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.     

EFFECT OF SOME GAS MIXTURES ON STORAGE QUALITY OF PLUMS1

Plums were stored in controlled atmospheres (CA) with five gas mixtures of the following O₂:CO₂ percentages; 1:1, 1:4, 4:4, 2:2 and 4:1, for 37 days at 2.5–3C. Fruit treated with CA displayed very low decay incidence at the end of the storage period plus 2 days ripening at 22C in air, in comparison with a very high decay incidence (88%) for control fruits. CA-treated fruit ripened normally, but slowly, after 2 days in ambient conditions. There were no clear differences among CA treatments in the quality attributes of total soluble solids, acidity, firmness or color. Treatment with 1% O₂ nd 4% CO₂, however, resulted in slightly firmer fruit, with higher acidity than the untreated checks.     

Changes in strawberry phenolics, anthocyanins, and antioxidant capacity in response to high oxygen treatments

Changes in fruit quality, decay, phenolic and anthocyanin content, and antioxidant capacity of strawberries (Fragaria × ananassa Duch. cv. Allstar) stored under air and high oxygen atmospheres at 5 °C were investigated. Freshly harvested strawberries were placed in jars and ventilated continuously with air or with 40, 60, 80, or 100 kPa O₂ at 5 °C for up to 14 days. Samples were taken initially, and after 3, 7, 10 and 14 days of storage. While fruit quality parameters such as titratable acidity, total soluble solids and surface color were only slightly affected by differing levels of O₂, the higher oxygen concentration treatments significantly reduced decay. Oxygen concentrations higher than 60 kPa also promoted increases in ORAC values, total phenolics and total anthocyanins as well as individual phenolic compounds analysed by HPLC during the initial 7 days of storage. However, this effect diminished with prolonged storage. No significant differences in ORAC values, total phenolics, total anthocyanins, or the individual phenolic compounds were observed among the high O₂ and air-stored fruits after 14 days of storage. These results indicate that high oxygen treatments exert the most effects on fruit quality and antioxidant capacity of strawberry fruit in the first 7 days of storage.     

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.     

Low O2 Atmospheres Affect Storage Quality of Zucchini Squash Slices Treated with Calcium

Calcium chloride treated or nontreated zucchini squash slices were stored in air or low O₂ (0.25, 0.5 and 1%) at 10°C. Respiration rate, ethylene production, and development of browning/decay were reduced under low O₂. Slices stored under 0.25% O₂ had less weight loss and browning/decay, and greater shear force and L-ascorbic acid content than those stored in air. Microbial count, pH, and color at the end of storage were improved by low O₂. Calcium treatment had no additive effect on maintaining quality of zucchini squash slices stored in 0.25% O₂ 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     

SENSORY, NUTRIENT AND CHLOROPHYLL CHANGES IN BROCCOLI FLORETS DURING CONTROLLED ATMOSPHERE STORAGE

Sensory (color, turgor, decay) and nutritional (vitamin C, β-carotene) quality of broccoli florets were evaluated during storage at 4C in air or under a controlled atmosphere containing 2% O₂+ 6% CO₂ (CA). Shelf-life, green color and chlorophyll retention were greater under CA than in air, although loss of stem turgor was accelerated. All samples stored in air had decayed sufficiently by the fourth week to be unfit for consumption, while samples stored under CA showed a few spots of decay after five weeks. However, CA was associated with browning at the cut surface of the stem. Retention of vitamin C was slightly greater in CA than in air, while β-carotene content increased at the end of CA storage. Returning the samples to ambient conditions for 24 h after storage under either conditions resulted in chlorophyll and vitamin C losses, whereas β-carotene content remained stable.     

EFFECT OF OXYGEN CONCENTRATION ON THE BIOCHEMICAL AND CHEMICAL CHANGES OF STORED LONGAN FRUIT

ABSTRACT

Longan fruits were stored for 6 days in atmosphere of 5, 21 (air) or 60% O₂ (balance N₂) at 28C and 90–95% relative humidity to examine effects of low and high O₂ concentration on enzymatic browning and quality attributes of the fruit. Changes in pericarp browning, pulp breakdown, disease development, total phenol content, activities of phenol metabolism‐associated enzymes, relative leakage rate, α,α‐diphenyl‐β‐picrylhydrazy (DPPH) radical scavenging activity, and contents of total soluble solids, titratable acidity and ascorbic acid were evaluated. Storage of fruit in a 5% O₂ atmosphere markedly delayed pericarp browning in association with maintenance of high total phenolic content and reduced activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase. Moreover, the fruit stored in a 5% O₂ atmosphere exhibited a lower relative leakage rate and higher DPPH radical scavenging activity than fruit stored in air. This presumably was beneficial in maintaining compartmentation of enzymes and substrates, and thus, reducing pericarp browning. Pulp breakdown and disease development were also reduced by exposure to a 5% oxygenatmosphere. On the contrary, exposure of longan fruit to a 60% O₂ atmosphere accelerated pericarp browning, pulp breakdown and decay development. PPO and POD activities and relative leakage rate were similar for control and 60% O₂‐treated fruit after 4 and 6 days of storage. Furthermore, treatment with 60% O₂ significantly decreased the phenolic content and DPPH scavenging activity of fruit. In addition, exposure to 5 or 60% O₂ resulted in a higher level of total soluble solids, but a lower level of ascorbic acid of longan fruit flesh. In conclusion, exposure to a 5% O₂ atmosphere showed great potential to reduce pericarp browning and extend shelf life of longan fruit.

PRACTICAL APPLICATIONS

Pericarp browning and pulp breakdown are the major causes of deterioration in postharvest longan. Conventional controlled atmosphere with low O₂ and high CO₂ is effective in maintaining quality and extending shelf life of fruits and vegetables, including inhibition of tissue browning. In this study, 5%‐controlled atmosphere reduced significantly pericarp browning, pulp breakdown and rot development. It could potentially be useful as a postharvest technology of longan fruit for reducing or replacing the use of chemicals such as SO₂ and fungicides, but it requires further investigation.     

Browning characteristics of fresh-cut ‘Tsugaru’ apples as affected by pre-slicing storage atmospheres

The change in browning characteristics of the slices processed from ‘Tsugaru’ apples stored at 0 °C for 5 months under controlled atmosphere (CA, 1 kPa O₂ + 1 kPa CO₂, 3 kPa O₂ + 3 kPa CO₂) or air has been investigated for 5 days at 20 °C. Respiration and ethylene production of the slices from apples stored in CA were retarded. Electrolyte leakage and browning index were lower in the slices from apples stored under CA than air. Vitamin C and phenolic contents in the slices from apples stored under air were maintained at higher level compared to the slices from apples stored under CA. Polyphenol oxidase activity in the slices was not affected by pre-slicing storage atmospheres. Therefore, the atmospheres of pre-slicing storage affected browning development in fresh-cut products of ‘Tsugaru’ apples and browning was found to be correlated with the levels of electrolyte leakage and phenolic compounds.     

Physiological responses and quality attributes of ‘Kyoho’ grapes to controlled atmosphere storage

This research studied the physiological responses and quality attributes of Kyoho grapes (Vitis vinifera X V. labrusca) to controlled atmosphere storage. The grapes were stored for up to 60 days in 95% relative humidity with four different conditions, 4% O₂+9% CO₂, 4% O₂+30% CO₂, 80% O_2, and air, as control. The examined physiological responses and quality attributes included polyphenol oxidase (PPO) activity, ethanol concentration, fruit detachment force (FDF), firmness, color, soluble solid content (SSC), titratable acidity (TA), ascorbic acid concentration (Vc), and sensory quality. PPO activity, FDF drop and decay incidence when stored in 4% O₂+30% CO₂ were more effectively controlled, but unacceptable alcoholic flavor and browning were detected after 45 days, compared with those stored in 4% O₂+9% CO₂ or 80% O₂. The fruits kept in 4% O₂+9% CO₂ or 80% O₂ had good quality during 60 days of storage. The results suggested that high O₂ atmosphere exhibited a potential for maintaining the quality of ‘Kyoho’ grapes during long-term storage.     

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.     

Effect of oxalic acid on control of postharvest browning of litchi fruit

Litchi (Litchi chinensis Sonn.) fruit, cv. Huaizhi, was treated with 2 and 4 mM oxalic acid and stored at room temperature to investigate the effect of oxalic acid on pericarp browning. The results showed that the pericarp browning indices of the fruit, treated with both oxalic acid concentrations, were significantly lower than that of the control, due to increase of membrane integrity, inhibition of anthocyanin degradation, decline of oxidation, and maintanance of relatively low peroxidase activity in the fruit during storage. It appears that application of oxalic acid can effectively control the pericarp browning of litchi fruit during postharvest storage.     

Changes in the quality of jaboticaba fruit (Myriciaria jaboticaba (Vell) Berg. cv. Sabará) stored under different oxygen concentrations

BACKGROUND: Jaboticaba (Myriciaria jaboticaba (Vell) Berg.) is a highly perishable Brazilian berry with a shelf life of only 2 days under ambient conditions. Low temperatures and controlled atmosphere (CA) have been used to extend the shelf life of perishable fruit. Thus the aim of this study was to determine the effect of CA with varying concentrations of oxygen (1, 5, 10, 15 and 21kPa) during cold storage (12.5 °C) of ‘Sabará’ jaboticaba fruit. RESULTS: Atmospheres with lower oxygen concentrations (1 and 5 kPa O₂) significantly reduced jaboticaba respiration rate. Fruit stored under these conditions had higher L* values, and titratable acidity (TA), and lower ratios of soluble solids content (SSC)/TA. However, at the lowest concentration of oxygen (1 kPa O₂), firmness decreased markedly compared to fruits stored at higher O₂ levels (P < 0.05). After only 2 days of storage at ambient temperature jaboticaba received a score of 1.6 (dislike strongly ? 1) compared to fruit stored under CA, which scored 7.4 (like moderately ? 7). After 9 days of storage, fruit from all treatments remained above the limit of acceptability (score 5) and were rated as 6.2. With respect to appearance, statistical differences between treatments were not observed. The total anthocyanin content was not affected by oxygen concentration but decreased 40.4% during CA storage. CONCLUSION: 'Sabará' jaboticaba fruit can be satisfactorily stored under atmospheres containing 5‐21 kPa O₂ at 12.5 °C for up to 6 days. Copyright © 2011 Society of Chemical Industry     

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.     

EXTENDED STORAGE LIFE OF LITCHI FRUIT USING CONTROLLED ATMOSPHERE AND LOW TEMPERATURE

The postharvest quality of litchi (Litchi chinensis Sonn.) cv. Bombay stored under controlled atmosphere (CA) at 3.5% O₂and 3.5% CO₂, 2C temperature and 92–95% relative humidity was studied. Fruits were also held in regular atmosphere (RA) maintained at 2C temperature and 92–95% relative humidity. Fruits kept at normal ambient conditions were used as controls. Various quality attributes measured revealed that fruits stored in CA exhibited Hunter “a” values of 11.2 after 56 days of storage, indicating the beneficial effect of CA on retaining the red color of litchi fruits. Fruits held in RA exhibited Hunter “a” values (7.9) lower than that of CA‐stored litchi, showing that browning of litchi was noticeable in RA. Loss of weight was lowest (4.9%) for the fruits stored in CA compared to those stored in RA (11.0%) and control (33.1%). Loss of acidity and ascorbic acid content of fruits stored in CA were less than that of RA. The smallest increase of litchi firmness and pericarp puncture strength of 2.2 and 3.9 times of initial level, respectively, were observed even after 56 days of storage in CA. Total soluble solid of litchi increased from 19.3° Brix at harvest to 23.0° Brix until 48 days of storage in CA after which it declined to 22.8 °Brix. The sensory evaluation of aril color and taste showed that the fruits held in CA were rated good throughout 56 days of storage.     

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.     

Mechanical parameters to assess quality changes in cherimoya fruit

 Several mechanical parameters obtained by means of compression and penetration tests, and changes in cherimoya (Annona cherimola Mill.) fruit quality during storage in air and two controlled atmospheres (CA), (3% O₂+0% CO₂ and 3% O₂+3% CO₂) were analysed. A gradient of softening was found among the equatorial and the apical areas of the flesh during CA storage, as assessed by localized penetration tests. The combination of low O₂/elevated CO₂ (3% O₂+3% CO₂) increased this gradient and had a greater inhibiting effect on skin softening than low O₂. It appeared that the prevention of softening by CA was stronger in the less mature tissues (equatorial and outer areas) than in the more mature tissues (apical and inner areas around the longitudinal axis). CA delayed or inhibited changes in fruit quality observed during air storage: increases in total soluble solids (TSS), titratable acidity (TA), and yellowness of the flesh (b), and diminution in flesh lightness of colour (L). A good relationship between an objective quality index (QI, where QI=TSS+TA+L/b) and the compression slope (CS) was found during storage under all the conditions tested. It is suggested that the relationship, QI=29.25+0.04×CS–0.0023×CS² could be useful when assessing stages of cherimoya fruit quality during storage under different conditions by performing a nondestructive, compression test.     

Mechanical parameters to assess quality changes in cherimoya fruit

 Several mechanical parameters obtained by means of compression and penetration tests, and changes in cherimoya (Annona cherimola Mill.) fruit quality during storage in air and two controlled atmospheres (CA), (3% O₂+0% CO₂ and 3% O₂+3% CO₂) were analysed. A gradient of softening was found among the equatorial and the apical areas of the flesh during CA storage, as assessed by localized penetration tests. The combination of low O₂/elevated CO₂ (3% O₂+3% CO₂) increased this gradient and had a greater inhibiting effect on skin softening than low O₂. It appeared that the prevention of softening by CA was stronger in the less mature tissues (equatorial and outer areas) than in the more mature tissues (apical and inner areas around the longitudinal axis). CA delayed or inhibited changes in fruit quality observed during air storage: increases in total soluble solids (TSS), titratable acidity (TA), and yellowness of the flesh (b), and diminution in flesh lightness of colour (L). A good relationship between an objective quality index (QI, where QI=TSS+TA+L/b) and the compression slope (CS) was found during storage under all the conditions tested. It is suggested that the relationship, QI=29.25+0.04×CS–0.0023×CS² could be useful when assessing stages of cherimoya fruit quality during storage under different conditions by performing a nondestructive, compression test. Received: 23 April 1998     

Effects of short‐term N2 treatment on quality and antioxidant ability of loquat fruit during cold storage

BACKGROUND: Loquat fruit is susceptible to microbial decay and quality deterioration during postharvest distribution. In this study, in a search for effective alternatives to methods currently used for quality maintenance, the effects of short‐term pre‐storage N₂ treatment on the quality and antioxidant ability of loquat fruit were investigated. RESULTS: Loquat fruits were exposed to 100% N₂ for 6 h at 20 °C and then stored at 5 °C for 35 days. Short‐term N₂ treatment significantly delayed the increase in fruit decay rate and decreases in total soluble solid and titratable acidity contents, thereby maintaining better eating quality and extending the storage life of fruits. It also markedly delayed increases in membrane permeability, malondialdehyde content and superoxide anion production rate. In addition, N₂‐treated fruits exhibited significantly higher superoxide dismutase and catalase activities and lower lipoxygenase activity than control fruits. CONCLUSION: Short‐term pre‐storage N₂ treatment effectively reduced fruit decay and maintained quality in loquat fruits during cold storage. The reduction in fruit decay and quality deterioration by the treatment was correlated with enhanced antioxidant ability and reduced lipid peroxidation. Copyright © 2009 Society of Chemical Industry