The effects of 1-methylcyclopropene treatment on the shelf life and quality of cherry tomato (Lycopersicon esculentum var. cerasiforme) fruit

The use of 1‐methylcyclopropene (1‐MCP) to extend the shelf life of cherry tomato (Lycopersicon esculentum var. cerasiforme) was investigated. Higher concentrations of 1‐MCP delayed the ethylene induced climacteric peaks in mature green (MG) and breaker (BR) fruits. Thirteen days after treatment, control fruits were 55% as firm as fruit treated with 0.11 μL L^?1 1‐MCP. The initiation of fruit softening, chlorophyll degradation and accumulation of lycopene and carotenoids was delayed in treated fruits. Higher 1‐MCP concentrations inhibited the accumulation of lycopene and carotene such that the colour of the fruit did not reach that of control fruit. Treatment of MG cherry tomatoes with 1‐MCP enhanced shelf life optimally, while treatment of BR fruits was beneficial where full colour and high content of lycopene and carotenoids is important. Differentiation of the different stages of ripening before application of 1‐MCP is needed in order to succeed in accomplishing different postharvest objectives.     

Influence of different concentrations of 1-methylcyclopropene on the quality of tomato harvested at different maturity stages

BACKGROUND: A wide range of 1‐methylcyclopropene (1‐MCP) concentrations as well as various treatment durations have been studied in tomatoes by different researchers. However, little is known about interaction of 1‐MCP doses and maturity stages of tomatoes. Therefore the effects of different concentrations of 1‐MCP on storage and postharvest quality of ‘Zorro’ tomatoes harvested at mature green or pink maturity stages were investigated in a 2‐year trial study. RESULTS: Higher concentrations of 1‐MCP delayed and/or inhibited all parameters related to fruit ripening, such as lycopene, chlorophyll, surface color, polygalacturonase (PG) activity and soluble solids content/titratable acidity (SSC/TA), and these effects were greater in tomatoes harvested at the mature green stages. Lower concentrations of 1‐MCP slightly reduced the loss in general quality features compared with untreated tomatoes. CONCLUSION: The results suggest that 1‐MCP, especially at higher doses, is effective for delaying ripening of mature green tomatoes. Mature green fruits treated with 1000 nL L^?1 1‐MCP were stored for 35 days without significant decreases in quality characteristics such as elasticity, surface color and SSC/TA with certain physiological processes (ethylene production, PG activity, lycopene synthesis). Copyright © 2011 Society of Chemical Industry     

EFFECTS OF 1‐METHYLCYCLOPROPENE AND MODIFIED ATMOSPHERE PACKING ON POSTHARVEST LIFE AND QUALITY IN TOMATOES

ABSTRACT

The effects of 1‐methylcyclopropene (1‐MCP), modified atmosphere packaging (Xtend, StePac L.A. Ltd., Tefen, Israel) and their combination were investigated on storage and quality maintenance of tomatoes cv. “Perla” harvested at two maturity stages. 1‐MCP treatment was performed in 1,000 nL/L doses for 24 h while untreated fruits were considered as control. Fruits were stored at 12C with 90% relative humidity for 21 days. Weight loss, skin color, elasticity, lycopene, ascorbic acid, soluble solid content (SSC), titratable acidity (TA) and SSC/TA were evaluated with the intervals of 7 days. MAP with and without 1‐MCP reduced weight loss and maintained to elasticity compared with control and 1‐MCP alone. Nevertheless, 1‐MCP or its combination with MAP significantly delayed changes in parameters related to fruit ripening, such as skin color, lycopene, TA and SSC/TA increase in both ripening stages. Overall results indicated that the combination of 1,000 nL/L 1‐MCP and modified atmosphere package was the most effective treatment in both ripening stages.

PRACTICAL APPLICATIONS

Tomato is a climacteric fruit and its ripening depends on ethylene production physiology. 1‐Methylcyclopropene (1‐MCP) prevents ethylene action by blocking ethylene receptors and extends the storage life of tomatoes. Modified atmosphere packaging (MAP) of fresh fruits and vegetables refers to the still evolving technique of matching the respiration of the product with the O₂ and CO₂ permeability of packages in order to modify the oxygen and carbon dioxide concentrations of the atmosphere to desired levels within the package. Recent studies revealed that combined applications of 1‐MCP and MAP have significant effects on maintaining storage quality of banana, litchi and plums. This study was conducted on the investigation of the effects of 1‐MCP and MAP combination on storage duration and quality of tomatoes harvested at different maturity stages.     

Effect of pre‐ripening chilling temperatures on ripening,shelf life and quality of bananas treated with 1‐methylcyclopropene

Ethylene production, shelf life and fruit quality of Cavendish bananas (cv. Williams), held at different pre‐ripening storage temperatures (5 °C, 10 °C or 15 °C) prior to ethylene and/or 1‐methylcyclopropene (1‐MCP) application, were determined and compared. Levels of ethylene production during ripening were highest for control fruit that had been stored at 5 °C followed by 10 °C and then 15 °C. 1‐MCP treatment (at 300 nL L^?1) had no effect on ethylene production of fruit that had been stored at 10 °C by day 10 of storage, but ethylene production was significantly higher for fruit that had been stored at 15 °C and lower for those stored at 5 °C before 1‐MCP treatment. 1‐MCP also increased shelf life to a greater extent when applied to fruit that had been stored at 10 °C or 15 °C. Even though 1‐MCP had no significant effect on under peel chilling injury, it increased discolouration significantly, regardless of storage temperature. Firmness of 1‐MCP‐treated fruit decreased significantly compared to the control when fruit were held at 5 °C or 15 °C prior to ripening (and 1‐MCP application) but had no effect on fruit stored at 10 °C before ripening. These results indicate that pre‐ripening storage temperature affects ripening, shelf life and quality in both ethylene and 1‐MCP‐treated bananas.     

Extending the shelf‐life of bananas with 1‐methylcyclopropene and a chitosan‐based edible coating

BACKGROUND: The marketability of bananas over long distances has been limited due to their highly perishable nature and sensitivity to ethylene. To increase the shelf‐life several alternatives have been tested in attempts to maintain quality characteristics. We evaluated the effects of 1‐methylcyclopropene (SmartFresh^SM, 1‐MCP) and a chitosan‐based edible coating (FreshSeal^®, EC), applied alone or combined, on bananas at ripeness stage 3. All fruits were stored for 8 days at 22 °C, 85% RH. Color development, weight loss, firmness, physiological, sensory and chemical variables were evaluated. RESULTS: After 3 days, control and EC‐treated fruits were completely yellow (°Hue = 90), while 1‐MCP treated fruits alone and combined with EC were still showing some green colorations on tips and neck of fingers. After 7 days, fruits treated with the combination (EC + 1‐MCP) reached a Hue value of 90. Firmer fruits were observed with 1‐MCP alone or combined with EC. A decrease of 0.15% titratable acidity and an increase of 8°Brix were observed in all treatments during the experiment. The incidence of sugar spots was delayed and diminished on fruits treated with 1‐MCP either alone or combined. Sensory results showed no adverse effects by using the 1‐MCP or the edible coating. CONCLUSION: The combined treatment of EC + 1‐MCP could be used to extend the commercial life of bananas for up to four more days. Copyright © 2009 Society of Chemical Industry     

Effect of Cold and Heat Shock Treatment on the Color Development of Mature Green Tomatoes and the Roles of Their Antioxidant Enzymes

Color is the most important marker of the quality and ripeness of tomato fruits. To study the effect of cold shock treatment (CST; 0 °C, 3 h) and heat shock treatment (HST; 50 °C, 2 min) on the color development of mature green tomatoes and the roles of antioxidant enzymes, we measured color, the levels of malondialdehyde (MDA), ascorbic acid, and antioxidant enzymes at 20 and 10 °C storage conditions. HST retarded the ripening of mature green tomatoes, delayed color development, reduced MDA content, and increased superoxide dismutase (SOD) and peroxidase (POD) activities in tomatoes stored at 20 or 10 °C, as well as increased catalase (CAT) activity in tomatoes stored at 10 °C. In comparison with controls, CST accelerated the development of senescence in mature green tomatoes stored at 20 or 10 °C, which reflects faster color development and higher MDA content, resulting from the low activities of SOD and POD. These results suggested that, with regard to the antioxidant enzymes SOD and POD, CST had a different effect on color development compared with that of HST in mature green tomatoes stored at 20 or 10 °C. Furthermore, these results implied that SOD and POD played significant roles in the antioxidant system in CST- and HST-treated mature green tomatoes stored at 20 or 10 °C, and CAT was the crucial antioxidant enzyme to resist cold storage in HST-treated mature green tomatoes stored at 10 °C.     

The effects of ethanol treatment on the metabolism,shelf life and quality of stored tomatoes at different maturities and temperatures

Two maturity stages of commercially grown tomatoes (breaker and mature green) were exposed to ethanol vapour (2 ml ethanol kg⁻¹ fruit) for 6 h at 20 °C prior to storage at 5 °C and 20 °C. During storage the colour, firmness and composition changes were examined every 3 and 7 days. The results showed that ethanol vapour treatment could significantly slow down the colour changes and softening of both mature green and breaker tomatoes with greater effects when stored at 5 °C. There was no difference between the two maturity stages in retardation of softening during storage; in contrast the maturity stage had a highly significant effect in the colour development of stored tomatoes. When the fruit stored at 5 °C was then held at 20 °C for 7 days the ripening process was accelerated but the fruit did not reach the same level of colour development as the fruit stored at 20 °C continuously. The results suggest that ethanol vapour pretreatment could be used as a cheap and easy method to extend the storage life of tomatoes. © 1999 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     

Polyamine Accumulation Following Hot-Water Dips Influences Chilling Injury and Decay in'Friar' Plum Fruit

Mature‐green (Prunus salicina Lindl. cv.‘Friar’) plums were treated in water at 40°C for 40 min, 45°C for 35 min, 50°C for 30 min or 55°C for 25 min, stored at 0°C for 35 d plus 9 d of ripening at 20 to 25°C. During cold storage, putrescine and cadaverine accumulated most compared to spermine and spermidine, especially in fruits treated at 45 or 50°C, compared to other treatments. Chilling injury (CI) and decay symptoms were severe in fruits of control, 55 and 40°C‐treated fruits. Decay incidence was also high in fruits stored at room temperature. Chilling injury and decay symptoms were retarded in fruits treated at 45 and 50°C, which also maintained increased polyamines and low ethylene. By the end of their shelf life, only 45 and 50°C‐HWD treated fruits were fit for market.     

Quality of Fungicide Treated and Individually Shrink-Wrapped Tomatoes

Fungicide-treated mature green and pink tomatoes were individually shrink-wrapped with plastic films and stored at 13°C and 18°C. Shrink-wrapped pink tomatoes lost less water than unwrapped tomatoes, but there were no significant shelf-life or quality differences. The shelf-life of mature green tomatoes at 18°C, however, was increased 10 days by shrink-wrapping. Color development of wrapped mature green tomatoes at 18°C was delayed. Wrapped fruit at both temperatures were firmer than the controls. Titratable acidities and soluble solids of wrapped fruit were lower than those of the unwrapped fruit at 13°C, while no significant changes were observed in citric acid or monosaccharide concentrations. The differences in titratable acidities and soluble solids in the wrapped and unwrapped fruit stored at 18°C were not significant.     

Influence of Different Factors on Firmness and Color Evolution During the Storage of Persimmon cv. 'Rojo Brillante'

‘Rojo Brillante’ persimmons were harvested in 2 different dates, early and late, and then submitted to 1‐methylcyclopropene (1‐MCP) treatment (500 nL/L) before stored at 1 or 15 °C up to 50 or 30 d, respectively. The influence of harvest date, 1‐MCP treatment, orchard, storage time, and temperature on firmness loss and color evolution during storage of ‘Rojo Brillante’ persimmon was studied. Statistical models that allowed the prediction of these 2 quality parameters during the storage, as well as the modeling of the behavior of both of them, were also evaluated. The softening, as a consequence of chilling sensitiveness when stored at 1 °C, was more accentuated in the early harvested fruit. In storage at 15 °C, also, the firmness loss was faster in fruit harvested earlier. 1‐MCP treatment drastically reduced chilling injury (CI) symptoms at 1 °C and retarded firmness loss at 15 °C, both of these effects being dependent on harvest date. The model presented to study the firmness and color relationship offers an important tool to predict firmness from fruit color measurements.     

1-MCP Treatment Prolongs Postharvest Life of 'Santa Rosa'Plums

'Santa Rosa’plums were treated with concentrations of 0‐ (control), 0.5‐, or 0.75‐μL/L 1‐methylcyclopropene (1‐MCP) for 24 h at 1°C and stored at 1 °C for up to 40 d. Ethylene and CO₂ production, firmness, weight loss, Brix, acidity, color evolution, and ethanol and acetaldehyde concentrations were determined periodically after cold storage and after subsequent shelf life of 5 and 8 d at 20 °C. 1‐MCP strongly inhibited ethylene and CO₂ production. Higher values of firmness were observed in 1‐MCP‐treated plums compared with control. 1‐MCP treatment delayed color evolution, reduced acidity loss, and inhibited ethanol and acetaldehyde production. 1‐MCP did not affect weight loss or sugar content.     

The hurdle effect of osmotic pretreatment and high‐pressure cold pasteurisation on the shelf‐life extension of fresh‐cut tomatoes

Tomatoes are perishable products due to the activity of microorganisms and endogenous enzymes. The objective was to produce cut tomatoes with extended shelf life, using the combined hurdle effect of osmotic pretreatment (OD) and high pressure (HP), instead of a conventional one‐step thermal process. Samples were processed in a multicomponent osmotic solution at 35 °C, subsequently cold‐pasteurised in pack at 600 MPa and stored at 5–15 °C. Quality deterioration during isothermal and nonisothermal storage was kinetically modelled. Both OD process and OD‐HP combined process caused an increase in lycopene content that was well retained. Texture, colour and flavour of treated samples were evaluated as similar to fresh, with OD‐HP samples showing better retention during storage. Being microbiologically stable, shelf life of OD‐HP samples was limited by sensory deterioration, whereas OD samples were rejected due to eventual microbial growth. Shelf life of OD and OD‐HP samples was estimated at 77 and 181 days, respectively, at 5 °C.     

Postharvest response of ‘Brown Turkey’ figs (Ficus carica L.) to the inhibition of ethylene perception

The potential use of 1‐methylcyclopropene (1‐MCP) alone or as a supplement to cold storage to delay the softening of ‘Brown Turkey’ figs (Ficus carica L.) was studied. Figs were treated with 0, 0.25, 0.5 or 5 µl l^?1 1‐MCP at 25 °C for 8 h and stored at 20 °C until evaluated. Figs treated with 0.5 or 5 µl l^?1 1‐MCP had higher ethylene production and respiration rates but slower softening than untreated fruit and those treated with 0.25 µl l^?1 1‐MCP. Early‐harvested firm figs and late‐harvested soft figs were untreated or treated with 0.5 or 5 µl l^?1 1‐MCP at 25 °C and stored at 0 °C for 19 days. Firm figs treated with 1‐MCP showed an early peak in ethylene synthesis, higher respiration rate and were firmer than control fruit. In contrast, soft figs did not respond to 1‐MCP except for a late increase in respiration rates of fruit treated with 5 µl l^?1 1‐MCP. 1‐MCP appeared to have a relatively limited effect on slowing ripening of ‘Brown Turkey’ figs and its effect was influenced by ripening stage. Copyright © 2005 Society of Chemical Industry     

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.     

Antioxidant properties and shelf‐life extension of fresh‐cut tomatoes stored at different temperatures

BACKGROUND: The feasibility of using modified atmosphere packaging (5 kPa O₂ + 5 kPa CO₂) to maintain the antioxidant properties of fresh‐cut tomatoes during shelf‐life was assessed through storage at different temperatures (5, 10, 15 and 20 °C). Health‐related compounds, antioxidant capacity, microbiological counts, physicochemical parameters and in‐package atmosphere of tomato slices were determined. RESULTS: Initial lycopene, vitamin C and phenolic contents and physicochemical parameters of tomato slices were well maintained for 14 days at 5 °C. Lycopene and total phenolic contents were enhanced over time in tomato slices stored at 15 and 20 °C. However, this increase in antioxidant compounds of fresh‐cut tomatoes during storage may be associated with excessive amounts of CO₂ (R² = 0.5679–0.7328) in the packages due to microbial growth. Although keeping tomato slices at temperatures above 10 °C increased their antioxidant content, the shelf‐life of the product was reduced by up 4 days. CONCLUSIONS: A storage temperature of 5 °C is appropriate for maintaining the microbiological shelf‐life of fresh‐cut tomatoes for up to 14 days and also allows the antioxidant properties of tomato slices to be retained over this period, thus reducing wounding stress and deteriorative changes. Copyright © 2008 Society of Chemical Industry     

The microbial safety of strawberry and raspberry fruits packaged in high-oxygen and equilibrium-modified atmospheres compared to air storage

Microbial safety of strawberry and raspberry fruits was assessed after shelf‐life extension by two new packaging systems, high‐oxygen atmospheres (HOA) and equilibrium‐modified atmospheres (EMA), in combination with an ethylene absorbing film. Both fruits had a shelf‐life of 3 days at 7 °C when macroperforated films were used. Strawberry fruits were acceptable for 5 days in both packages, raspberries had a shelf‐life of 7 and 5 days when using EMA and HOA respectively. Escherichia coli, Salmonella spp. and Listeria monocytogenes were artificially inoculated onto packaged fruits. All were able to survive on packaged fruits stored at 7 °C. Raspberries showed an enhanced inactivation of Salmonella during storage time in both types of packaging. Growth of L. monocytogenes was observed on the calyx of strawberries after the end of the established shelf‐life. Generally, increasing the shelf‐life of the fruits with EMA and HOA did not give an increased microbial risk.     

Quality of mango fruits during storage: effect of synthetic and eco‐friendly films

Mango (Mangifera indica) cv ‘Alphonso’ fruits, harvested 40–50 days after flowering, were stored at 27 ± 1 °C and 65% RH under three conditions of packaging: (1) perforated plastic boxes, (2) wax lined cartons sealed with low‐density polyethylene (LDPE) film, and (3) wax lined cartons sealed with chitosan films. The weight loss, firmness, Hunter colour values and acidity were determined periodically during storage. Sensory analysis was carried out to determine colour, firmness, flavour qualities and also defective spots. Principal component analysis (PCA) of the results indicated that fruits stored in perforated plastic boxes and LDPE film‐sealed cartons differed significantly with respect to mango flavour, firmness and development of defective spots, while those in chitosan film sealed cartons retained the desirable qualities for a longer period (up to 20 days) without developing defective spots. The higher level of carbon dioxide and lower level of oxygen, or lower rate of oxygen transmission, associated with chitosan films delay ripening, and the higher water vapour transmission rate minimizes the rate of transpiration and prevents condensation of water droplets on the film. This helps in establishing equilibrium moisture content of mangoes in the cartons, which, in turn, extends the shelf life of fruits for a longer period. Copyright © 2004 Society of Chemical Industry     

EFFECT OF EVAPORATIVE COOLING STORAGE ON RIPENING AND QUALITY OF TOMATO

Tomatoes (Lycopersicon esculentum Mill cv. Rupali) ripened in evaporative cooling (EC) storage conditions (20°C–25°C, 92–95% RH) were compared with control fruits stored under room conditions (28°C–33°C, 45–65% RH) during summer in Mysore. EC ripened tomatoes on the 15th day reached 100% ripening index (RI) with a value of 2.48 for the ratio of redness to yellowishness (a/b) and hue angle (θ) of 22.1° whereas the control tomatoes on the same day reached a maximum 83.3% RI with a/b ratio of 1.59 and a hue angle of 32.9°. Higher development of chroma and total color difference were exhibited by EC stored tomatoes than control samples. The lycopene content of EC ripened fruits double that of the control. EC stored fruits showed lower values for rupture and shear stresses. The rate of moisture loss for control fruits was 6.5 times as great as for EC stored tomatoes.