`Redcort Cortland' and `Redmax' and `Summerland McIntosh' apples (Malus ×domestica Borkh.) were treated with 900 nL·L-1 of 1-methylcyclopropene (1-MCP) for 24 hours at 20 °C before storage and were kept at 3 °C in either a controlled atmosphere (CA) of 2 kPa O2 and <2.5 kPa CO2 or in an air (RA) environment for up to 9 months. After 4.5 months, half of the fruit were treated with a second 900 nL·L-1 1-MCP application in air at 3 °C for 24 hours and then returned to RA or CA storage. At harvest and following removal at 3, 6, and 9 months and a 7-day shelf life at 20 °C, fruit firmness, titratable acidity (TA) and soluble solids content (SSC) were measured, while internal ethylene concentrations (IEC) in the apple core were quantified after 1 day at 20 °C. Upon storage removal and following a 21-day shelf life at 20 °C, disorder incidence was evaluated. 1-MCP-treated apples, particularly those held in CA-storage, were more firm and had lower IEC than untreated fruit. Higher TA levels were maintained with 1-MCP in all three strains from both storages, while SSC was not affected. Following the 6- and/or 9-month removals, 1-MCP suppressed superficial scald development in all strains and reduced core browning and senescent breakdown in RA-stored `Redmax' and `Summerland' and senescent breakdown in RA-stored `Redcort'. 1-MCP generally maintained the quality of `Cortland' and `McIntosh' fruit held in CA and RA environments (particularly the former) to a higher degree than untreated apples over the 9-month storage period. A second midstorage application of 1-MCP at 3 °C did not improve poststorage fruit quality above a single, prestorage treatment.
John M. DeLong, Robert K. Prange, and Peter A. Harrison
Allan B. Woolf and Michael Lay-Yee
`Hass' avocados [Persea americana Mill.] were pretreated in water (38 °C for up to 120 min) immediately before 50 °C hot water treatments of up to 10 min. Fruit were stored for 1 week at 6 °C and ripened at 20 °C. External browning was evaluated immediately upon removal from cold storage, and fruit quality evaluated when fruit were ripe. Pretreatments at 38 °C tended to reduce the levels of external browning, skin hardening, and internal disorders, such as tissue breakdown and body rots, that were associated, and increased, with longer hot water treatments. A pretreatment of 60 min was the most effective for eliminating external browning, and reducing hardening of the skin when fruit were ripe following hot water treatment. Examination of heat shock protein (hsp) gene expression in avocado skin tissue, showed that levels of hspl7 and hsp70 homologous mRNA increased with increasing pretreatment duration. The results demonstrate that 38 °C pretreatments increase the tolerance of avocado fruit to subsequent hot water treatments.
Carlos H. Crisosto, F. Gordon Mitchell, and Zhiguo Ju
The susceptibility to chilling injury (CI) or internal breakdown (IB) was evaluated in the most currently planted yellow- and white-flesh peach [Prunus persica (L.) Batsch] and nectarine [Prunus persica var. nectarine (L.) Batsch] and plum [Prunus salicina Lindel] cultivars from different breeding sources and fruit types. Cultivars were segregated into three categories (Cat. A, B, and C) according to their susceptibility to CI or IB symptoms (mealiness and flesh browning) when exposed to 0 °C or 5 °C storage temperatures. Cultivars in Cat. A did not develop any symptoms of CI after 5 weeks of storage at either temperature. Cultivars in Cat. B developed symptoms only when stored at 5 °C within 5 weeks of storage. Cultivars were classified in Cat. C when fruit developed CI symptoms at both storage temperatures within 5 weeks of storage. Most of the yellow- and white-flesh peach cultivars developed IB symptoms when stored at both storage temperatures (Cat. C). Most of the new nectarine cultivar introductions did not develop CI symptoms when stored at 0 °C or 5 °C after 5 weeks (Cat. A). Three out of six plum cultivars tested had CI symptoms within 5 weeks storage at 0 °C. However, all of the plum cultivars tested developed CI symptoms when stored at 5 °C (Cat. B). The importance of proper temperature management during postharvest handling was demonstrated.
S.R. Drake, D.C. Elfving, and T.A. Eisele
Quality of `Cripps Pink' apples (Malu × domestica) harvested at a starch index of 2 and 4 was evaluated over three crop seasons. Apple quality was evaluated after harvest and after regular atmosphere (RA) and controlled-atmosphere (CA) storage at 1% O2 and 1% CO2, 1% O2 and 3% CO2, and 1% O2 and 5% CO2 (1 year only) at 1 ºC (33 to 34 ºF). Over three seasons, commercially acceptable fruit quality was achieved on either harvest date following both long-term RA and CA storage. Fruit size was not different between apples harvested at a starch index of 2 or 4. Firmness and acids remained at acceptable levels [62 N (14 lb) and ≥0.50%, respectively] in `Cripps Pink' apples regardless of maturity, storage time or storage conditions. Delaying harvest after a starch index of 2 was achieved increased soluble solids concentration (SSC), SSC to TA (titratable acidity) ratio, peel color, malic acid and citric acid concentrations but decreased fructose content. `Cripps Pink' apples responded well to CA storage conditions of 1% O2 with 1% or 3% CO2, but displayed significant firmness loss and greatly increased internal breakdown at 1% O2 and 5% CO2 at 1 ºC.
J.G. Luza, R. van Gorsel, V.S. Polito, and A.A. Kader
Fruits of mid- (`O'Henry'), late (`Airtime'), and extra-late-season (`Autumn Gem') peach [Prunus persica (L.) Batsch] cultivars were examined for changes in cell wall structure and cytochemistry that accompany the onset of mealiness and leatheriness of the mesocarp due to chilling injury. The peaches were stored at 10C for up to 18 days or at SC for up to 29 days. Plastic-embedded sections were stained by the Schiff's-periodic acid reaction, Calcofluor white MR2, and Coriphosphine to demonstrate total insoluble carbohydrates, ß-1,4 glucans, and pectins, respectively. Mealiness was characterized by separation of mesocarp parenchyma cells leading to increased intercellular spaces and accumulation of pectic substances in the intercellular matrix. Little structural change was apparent in the cellulosic component of the cell walls of these fruits. In leathery peaches, the mesocarp parenchyma cells collapsed, intercellular space continued to increase, and pectin-positive staining in the intercellular matrix increased greatly. In addition, the component of the cell walls that stained positively for ß-1,4 glucans became thickened relative to freshly harvested or mealy fruit. At the ultrastructural level, dissolution of the middle lamella, cell separation, irregular thickening of the primary wall, and plasmolysis of the mesocarp parenchyma cells were seen as internal breakdown progressed.
A.H.D. Francesconi, C.B. Watkins, A.N. Lakso, J.P. Nyrop, J. Barnard, and S.S. Denning
Fruit maturity, quality, calcium concentration and economic value of `Starkrimson Delicious' (Malus domestica Borkh.) apples, under a range of crop levels and European red mite [Panonychus ulmi (Koch)] cumulative mite-days (CMD), were best explained by local surface regression models involving CMD and crop load. Fruit from trees with low CMD and a light crop (125 fruit/tree, about 20 t/ha) were the most mature at harvest. Those fruit had higher ethylene concentrations, starch pattern indices, soluble solids concentrations, and watercore incidence at harvest than fruit from trees with low CMD and a normal crop (300 fruit/tree, about 40 t/ha), or with high CMD at any crop level. Those fruit also had higher incidences of watercore and internal breakdown after 4 months of cold storage. Calcium concentrations in fruit increased as crop load and CMD increased. Whole-canopy net CO2 exchange rate per fruit related better to fruit quality and calcium concentrations than either crop load or CMD alone, but was always a much worse predictor than local surface regressions. Low CMD and normally cropped trees had the highest crop value; lightly cropped trees had an intermediate crop value; while high CMD and normally cropped trees had the lowest crop economic value. Crop load should be considered when defining action thresholds for mites, and harvest schedules for apples should reflect crop load and mite populations on apple trees.
Yu-Xiong Zhong, Jian-Ye Chen, Hai-Ling Feng, Jian-Fei Kuang, Ruo Xiao, Min Ou, Hui Xie, Wang-Jin Lu, Yue-Ming Jiang, and He-Tong Lin
, M. Diamantidis, G. Mignani, I. 2006 Cell wall physicochemical aspects of peach fruit related to internal breakdown symptoms Postharvest Biol. Technol. 39 69 74 McQueen-Mason, S.J. Cosgrove, D
Adel A. Kader
Postharvest losses of horticultural perishables between the production and retail distribution sites are estimated to range from 2% to 23%, depending on the commodity, with an overall average of about 12% of what is shipped from U.S. production areas to domestic and export markets. Estimates of postharvest losses in developing countries are two to three times the U.S. estimates. Losses in dried grains, legumes, nuts, fruits, vegetables, and herbs and spices range from 1% to 10%, depending on their moisture content, temperature and relative humidity of transport and storage facilities, and protection against pathogens and insects. Reduction of these losses can increase food availability to the growing population, decrease the area needed for production, and conserve natural resources. Strategies for loss prevention include use of genotypes that have longer postharvest-life, use of an integrated crop management system that results in good keeping quality of the commodity, and use of the proper postharvest handling system that maintains quality and safety of the products. Biological (internal) causes of deterioration include respiration rate, ethylene production and action, rates of compositional changes, mechanical injuries, water loss, sprouting, physiological disorders, and pathological breakdown. The rate of biological deterioration depends on several environmental (external) factors, including temperature, relative humidity, air velocity, and concentrations of carbon dioxide, ethylene, and oxygen. Socioeconomic factors that contribute to postharvest losses include governmental regulations and policies, inadequate marketing and transportation systems, unavailability of needed tools and equipment, lack of information, and poor maintenance of facilities. Although minimizing postharvest losses of already produced food is more sustainable than increasing production to compensate for these losses, less than 5% of the funding of agricultural research is allocated to postharvest research areas. This situation must be changed to increase the role of postharvest loss reduction in meeting world food needs.
Renae E. Moran, Jennifer R. DeEll, and Dennis P. Murr
, irregularly shaped, brown lesions on the apple peel ( Meheriuk et al., 1994 ; Snowdon, 1990 ). Damage can also extend into the flesh, and the lesions are often invaded by secondary infections. On the other hand, soggy breakdown is an internal disorder. The
Rachel S. Leisso, Ines Hanrahan, James P. Mattheis, and David R. Rudell
rates may affect symptom development. Previous research also reveals increases in ethanol and fermentative odors concurrent with soggy breakdown development ( Smock, 1977 ). Internal CO 2 injury of ‘Honeycrisp’ apple fruit has not been exhaustively