little loss in storability. These results will aid in design of treatment regimes to maximize fresh market apple quality.
Session 45F, Fruit & Vegetable Products: Fruits (Fresh)
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