Role of Acetaldehyde Production in the Removal of Astringency from Persimmon Fruits under Various Modified Atmospheres

Astringency of persimmons was removed by enclosing the fruits in polyethylene bags under vacuum or by replacing air with N₂ or CO₂. Acetaldehyde produced by the fruit under these conditions accumulated at different rates. The rate of the deastringency process was directly proportional to the level of acetaldehyde accumulation. Thus, the fruit held at 20°C in CO₂ was the first to lose its astringency, but showed internal browning after 1 wk. Fruits under vacuum or N₂, where less volatiles accumulated, maintained their high quality and firmness for 2 wk at 20°C or 3 months at ? 1°C. However, fruit held under vacuum began to show internal browning when acetaldehyde accumulated above a certain level.     

Induction of certain aroma volatiles in feijoa fruit by postharvest application of acetaldehyde or anaerobic conditions

Postharvest application of acetaldehyde (AA) vapour or anaerobic conditions of N₂ or CO₂ for 24 h to hand-picked feijoa (Feijoa sellowiana Berg) fruits caused the accumulation of volatiles, which increased fruit aroma and flavour. The volatiles, AA, ethanol, ethyl acetate and ethyl butyrate, were produced at high concentrations in treated fruit held for 13 days in storage at 20°C whereas in the control fruits the levels remained very low. A sensory panel judged the treated fruits to be sweeter than the controls, although there was no significant difference in the total soluble solids or acidity between the treated and the non-treated feijoas. Treatment with 98% N₂ for 24 h was most effective for volatile production. Moreover, fruits in the N₂ treatment maintained the best appearance after storage for 13 days at 20°C.     

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

A suitable method of storing, for processing immature green mangoes in a fresh state was sought. Fruits were stored at three temperatures (1OC, 20C and 30C) either in sealed low density polyethylene (LDPE) bags or paper bags or they were waxed before storage. Storage above 20C proved unsuitable for fruits held longer than one week. Sixty percent of fruits stored at 10C in LDPE bags showed no evidence of pathological infection. Development of severe chilling injury limited the use of waxed and control fruits beyond 14 days at 10C. There were no visible symptoms of chilling injury in fruits stored at 10C in LDPE bags. The majority of fruits stored in LDPE bags at 10C maintained good quality characteristics with acceptable flavor and minimal changes in chemical composition up to 21 days.     

A simple pretreatment with low O2 to alleviate superficial scald in Granny Smith apples

Sealing Granny Smith apples in a low‐O₂ atmosphere for 7 days at 20 °C (LO₂‐20C) prior to cold storage reduced superficial scald development after 6 and 8 months at 0 °C plus 10 days at 20 °C. This LO₂‐20C treatment reduced the O₂ levels that induce endogenous production of significant amounts of CO₂, acetaldehyde and ethanol, and thereby reduced ethylene production in cold storage, which in turn reduced scald development. Treatment with ethanol vapour (20 mL L^?1) for 1 day at 20 °C plus 6 days at 1 °C or with low O₂ for 1 day at 20 °C plus 6 days at 1 °C (LO₂‐1C) did not reduce scald effectively. 1‐Methylcyclopropene (1‐MCP) treatment at 0.5 µL L^?1 was the most efficient at reducing scald development. In all treatments, superficial scald development proceeded from the distal blossom end towards the proximal stem end of fruits. After 6 months of cold storage at 0 °C, peel browning and membrane leakage, measured as electrical conductivity in situ, were greater at the blossom end than at the stem end of control, ethanol‐ and LO₂‐1C‐pretreated fruits. In LO₂‐20C‐ and 1‐MCP‐pretreated fruits, colour indices (hue angle, lightness and chroma) and electrolyte leakage were similar at both the stem and blossom ends and were associated with less scald development after 6 months at 0 °C. The reduction in scald development was also associated with lower peroxidase and polyphenol oxidase activities in the peel of LO₂‐20C‐ and 1‐MCP‐pretreated fruits. A simple treatment at 20 °C (LO₂‐20C) prior to regular cold storage could also be suitable for organically grown apples that cannot be treated with diphenylamine or 1‐MCP. Copyright © 2007 Society of Chemical Industry     

Methyl jasmonate reduces chilling injury symptoms and enhances colour development of ‘Kent’ mangoes

Treatment of mango (Mangifera indica cv ‘Kent’) fruits with methyl jasmonate (MJ) vapour for 20 h at 20 °C reduced chilling injury (CI) symptoms and enhanced skin colour development. MJ at 10^?4 M was the most effective concentration for reducing CI and decay in fruits stored at 5 °C followed by 7 days at 20 °C (shelf‐life period). The use of 10^?5 M MJ enhanced yellow and red colour development of mangoes stored at 20 °C. These fruits possessed higher L*, a* and b* values than untreated fruits and those treated with 10^?4 M MJ. Ripening processes were inhibited by cold storage (5 °C) in control fruits. After cold storage and shelf‐life period, fruits treated with 10^?5 M MJ ripened normally and contained the highest total soluble solids (TSS). These fruits also maintained higher sugar and organic acid levels than fruits subjected to other treatments. We concluded that MJ treatment could be used to reduce decay and CI symptoms and also to improve colour development of mango fruits without adversely affecting quality. © 2001 Society of Chemical Industry     

Effect of aminoethoxyvinylglycine and low-pressure storage on the post-storage production of aroma volatiles by Golden Delicious apples

Golden Delicious apple fruits untreated (control) or treated pre-harvest with the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG) were stored at 2°C under either ambient pressure or low pressure (6.7 kPa; LPS). The production of aroma volatiles during post-storage periods at 20°C was measured on fruits stored for 3, 5, 7 and 9 months. Aroma production of AVG- or LPS-treated fruits immediately after storage was considerably lower. However, after 14 days at 20°C, aroma production almost reached values for control fruits (AVG fruits had to be treated with 50 μl C₂H₄ litre^?1). After the longer storage this effect of a post-storage period at 20°C declined gradually and finally was almost absent. Only a post-storage period at 2°C in a normal atmosphere followed by a period at 20°C was now able to partially revive long-stored fruits from this ‘residual’ effect of AVG or LPS. It is suggested that changes in the sensitivity of fruits to C₂H₄ are responsible for the observed decline in aroma production.     

Ethylene production,respiration and gas exchange modelling in modified atmosphere packaging for banana fruits

A mathematical model was developed from experimental measurements to describe the evolution of the O₂, CO₂ and ethylene in a modified atmosphere packaging system for Cavendish bananas. The respiration and ethylene production in the fruits were experimentally obtained from a closed system method and then represented by Michaelis–Menten equations of enzyme kinetics. The gas transfer through the packaging was described by a Fick's diffusion equation, and the temperature dependence was represented based on the Arrhenius law. The model was validated by packaging the fruit in perforated bags of polypropylene and low density polyethylene at 12 °C for a period of 8 days. With the developed model it was possible to satisfactorily describe the experimental evolution of the gas content in the headspace of the packages, obtaining coefficients of determination (R²) of 0.93 for the O₂ levels, 0.90–0.91 for the CO₂ levels, and 0.89–0.93 for the ethylene levels.     

Relationships between volatile production,fruit quality and sensory evaluation of Fuji apples stored in different atmospheres by means of multivariate analysis

Aroma compounds, quality parameters and sensory characteristics of Fuji apples were analysed after 3, 5 and 7 months of storage at 1 °C in normal air (AIR; 210 l m^?3 O₂/0.3 l m^?3 CO₂) and in controlled atmospheres with O₂/CO₂ ratios of 10 l m^?3/10 l m^?3 (ULO1), 10 l m^?3/20 l m^?3 (ULO2) and 30 l m^?3/20 l m^?3 (SCA). After storage the apples were kept at 20 °C for 1, 5 and 10 days. The components that contributed most to the characteristic aroma of Fuji apples were ethyl 2‐methylbutanoate, 2‐methylbutyl acetate and hexyl acetate. The highest aroma compound production was found in ULO1 fruits after 5 months of cold storage and 1 day of shelf‐life. After 3 and 5 months of storage, ULO1 fruits showed the highest firmness after both 1 day and 10 days at 20 °C. After 7 months of storage plus 1 day at 20 °C, ULO2 fruits showed higher titratable acidity and soluble solid content; fruit firmness was also maintained throughout the shelf‐life period. Generally, background and superficial colour were not influenced by storage conditions. A statistically significant correlation was found between aroma compounds, quality parameters and sensory evaluation. Copyright © 2003 Society of Chemical Industry     

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 water stress on the post-harvest quality of two leafy vegetables,telfairia occidentalis and pterocarpus soyauxii during storage

The effect of water stress (excessive water loss) on the post-harvest quality of two leafy vegetables, Telfairia occidentalis and Pterocarpus soyauxii, at ambient (30–35°C) and low temperature (10°C) was investigated in south-eastern Nigeria. The effect of seal-packaging the vegetables in polyethylene and paper bags on quality decline of the leafy vegetables was also monitored. Unsealed leaves of T occidentalis and P soyauxii rapidly lost water during storage at either ambient or low temperature. There were decreases in the chlorophyll, protein and ascorbic acid contents in the stressed leaves. Packaging of the leaves in polyethylene bags alleviated these losses. Sealing of the leaves in polyethylene bags also alleviated water stress.     

Postharvest Physiology and Quality Maintenance of Sliced Pear and Strawberry Fruits

Sliced strawberries (cvs.‘Pajaro’ and 'G-3′) and partially ripe pears (cv.‘Bartlett’) were dipped in various solutions (citric acid, ascorbic acid, and/or calcium chloride) and stored in air or in controlled atmospheres (CA) for 7 days at 2.5°C followed by one day at 20°C. Fruit slices respired at a higher rate than whole fruits at both temperatures. CA storage suppressed respiration and ethylene production rates of sliced fruits. Firmness of strawberry and pear slices was maintained by storage in air + 12% CO₂ and in a 0.5% O₂ atmosphere, respectively, or by dipping in 1% calcium chloride. These treatments also resulted in lighter colored pear slices than the air control treatment.     

Improved keeping quality of minimally fresh processed celery sticks by modified atmosphere packaging

Recommended storage conditions of green celery sticks are 4 °C for 10 days, but there are no reports about optimal modified atmosphere packaging (MAP) conditions to preserve them longer. The objective of this research was to describe the gas composition of MAP generated by two polymeric films and its effects on chemical, sensorial and microbial quality, and physiological disorders of celery sticks stored at 4 °C for 15 days. Green sticks of 15-cm length of ‘Trinova’ cv. were placed in hermetically sealed plastic bags: low-density polyethylene, oriented polypropylene (OPP) and polyethylene-perforated bags as control (air). The O₂ and CO₂ concentrations, soluble solid content, pH, titratable acidity, colour, sensorial quality and sugar and organic acids contents were monitored. Compared to the control, both MAP treatments improved the sensory quality, avoided the loss of green colour, decreased the development of pithiness and retarded the growth of microorganisms. In any treatment neither off-odours nor off-flavours were detected. After 15 days at 4 °C within the OPP bags a steady-state atmosphere of 6 kPa O₂+7 kPa CO₂ was reached and celery sticks stored under these bags showed the best quality.     

Poststorage Behavior of Apple Fruit After Low Oxygen Storage as Influenced by Temperatures During Storage and in Transit

‘Delicious’, ‘Newtown’ and ‘Granny Smith’ apples (Malus domestica Borkh.) maintained acceptable flesh firmness and high levels of titratable acids and soluble solids after 9 months of storage in 1% 0₂ at either 0°C or 3.3°C. Low-0₂-stored ‘Delicious’ were kept at 0°C for 6 wk without developing physiological disorders before or after 8 days of ripening at 20°C. Storage at 3.3°C caused ‘Delicious’ to soften faster during 6 wk of post-storage holding plus 8 days of ripening. ‘Newtown’ apples developed flesh browning and alcohol flavor after 9 months of low 0₂ storage at 0°C. ‘Newtown’ fruit stored at 3.3°C developed only minimal incidence of flesh browning and alcohol flavor. ‘Granny Smith’ fruit were free from scald, core flush, flesh browning and alcohol flavor after low 0₂ storage, regardless of storage temperature. However, core flush and flesh browning appeared when ‘Granny Smith’ were kept for 6 wk at 0°C plus 8 days at 20°C.     

Some postharvest factors associated with the occurrence of chilling injury in banana

Unripe Cavendish banana fruits were stored at 5–7°C under normal or 0.14 normal atmospheric pressure for two weeks, with or without a continuous supply of ethylene, prior to ripening at 20°C. Pulp/peel ratio, colour index and production of volatile were measured following prestorage at chilling temperature, and after reaching ripeness at 20°C. CO₂ and C₂H₄ production were also measured at 20°C. The results show that green fruits had lower pulp/peel ratios than treated green fruits while the reverse was true following ripening at 20°C. Yellow colour development was retarded by 5°C pretreatment, and low pressure storage had no noticeable effect on colour index. Prestorage at 7°C, however, improved colour development slightly. Acetates, butyrates and alcohol produced by fruits prestored at chilling temperature and 0.14 normal atmospheric pressure showed both qualitative and quantitative differences compared with those produced by non-chilled fruits.     

Effect of Processing and Storage on The Antioxidant Activity of Frozen and Pasteurized Shadblow Serviceberry (Amelanchier canadensis)

Serviceberry fruits were pasteurised in glass jars at two temperatures, 85 and 100°C, while another batch was packed in polyethylene bags and frozen at a temperature of ?20 ± °C. Processed fruits were stored for 10 months: frozen fruit at ?20 ± 1°C; and pasteurised fruit at room temperature without access to light. Refrigerated storage and pasteurization lowered the DPPH antioxidant activity of serviceberry fruit. In the former, the change was not great, whilst pasteurisation caused an approximately twofold increase in EC50. On the basis of total anthocyanin content and total polyphenolic content measurements, it would appear that the antioxidant properties of serviceberry were affected mainly by anthocyanins. Pasteurising at 100°C allowed slightly better preservation of these compounds during long-term storage.     

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     

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.     

Changes in sterol and phospholipid composition of apples during storage at low temperature and low oxygen concentration

Free sterol and phospholipid in the cortical tissue of apple were determined during storage of the fruits in air at 12 and 3.5°C and in 2 kPa O₂ (98 kPa N₂) at 3.5°C. In air at 12°C, the sitosterol content declined slightly (about 4%) during fruit ripening whilst phospholipid increased about 8%. At 3.5°C in air and 2 kPa O₂, sitosterol content increased by 16% and phospholipid by 25–31%. The increase in phospholipid in 2 kPa O₂ occurred more slowly than in air. Transfer of apples to air after 33 or 64 days in 2 kPa O₂ led to rapid accumulation of phospholipid in the fruit (20% and 10%, respectively) compared with apples maintained in 2 kPa O₂. An increase in concentration of phosphatidylcholine (PC) accounted for most of the change observed in total phospholipid.     

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.