Chilling injury of fruits and vegetables

Abstract

Chilling injury affects many fruits and vegetables. Most crops of tropical and subtropical origin are sensitive to chilling injury. Some crops of Temperate Zone origin are also susceptible. These crops are injured by low, but nonfreezing, temperatures. At these temperatures, the tissues weaken because they are unable to carry on normal metabolic processes. Various physiological and biochemical alterations occur in the sensitive species in response to low‐temperature exposure. These alterations lead to the development of a variety of chilling injury symptoms, such as surface pitting, discoloration, internal breakdown, failure to ripen, growth inhibition, wilting, loss of flavor, and decay. This review article describes the changes in membrane lipids, permeability, proteins, carbohydrates, energy supply, respiration, ethylene production, and other metabolic processes that are affected by chilling temperatures. Methods for alleviation of chilling injury‐such as temperature preconditioning, intermittent warming, chemical treatments, hormonal regulation, controlled atmosphere storage, genetic manipulation, and other methods—are also discussed.     

不同贮藏温度及时间对黄瓜果实冷害发生的影响

为了研究不同贮藏温度及贮藏时间对黄瓜果实冷害的影响规律,对0～20℃的贮藏温度下,在贮藏时间15d内的黄瓜果实的细胞膜电解质渗透率进行了系统测试。结果表明:黄瓜冷害的发生与贮藏温度及处理时间有关,而电解质渗透率的变化能很好地体现不同贮藏温度及时间下,黄瓜细胞组织受损程度及与冷害发生的关系。研究发现,0℃下的渗透率最高,渗透率变化最为明显,渗透率增量最大。表明贮藏温度越低,电解质渗透率变化越明显,出现跃变的时间越早,则黄瓜冷害发生得越早;随着贮藏时间的延长,细胞膜电解质渗透率随之增加,冷害随之加重。同时,适当的变温处理可以有效地缓解和抑制冷害的发生,延长贮藏期。     

不同温度对冬枣冷害程度的影响

为了探讨冬枣冷害发生的温度以及不同低温下冬枣的冷害程度,确定冬枣最佳的贮藏温度,防止贮藏过程中冷害造成的损失,进行了相关实验研究。将冬枣分别在-0.5、-1.5、-2.0、-2.5、-3.0℃下贮藏,测定贮藏过程中冬枣的冷害指数、各项营养指标和生理指标的变化。结果表明:随着温度的降低,冬枣的冷害程度加剧,其中-0.5℃处理组在整个贮藏过程中均未出现冷害症状;-1.5℃处理组仅在贮藏末期90d时出现个别的冷害症状;-2.0、-2.5、-3.0℃处理组在贮藏的中后期均出现冷害症状,其中-3.0℃处理组细胞膜透性、MDA含量、乙醇含量和PPO活性显著高于其它处理组,总酚含量显著低于其它处理组,冷害症状最为严重。     

Modified atmosphere packaging confers additional chilling tolerance on ethylene-inhibited cantaloupe Charentais melon fruit

Cantaloupe Charentais melon fruits are subject to chilling injury when stored at low temperatures, around 2 °C. Ethylene-suppressed cantaloupe Charentais melon, expressing a 1-aminocyclopropane-1-carboxylic acid (ACC)-oxidase gene in antisense orientation, showed strong, but not total, resistance to chilling injury, allowing an extended storage at low temperatures. Modified atmosphere packaging (MAP) is known to alleviate chilling injury symptoms in a variety of chilling-sensitive horticultural commodities. In the present work, we have compared the effects of MAP in non-retractile plastic film and storage in air on ethylene production, respiratory activity, development of chilling injury symptoms, water loss, ion leakage and accumulation of ethanol and acetaldehyde in wild-type and ethylene-suppressed melons, during storage at 2 °C and after re-warming at 22 °C. MAP reduced chilling injury and extended the postharvest life of wild-type fruit and conferred additional chilling resistance on ethylene-suppressed melons. Reduction of ethylene production and water loss are necessary to prevent chilling injury symptoms in melon.     

The chilling of carcasses

Biochemical processes and structural changes that occur in muscle during the first 24h postmortem play a great role in the ultimate quality and palatability of meat and are influenced by the chilling processes that carcasses are subjected to after slaughter. For beef and lamb, employing chilling parameters that minimize cold shortening is of greatest importance and can be best addressed by ensuring that muscle temperatures are not below 10°C before pH reaches 6.2. For pork, because of the impact of high muscle temperatures and low pH on the development of pale, soft, and exudative (PSE) pork, a more rapid chilling process is needed to reduce PSE with the recommended internal muscle temperature of 10°C at 12h and 2-4°C at 24h. Spray chilling, a system whereby chilled water is applied to carcasses during the early part of postmortem cooling, is used to control carcass shrinkage and to improve chilling rates through evaporative cooling. Delayed chilling can be used to reduce or prevent the negative effects of cold shortening; however, production constraints in high-volume facilities and food safety concerns make this method less useful in commercial settings. Electrical stimulation and alternative carcass suspension programs offer processors the opportunity to negate most or all of the effects of cold shortening while still using traditional chilling systems. Rapid or blast chilling can be an effective method to reduce the incidence of PSE in pork but extreme chilling systems may cause quality problems because of the differential between the cold temperatures on the outside of the carcass compared to the warm muscle temperatures within the carcass (i.e., muscles that are darker in color externally and lighter in color internally).     

冷害对茄子果实贮藏品质的影响

研究冷害对茄子果实贮藏品质的影响,旨在阐明冷害温度下茄子果实品质劣变的规律。茄子采后分别于冷害温度[(40 ± 1)℃,简称4℃]和非冷害温度[(13 ± 1)℃,简称13℃]贮藏10d,定期测定贮藏期间两组的品质变化。结果显示,4℃条件下茄子果实在第4 天表面出现轻微褐变,随后日趋严重,而在13℃条件下的果实10d 内未发生冷害症状。冷害会加速茄子采后失重率和膜透性的上升,促进叶绿素、可滴定酸(TA)和VC 含量下降,促进贮藏中、后期(4～10d)可溶性糖、还原糖、可溶性蛋白和游离氨基酸含量下降。可见,冷害会促进茄子采后贮藏品质的劣变,降低茄子的食用价值和商品价值。     

不同贮藏温度对采后伽师瓜果实冷害及品质的影响

为了研究不同贮藏温度对采后伽师瓜果实冷害及品质的影响,分别对0.5、3.0 ℃和21.0 ℃贮藏条件下的 伽师瓜果实的腐烂率、质量损失率、冷害指数、硬度及脂肪酸去饱和酶（fatty acid desaturases,FADs）、脂氧合 酶（lipoxygenase,LOX）、三磷酸腺苷酶（adenosine triphosphatase,ATPase）活力变化进行测定。结果表明：伽 师瓜果实冷害的发生与贮藏温度及持续时间相关,3.0 ℃和0.5 ℃贮藏易遭受冷害,但0.5 ℃贮藏条件下冷害出现较 晚,低温更好地缓解了果实的腐烂现象,维持较高的FADs和ATPase活力,抑制了LOX活力的升高,提高了果实的 抗寒性;21.0 ℃贮藏虽未发生冷害,但果实质量损失率较大,腐烂率较高。不同贮藏温度下伽师瓜果实各种指标的 测定结果表明0.5 ℃条件下贮藏果实品质更好。     

加热预处理对青梅低温贮藏品质的影响

将绿熟期青梅用30℃热风分别处理24、48h后,与无处理果实一起,在青梅冷害发生临界温度5℃下贮藏,通过测定贮藏期间青梅的乙烯生成量、呼吸速率以及主要化学成分的变化,探讨加热预处理对减轻青梅冷害的效果及对果实贮藏品质的影响。结果表明:经30℃-48h处理虽然在减轻冷害方面表现出一定效果,但该处理果实的硬度下降较快,外观颜色的黄化进展也明显快于30℃-24h处理和对照,且贮藏后期腐烂较严重,果实的贮藏期只有36d;30℃-24h加热预处理可有效抑制青梅冷害的发生,其它贮藏品质指标也较好,果实的贮藏期可达到50d,比无处理果延长了7d。     

Enhancement of Chilling Stress Tolerance of Tomato Fruit by Postharvest Brassinolide Treatment

Tomatoes, originally a tropical fruit, cannot easily be stored at low temperatures, due to the risk of chilling injury (CI). To develop an effective technique to reduce CI, the effects of treatment with 0, 3, and 6 μM brassinolide (BR) on chilling injury, electrolyte leakage (EL), contents of malondialdehyde (MDA) and proline, and activities of phospholipase D (PLD) and lipoxygenase (LOX) were investigated in tomato fruit stored at 1 °C for 21 days. Treatment with BR, especially at 6 μM, significantly alleviated chilling injury, reduced EL and MDA content, and increased proline content. Also, fruit treated with BR exhibited significantly lower PLD and LOX activities as compared with the control fruit. These results suggest that PLD and LOX are associated with the induction of CI in tomato fruit. BR might reduce CI by inhibiting PLD and LOX activities and by enhancing membrane integrity.     

QUALITY OF PINK TOMATOES (cv. BUFFALO) AFTER STORAGE UNDER CONTROLLED ATMOSPHERE AT CHILLING AND NONCHILLING TEMPERATURES

Greenhouse-grown pink tomatoes (cv. Buffalo) were stored in air or in a controlled atmosphere (CA) of 4% O₂ plus 2% CO₂, to study the effect of CA at chilling and nonchilling temperatures on fruit quality characteristics. Tomatoes could be stored in CA at 12C for three weeks with no major changes in fruit appearance. CA was effective in delaying color development and ripening at this temperature. The soluble solids content was lower after CA storage, but no significant differences in firmness, pH or titratable acidity were observed between storage in air or CA. Storage in CA at 12C was also effective in reducing decay. However, at 6C, fruit showed high incidence of decay after both air and CA storage. CA did not alleviate chilling injury symptoms relative to air-stored samples and may have caused CO₂ injury. Water loss was greater under CA at both temperatures.     

Alleviation of chilling injury in postharvest tomato fruit by preconditioning with ultraviolet irradiation

BACKGROUND: Tomato fruit is usually stored at low temperatures for delayed ripening and extended shelf life. However, tomato fruit is susceptible to chilling injury when exposed to low temperatures. In this study, the potential effects of preconditioning with UV‐C or UV‐B irradiation on chilling injury of postharvest tomato fruit were investigated. RESULTS: Mature–green tomato fruit were exposed to 4 kJ m^?2 UV‐C or 20 kJ m^?2 UV‐B irradiation and stored for 20 days at 2 °C and subsequently 10 days at 20 °C. UV irradiation was effective in reducing chilling injury index and delaying ethylene peak. Furthermore, UV irradiation preserved storage quality as manifested by reduced weight loss, better retention of firmness, and higher contents of total soluble solids, soluble protein and soluble sugar during subsequent storage at 20 °C. UV‐C irradiation significantly delayed the development of the red colour after 10 days of storage at 20 °C. On the other hand, UV irradiation decreased total phenolics content and antioxidant capacity, suggesting possibly reduced stress response to low temperature resulted from enhanced physiological adaptation by UV preconditioning. CONCLUSION: Our results suggest that preconditioning with UV‐C or UV‐B irradiation in appropriate doses had a positive effect on alleviating chilling injury in postharvest tomato fruit. Copyright © 2012 Society of Chemical Industry     

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

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.     

氯化钙处理对李果实抑制冷害作用的影响

为探索减轻李果实冷害的新途径,以串红李子为试材,对李果实经不同质量分数的氯化钙处理后冷害与酶促褐变机理进行研究。结果表明,对照果在冷藏12d后,多酚含量和PPO活性都呈现上升趋势,MDA含量和冷害指数开始逐渐增加,说明此时冷害已经开始启动。而氯化钙处理则延缓多酚含量的上升趋势,提高PPO、POD、CAT的活性,外观冷害指数明显降低,内部冷害指数和MDA含量只有2%氯化钙处理的明显低于对照,SOD活性变化不大,只2%氯化钙处理明显高于其他处理果,说明氯化钙处理从外观上明显地抑制了李果实冷害的发生,综合分析比较内外两种冷害指数,只有2%氯化钙处理抑制冷害的效果最好,贮藏期末多酚含量是对照果的1.16倍,POD活性是对照果的3.7倍,贮藏72d时内部冷害指数只有42%,而对照果达57%,所以,李果实经2%氯化钙处理后贮藏品质最好。     

QUALITY CURVES FOR MANGO FRUIT (CV. TOMMY ATKINS AND PALMER) STORED AT CHILLING AND NONCHILLING TEMPERATURES

“Tommy Atkins” and “Palmer” mangoes were harvested medium‐ripe held for 7–20 days at five different temperatures and evaluated for quality attributes. The objective of this work was to obtain quality curves at chilling and nonchilling temperatures and to identify, for each temperature, which quality factors limit mango marketability. Chilling injury and increased fruit softness were the limiting quality factors for mango stored at 2 and 5C. Softening of the fruit, changes in color and development of decay were the limiting quality factors for mango stored at 12, 15 and 20C. Prediction of mango shelf life calculated from the data reported in the literature is not precise unless the characteristics of the fruit and environmental factors involved are well known. The curves obtained from quality evaluations for each temperature showed that a single quality attribute cannot be used to express loss of quality of mango over the normal physiological range of temperatures.     

24-表油菜素内酯对杏果实采后抗冷性与可溶性糖含量的影响

为了探究24-表油菜素内酯对杏果实采后抗冷性与可溶性糖含量变化的影响,以新疆‘赛买提’杏为实验材料,用质量浓度0.9 mg/L的24-表油菜素内酯减压渗透处理后置于温度0 ℃、相对湿度90%～95%的冷库贮藏,定期测定杏果实的冷害指数、冷害发病率、丙二醛含量、细胞膜透性及可溶性糖含量变化。结果表明：24-表油菜素内酯可明显降低杏果实低温贮藏期间冷害指数、冷害发病率、丙二醛含量、细胞膜透性,显著提高杏果实果糖、山梨醇和葡萄糖含量（P＜0.05）,降低蔗糖含量（P＜0.05）。表明24-表油菜素内酯能够增强杏果实抗冷性,其可能与诱导果糖、山梨醇和葡萄糖含量的变化密切相关。     

Reducing Chilling Injury of Loquat Fruit by Combined Treatment with Hot Air and Methyl Jasmonate

The effects of a combined treatment of hot air (HA, 38 °C for 6 h) and methyl jasmonate (MeJA, 16 μmol L^?1) on chilling injury, fruit quality, and physiological changes in loquat fruit stored at 1 °C were investigated. The results showed that treatment with HA or MeJA alone both significantly alleviated chilling injury in loquat fruit compared with the control, while their combination had the lowest level of chilling injury symptoms and highest quality. The activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, and catalase were enhanced by the combination of HA and MeJA. In addition, the combined treatment significantly inhibited the activities of phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase, which resulted in lower lignin content. Highest level of polygalacturonase activity and water-soluble pectin content and lowest level of protopectin content were also observed in the combined treatment. These results suggested that the enhanced chilling tolerance by combination of HA and MeJA treatment in loquat fruit was related to the induction of antioxidant enzymes and the inhibition of lignin biosynthesis. The combination of HA and MeJA treatment could be a useful technique to alleviate chilling injury and maintain quality of loquat fruit during cold storage.     

Review on tropical root and tuber crops. II. Physiological disorders in freshly stored roots and tubers

Tropical root and tubers, including cassava, sweet potato, yams, and aroids, have been reported to show an increase in respiratory activity after harvest and injury and subsequent storage in association with their deterioration. This leads to loss of water and carbohydrate. Cassava roots often show discoloration of the tissue with development of pigments in the xylem vessels (vascular streaking or primary/physiological deterioration). This has been established to be enzymatic in nature. Pruning the cassava stem, leaving about a 20‐ to 30‐cm stub prior to harvest, could delay the onset of primary deterioration. Sweet potato roots and yam tubers show a peak respiratory activity immediately or 1 d after harvest. The respiratory rate, however, declines during the subsequent storage period. Yam tubers show a further increase in respiratory activity at the breakage of dormancy occurring at the time of sprouting. Dormancy in yam tubers has been studied in some detail. Different species of yams vary in their dormancy period, a major factor that accounts for the variation in their storage life. Little information is available on the dormancy of sweet potato and aroids. Tropical roots and tubers exhibit “chilling injury” when stored at temperatures below a critical level. The critical cold‐storage temperatures range between 10 and 15°C for different tropical root and tuber crops.     

低温贮藏对“翠香”猕猴桃冷害和品质的影响

研究以"翠香"猕猴桃为试材,比较两种温度(0±0.5℃和2±0.5℃)下,贮藏果实的冷害发生情况及品质差异,同时关注果实贮藏期间果实苦味的产生,以期找出果实苦味产生的原因。结果表明,0±0.5℃贮藏时,果实硬度保持较好,果实呼吸强度下降,有冷害和褐变发生,并伴有果实发苦现象;而2±0.5℃贮藏的果实未见冷害和褐变发生,色度得以保持,多酚氧化酶(PPO)和过氧化物酶(POD)活性下降,极显著延缓了细胞膜透性的升高,此外,果实可溶性固形物和维生素C的含量也显著提高,果实没有出现苦味。试验中发现"翠香"猕猴桃苦味现象和冷害伴随产生,并随着冷害发展加重,推测"翠香"果实的苦味可能是由冷害造成的。     

菜豆冷害生理及其防治措施的研究

研究了热处理与间歇升温对菜豆冷害及其生理生化的影响,结果表明：间歇升温与热处理延缓了由于冷害引起的菜豆呼吸强度的上升、电导的增加和过氧化物酶活性的增强;降低了菜豆的表面水浸凹陷与锈斑的发生。两处理相结合具有协同增效作用,既能有效抑制表面水浸凹陷,又可阻止锈斑的发生,是防止菜豆冷害发生的有效措施。     

水杨酸处理对杏果实冷害及活性氧代谢的影响

以新疆塞买提杏为实验材料,用质量浓度0.01 g/L的水杨酸以减压渗透方式处理,置于温度0 ℃、湿度90%～95%的冷库贮藏。定期测定杏果实冷害指数和冷害发病率及与活性氧代谢相关的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）、超氧阴离子自由基（O2－·）的产生速率以及过氧化氢（H2O2）的含量。结果表明：质量浓度0.01 g/L的水杨酸处理能明显降低杏果实冷害发生率,减缓杏果实贮藏期间CAT和POD活性的下降,有效提高杏果实SOD的活性,抑制O2－·产生速率和H2O2含量的增长。说明水杨酸处理可减轻杏果实的冷害发病率,这与水杨酸处理能防止杏果实冷藏期间过高的氧化伤害,维持杏果实活性氧代谢平衡密切相关。