Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: P.A. Carter x
Clear All Modify Search

Natural sun-dried raisins are susceptible to crop loss and quality reduction when rainfall occurs during the 2-3 week drying period. The purpose of this experiment was to determine the effect of rainfall at selected stages of the raisin drying period on raisin quality. Thompson Seedless grapes were harvested and dried in the field using normal commercial practices. Raisins were moved to a humid chamber at the green, brown, turn, and roll stages of the drying period. Then, raisins were misted with 6.4 or 25.4 mm of water to simulate rainfall. Samples remained under humid conditions for approximately 48 hours after which they were returned to the field to complete the drying process. Raisin quality was evaluated by USDA incoming inspection procedures. The amount of rainfall had little effect on raisin quality at the levels in this experiment. However, raisin quality was significantly reduced when rainfall occurred at the green and brown stage of drying. Raisins which received rainfall at the turn and roll stages of drying were of comparable quality as control raisins.

Free access

The current study was conducted to relate ice formation to the pattern and rate of leaf and stem injury of Satsuma mandarins on trifoliate orange rootstock. Potted trees were unacclimated, moderately acclimated or fully acclimated by exposing trees to 32/21 °C, 15/7 °C or 10/4 °C, respectively. Freezing treatments consisted of decreasing air temperature at 2 °C·h-1 until ice formed as evidenced by exotherms determined using differential thermal analysis of stems. Air temperature was then decreased, held constant, or increased and held constant to simulate severe, moderate and mild freeze conditions, respectively. All treatment exhibited exotherms at -2 to -4 °C, which were smaller with milder freezing treatments. Only the fully acclimated trees exhibited multiple exotherms. Leaf watersoaking, an indication of ice formation, occurred concurrently with stem exotherms except for fully acclimated trees where there was up to a 30-min delay and which corresponded with the second exotherm. Electrolyte leakage of leaves began to increase near the peak of the stem exotherm, but increased more slowly with milder freezing temperature treatments. In some treatments, electrolyte leakage reached a plateau near 50% but leaves survived. Leaves died when whole-leaf electrolyte leakage exceeded 50%. These data are discussed within the framework of a proposed mechanism of injury of Satsuma mandarin leaves by subfreezing temperatures, especially multiple exotherms of fully acclimated trees, and the plateau of electrolyte leakage of leaves at the critical level for survival.

Free access