Impact of controlled atmosphere storage on physiological quality of soybean seed

Soybean seed tends to lose its quality property if kept in inappropriate storage conditions. The aim of this work was to evaluate the effect of different oxygen (O₂) and carbon dioxide (CO₂) partial pressures, combined with different temperatures on the soybean seed physiological potential maintenance. In 2017, seed of the cultivars 8473 RSF and TECIRGA 6070RR were stored for 7 months under: [1] ambient air; controlled atmosphere (CA) with [2] 1 kPa O₂ + 0.04 kPa CO₂; [3] 2 kPa O₂ + 0.04 kPa CO₂; [4] 2 kPa O₂ + 30 kPa CO₂; and [5] 2 kPa O₂ + 80 kPa CO₂. In 2018, seed of NA 5909 RG and FEPAGRO 37RR were stored for 7 months under the following conditions: [1] ambient air; and CA with [2] 1 kPa O₂ + 0.04 kPa CO₂; [3] 1 kPa O₂ + 15 kPa CO₂; [4] 1 kPa O₂ + 30 kPa CO₂; [5] 2 kPa O₂ + 0.04 kPa CO_2. In both years the storage conditions were conducted at three temperatures (20, 25 and 30 °C). The seed were stored with moisture content between 11 and 11.5. The reduction of the O₂ until 1.0 kPa maintained higher germination, however, storage above 25 °C is not recommended. High CO₂ partial pressure did not have additional effects on physiological quality conservation compared to solely low O₂. Seed of 8473 RSF stored at 25 and 30 °C resulted in low germination, regardless of the CA condition. NA 5909 RG reached 80% of germination, when CA was used, regardless of temperature. The ambient air did not maintain the seed physiological quality when stored at 25 and 30 °C and CA may efficiently maintain the physiological quality of soybean seed after 7 months, even in the higher temperature for NA5909 RG, but not for the other cultivars.     

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.     

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 chill storage and modified atmosphere packaging (MAP) on antioxidant activity,anthocyanins, carotenoids,phenolics and sensory quality of ready-to-eat shredded orange and purple carrots

Ready-to-eat shredded orange and purple carrots, packed in air (control), or in modified atmosphere packaging [MAP; (90%N₂ + 5%O₂ + 5%CO₂ and 95%O₂ + 5%CO₂)], and stored chilled for up to 13 days, were examined for their antioxidant activity and contents of anthocyanins, carotenoids and phenolics, as well as sensory quality. Total antioxidant activity, carotenoids and phenolics of purple carrots were initially 2.8-, 2.3- and 2.9-fold higher than orange carrots, respectively. Total antioxidant activity remained relatively constant in orange carrots during storage under all treatment conditions, whereas a highly significant decrease (P<0.01) in (95%O₂ + 5%CO₂)-treated purple carrots was observed. The content of anthocyanin, only found in purple carrots, was decreased slightly during the storage period, and this was particularly significant in the 95%O₂ + 5%CO₂ treatment. In both orange and purple carrots, loss of total carotenoids occurred in the 95%O₂ + 5%CO₂ treatment. Total phenolic content of purple carrots increased at a much higher rate during storage than orange carrots. The MAP treatment (90%N₂ + 5%O₂ + 5%CO₂) gave better sensory quality and extended shelf-life for purple carrots (∼2–3 days longer shelf-life than other treatments,) but, no difference was observed for orange carrots. Shredded purple carrot can be stored under 90%N₂ + 5%CO₂ + 5%O₂ treatment for up to 10 days and high nitrogen treatment may be used in maintaining the storage quality of shredded purple carrots. Thus, purple carrots may be used in place of orange carrots to take advantage of their nutraceutical components.     

Effectiveness of ozone in combination with controlled atmosphere on quality characteristics including lignification of carrot sticks

Fresh-cut carrots were ozonized in water (1:2 w/v; @ 200 mg O₃/h) for 10 min and stored under controlled atmosphere (CA) conditions (2% O₂, 5% CO₂ and 93% N₂) at 6 ± 1 °C and 85% RH for up to 30 d. Ozonation was found to reduce lignification and maintaining the keeping quality of fresh-cut carrots during CA storage. The maximum decrease in respiration and ethylene emission rates were obtained by the combination of CA with ozone followed by CA alone and ozonation compared with the control samples kept under low temperature (6 ± 1 °C). Significant (p < 0.05) reduction in ascorbic acid, carotenoids and oxidative enzymes such as polyphenol oxidase (PPO) and peroxidase (POD) were observed due to ozonation and CA storage. The control of lignification by ozone in synergy with CA was characterized by decrease in L∗ values. The results highlighted the positive role of ozonation in combination with CA storage in controlling lignification and microbial spoilage of carrot sticks.     

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.     

The role of peroxidase on the antioxidant potential of fresh-cut ‘Piel de Sapo’ melon packaged under different modified atmospheres

The effects of different initial in-package O₂ and CO₂ concentrations (2.5 kPa O₂ + 7 kPa CO₂, 10 kPa O₂ + 7 kPa CO₂, 21 kPa O₂, 30 kPa O₂ and 70 kPa O₂) on peroxidase activity, vitamin C content, total phenolics and antioxidant capacity of fresh-cut ‘Piel de Sapo’ melon have been investigated for 14 days at 4 °C. The radical scavenging activity of fresh-cut melon strongly increased after 9 days storage related to a synthesis of phenolic compounds, especially under 2.5 kPa O₂ + 7 kPa CO₂ atmospheres. Low O₂ levels best maintained vitamin C and phenolic content during the storage. However, stressful too-low O₂ and high CO₂ levels induced an important increase of peroxidase activity under 2.5 kPa O₂ + 7 kPa CO₂ atmosphere, which was directly related to changes of vitamin C throughout storage. Therefore, 70 kPa O₂ atmospheres are proposed to prevent anaerobic conditions during storage of fresh-cut melon and thus, reduce wounding stress and deteriorative changes related to high peroxidase activity in tissue.     

Effect of oxygen on aroma volatiles and quality of fresh-cut cantaloupe and honeydew melons

Cantaloupe and honeydew melon cultivars were processed and stored under a high oxygen passive modified atmosphere packaging (MAP) or reduced oxygen controlled atmosphere (CA; 5 kPa O₂ + 10 kPa CO₂ and balance N₂) for 14 days at 5 °C. Atmosphere did not affect softening rate or soluble solids content and had a negligible effect on colour. Volatile compounds known as flavour-important in melons were extracted using stir bar sorptive extraction (SBSE) and quantified via GC–MS. Acetate esters increased more in MAP than in CA. Non-acetate esters increased markedly in both cultivars and storage types. Alcohols were more abundant in honeydew than in cantaloupe. Aldehydes decreased during storage in both cultivars and storage types. Lower O₂ availability under CA conditions likely suppressed some of the esters relevant to the aroma of fresh-cut melon. Results suggest that package O₂ levels are more important in determining aroma than other quality attributes of fresh-cut melon, and high O₂ levels may be required to reveal desirable aroma compounds.     

Effect of UV-B light and different cutting styles on antioxidant enhancement of commercial fresh-cut carrot products

Wounding stresses resulting from fresh-cut processing are known to enhance the antioxidant capacity (AC) of carrots by increasing the synthesis of phenolic compounds. Ultraviolet-B (UV-B) light exposure further promotes the formation of phenolic compounds. Changes in total soluble phenolics (TSP), 5-O-caffeoylquinic acid (5-CQA), total carotenoids, AC, and phenylalanine ammonia-lyase (PAL) activity of five commercial fresh-cut carrot products (baby carrots, carrot stixx, shredded carrots, crinkle cut coins, and oblong chips) were evaluated after exposure to UV-B dosage at 141.4 mJ/cm². Significant increases in TSP, AC and 5-CQA levels were observed for each sample following UV-B exposure. Increases in PAL activity were also observed in all carrot products, except crinkle cut coins. Total carotenoids of the carrot products were unchanged by UV-B exposure. Increases in AC levels corresponded directly with increases in the area/weight ratio (exposure area) of the fresh-cut carrot products.     

Quality of fresh-cut tomato as affected by type of cut,packaging, temperature and storage time

Long-life Calibra tomatoes (Lycopersicum esculentum Mill.) were minimally fresh processed in slices or wedges and packaged in polypropylene (PP) trays. Passive and active (3 kPa O₂+0 kPa CO₂ and 3 kPa O₂+4 kPa CO₂) modified atmosphere packages (MAP) were used at 0 and 5 °C. After 14 days, the gas composition within passive MAP packages was 11–13 kPa O₂+5.5–6 kPa CO₂ and 8–9.5 kPa O₂+10.5–11.5 kPa CO₂ at 0 and 5 °C, respectively. The gas composition reached in active MAP at both temperatures for both types of cuts was around 7–10.5 kPa O₂ and 7–9 kPa CO₂. The highest C₂H₄ level (15 L L^–1) was found in passive MAP at 5 °C, while in active MAP at both temperatures about 6 L L^–1 C₂H₄ accumulated. After 7 days of storage at 0 °C, the tomato pieces showed better aroma, appearance and overall quality than those stored at 5 °C. No difference between MAP treatments was found, although both led to a better appearance and overall quality than controls in air. After 14 days at 0 °C, only MAP treatments kept a good flavour, overall quality and texture, with no differences between them. After 14 days at 5 °C in all treatments, the flavour fell below a fair condition and the slices showed a slight senescence. MAP significantly reduced total plate counts (TPC) of slices at 5 °C, although only active MAP reduced TPC in wedges after 14 days at 5 °C. A visibly better appearance and overall quality was found in slices than in wedges. The main factors influencing the quality of tomato pieces were the storage duration and temperature. To keep the quality of fresh-cut tomatoes, one should consider three factors for selection: a suitable low chilling sensitive tomato cultivar, an adherent placenta and optimal maturity stage at harvest.     

Cold storage conditions affect the persistence of diphenylamine, folpet and imazalil residues in ‘Pink Lady’ apples

‘Pink Lady^®’ apples (Malus domestica) fruit were harvested at commercial maturity treated with three different agrochemical products, and stored at 1 °C under either air or controlled atmosphere conditions (2.5 kPa O₂ + 3 kPa CO₂ and 1 kPa O₂ + 2 kPa CO₂) for 15 and 28 weeks. Diphenylamine, folpet and imazalil contents in both skin and flesh were simultaneously determined after cold storage plus a simulated marketing period of 1 or 7 days at 20 °C. Results showed that apples stored in 2.5 kPa O₂ + 3 kPa CO₂ retained higher contents of diphenylamine residues in comparison with those stored in 1 kPa O₂ + 2 kPa CO₂ or refrigerated air. Significant differences in imazalil skin contents were found throughout the simulated marketing period at 20 °C after storage for 28 weeks in controlled atmospheres.     

Preservation of precut white cheese by modified atmosphere packaging

Effects of modified atmosphere packaging (MAP) on storage stability and quality of precut fresh and aged white cheese were investigated. Fresh or aged white cheese was cut into small cubes and packaged in five different atmospheres [0% O₂ + 0% CO₂ + 100% N₂ (MAP1), 10% O₂ + 0% CO₂ + 90% N₂ (MAP2), 0% O₂ + 75% CO₂ + 25% N₂ (MAP3), 10% O₂ + 75% CO₂ + 15% N₂ (MAP4) and aerobic (air)]. Control samples were packaged in brine and vacuum for fresh and aged white cheese, respectively. Changes in gas composition, total plate count, lactococci, lactobacilli, yeast and mould counts, proteolysis, lipolysis, pH, colour, texture and sensory properties were investigated during refrigerated storage. The best packaging treatment for the fresh cheese was MAP3, as it inhibited mould growth and protected the hardness. MAP2 can be recommended for the packaging of the aged cheese, as it decreased lipolysis.     

Innovative active modified atmosphere packaging improves overall quality of fresh-cut red chard baby leaves

The antimicrobial effects and quality changes of O₂, He, N₂ or N₂O-enriched active modified atmosphere packaging -MAP- (100 kPa initial gas partial pressure) compared to a chlorinated −100 mg L⁻¹ NaClO- passive MAP (control) in fresh-cut Red Chard baby leaves up to 8 days at 5 °C were studied. High O₂ MAP (>85 kPa O₂) inhibited natural microflora growth during 7 days at 5 °C. Regarding control treatment, no differences for He and N₂O-enriched MAPs on microbial growth were found although control samples were previously disinfected. Initial total phenolics content (613 mg ChAE kg⁻¹ fw) increased up to 61-93% after 6 days at 5 °C under O₂, He, and N₂-enriched MAPs. Vitamin C content decreased up to 67% after shelf life in control samples while lower decreases were monitored in samples stored under non-conventional MAPs. He-enriched MAP preserved the total chlorophylls content throughout shelf life. After 8 days at 5 °C the overall sensory quality of all treatments showed a moderate decrease while still being scored at the limit of usability. In conclusion, He and O₂-enriched MAPs are useful tools in the preservation of fresh-cut Red Chard quality.     

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     

Effect of pulsed electric field processing on carotenoid extractability of carrot purée

The purpose of this research was to study the effect of electric field strength (0.1–1 kV cm^?1) and frequency (5–75 Hz) during pulsed electric field (PEF) processing on the extractability of carotenoids in carrots, which was examined using different vegetable oils. Increasing electric field strengths up to 1 kV cm^?1 at 5 Hz significantly (P < 0.05) increased the extraction of carotenoids from carrot pomace. Increasing frequency above 10 Hz at 1 kV cm^?1 did not improve the carotenoids extraction. The yield of carotenoids extracted was dependent on the vegetable oils. Sunflower and soya bean oils had the highest carotenoid extractability, and peanut oil was the lowest for carrot pomace treated at 0.6 kV cm^?1 and 5 Hz, but no significant difference was observed among vegetable oils for carrot pomace treated at 50 Hz. This study suggests that PEF can improve the carotenoids extractability of carrots depending on the electric field strength and frequency used.     

Microstructure changes of sodium carbonate-soluble pectin of peach by AFM during controlled atmosphere storage

Yellow peaches (Prunus persicu L. Batsch.) were stored under controlled atmospheres (CA) of 2% O₂ + 5% CO₂, 5% O₂ + 10% CO₂, 2% O₂ + 10% CO₂, 5% O₂ + 5% CO₂, and normal atmosphere at 2 °C, to investigate the effects of different concentrations of O₂ and CO₂ on the structure of a single sodium carbonate-soluble pectin (SSP) molecule. The microstructure changes, including aggregates and branches, were studied by atomic force microscopy (AFM) at initially, on the 15th and 45th day. The microstructure of SSP molecules and polymers showed that aggregates separated gradually with the storage time. The degradation took place in the linear backbone as well as in side chains. The degradation of SSP molecules was inhibited by lower O₂ and higher CO₂ concentrations. Almost all of the chains were composed of four basic units with widths of 11.719, 15.625, 19.531 and 17.578 nm, which can be visualized and calculated exactly by AFM. This indicated that parallel linkage or intertwist between the basic units was a fundamental characteristic of SSP molecules.     

Microbial Changes in Shredded Iceberg Lettuce Stored under Controlled Atmospheres

Our purpose was to determine initial microbial populations in shredded Iceberg lettuce (Lactuca sativa L.) cv ‘Great Lakes’, and to study their changes under different controlled atmospheres. Lettuce was shredded, washed, disinfected, water rinsed and centrifuged before being stored for 12 days under air, 3% O₂, 3% O₂+ 5% CO₂ or 3% O₂+ 10% CO₂. Microbiological analysis and assessment of visual quality were carried out every 3 days. No human pathogens were found. Controlled atmospheres had little or no effect on the microbiological populations studied. A 3% O₂+ 10% CO₂ atmosphere maintained acceptable visual quality of lettuce, without appreciably affecting microbial development.     

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 Controlled Atmosphere Storage and Chitosan Coating on Quality of Fresh-Cut Jackfruit Bulbs

Fresh-cut jackfruit bulbs were evaluated for quality changes as effect of an additive pretreatment with CaCl₂, ascorbic acid, citric acid, and sodium benzoate followed by chitosan coating. Different types of samples such as pretreated and coated, only pretreated, only coated, and untreated were subjected to controlled atmosphere (CA) storage (3 kPa O₂?+?6 or 3 kPa CO₂; N2 balance) or normal air at 6 °C. CA conditions, pretreatment, as well as chitosan coating in synergy with each other, could significantly minimize the loss in total phenolics and ascorbic acid content of the samples to the levels of around 5% and 17%, respectively, during extended storage up to 50 days. Chitosan coating could also restrict the changes in microbial load. The CA condition of 3 kPa O₂?+?6 kPa CO₂ was found to render higher efficacy in retaining quality attributes of the samples.