Protecting the postharvest quality of avocado.
Arpaia, M. L.; Ontai, S. L.; Reints, J. S., Jr.;
California Avocado Society Yearbook Year: 1992 Vol: 76 Pages: 93-97
1992
บทคัดย่อ
In southern California, fruits of cv. Hass may be left for 12 h or longer in the field after harvest. During periods of high summer temperatures, fruit pulp temperatures may exceed 100 deg F when fruits are unprotected. The effects of delays in cooling (up to 24 h) and different temperatures (68, 86 or 104 deg ) on subsequent storage life were investigated. Various quality parameters were evaluated, such as firmness following storage, the incidence of physiological disorders and the time taken to attain eating-ripeness following storage. The warmer the fruits during cooler delays, the greater were subsequent fruit softening and physiological and pathological breakdown, especially in fruits held at 104 deg . It was concluded that Hass fruits ideally should be cooled within 6 h of harvest and, if delays should occur, fruit pulp temperatures should be held below 86 deg . In a further study, changes in pulp temperature were compared when harvesting bins were covered with 3 different materials, viz.brown wrapping paper, a space blanket [aluminized] with the reflective side upwards and leaves + branches. Fruits were picked in early morning, temperatures were recorded from 10.20 h and after 16.00 h the fruits were removed and stored for 6 weeks at 41 deg . After storage, they were held for 3 days at 68 deg to ripen and were then evaluated. Pulp temperatures in fruits at the bottom of the bins were essentially unaltered through the testing time, regardless of covering material, whereas those in fruits at the top of the bin varied considerably. At the end of the test there was a difference of around 40 deg between fruits in the uncovered control bin and those in the bin covered by leaves + branches. The incidence of moderate-severe flesh discoloration was 7-10% in fruits at the bottom of the bins; at the top of the bins it ranged from <5% (leaves + branches) though <25% (space blanket) to >30% in paper-covered and control bins. The incidence of decay (generally stem-end rot) was negligible at the bottom of the bins (except for control where it was 10%); at the top of the bins it was <5% for leaves + branches, <10% for paper and space blanket but >40% for control. In a third study, 5 bin covers were compared with control for fruits held for 4 weeks at 41 deg . As before, the bin covered with leaves + branches remained the coolest. Fruit weight loss in the bin was influenced both by position and type of cover. At the bottom it averaged 0.14% with little difference between treatment. At the top it ranged from 0.60% in control to around 0.30% in the covered bins. For all parameters evaluated, fruits from the bin covered with leaves + branches had the least amount of final weight loss and internal breakdown.