Quality Changes During Harvesting and Handling of 'Valencia' Oranges

External and internal quality of 'Valencia' oranges was monitored at 7 stages of the commercial harvesting and handling process. The greatest amount of external damage was found in fruit collected at the pallet bin and at pack inghouse departure. Mechanical damage incurred at harvest was largely removed during grading, but additional damage occurred in the packinghouse. No further external damage occurred after this point. Peel and pulp temperatures, moni tored during transport from the packinghouse to the warehouse, decreased l°F/hr over a 20 hr transportation period. Pulp temperatures were always greater than the peel during this time. Percent acid, measured in fruit initially col lected after each marketing event and after 4 weeks storage at 50°F, 90% RH, declined significantly only in stored fruit late in the handling sequence. Brix of initially evaluated and stored fruit increased significantly after harvest and remained high during handling. Waxing with a solvent-based wax had no significant effect on % acid or °Brix. Juice ethanol in creased in stored fruit collected at packinghouse departure and increased only slightly thereafter; whereas, a significant increase in non-stored fruit occurred only in fruit collected at simulated consumer storage. The Florida citrus industry produces a high quality fresh fruit crop for domestic and international markets. Fruit destined for fresh market are subject to a variety of handling events that can ultimately affect the external ap pearance and internal quality of the fruit. Hand harvesting of round oranges has often resulted in a variety of external damages, the highest percentage of which were plugged fruit (2, 8, 10). Although packinghouse grading removed any fruit with external defects, a high percentage of fruit which had plugging damage (stem-end tears) passed through the packinghouse unnoticed and were found in the final packed carton. No further increase in external damage was found during later handling events. Decay Florida Agricultural Experiment Station Journal Series No. N-00344. Proc. Fla. State Hort. Soc. 103: 1990. was not detected until the retail and consumer marketing channels (2). Internal quality can also be affected by harvesting and handling events. Whereas external damage occurred primarily at harvest, internal quality of 'Hamlin' oranges was most affected during later handling events (2). A rapid and significant decline in % acid and °Brix was measured in stored fruit originally collected at packinghouse depar ture. Acid and Brix remained low but unchanged through out the remainder of the marketing sequence. A sharp increase in % juice ethanol, an indicator of anaerobic metabolism (3), was also measured during the later portion of the marketing sequence. Although the data suggested that packinghouse treatment, such as wax application, re sulted in change in internal quality (2), measurements were only performed on stored fruit and not on those initially brought from each marketing event. Thus, the effect of time of storage and handling event could not conclusively be separated. A study was initiated in 1989 to provide additional data on the effects of harvesting and handling on external and internal quality of 'Valencia' oranges. Internal quality was assessed directly after fruit collection and after storage to clarify the effects of handling and storage. Seven sampling points were chosen along the commercial harvesting and handling sequence, and the effects of waxing on internal quality was also assessed. Materials and Methods Plant material. 'Valencia' oranges {Citrus sinensis Linn. Osbeck) were harvested in April from an established grove in central Florida. Fruit were hand harvested simultane ously by a commercial grove crew (commercial fruit) and by a selected crew from the Citrus Research and Education Center, Lake Alfred, FL (control fruit). Only fruit of size 125 (fruit/carton) were harvested. Fruit from 7 specific points along the commercial harvesting and handling se quence (Table 1) were evaluated. After each harvesting and handling point, commercial fruit were divided into 2 subsamples, each containing 2 cartons. One subsample was evaluated for external quality immediately and then inter nal quality determined as described below; the other was stored at 50°F, 90% RH for 4 weeks, and then analyzed. Control fruit were harvested directly into cartons and transported to the LA-CREC. Fruit were divided into 4 subsamples, each containing 2 cartons. Each subsample was washed and 1000 ppm TBZ applied. Two subsamples