76C-9 |
Influence of bioregulators on apple fruit quality |
M. A. DRAKE, Dept. Food Science, North Carolina State University, Raleigh, NC 27695, S. R. Drake, Tree Fruit Research Lab, USDA-ARS, Wenatchee, WA 98801, D. C. Elfving, Tree Fruit Research Lab, Washington State University, Wenatchee, WA, and T. A. Eisele, Tree Top, Inc., Selah, WA. 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. The objectives of this study were to determine the effects of pre-harvest application of ethephon (Ethrel) and/or aminoethoxyvinylglycine (ReTain) on composition, physical and sensory attributes of 'Scarletspur Delicious' apples. Treatments were applied preharvest (1,2 and 4 weeks) as a one-way treatment arrangement in a randomized complete-block design. Treatments (6) were applied to 2-tree plots for a total of 60 trees. Following harvest, instrumental measures of fruit quality were evaluated (flesh firmness, titratable acidity, sugar/acid ratio, soluble solids content, starch, individual carbohydrates). Consumer acceptance (n=200) was determined on whole fruit and juice. Preharvest application of ethephon (EthrelŪ) at 150 or 300 mg a.i./liter dilute application produced rapid changes (over as little as 7 days after application) in 'Scarletspur Delicious' fruit quality that were detectable by sensory analysis. Instrumental measurements of fruit quality showed either no change (flesh firmness, titratable acidity, sugar/acid ratio, peel color) or minor changes (soluble solids content, flesh starch level). Ethephon applied 2 weeks before harvest following a ReTain application resulted in fruit at harvest that received higher consumer acceptance scores for texture and flavor compared to controls and ReTain alone while maintaining firmness, higher soluble solids and reduced acidity. ReTain-treated fruit subsequently treated with Ethephon may permit a temporary ethylene burst from the ethephon application to beneficially influence fruit quality factors while preventing the onset of the climacteric ripening response. It may be possible to use bioregulators in the orchard to improve fruit characteristics that contribute to maximum consumer quality while maintaining the ability of the fruit to be stored and marketed in the normal manner.
Session 76C, Fruit & Vegetable Product: Fresh Fruits and Vegetables
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