Development Of Chilling Injury Research Articles

SUSCEPTIBILITY OF SPANISH MELON FRUITS TO CHILLING INJURY DURING COLD STORAGE

Melon (Cucumis melo) type 'Piel de Sapo' like other members of the Cucurbitaceae, it is chilling injury (CI) sensitive. The object of this work was to analyze the chilling injury development in melon fruits, type 'Piel de Sapo' var. Sancho, under different cold storage conditions and treatments: 1-MCP, ethylene, and sucrose esters of fatty acids (SE). Melon fruits were stored at 2 and 8°C for 34 days. Sampling was performed during cold storage, before and after transfer to 20°C. Evolution of chilling injury symptoms, electrolyte leakage, ethylene and CO 2 production, ethanol and acetaldehyde, firmness, and sensorial analysis were determined. Spanish melon fruits of the Type 'Piel de Sapo' are sensitive to C.I. a temperature of 2°C, and can be conserved for 10 days with limitations. However, at 8°C it is possible to extend shelf life to 40 days with the presence of only traces of damage. Ethylene applied externally and 1-MCP protected the fruits against C.I.; however, ethylene decreased flesh firmness quickly shortering shelf life. 1-MCP temporarily delayed ripening and senescence, apparently by blocking the receptors of ethylene.

Hot water treatment to reduce chilling injury and fungal development and improve visual quality of two Opuntia ficus indica fruit clones

Cactus plantations in semi-arid lands produce large quantities of cactus fruits with short shelf lives (about 3 weeks) in sparsely populated areas where production rapidly surpasses demand. Improvements in shelf life are needed to (1) permit international shipments by refrigerated ship of approximately 3 week duration, (2) to be compatible with 2 °C fruit fly quarantine treatments, (3) to function without the use of fungicides as none are currently registered and as registration for additional minor crops is not likely. Thus storage temperatures likely to avoid and cause chilling injury (2 and 8 °C) were evaluated with hot water (52 °C) dips for a spineless local variety not well accepted for export and a spiny orange fruited clone 1287 selected for export. The results were: the hot water treatment was greatly beneficial in reducing chilling injury, fungal development and improving visual quality, clone 1287 has better long-term storage properties than the local variety, and the 2 °C temperatures approved for the control of fruit fly would not cause chilling injury to either the local or the orange variety, if the fruits were subjected to the heat treatment.

Storage temperature effects on moisture loss and the development of chilling injury in Lanes Late navel orange

The navel orange cultivar Lanes Late is an important export commodity for the Australian citrus industry with key markets in Asia and the United States of America. Low temperatures during storage and transport are used to extend postharvest life and for the purpose of insect disinfestation, making fruit more prone to chilling injury. The effects of low temperature and storage duration on the development of chilling injury were therefore examined. Cartons of about 100 fruit were stored at 3, 1 or –1°C for 0, 10, 20 or 30 days before transfer to a 22°C post-storage observation room. Fruit were assessed for chilling injury at transfer and every 10 days post-storage for 30 days. At all observation times the main effects of temperature and storage duration on the incidence of chilling injury and chilling injury index were significant with no interaction. The highest incidences of chilling injury were observed for fruit stored at –1°C (21%) and for 30 days (28%). Similarly, the chilling injury index was greatest for fruit stored at –1°C (0.47) for 30 days compared with fruit stored at 3 and 1°C (0.34 and 0.27, respectively). The incidence of chilling injury and the chilling injury index increased 2.1- and 3.0-fold, respectively, between the 10 and 30 day post-storage observations. Moisture loss was positively correlated with the chilling injury index (R2 = 0.53; P<0.001), supporting the hypothesis that moisture loss and time are important determinants of the expression of chilling injury. Based on this study, it is recommended that fruit storage and transit time be kept to ≤20 days and transport temperatures are maintained at ≥1°C. The expression of chilling injury could be minimised by reducing the post-storage handling time when moisture loss is expected to be highest.

Changes in ACC and conjugated ACC levels following controlled atmosphere storage of nectarine

Low temperature disorders of nectarines are thought to be expressions of chilling injury. Chilling injury is a form of stress usually associated with increased synthesis of ethylene and its immediate precursor, aminocyclopropane-1-carboxylic acid (ACC). However, other mechanisms for the development of chilling injury have been proposed. To help determine the nature of the processes leading to chilling injury in nectarines (Prunus persica) and how the gaseous composition of the storage atmosphere effects the development of low temperature disorders, levels of ACC and conjugated ACC were measured in fruit of the cv. Arctic Snow. These compounds were measured in fruit ripened at 20°C immediately after harvest, in fruit on removal from cold storage and in fruit ripened at 20°C following cold storage. During storage, fruit were kept at 0°C in the 4 following atmospheres: air; air + 15% CO2; air + 15 µL/L ethylene; and air + 15% CO2 + 15 µL/L ethylene. Concentrations of ACC remained low in all treatments and no significant changes in ACC levels due to added ethylene or CO2 were observed. Concentrations of conjugated ACC were about 10-times that of ACC and again were not influenced by the composition of the storage atmosphere. No significant changes in either ACC or conjugated ACC were observed until after flesh bleeding, the major symptoms of low temperature disorder expressed in these fruit, had begun to appear. It was concluded that disorders in nectarines stored at low temperatures are not a stress response involving a disruption of ethylene metabolism but may be associated with differential changes in the metabolism of enzymes associated with normal ripening.

Effect of commercial conditioning and cold quarantine storage treatments on fruit quality of “Rouge La Toma” grapefruit (Citrus paradisi Macf.)

We evaluated the effect of cold quarantine treatments on the development of CI and temperature conditioning on the induction of low temperature tolerance in “Rouge La Toma” grapefruit (Citrus paradisi Macf.), and their effects on acetaldehyde, ethanol and d-limonene contents and sensory characteristics. Various treatments, non-conditioned + quarantine at 2 °C and 85% RH for 18 days + storage at 13 °C and 85% RH for 4 days or 17 days + marketing period at 20 °C and 85% RH for 7 days; conditioned at 15 °C and 85% RH for 7 days + quarantine at 2 °C and 85% RH for 18 days + storage at 13 °C and 85% RH for 4 days or 17 days + marketing period at 20 °C and 85% RH for 7 days; storage at 13 °C and 85% HR for 22 days or 35 days + marketing period at 20 °C and 85% RH for 7 days (control treatments), were assayed. By the end of the simulated marketing period, the conditions did not promote chilling injury development in “Rouge La Toma” grapefruit. After the simulated marketing period, acetaldehyde, ethanol and d-limonene contents were not affected in fruit stored under treatments that included cold quarantine. In some cases, treatments that included temperature conditioning significantly increased acetaldehyde and ethanol levels, however, the amounts detected were comparable with fresh grapefruit juice. In general, the storage times involved in the treatments assayed, did not promote increases in the acetaldehyde and ethanol levels. Conversely, fruit stored at non-chilling temperatures (control treatments) had higher levels of d-limonene compared to those which underwent treatments that included cold quarantine. In addition, a significant increase in d-limonene levels between the initial time of the treatments and the end of the marketing period was observed, for all treatments, with the highest and most variables levels observed in fruit stored under control treatments. Sensory characteristics, such as sweet, acid and bitter taste and typical flavor intensity, in general, were not affected by the postharvest handling practices applied. Therefore, it can be concluded that the cold quarantine treatment and temperature conditioning may have important commercial applications for “Rouge La Toma” grapefruit (Citrus paradisi Macf.) without adversely affecting its quality.

Increasing ‘Blackamber’ plum (Prunus salicina Lindell) consumer acceptance

‘Blackamber’ plum (Prunus salicina Lindell) consumer acceptance and market life were highly dependent on harvest date. For fruit within the most common industry ripe soluble solids concentration (RSSC) range (10.0–11.9%), ripe titratable acidity (RTA) played a significant role in consumer acceptance. Plums within this RSSC range combined with low RTA (≤0.60%) were disliked by 18% of consumers, while plums with RTA ≥1.00% were disliked by 60% of consumers. Plums with RSSC ≥12.0% had ∼ 75% consumer acceptance, regardless of RTA. Fruit harvested between 35.6 and 17.8 N had high consumer acceptance because of lower RTA and higher RSSC than earlier harvested fruit. Ripening plums before consumption decreased TA by approximately 30% from the TA measured at harvest. In some cases, this decrease in TA during ripening may increase the acceptability of plums that would otherwise be unacceptable. Development of chilling injury (CI) symptoms limited market life of fruit harvested early (44.5–35.6 N) and late (17.8–13.3 N). Late harvested fruit were more likely to develop flesh translucency (overripe or bladderiness) when stored at 5 ◦ C, whereas early harvested fruit had low consumer acceptance and were more prone to develop flesh bleeding/browning during storage at 0 or 5 ◦ C. Based on this work, ‘Blackamber’ plums are well adapted to late harvest but proper postharvest temperature management, including ripening, and marketing within its market life potential are necessary to avoid the onset of storage disorders and maintain flavor. © 2004 Elsevier B.V. All rights reserved.

Effects of high oxygen concentration on pro- and anti-oxidant enzymes in peach fruits during postharvest periods

Peach fruits ( Amygdalus persica cv. Okubao) were stored in air, controlled atmospheres (CA) of 5% O 2 plus 5% CO 2, or CA with high O 2 concentration (70% O 2 plus 0% CO 2 for 15 days, then in CA with 5% O 2 plus 5% CO 2) at 0 °C, to determine the effects of different O 2 and CO 2 atmospheres on the activities of lipoxygenase (LOX), peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), as well as malondialdehyde (MDA) content and membrane integrity during storage periods with or without 3 days of post-storage ripening at 20 °C. SOD, CAT and POD activities of the fruits stored in air markedly decreased during the first 30 days of storage, while LOX activity increased after 15 days. CA (5% O 2 plus 5% CO 2) reduced chilling injury, and delayed the reduction of SOD, CAT and POD activities compared to the control. CA with high O 2 treatment induced SOD and CAT activities and maintained membrane integrity, but no significant effect on alleviating chilling injury was found compared to CA storage. The results indicated that the decrease of SOD and CAT might contribute to the development of chilling injury in peach fruits.

Cell wall metabolism during the development of chilling injury in cold-stored peach fruit: association of mealiness with arrested disassembly of cell wall pectins.

Partially tree-ripened ripe fruit of peach (Prunus persica L.) were stored for 1-4 weeks at 5 degrees C and then ripened at 20 degrees C for 3 d to induce chilling injury. With increasing cold storage the incidence and severity of mealiness symptoms increased progressively, manifested as reduced quantities of free juice and internal flesh browning. Relative to juicy fruit, tissue of mealy fruit showed altered intercellular adhesion when examined by microscopy and, upon crushing, a higher proportion of cells remained intact and did not release cellular contents. Substantial alterations in the metabolism of cell wall polysaccharides were observed. Chelator-soluble polyuronides from mealy fruit were partially depolymerized during cold storage in a manner dissimilar to that in unripe or ripe juicy fruit, and were not depolymerized further during the ripening period. The solubility of these high molecular weight pectins remained low, and did not show the increase characteristic of juicy fruit. Furthermore, in mealy fruit the dramatic decline in the polymeric Ara content of base-soluble, matrix glycan-enriched fractions occurring during normal ripening was absent, indicating diminished disassembly of an arabinan-rich polysaccharide firmly attached to cellulose. A corresponding rise in the polymeric Ara content of the most soluble pectin fraction was also absent, as was a decline in the Gal content of this extract. The depolymerization of matrix glycans showed only minor differences between juicy and mealy fruit. After cold storage and ripening, the activities of endo-1,4-beta-glucanase (EC 3.2.1.4), endo-1,4-beta-mannanase (EC 3.2.1.78), beta-galactosidase (EC 3.2.1.23), alpha-arabinosidase (EC 3.2.1.55), and particularly endo-polygalacturonase (EC 3.2.1.15) were lower in mealy fruit than in juicy fruit, whereas pectin methylesterase activity (EC 3.1.1.11) was lower in slightly mealy and higher in very mealy fruit. The data suggest that cold storage affects the activities of numerous cell wall-modifying enzymes, with important consequences for pectin metabolism. These changes alter the properties of the primary wall and middle lamella, resulting in tissue breakage along enlarged air spaces, rather than across cells, which reduces the amount and availability of free juice upon tissue fragmentation.

Reduction of postharvest rind disorders in citrus fruit by modified atmosphere packaging

Abstract Citrus fruit are relatively non-perishable, and can normally be stored for long periods of 6–8 weeks. However, the development of various types of rind disorders limits the postharvest storage capability, and causes massive commercial losses. In the present study, we found that modified atmosphere packaging (MAP) in “bag-in-box” Xtend® films (XF) effectively reduced the development of chilling injury (CI) as well as other types of rind disorders that are not related to chilling, such as rind breakdown, stem-end rind breakdown (SERB) and shriveling and collapse of the button tissue (aging). In all cases, microperforated films (0.002% perforated area) that maintained CO2 and O2 concentrations of 2–3 and 17–18%, respectively, inside the package were much more effective in reducing the development of rind disorders than macroperforated films (0.06% perforated area), which maintained CO2 and O2 concentrations of 0.2–0.4 and 19–20%, respectively. In both types of package, the relative humidity (RH) was ∼95%. No major differences were found between the effectiveness of polyethylene (PE) and XF packages, despite the fact that XF prevents water condensation inside the bags. Overall, microperforated and macroperforated XF packages reduced rind disorders not related to chilling (rind breakdown, SERB and aging) after 5 weeks of storage at 6 °C and 5 days of shelf life conditions by 75 and 50%, respectively, in ‘Shamouti’ orange, and by 60 and 40%, respectively, in ‘Minneola’ tangerines. Similarly, microperforated and macroperforated XF packages reduced the development of CI after 6 weeks of cold storage at 2 °C and 5 days of shelf life conditions by 70 and 35%, respectively, in ‘Shamouti’ oranges and by 75 and 45%, respectively, in ‘Star Ruby’ grapefruit. Furthermore, storage of unwrapped ‘Shamouti’ oranges in high RH (95%) also reduced rind disorders by 40–50%, similarly to the effects of the macroperforated films. In the light of these data, we suggest that MAP reduces the development of rind disorders in citrus fruits via two modes of action: the first, which is common to both microperforated and macroperforated films is by maintaining the fruit in a high RH environment; the second, which is specific to the microperforated film, involves maintaining a modified atmosphere environment with elevated CO2 and lowered O2 levels.

Methyl jasmonate and modified atmosphere packaging (MAP) reduce decay and maintain postharvest quality of papaya ‘Sunrise’

Exposure of papaya (Carica papaya L., cv. Sunrise) fruit to methyl jasmonate (MJ) vapors (10−5 or 10−4 M) for 16 h at 20 °C inhibited fungal decay and reduced chilling injury development and loss of firmness during storage for 14–32 days at 10 °C and 4 days shelf life at 20 °C. MJ-treated fruit also retained higher organic acids than the control fruit. Low density polyethylene film packaging prevented water loss and further loss of firmness as well as inhibiting yellowing (b* values) of papaya fruit. The modified atmosphere created (3–5 kPa O2 and 6–9 kPa CO2) inside the package did not induce any off-flavor development during storage at 10 °C. The postharvest quality of papaya was enhanced significantly by combining the MJ-treatments and MAP. Use of MJ at 10−5 M with MAP is beneficial to maintaining postharvest quality of papaya during low temperature storage and shelf-life period.

Preprocessing storage conditions for green ‘Conservolea’ and ‘Chondrolia’ table olives

Green olives (Olea europaea L. cvs. ‘Conservolea’ and ‘Chondrolia’ ), destined for Spanish-style processing, were harvested at the beginning and the end of commercial harvest period and stored at 5 and 7.5 °C in air or various controlled atmospheres. Olive quality was measured periodically and included mass loss, skin color, flesh firmness and chilling injury symptoms, mainly internal browning. Larger samples of ‘Conservolea’ olives were commercially processed with the Spanish method after storage for objective quality determination and taste panel evaluation. Mass loss of fresh olives during storage was generally low and no fruit decay was encountered. Fresh ‘Chondrolia’ green olives were very sensitive to chilling injury. They lost their capacity to develop skin color and ripen after 2–4 weeks of cold storage with excessive internal browning, resulting in pitting and external discoloration. Fresh ‘Conservolea’ green olives developed skin color, especially at 7.5 °C, and after storage in air, 2 or 5 kPa CO2. Fruit stored at 2 kPa O2 in the presence or not of high CO2 retained their green color for more than 2 months. ‘Conservolea’ olives slightly softened during storage but with longer storage, in parallel with chilling injury development, a rehardening of the fruit flesh was measured, possibly an additional chilling injury symptom. Storage at 5 °C and combinations of 2 kPa O2 and 2 or 5 kPa CO2 increased susceptibility to chilling injury, although fruit successfully retained skin green color. Objective and subjective quality evaluation of processed ‘Conservolea’ olives gave similar differences between treatments. Abnormal flavor seemed to be an additional result of chilling injury. In conclusion, ‘Conservolea’ green olives can be stored up to 37 days at 5 °C in air or for up to 22 days at 7.5 °C and 2 kPa O2 plus 5 kPa CO2.

Activity of enzymatic antioxidant defense systems in chilled and heat shocked cucumber seedling radicles

Chilling whole cucumber seedlings that had 10‐mm long radicles for 4 days at 2.5°C significantly inhibited subsequent radicle growth both by increasing the time it took the seedlings to recover from chilling and attain a linear rate of radicle growth, and by decreasing the subsequent rate of linear growth. Exposing cucumber seedlings to 45°C for up to 20 min had no effect on subsequent radicle growth, while longer exposures produced reductions in growth. A heat shock at 45°C for 10 min induced the optimal protection to 4 days of chilling at 2.5°C by reducing chilling inhibition from 60 to 42%. Two hours after being chilled, heat shocked or heat shocked and then chilled, there was no difference in protein content of the apical 1 cm of the seedling radicle among these treatments and the non‐heat shocked, non‐chilled control. Two days after treatment, the protein content was still similar in tissue that had been heat shocked or heat shocked and chilled, while it was significantly reduced in tissue that had been chilled. In general, 2 h after treatment, the activity of the 5 antioxidant enzymes examined in this study [superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11), guaiacol peroxidase (GPX; EC 1.11.1.7) and glutathione reductase (GR; EC 1.6.4.2)] were reduced by chilling and unaffected or increased by heat shock. When heat shock was followed by chilling, there was a consistent effect of the heat shock treatment on preventing the loss of enzyme activity following chilling. This protective effect of the heat shock treatment was even more pronounced after 2 days of recovery at 25°C for SOD, CAT and APX. In contrast, the activity of GR and GPX was substantially higher in chilled tissue than in tissue that had been heat shocked before being chilled. Elevated levels of GR and GPX therefore appear to be correlated with the development of chilling injury, while elevated levels of SOD, CAT and APX appear to be correlated with the development of heat shock‐induced chilling tolerance.

Induction of resistance to Penicillium digitatum and chilling injury in ‘Star Ruby’ grapefruit by a short hot-water rinse and brushing treatment

SummaryPostharvest heat treatments have been used for many years as alternatives to chemical control of fungal diseases and insect infestation of fruits and vegetables. In this study, the effects of a new hot-water brushing (HWB) treatment on the resistance of red grapefruit (C. paradisi cv. Star Ruby) to green mould decay caused by Penicillium digitatum (Pers.: Fr.) Sacc. and on the development of chilling injury (CI) symptoms during cold storage were examined. The HWB treatment comprises rinsing hot water on the fruits as they move along a belt of brush rollers. A twenty second HWB treatment at 59 or 62° reduced decay, after arti®cial inoculation of wounded fruit, by 52 or 70%, respectively, compared with control unwashed fruit, whereas rinsing and brushing the fruit with tap water (~20°) or with hot water at 53 or 56°, were ineffective. HWB treatments applied 1–3 d prior to inoculation were most effective in enhancing the disease resistance of fruit, but were much less effective when the fruit were inoculated on the same day or 7.d later. HWB treatments at 59 or 62° for 20.s also significantly reduced the CI index and the percentage of fruit displaying CI symptoms by 42 and 58%, respectively, after six weeks’ storage at 2° and an additional week at 20°. Furthermore, HWB treatments cleaned the fruit and improved its general appearance without causing any surface damage, and did not influence fruit weight loss, percentage of total soluble solids (TSS) in the juice, juice acidity or fruit colour.

Inhibition of ethylene biosynthesis by antisense ACC oxidase RNA prevents chilling injury in Charentais cantaloupe melons

ABSTRACTNon‐freezing low temperature storage causes injury to melons and most other fruit and vegetables of tropical and subtropical origin. We demonstrate here that ethylene suppression through an antisense ACC oxidase (ACO) gene considerably reduced the sensitivity of Charentais cantaloupe melons to chilling injury. In contrast to wild‐type fruit, antisense ACO melons did not develop the characteristic chilling injury of pitting and browning of the rind neither when stored at low temperature (3 weeks at 2 °C) nor upon rewarming. Treating antisense melons with 10 p.p.m. ethylene for more than 1 d prior to cold storage resulted in the restoration of chilling sensitivity. When the ethylene treatment was performed after cold storage, the chilling injury symptoms did not appear. The tolerance to chilling was associated with a lower accumulation of ethanol and acetaldehyde, reduced membrane deterioration and higher capacity of the fruit to remove active oxygen species. The activities of catalase, superoxide dismutase and peroxidase were markedly increased in antisense ACO fruit in comparison with wild‐type fruit, particulary upon rewarming and post‐storage ethylene treatment. Severe chilling injury symptoms were correlated with a lower activity of activated oxygen scavenging enzymes. These results demonstrate that ethylene acts in conjunction with low temperature to induce metabolic shifts that participate in the development of chilling injury.

Peach size affects storage, market life

During the 1995 season, large (~275g), medium (~175g) and small (~125g) ‘O'Henry’ peaches were stored in either air, 5% CO2 + 2% O2 or 17% CO2 + 6% O2 at 380F (3.30C). Large ‘O'Henry’ peaches benefited more from the 17% CO2 + 6% O2 than from either the 5% CO2 + 2% O2 or the air storage treatment. During the 1996 season, large, medium and small ‘Elegant Lady’ and ‘O'Henry’ peaches were stored in air or in 17% CO2 + 6% O2 at either 320F (00C) or 380F. Fruit size, storage atmosphere and temperature all had significant effects on chilling injury development. Small peaches stored in air at 320F had a longer market life than large fruit. At both storage temperatures, large ‘Elegant Lady’ and ‘O'Henry’ peaches had a longer market life under controlled atmosphere than under air storage. However, at 380F, small ‘Elegant Lady’ fruit in controlled atmosphere showed browning in the flesh. This suggests that 17% CO2 + 6% O2 may induce flesh browning in small ‘Elegant Lady’ peaches. In both years, lack of juiciness (mealiness/leatheriness) was observed before the development of flesh browning. Thus market life depended on the incidence of mealiness/leatheriness rather than on flesh browning.

339 Postharvest Physiological and Physico-chemical Responses of Jute (Chorchorus olitorius Linn.) to Various Temperature Conditions

The physiological and physico-chemical responses of jute, a tropical green leafy vegetable, to several temperature conditions were determined during postharvest storage. Jute were sourced from wholesale market and harvested from the university farm, packed in low-density polyethylene bags and stored at 1 to 30 °C and 1 to 20 °C, respectively, before it was analyzed for postharvest quality changes. There was no significant difference in the time-temperature tolerance of both leaves in all treatments. At 1 °C and 8 °C, both jute showed high sensitivity to chilling injury, which manifested by browning of the stems, darkening of young and mature leaves, wilting, and excretion of slimy substances. These symptoms developed within 3 to 9 days at 1 °C and 5 to 13 days at 8 °C, and it seems related with the decrease of ortho-diphenol content. The chlorophyll fluorescence of jute measured in terms of Fv: Fmax ratio decreased before the onset of browning and remained at lower levels during development of chilling injury at 1 and 8 °C. The ethylene concentration decreased after increasing for 1 day at 8 °C and before chilling injury occurred at 1 °C. However, at 15, 20, and 30 °C, both jute were more susceptible to yellowing with chlorophyll degradation and abscission of leaves due to senescing effect of high-temperature storage. Senescent symptoms were evident within 1 to 5 days at 30 °C and 3 to 7 days at 15 and 20 °C. Jute with stems partly immersed in water during storage had lower respiration rates at 1 and 8 °C due to its sensitivity to chilling injury manifested by wilting of leaves within 1 to 4 days of storage.

STORAGE OF IMMATURE GREEN MANGO (Mangifera indica, L.) FRUIT FOR PROCESSING

ABSTRACT A suitable method of storing, for processing immature green mangoes in a fresh state was sought. Fruits were stored at three temperatures (1OC, 20C and 30C) either in sealed low density polyethylene (LDPE) bags or paper bags or they were waxed before storage. Storage above 20C proved unsuitable for fruits held longer than one week. Sixty percent of fruits stored at 10C in LDPE bags showed no evidence of pathological infection. Development of severe chilling injury limited the use of waxed and control fruits beyond 14 days at 10C. There were no visible symptoms of chilling injury in fruits stored at 10C in LDPE bags. The majority of fruits stored in LDPE bags at 10C maintained good quality characteristics with acceptable flavor and minimal changes in chemical composition up to 21 days.

Ripening Affects High-Temperature-Induced Polyamines and Their Changes during Cold Storage of Hybrid Fortune Mandarins

Polyamine levels were measured in the flavedo of three ripening stages of Fortune mandarins exposed to high-temperature conditioning before storage at a chilling (2 °C) and a nonchilling temperature (12 °C). Increasing periods of conditioning at 37 °C delayed the development of chilling injury (CI) and produced an increase in the content of the polyamines in the following proportion: spermine > spermidine > putrescine. Storage at 2 °C of conditioned fruits reduced the polyamine titer to levels similar to those of nonconditioned fruits. Changes in polyamines during storage of conditioned and nonconditioned fruits were dependent on the ripening stage of the fruit. In general, the levels of polyamines in nonconditioned fruits stored at 2 and 12 °C were similar. No change in spermine was induced in the most mature fruits at 2 °C or in response to high-temperature conditioning despite conditioning-reduced CI. With this exception, the data indicate that conditioning fruits at 37 °C elevated the content of poly...

Modulation of phospholipase D and lipoxygenase activities during chilling. Relation to chilling tolerance of maize seedlings

Phospholipase D (phosphatidylcholine choline hydrolase, EC 3.1.4.4) and lipoxygenase activities (linoleate: oxygen oxidoreductase, EC 1.13.11.12) were analysed in chilling-susceptible and chilling-tolerant maize ( Zea mays L.) seedlings in relation to their chilling tolerance. Before chilling, phospholipase D activity in the leaf microsomal fraction was 2-fold higher in the chilling-susceptible CO 316 when compared to that of paclobutrazol-treated, chilling-tolerant CO 316. Phospholipase D activity in the heavy membrane fraction comprising chloroplast and mitochondria showed a 3 to 4-fold increase during chilling and post-chilling periods, albeit with temporal variations. An increase in cytosolic phospholipase D activity was observed only in CO 316 and CO 328. Also, phospholipase D activity in the heavy membrane and cytosolic fractions of roots increased in CO 316 during chilling and post-chilling periods. Lipoxygenase activity was low in both leaves and roots of CO 328. Paclobutrazol treatment of CO 316 did not appear to affect the level of cytosolic lipoxygenase activity in roots during the early part of chilling and post-chilling, but increased the activity in leaves. The results suggest that during chilling and post-chilling periods, temporal variations in phospholipase D and lipoxygenase activities in both leaves and roots of CO 316, CO 316P and CO 328 could result in differential metabolism of phospholipids. Enhanced degradation coupled with low levels of turnover could lead to development of chilling injury in the tissue.

Development of chilling injury in five jicama cultivars

Five commercially important jicama ( Pachyrhizus erosus ) cultivars (`Agua Dulce', `Cristalina', `San Juan', `San Miguelito', and `Vega de San Juan') were stored at 10°C and 13°C to study postharvest quality changes and chilling susceptibility. Decay development, weight loss after storage, internal color and texture, respiration rates and ion leakage were the parameters used to evaluate differences in chilling susceptibility. All cultivars were very chilling sensitive, with symptoms of injury occurring after 1 week at 10°C plus 1 week at room temperature. Roots of cvs `Vega de San Juan' and `San Miguelito' were the most and least tolerant to 10°C storage, respectively. Roots stored at 13°C showed few internal quality changes over a 5-month period, although weight loss exceeded 35%.