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% O₂ plus 5% CO₂, or CA with high O₂ concentration (70% O₂ plus 0% CO₂ for 15 days, then in CA with 5% O₂ plus 5% CO₂) at 0 °C, to determine the effects of different O₂ and CO₂ 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% O₂ plus 5% CO₂) reduced chilling injury, and delayed the reduction of SOD, CAT and POD activities compared to the control. CA with high O₂ 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.     

Effect of Ultrasound Combined with Controlled Atmosphere on Postharvest Storage Quality of Cucumbers (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.)

The purpose of this study was to quantify the effectiveness of ultrasound treatment combined with controlled atmosphere storage (UCA) in preserving quality of cucumbers (Cucumis sativus L.) compared with the controlled atmosphere storage (CA) alone. The combination of ultrasound (especially at 200 W for 10 min) with CA (5% O₂?+?2% CO₂?+?93% N₂) storage was most effective in preserving the fresh-like quality of cucumbers. The treatment reduced the loss in mass, firmness, soluble solids content and color, maintained cell wall integrity, and limited the redistribution of water in cucumbers. UCA significantly better preserved the flavor volatiles and retained the taste characteristics. This method also better preserved the intermolecular hydrogen and carbonyl bonding in aldehyde and ketone compounds of cucumbers which helped them to preserved longer. These results suggested that UCA can be a much effective preservation method than CA alone for fruits and vegetables.     

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.     

Chitosan-limonene coating in combination with modified atmosphere packaging preserve postharvest quality of cucumber during storage

Since cucumbers suffer from a short postharvest life, applying different technologies is increasingly used as effective ways to increase their shelf life and quality. In this study a combination of chitosan-limonene coating and MAP storage has been used as a postharvest treatment to maintain cucumber quality. Samples were stored in three different packages: A (21% O₂, macro-perforated package to be in equilibrium with air); package B (active MAP, starting concentrations 10% O₂?+?5% CO₂); package C (passive MAP starting concentrations 21% O₂?+?0.1% CO₂); they were stored at three temperatures (20, 10, and 4 °C). Quality parameters of cucumber such as weight loss, firmness, color, pH, fungal growth, T_g, organoleptic properties were determined. Interactive effects of coating, package, temperature, and storage time showed that coating and MAP in general had positive effects on several quality aspects. Coating combined with active MAP had the most positive effect on most postharvest attributes. However, using active MAP at higher temperature led to quality problems and is only useful if storage time is short. The combined usage of active MAP and chitosan-based coating on cucumber represents an innovative and interesting method for commercial application.     

Controlled and modified atmospheres influence chilling injury,fruit quality and antioxidative system of Japanese plums (Prunus salicina Lindell)

Our objective was to compare the effects of controlled atmosphere (CA) and modified atmosphere packaging (MAP) on fruit quality, chilling injury (CI) and pro‐ and antioxidative systems in ‘Blackamber’ Japanese plums. Matured fruit were stored for 5 and 8 weeks at 0–1 °C in normal air, CA‐1 (1% O₂ + 3% CO₂), CA‐2 (2.5% O₂ + 3% CO₂) and MAP (~10% O₂ and 3.8% CO₂). CA was more effective than MAP in retention of flesh firmness and titratable acidity during cold storage. Fruit stored in CA‐1 showed reduced CI and membrane lipid peroxidation after 5 and 8 weeks of cold storage. Low O₂ atmospheres appeared to limit the generation of reactive oxygen species (ROS) and their efficient scavenging through the concerted action of superoxide dismutase and peroxidase. The role of ascorbate–glutathione (AsA–GSH) cycle in the regulation of oxidative stress was also studied during and after storage in different atmospheres. In conclusion, optimum CA conditions delayed fruit ripening and CI through augmentation of antioxidative metabolism and suppression of oxidative processes.     

QUALITY OF 'ANJOU' PEARS AFTER DIFFERENT TYPES OF CONTROLLED ATMOSPHERE STORAGE

‘Anjou’ pears (Pyrus communis, L) were subjected to seven different controlled atmosphere (CA) storage practices and stored at 1C, for 90, 150 or 210 days plus 30 days at regular air atmosphere (RA). CA storage treatment conserved pear qualities to a certain extent regardless of storage treatment. Establishment of CA conditions (2% O₂ and < 1 % CO₂ on warm pears (20C), prior to cooling, resulted in reduced firmness, finish and color and increased amount of scald, shrivel and physiological disorders. Pears held in CA storage (2% O₂ and < 1 % CO₂) for 90 days and an additional 30 days in RA storage maintained good quality. When held for longer storage periods, firmness, finish and color decreased, and scald, shrivel and physiological disorders increased.     

Fermentation of Cucumbers in Anaerobic Tanks

A procedure was developed and tested for fermentation of cucumbers at low concentrations of NaCl in experimental, anaerobic tanks. The procedure included washing of the cucumbers, use of a buffered cover brine composed of 0.045M calcium acetate, sodium chloride to equilibrate at 2.7% or 4.6%, Lactobacillus plantarum culture, and N₂ purging to remove dissolved CO₂. The fermentations were predominantly homofermentative, lactic acid accounting for 95% of the cucumber sugars fermented. Firmness retention of the fermented cucumbers during storage for 1 year was improved by heating packaged products to 69°C before storage, but firmness retention was acceptable in un-heated products.     

QUALITY OF PACKED AND BIN STORED 'ANJOU' PEARS AS INFLUENCED BY STORAGE ATMOSPHERE AND TEMPERATURE

Packed pears (Pyrus communis‘d’‘Anjou’) were stored under four individual controlled atmosphere (CA) storage conditions (#1: CA of 1.5% O₂ and < 1% CO₂ at −1.5C; #2: CA of 1.5% O₂ and < 1% CO₂ at + 1.5C; #3: CA of 1.5% O₂ and 3.0% CO₂ at −1.5C; #4: CA of 1.5% O₂ and 3.0% CO₂ at + 1.5C). Loose pears in bins were stored under three CA storage conditions (#1: CA of 1.5% O₂ and <1% CO₂ at −1.5C; #2: CA of 1.5% O₂ and 3.0% CO₂ at −1.5C; #3: CA of 1.5% O₂ and 3.0% CO₂ at +1.5C). For packed pears, increased CO₂ in the storage atmosphere resulted in retention of peel color, reduced firmness loss and enhanced subjective scores, particularly for finish and stem condition. Pears stored loose in bins, prior to packing in late January in an atmosphere containing 3.0% CO₂ aided firmness retention, reduced scald and greatly enhanced subjective quality scores for appearance, finish and scuffing. Storing ‘Anjou’pears in a 3.0% CO₂ atmosphere allows for storing pears loose in bin and packing in late January with little or no quality losses compared with using the standard 1.0% CO₂ in the storage atmosphere.     

Control of internal browning and quality improvement of ‘Fuji’ apples by stepwise increase of CO2 level during controlled atmosphere storage

To control internal browning injury and to reduce quality loss in ‘Fuji’ apples during storage, a stepwise controlled atmosphere (CA) method was applied in this study. Both non‐bagged and bagged apples during maturation were stored at 0 °C under 1% O₂ + 1% CO₂, 1% O₂ + 3% CO₂ or air for 10 months, and 1% O₂ + 1% CO₂ for 2 months followed by 1% O₂ + 3% CO₂ for 8 months (stepwise CA). The concentrations of internal ethylene and carbon dioxide in apples kept for 24 h at 20 °C after storage under CA conditions were maintained at low level, but there was no effect of stepwise CO₂ increase on internal gas concentrations. The non‐bagged and bagged apples stored under stepwise CA were not significantly different from those stored under 1% O₂ + 3% CO₂ continuously for 10 months in term of flesh firmness, titratable acidity and yellowing index. However, the apples stored under stepwise CA were firmer, more acid and greener than those stored under 1% O₂ + 1% CO₂ continuously for 10 months. Internal browning injury occurred in apples stored under 1% O₂ + 3% CO₂ continuously for 10 months, but it was suppressed completely by stepwise CA storage. The stepwise CA, increasing of CO₂ level after holding at 1% CO₂ for the first 2 months of storage, was effective in maintaining the quality and controlling the internal browning injury in non‐bagged and bagged ‘Fuji’ apples. Copyright © 2005 Society of Chemical Industry     

Controlled Atmosphere and Ethylene Effects on Quality of California Canning Apricots and Clingstone Peaches

Storage at 2% O₂ plus 5% CO₂ at 1.1°C maintained higher flesh firmness and lower pH and retarded decay more effectively than air storage of immature (M1) and over-mature (M3) Patterson and Tilton apricot fruits. CA storage of fruits picked at the optimum maturity stage (M2) produced little benefit over air storage, however. -Treatment with 100 ppm ethylene for 48 hours accelerated softening and color change at 20°C compared to ripening in air and may potentially be used to prepare immature apricot fruits for canning in the shortest possible time. Large differences in storageability and canned quality following storage were found among the five clingstone peach cultivars tested. Loadel and Carolyn: peaches, if in sound condition at harvest, can be stored for up to 4 wk under 2% O₂+ 5% CO₂ at 1.1°C. Andross, Klamt and Halford peaches should be stored for shorter storage periods only. Fruits ripened at 20°C with ethylene (100 ppm for 48 hr) were similar to those ripened without it in appearance, texture, and flavor.     

梯度热水处理减轻贮后黄瓜冷害与细胞壁代谢的关系

为探讨梯度热水处理减轻贮后黄瓜冷害与细胞壁代谢的关系,分别以4℃贮藏2、4、6d后不做热处理的"申青"黄瓜为对照(CK),研究了不同梯度热水处理(TG10:黄瓜依次进行14℃,4 min;24℃,4 min;34℃,4 min;44℃,4 min浸泡处理;TG20:黄瓜依次进行24℃,8 min;44℃,8 min浸泡...     

QUALITY OF ‘GALA’ APPLES AS INFLUENCED BY HARVEST MATURITY,STORAGE ATMOSPHERE AND CONCOMITANT STORAGE WITH ‘BARTLETT’ PEARS1

Controlled atmosphere (CA) storage for 45 or 90 days following harvest reduced quality losses for both ‘Gala’apples and ‘Bartlett’pears compared with fruit from regular atmosphere (RA) storage. Fruit stored in CA were firmer, had higher acidity and less color change than fruit from RA storage. Apples and pears stored together in CA maintained good quality and compared favorably with apples or pears stored separately. There was no difference in fruit quality between fruit stored at 1% O₂ and 1% CO₂ compared with fruit stored in 2% O₂ and 3% CO₂. Fruit harvested at a more advanced stage of maturity deteriorated more quickly in storage than earlier harvested fruit. A combination of 45 days in CA followed by 30 days RA resulted in apples that were superior in quality to apples stored for 75 days in RA alone.     

QUALITY CHANGES OF FRESH-CUT HONEYDEW MELONS DURING CONTROLLED ATMOSPHERE STORAGE

Quality, physiology, and microbial population were monitored with honeydew cubes held in air or controlled atmosphere (CA) of 2% 0₂+ 10% CO₂ at 5C and 4%0₂+ 10% CO₂ at 10C. The CA was beneficial in maintaining quality of honeydew cubes. Quality deteriorated rapidly with concomitant increase in respiration rate during the latter half of the 6-day at 10C or 10-day at 5C shelf-life. The shear force of samples was maintained by CA at 10C, but the visual quality was poor when that benefit was still noticeable. At 5C, an effect ofCA was not noted because the low temperature did not allow the shear force to decrease. The bacterial population was less on honeydew cubes held in CA than in air. Modified atmosphere with these gas mixtures would be beneficial in maintaining quality and retarding microbial growth on honeydew cubes, but strict temperature control is essential to avoid anaerobic respiration.     

Quality and biochemical changes of longan (Dimocarpus longan Lour cv. Daw) fruit under different controlled atmosphere conditions

Sulphur dioxide has been used to control pericarp browning in longan fruit. However, due to health and regulatory concerns, alternative treatments should be tested. The objective of this study was to find the tolerance levels of longan fruit to low O₂ (2%, 5%, 10% and 15%) and elevated CO₂ (5%, 10%, 15% and 20%) at 2 °C. According to the tolerance study, controlled atmospheres (CA) of 5% O₂ + 5% CO₂, 5% O₂ + 10% CO₂ and 5% O₂ + 15% CO₂ were compared with normal air (control) at 2 °C. Pericarp browning and decay incidence of longan were significantly (P ≤ 0.05) higher in control than all the CA treatments. CA storage reduced polyphenol oxidase (PPO) activity, maintained L* value and slowed down a decrease in total phenolic contents (TPC). Pericarp browning was highly correlated with PPO, L* and TPC.     

Fermentation of Cucumbers Brined with Calcium Chloride Instead of Sodium Chloride

ABSTRACT: Waste water containing high levels of NaCl from cucumber fermentation tank yards is a continuing problem for the pickled vegetable industry. A major reduction in waste salt could be achieved if NaCl were eliminated from the cucumber fermentation process. The objectives of this project were to ferment cucumbers in brine containing CaCl₂ as the only salt, to determine the course of fermentation metabolism in the absence of NaCl, and to compare firmness retention of cucumbers fermented in CaCl₂ brine during subsequent storage compared to cucumbers fermented in brines containing both NaCl and CaCl₂ at concentrations typically used in commercial fermentations. The major metabolite changes during fermentation without NaCl were conversion of sugars in the fresh cucumbers primarily to lactic acid which caused pH to decrease to less than 3.5. This is the same pattern that occurs when cucumbers are fermented with NaCl as the major brining salt. Lactic acid concentration and pH were stable during storage and there was no detectable production of propionic acid or butyric acid that would indicate growth of spoilage bacteria. Firmness retention in cucumbers fermented with 100 to 300 mM CaCl₂ during storage at a high temperature (45 °C) was not significantly different from that obtained in fermented cucumbers with 1.03 M NaCl and 40 mM CaCl₂. In closed jars, cucumber fermentations with and without NaCl in the fermentation brine were similar both in the chemical changes caused by the fermentative microorganisms and in the retention of firmness in the fermented cucumbers.     

Shelf-Life Extension of American Fresh Ginseng by Controlled Atmosphere Storage and Modified Atmosphere Packaging

American ginseng roots were treated with an antimicrobial agent, and stored under various CA (2,5, and 8% CO₂) or MA conditions to extend the shelf-life. Changes in respiration rates during CA storage, gas composition in packages, saponin and free sugar content, and other quality factors were monitored during storage. The respiration rate of ginseng increased rapidly during the first month of high CO₂ CA storage and then slowly decreased to stable levels after 3 mo storage. In MA studies, the equilibrium CO₂ concentration was attained after 20 days. There were no noticeable changes in appearance, saponin content and free sugars after 3 mo CA (5% CO₂) storage and MA packages.     

Effect of chemical treatment on the fatty acid composition of european cucumber fruit during cold storage

Mature green European cucumber fruits (Cucumis sativus L. cv. ‘V-5’), grown in the greenhouse, were treated with butylatedhydroxytoluene (BHT) and calcium chloride, stored at 4°C for 7 days and transferred to 20°C for another 7 days. There were no visible symptoms of chilling injury on cucumbers during cold storage, but surface pitting and shrinking started 2 days after fruits had been transferred to 20°C. Total lipid content was not affected by chilling or chemical treatment, but changes in the lipid classes were observed. Neutral lipids were increased and phospholipids decreased. Laurie and myristic acids were decreased by chilling and chemical treatment, and palmitic acid increased in each lipid class with BHT treatment. Linoleic acid was increased by CaCl₂ treatment in each fraction. Linolenic acid response varied with chilling and chemical treatment. The unsaturation ratio of 18-carbon acids was increased for total lipids and phospholipids.     

Effect of controlled atmospheres with varying O2/CO2 levels on the postharvest senescence and quality of broccoli (Brassica oleracea L. var. italica) florets

Controlled atmosphere (CA) has been widely used to help extend the shelf life and maintain the quality of horticultural products. In the present study, broccoli (Brassica oleracea L. cv. Youxiu) florets were stored under CA with high levels of O₂/CO₂ at 15 °C, including 100 % O₂, 80 % O₂ + 20 % CO₂, 60 % O₂ + 40 % CO₂, 40 % O₂ + 60 % CO₂, and air (control), to determine the effects of CA on storage period and on some physiological properties during storage. The results showed that compared with the control, the treatments combining O₂ and CO₂ effectively extended the storage period and inhibited respiration rate, ethylene production, and reductions in weight loss, chlorophyll, and ascorbic acid levels. Moreover, the CA treatments inhibited the increases in both superoxide radicals (O ₂ ^?· ) production rate and hydrogen peroxide (H₂O₂) level and reduced malondialdehyde accumulation, which could be beneficial in delay of senescence by alleviation of oxidative damage. In addition, broccoli florets exposed to CA conditions maintained lower activities of superoxide dismutase and peroxidase that are responsible for scavenging of O ₂ ^?· and H₂O₂ and alleviating lipid peroxidation. Among the treatments, the maximum efficacy was observed with a CA of 40 % O₂ + 60 % CO₂, which prolonged the storage period of broccoli heads to 17 days (d) compared with 4 d under air treatment. Conversely, 100 % O₂ treatment accelerated senescence and deterioration in the quality of broccoli, resulting in a shorter storage period. These results suggest that the establishment of an appropriate CA condition with high levels of O₂/CO₂ may be an ideal strategy for maintaining the quality of broccoli florets during storage.     

Viability of commercial cucumber fermentation without nitrogen or air purging

BackgroundBloated cucumber defect, resulting from the accumulation of the biologically produced carbon dioxide (CO₂) in the fruit, reduces yield and economic gains for the pickling industry worldwide. It was the aim of this review to identify commonalities among effective strategies to reduce bloater defect and determine the theoretical viability of commercial cucumber fermentations without bloater defect and/or purging.Scope and approachThis article summarizes the known causes of fermented cucumber bloating defect, including sources of CO₂, and the strategies developed to mitigate the production of the carbonic gas such as controlled fermentation, inoculation of selected starter cultures, cover brine acidification and reformulation and the application of air or nitrogen purging.Key findings and conclusionsIt was understood that microbial activity during fermentation, cucumber tissue respiration, as well as the pressure in the fruits and fermentation tanks, ambient temperature and cover brine composition, impact the levels of dissolved CO₂ in the system. Although the biological conversion of oxygen to CO₂ reduces the cucumbers internal gas pressure, the dissipation of the gas from the tissue is reduced by brining. Once the gas accumulates in the cucumber tissue in concentrations high enough to displace it, the irreversible formation of hollow cavities or bloaters occurs. Residual CO₂ is produced by acid-preserved cucumbers, presumably by tissue respiration, which results in the absence of bloating. Thus, microbial activity seems to contribute most of the CO₂ needed for cucumbers to bloat. It is speculated that colonization of the internal cucumber tissue by indigenous microbes, in particular aerobic gram-negative bacteria, results in the localized production of CO₂ causing bloating defect early in the fermentation. It is concluded that effective manipulation of the microbiota, reduction of dissolved oxygen levels and the use of adequately selected starter cultures may enable cucumber fermentations of acceptable quality without purging.     

SHORT‐TERM CONTROLLED ATMOSPHERE STORAGE FOR STORAGE‐LIFE EXTENSION OF WHITE‐FLESHED PEACHES AND NECTARINES1

Abstract Response of white‐fleshed peaches (‘Sugar Lady’, ‘Snow Giant’, ‘White Lady’and ‘Snow King’) and nectarines (‘Arctic Queen’and ‘Arctic Rose’) to controlled‐atmosphere (CA) storage is cultivar dependent. Samples of fruit of these six cultivars were collected just prior to commercial harvest and held in either regular‐atmosphere (RA) storage at 1C or controlled‐atmosphere (CA) storage at 2% O₂ and 6, 12 or 18% CO₂, all at 1C. Four of the six cultivars (‘Snow Giant’, ‘White Lady’, ‘Snow King’and ‘Arctic Queen’) displayed excessive internal browning and poor flesh color after only 30 days of storage and should not be considered for long storage (+30 days). While ‘Sugar Lady’and ‘Arctic Rose’performed better and are possible candidates for CA storage, they should not be stored more than 45 days after harvest. The value of CA storage to extend the marketing of white‐fleshed peaches and nectarines is questionable at best. If CA storage is to be used for storage‐life extension of white‐fleshed peaches and nectarines, O₂ level should be maintained at 2% or less and CO₂ level maintained at 12% or higher.