File Name: chilling injury of fruits and vegetables .zip
Written by Karen L.
- Postharvest Heat Treatment for Mitigation of Chilling Injury in Fruits and Vegetables
- Cooperative Extension Publications
- Effects of Harvest Maturity on Chilling Injury and Storage Quality of Apricots
- Symptoms of frost, freezing and chilling injury on vegetables
Postharvest Heat Treatment for Mitigation of Chilling Injury in Fruits and Vegetables
Immature, vegetable-like fruits are produced by crops of great economic importance, including cucumbers, zucchini, eggplants and bell peppers, among others. Because of their high respiration rates, associated with high rates of dehydration and metabolism, and their susceptibility to chilling injury CI , vegetable fruits are highly perishable commodities, requiring particular storage conditions to avoid postharvest losses. This review focuses on the oxidative stress that affects the postharvest quality of vegetable fruits under chilling storage.
We define the physiological and biochemical factors that are associated with the oxidative stress and the development of CI symptoms in these commodities, and discuss the different physical, chemical and biotechnological approaches that have been proposed to reduce oxidative stress while enhancing the chilling tolerance of vegetable fruits. A number of immature vegetable-like fruits are produced by dicotyledonous species of great economic importance, within the families Cucurbitaceae pumpkins, cucumbers, zucchini, bitter gourds and luffa , Solanaceae eggplants, bell peppers , Fabaceae peas, broad beans , and Malvaceae okra.
These are herbaceous and annual species of subtropical or tropical origin, contributing with fibre, vitamins and other non-nutritive but beneficial additions to the human diet. Thus, eggplant fruit is rich in polyphenols, including hydroxycinnamic acid and its derivative chlorogenic acid, which have a potent antioxidant capability [ 1 ]. Eggplants and other immature fruits are also excellent sources of natural pigments and other antioxidant constituents such as chlorophyll a, chlorophyll b, and ascorbate [ 2 ].
Moreover, cucumber cucurbitacins exhibit anti-cancer activity as well as having purgative, anti-inflammatory and cosmetic pharmacological applications [ 5 ]. These medicinal properties are highly valued, both for their therapeutic activity within Indian and Chinese folk medicine and for use in the cosmetic industry [ 6 ]. In zucchini and other types of summer and gourd squash, the content of antioxidant compounds is of increasing interest for breeders, who have tried to increase the content of carotenoids and other nutritional compound and to improve external appearance and organoleptic characteristics [ 7 , 8 ].
Bitter gourd is notable for its medicinal properties. It is traditionally used in India, Korea, China and other Asiatic countries for the treatment of diabetes, its most common traditional use, but it is also used for the treatment of several illness such as dysmenorrhea, rheumatism, psoriasis and other [ 9 ].
Its medicinal properties are based on its high content of phenolic and saponin compounds, which are associated with antioxidant activity [ 10 , 11 ], and other compounds such as cucurbitane-type triterpenoids, and cucurbitane-type triterpene glycoside and insulin-like peptide [ 12 , 13 , 14 ].
The immature fruit of bitter gourd contains a high vitamin C content and it is a good source of vitamin A and some minerals such as iron [ 10 , 11 , 15 ]. Fresh luffa fruits are used as vegetables, but their seeds are used in traditional medicine in China due to antipyretic and anthelmintic properties [ 16 ]. The constituents of luffa fruits show antioxidant activity, due to their high vitamin C content, plus carotenoids and phenolic compounds such as catechins, flavonoids and anthocyanins [ 17 ].
These compounds show preventive effects on several types of cardiovascular complaints and cancer [ 18 ]. Du et al. Moreover, the luffa fruit is a recognized antibacterial agent due to its high content in tannins [ 19 ].
The quality and the postharvest life of immature fruits are conditioned both by the developmental stage of immature fruits and the choice of harvest time [ 20 ]. Several harvesting indices HI , including fruit size and shape, colour, texture, glossiness, among others, have been developed to assess the harvest time of fruit and vegetables [ 21 ].
The mature fruit HI are related to maximum growth and full ripening, a process required for the fruits to acquire their optimal organoleptic properties [ 22 ]. In immature fruits, however, the key parameter of the HI is fruit size, which is mainly chosen on the basis of consumer and market demands.
Since vegetable fruits are green at the edible stage, before seeds are fully enlarged and hardened, they can be harvested at various stages of development [ 23 ]. Zucchini HI, for example, are mainly based on the size and colour required by the marked with an average length of about 20 cm , and the fruit being harvested just before hardening and darkening of fruit peel occurs and before undesirable seeds start to develop [ 24 ].
Firmness, colour and external glossiness are also common parameters used to define the HI of eggplants, cucumbers or bell peppers [ 25 ]. Cucumbers are harvested at nearly full size, but always before the seeds become hardened, at the moment when jelly-like material fills the seed cavity. The quality of a cucumber is also based on fruit glossiness, firmness and dark green peel [ 26 ]. Eggplants are harvested before reaching full size; however, there is a wide range of ontogeny stages at which they could be marketed [ 3 ] and the quality is primarily based on globular or elongated shape, firmness and a dark purple peel.
Okra pods, on the other hand, are harvested while they are still immature; that is, having accumulated enough mucilage, but before becoming fibrous. This generally occurs within two to six weeks after anthesis [ 27 ]. Despite their great commercial and cultural importance, vegetable fruits are very high perishable commodities. Their epidermis is not yet fully developed and they are harvested at a developmental phase in which storage compounds have not accrued.
Their high respiration rates, associated with high rates of dehydration and metabolism, lead to a rapid spoilage during storage [ 28 ]. The short commercial life of these fruits is therefore conditioned by their developmental stage at harvest time and their particular physiology during their postharvest storage conditions. Moreover, these products, due their tropical or subtropical origin, are susceptible to chilling injury CI when stored at low but non-freezing temperatures.
Three main factors are known to control the postharvest physiology of immature fruits: the respiration rate, the production of ethylene, and weight loss associated with dehydration. The respiration rate of immature fruit is much higher than that of mature fruit. Respiration can be controlled by several factors such as temperature and atmospheric composition.
Moreover, most vegetable fruits are susceptible to dehydration and mechanical injury [ 30 ]. Since mechanical injury also affects the fruit respiration rate, correct postharvest management that includes not only the control of the temperature but also the avoidance of mechanical damage is necessary to maintain the quality of the fruit [ 31 ].
The plant hormone ethylene is also important in controlling fruit physiology during its postharvest conservation period. Since they are immature at harvest, the fruits in question behave as non-climacteric and produces therefore a low rate of ethylene at harvesting and during storage [ 32 , 33 ]. In mature fruit the most conspicuous response to ethylene is related to ripening, but in green vegetables and immature fruits exposure to low levels of ethylene causes yellowing of green tissues, thus reducing the postharvest life of the commodities.
There are several factors promoting ethylene production, including mechanical injury, decay, insect damage and some types of stress such as low or high temperature. Also, the production level depended upon both the duration of cold storage and the period of conditioning time at room temperature [ 34 , 35 ]. It is indeed remarkable that, even after cold storage, ethylene production is dependent upon the level of sensitivity of the fruit to cold.
Thus, sensitive cultivars of zucchini presented higher ethylene production, while less sensitive ones showed a lower level [ 36 , 37 ]. This cold-induced ethylene production has also been observed in other immature fruits such as cucumbers, eggplants and other climacteric and non-climacteric fruits such as citrus, kiwis and pears, among others [ 38 , 39 , 40 , 41 , 42 ]. It is always associated with an upregulation of ethylene biosynthesis genes [ 37 , 43 , 44 , 45 , 46 , 47 ].
Dehydration is also a major cause of fruit wilting and softening, and negatively affects nutritional quality. The dermal system of fruits and vegetable cuticle, stomata, epidermal cells, trichomes is responsible for regulation of water loss. This system is developed during the growth and development stages of the fruit so that it can fulfil its function when the fruit is mature [ 48 ].
The partial development of the dermal system makes immature fruits highly susceptible to water loss. The first symptom associated with fruit dehydration is wilt, but in cucumbers it has been demonstrated that dehydration also upregulates the activity of the cell-wall-degrading enzymes like poligalacturonase and pectinesterase, which finally leads to fruit softening and shrivelling [ 49 ].
Moreover, water loss increases ethylene production, which, as Lurie et al. Massolo et al. The storage of fruit under cold conditions is a generalized technology used to avoid rapid decay and maintain quality. Low temperature slows down many of the processes responsible for the deterioration and loss of quality in vegetable fruits [ 52 ].
However, many fruits and vegetables, including immature fruits, are susceptible to chilling injury CI. Their storage at cold but non-freezing temperatures triggers a number of CI symptoms that irreversibly reduce the external and internal quality of the product [ 53 ].
Chilling injury refers to a syndrome that involves several physiological events, as well as the characteristic and recognizable symptoms of cold-stored fruit. The type and extent of this syndrome varies with the species, cultivar, cold storage conditions and other factors, including farming conditions.
For example, while in eggplants a characteristic expression of chilling injury includes a net browning of the pulp [ 51 ], in cucumbers and zucchinis the damage may include surface pitting, dehydration and large sunken areas, as well as discoloration.
There is, therefore, no one single symptom or type of damage that is common to all products and would allow for the assessment of CI in all commodities. Nevertheless, there are instances of several symptoms appearing together that can be recognized as the consequence of cold storage. Some CI changes occur at cellular level, including alterations of membrane structure, cell plasmolysis and increased electrolyte leakage [ 54 , 55 ].
Others changes imply alterations in the metabolism, including higher levels of ethylene production, and the accumulation of abnormal compounds such as malonyldialdehyde MDA as a resulted of either anaerobic respiration or oxidative damage [ 24 , 37 ]. One of the most notable CI-associated alterations, however, affects the external appearance of the fruit and include damage to the fruit surface, including pitting, large sunken areas, discoloration, translucent water-soaked spots and water-soaked areas and deep lesions that can reach the subepidermal tissues [ 55 ].
These macroscopic changes are commonly used to assess the extent of cold damage [ 24 , 36 , 46 , 56 ]. The most common CI symptoms in immature fruit include weight and firmness loss, electrolyte leakage, and appreciable damages to the fruit surface. In cucumbers, watery pitting is the main symptom of CI [ 57 ]. Ultrastructural analysis of this damage has revealed that they are associated with cracks in the cuticle and the sinking of epidermal cells near the stomata, which together lead to a raised transpiration rate, as well as a decay due to the growth of necrotrophic fungi [ 55 , 58 ].
Another specific symptom of CI in cucumbers is discoloration due to chlorophyll degradation that takes place at low temperature [ 59 ].
In the case of zucchini, pitting is the main chilling symptom. Microscopical analysis of this pitting has shown that the surface depressions are caused by cell death and cell collapse, associated with solubilisation of pectin and cell wall degradation [ 60 ]. At the mature green or breaker stage, before the fruit has completely ripened, bell peppers are also susceptible to cold storage, although the degree of susceptibility depends on the cultivar [ 62 , 63 ].
Green bell peppers show similar symptoms to those described as appearing in cucumbers and zucchini, along with shrivelling, resulting from fruit moisture loss and also seed browning [ 62 , 64 ].
These are also major chilling symptoms in eggplants [ 65 , 66 ]. Browning is caused by oxidation of phenolic compounds by the enzyme polyphenol oxidase PPO , which seems to be dependent on low temperature.
This enzyme catalyses the o-hydroxylation of monophenols to o -diphenol and further oxidation of o -diphenols to o -quinones, which react with amino acids or proteins, generating brown pigmentation [ 67 , 68 ]. Okra is moderately susceptible to CI, with the most common symptoms of chilling injury being water-soaked lesions, pitting, discoloration, appearance of mould or mildew and increased decay especially after removal to warmer temperatures, as during marketing.
The sensitivity to CI varies according to okra cultivars and phenological stage of pods. Young mucilaginous pods are more sensitive than larger pods.
The green pods turn a brownish olive-green, while yellow cultivars turn brown or brownish-red [ 69 , 70 , 71 ]. Luffa fruits are highly perishable and their postharvest life is no more than one week at room temperature. During the process of decay, the fruits appear yellow and are wilting. Luffa is highly sensitive to chilling injury and the most visible symptoms include discoloration, watery brown or black spots on and under the epidermis, and a higher level of decay including severe decomposition, especially if the fruit is being rewarmed after cold storage [ 72 , 73 ].
Table 1 shows the chilling injury symptoms in some vegetable-like fruits. The environmental and physical changes that the produce undergoes before and after harvest may induce the production of reactive oxygen species ROS , which are the cause of oxidative damage during the postharvest of immature fruit and vegetables, inducing decay of the product and loss of quality.
Oxidative stress starts with an elevated production of ROS as a result of numerous processes such as photosynthesis, respiration, photorespiration and oxidative burst, which occur at different cellular locations and within different cellular organelles [ 77 , 78 ]. ROS include superoxide anion, hydrogen peroxide, hydroxyl radical, nitric oxide, and peroxynitrite.
If the production of ROS increases dramatically, as occurs under environmental stress, hydroxyl radical reacts with membrane lipids, inducing peroxidation, which leads to membrane degradation. Malondialdehyde MDA is a product of this lipid peroxidation, and is used as an indicator of stress in some tissues [ 79 ]. During immature fruit postharvest, oxidative stress avoidance is important for the maintenance of fruit quality.
Two strategies have been developed to avoid or tolerate oxidative stress, generating a response that includes metabolic changes at biochemical and molecular level [ 80 ]. These changes include the induction of the enzymatic and non-enzymatic mechanisms of the antioxidant defence: superoxide anions are detoxified by the enzyme superoxide dismutase SOD , which produces hydrogen peroxide that can be scavenged by catalase CAT and several peroxidases POD such as thioredoxin peroxidase and glutathione peroxidase, as well as the enzymes belonging to the Foyer—Halliwell—Asada cycle [ 78 ].
In this cycle, ascorbate peroxidase APX uses ascorbate for the reduction of hydrogen peroxide.
Cooperative Extension Publications
Fresh apricots have high nutritional value and demand. Determination of the appropriate maturity is vital for fruit storage. The effects of harvest maturity on chilling injury and storage quality were investigated in this study. Chilling injury incidence, chilling index, and the physiological indicators were evaluated. The results showed that the incidence, index of chilling injury, and firmness in apricots of maturity class I were highest than other two groups, but maturity class I apricots did not ripe. Although the incidence and index of chilling injury in maturity class III were relatively low, fruit firmness decreased rapidly. The incidence and index of chilling injury of apricots in maturity class II were lower than those of fruits at maturity class I, whereas fruit firmness, soluble solid content, ascorbic acid level, and extractable juice quantity relatively were well-maintained.
Immature, vegetable-like fruits are produced by crops of great economic importance, including cucumbers, zucchini, eggplants and bell peppers, among others. Because of their high respiration rates, associated with high rates of dehydration and metabolism, and their susceptibility to chilling injury CI , vegetable fruits are highly perishable commodities, requiring particular storage conditions to avoid postharvest losses. This review focuses on the oxidative stress that affects the postharvest quality of vegetable fruits under chilling storage. We define the physiological and biochemical factors that are associated with the oxidative stress and the development of CI symptoms in these commodities, and discuss the different physical, chemical and biotechnological approaches that have been proposed to reduce oxidative stress while enhancing the chilling tolerance of vegetable fruits. A number of immature vegetable-like fruits are produced by dicotyledonous species of great economic importance, within the families Cucurbitaceae pumpkins, cucumbers, zucchini, bitter gourds and luffa , Solanaceae eggplants, bell peppers , Fabaceae peas, broad beans , and Malvaceae okra.
Chilling injury affects many fruits and vegetables. Most crops of tropical and subtropical origin are sensitive to chilling injury. 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.
Effects of Harvest Maturity on Chilling Injury and Storage Quality of Apricots
Horticultural commodities suffer chilling injury following exposure to extremely low temperatures, which results in visible symptoms and considerable quality loss. Therefore, it is of significance to understand the mechanism of this physiological disorder and to develop effective strategies to control it. Chilling stress causes alteration in structure and function of the plasma membrane, which is assumed to be the primary event in response to cold stress.
Low-temperature storage is widely used as a postharvest treatment applied for delaying senescence in vegetables and ornamentals and ripening in fruits, upholding their postharvest quality. But the refrigerated storage of tropical and subtropical crop plant species provokes a set of physiological alterations known as chilling injury CI that negatively affect their quality and frequently renders the product not saleable. The increasing demand for consumption of fresh fruits and vegetables, along with restriction on the use of synthetic chemicals to reduce CI, has encouraged scientific research on the use of heat treatments as an environment-friendly technology for CI mitigation.
Symptoms of frost, freezing and chilling injury on vegetables
Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. Tandel and A. Patel and B. Patel Published Chilling injury CI is a physiological disorder.
Мидж. Скорее. ГЛАВА 44 Фил Чатрукьян, киля от злости, вернулся в лабораторию систем безопасности. Слова Стратмора эхом отдавались в его голове: Уходите немедленно. Это приказ. Чатрукьян пнул ногой урну и выругался вслух - благо лаборатория была пуста: - Диагностика, черт ее дери.
Approaches to reduce chilling injury of fruits and vegetables. Hort. Rev. –95.  Wang, C.Y. Chilling injury.