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Maria Eloisa G. Quintana and Robert E. Paull

Ripe yellow papaya fruit in the markets frequently show green sunken areas called “green islands” (GI). This disorder seems to be caused by mechanical injury in a commercial postharvest handling system. Fruit at different stages of ripeness (5 to 50% yellow) were dropped from different heights (0 to 100 cm) onto a smooth steel plate to try to create GI. The injury sustained was not the same as GI seen in fruit from the handling system. Fruit (10 to 15% yellow) dropped on different grades of sandpaper (220 mesh to 36 mesh) from a height of 10 cm had injury symptoms similar to those seen on fruit from the handling system. These results suggest that abrasion damage was more important than impact damage in papaya fruit. Heating fruit at 48°C for -6 hours or until fruit core temperature (FCT) reached 47.5°C aggravated the severity of GI. Delaying the time of heating from the time of dropping did not significantly lower the severity of GI, except for fruit heated 24 hours after dropping. Waxing fruit alleviated the severity of GI. The results indicate that avoidance of abrasive surfaces such as the plywood walls of field bins is the best approach to avoiding the unsightly GI blemishes on papaya peel.

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Maria Eloisa G. Quintana and Robert E. Paull

`Solo' papaya (Carica papaya L.) fruit removed at different points from a commercial packing house showed that skin injury due to mechanical damage increased as fruit moved through the handling system. The occurrence of “green islands” -areas of skin that remain green and sunken when the fruit was fully ripe-apparently were induced by mechanical injury. Skin injury was seen in fruit samples in contact with the sides of field bins, but not in fruit taken from the center of the bins. Bruise-free fruit at different stages of ripeness (5% to 50% yellow) were dropped from heights of 0 to 100 cm onto a smooth steel plate to simulate drops and injury incurred during commercial handling. No skin injury occurred, although riper fruit showed internal injury when dropped from higher than 75 cm. Fruit (10% to 15% yellow) dropped onto sandpaper from a height of 10 cm had skin injury symptoms similar to those seen on fruit from the commercial handling system. These results suggest that abrasion and puncture injury were more important than impact injury for papaya fruit. Heating fruit at 48C for ≈6 hours or until fruit core temperature (FCT) reached 47.5C aggravated the severity of skin injury. Delays in the application of heat treatment from dropping did not reduce the severity of skin injury significantly, except for fruit heated 24 hours after dropping. Waxing fruit alleviated the severity of skin injury, whether applied before or after the heat treatment. Skin injury to papaya was caused by abrasion and puncture damage-not impact-and increased during postharvest handling of the fruit. The injury was associated mainly with fruit hitting the walls of wooden bins-bin liners may reduce this injury.

Open access

Sai Xu, Huazhong Lu, and Xiuxiu Sun

). However, postharvest litchi is very fragile, which is mainly indicated by its susceptibility to mechanical injury ( Chen et al., 2014 ) and high decay rate ( Zhang and Quantick, 1997 ). The fragility of postharvest litchi has been given much attention by

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Marcos D. Ferreira, Steven A. Sargent, Jeffrey K. Brecht, and Craig K. Chandler

very fragile and thus highly susceptible to mechanical injury. The major causes of postharvest strawberry losses are decay and accelerated senescence associated with bruising. Proper handling and temperature management significantly reduces these losses

Open access

Lan-Yen Chang and Jeffrey K. Brecht

strawberry fruit ( Szczesniak and Smith, 1969 ), which become more susceptible to mechanical injury as the ripening process proceeds. Strawberries are harvested when mostly or fully ripe according to the commercial standard for U.S. No. 1 grade, which states

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Judith A. Abbott, A. Raymond Miller, and T. Austin Campbell

Mechanical stress received by pickling cucumbers (Cucumis sativus L.) during harvest can cause physiological degeneration of the placental tissues, rendering the cucumbers unsuitable for use in some pickled products. Cucumbers were subjected to controlled stresses by dropping and rolling under weights to induce such degeneration. Following storage at various temperatures for O, 24, and 48 hours, refreshed delayed light emission from chlorophyll (RDLE) was measured and transmission electron micrographs of chloroplasts were made. Mechanical stress rapidly suppressed RDLE and induced accumulation of starch granules within the chloroplasts. Rolling usually had a greater effect on RDLE than did dropping. After 48 hours, RDLE suppression persisted; starch granules were no longer evident in chloroplasts from mechanically stressed fruit, but very electron-dense inclusions had developed in the chloroplasts. Storage temperatures affected RDLE levels but had minimal interaction with stress responses. Cucumber lots subjected to excessive mechanical stress likely could be detected using RDLE measurement.

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Dale E. Marshall and Roger C. Brook

The tender skin of bell peppers (Capsicum annuum L.) covers a crisp, fragile flesh that is easily bruised, cracked or crushed. During commercial harvest and postharvest handling operations, bell peppers undergo several transfers, each of which has the potential for causing mechanical injury to the peppers. These mechanical injuries include abrasions, cuts, punctures, and bruises, which affect the market grade and reduce pepper quality and subsequent life. Previous research on handling fresh vegetables and fruits has shown that the instrumented sphere (IS) is a tool that can help identify potentially damaging impacts during harvest and postharvest handling operations. For the study reported, the IS was used to evaluate the damage potential for peppers being hand harvested, and for peppers on a packing line. Studies in the field attempted to duplicate how pickers harvest peppers into pails and then empty them into empty wooden pallet bins. For the packing line evaluated, the diverging roll-sizer had the greatest potential for damage. Adding cushioning to hard surfaces and removing the metal support from under the cross-conveyor would help to reduce pepper damage. Cushioned ramps, and hanging flaps or curtains should be used to help reduce acceleration and drop height between pieces of equipment. All locations should be cushioned where peppers impact a hard surface, and drop height should be limited to 3 inches (8 cm) on a hard surface and 8 inches (20 cm) on a cushioned surface. The speed of all components in the system should be checked and adjusted to achieve full line flow of peppers without causing bruising. Workers must receive instruction on the significance of bruising during the harvest and postharvest operations.

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Celso L. Moretti, Elizabeth A. Baldwin, Steven A. Sargent, and Donald J. Huber

Tomato (Lycopersicon esculentum Mill.) fruit, cv. Solar Set, were harvested at the mature-green stage and treated with 50 μL·L-1 ethylene at 20 °C. Individual fruits at the breaker stage (<10% red color) were dropped onto a solid surface to induce internal bruising. Dropped and undropped fruit were stored at 20 °C until red-ripe, at which time pericarp, placental, and locule tissues were excised. Tissues from dropped tomatoes were examined for evidence of internal bruising and all tissues were analyzed for selected volatile profiles via headspace analysis. Individual volatile profiles of the three tissues in bruised fruit were significantly different from those of corresponding tissues in undropped, control fruit, notably: trans-2-hexenal from pericarp tissue; 1-penten-3-one, cis-3-hexenal, 6-methyl-5-hepten-2-one, cis-3-hexenol and 2-isobutylthiazole from locule tissue; and 1-penten-3-one and β-ionone from placental tissue. Alteration of volatile profiles was most pronounced in the locule tissue, which was more sensitive to internal bruising than the other tissues. Changes observed in the volatile profiles appear to be related to disruption of cellular structures.

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Celso L. Moretti, Steven A. Sargent, Donald J. Huber, Adonai G. Calbo, and Rolf Puschmann

`Solar Set' tomatoes (Lycopersicon esculentum Mill.) were harvested at the mature-green stage of development and treated with 50 μL·L-1 ethylene at 20 °C. Breaker-stage fruit were dropped from 40 cm onto a solid surface to induce internal bruising and held along with undropped fruit at 20 °C. At the ripe stage, pericarp, locule, and placental tissues were analyzed for soluble sugars, vitamin C, pigments, titratable acidity, soluble solids content, pericarp electrolyte leakage, extractable polygalacturonase activity, and locule tissue consistency. Bruising significantly affected chemical composition and physical properties of pericarp and locule tissues, but not placental tissue. For bruised locule tissue, carotenoids, vitamin C, and titratable acidity were 37%, 15%, and 15%, lower, respectively, than unbruised fruit. For bruised pericarp tissue, vitamin C content was 16% lower than for unbruised tissue, whereas bruising increased electrolyte leakage and extractable polygalacturonase activity by 25% and 33%, respectively. Evidence of abnormal ripening following impact bruising was confined to locule and pericarp tissues and may be related to the disruption of cell structure and altered enzyme activity.