Prediction of Changes in Color of Tomatoes during Ripening at Different Constant Temperatures

Vine-ripened and ethylene-treated tomatoes (cv. ‘Sunny’) were ripened at 15, 18, 21, and 25°C and evaluated for color using a colorimeter. Computer models were developed from the objective data to predict changes in color components (value, hue angle, chroma). Computer-predicted results were then converted to sensory equivalent scores to provide a basis for quality management of tomatoes within a handling and distribution system. The models obtained reasonably estimated changes in vine-ripened tomatoes (cv.‘Flora-Dade’) ripened at 15, 21, and 25°C, but were less successful at predicting changes in ethylene-treated fruit.     

Use of the APIZYM Testing System to Assess the State of Ripeness of Banana Fruit

The APIZYM activity profiles of untreated fruit ripening at 20°C and 85% RH were compared with those from fruits treated with Pro-long, a fruit coating material, and fruit stored under controlled atmosphere conditions (5% O₂, 95% N₂) at the same temperature and RH. Banana fruits coated with Pro-long or stored under CA conditions ripened more slowly than untreated fruits, and this was reflected in lower activity of some enzymes during the storage period in coated and CA-stored fruit. Reduced activity in these treatments was more noticeable at day 4 of storage than day 7; however, even at day 7, the activity of certain enzymes was still lower than in controls.     

Effect of Chilling Exposure of Tomatoes During Subsequent Ripening

Mature green tomatoes were stored at 4°C, ≥ 90% RH, for up to 39 days and transferred to 21°C, ≥ 90% RH, for further ripening. After 15 days of chilling exposure, stimulation of C₂H₂ production and increased susceptibility to decay were observed when the fruit was ripened at ambient temperatures. As chilling exposure increased, C₂H₄, production upon removal to 21°C returned to the level of the control. Irreversible inhibition of color development was observed in fruit exposed to 4°C for 34 days and an increase in CO₂ production was noted upon warming of tomatoes chilled for 39 days.     

Ripening and Cold Storage Changes in the Quality Characteristics of Nonmelting Clingstone Peaches (FLA 9-20C)

Minolta “a” values, SS/TA ratio, sucrose, total sugar contents, and sweet sensory scores increased significantly with increased degree of maturity of unripened peaches. Firmness, Minolta “L” values, hue angle, TA, sorbitol, green and sour flavor attributes, and peach complex and fruity/ester aromas decreased significantly with maturity. Maturity 1 and 2 peaches stored for 8 wk at 0° C and subsequently ripened showed no significant change in physical characteristics except for firmness which increased at 8 wk storage. Maturity 1 and 2 peaches could be ripened at 20° C for up to 15 days and stored at 0° C for 8 wk without notable change in quality.     

CHARACTERIZATION OF TOMATO RIPENING PROCESS AS INFLUENCED BY INDIVIDUAL SEAL-PACKAGING AND TEMPERATURE

Tomatoes were individually seal-packaged and ripened at two temperatures, 12 and 21° C. Both the temperature and seal-packaging delayed the tomato ripening process. The delay in ripening due to seal-packaging occurred prior to the ‘turning’ and ‘pink’ USDA color maturity stage when stored at 21° C and 12° C, respectively. Lower concentrations of lycopene were associated with lower chroma values in seal-packaged fruits. Both temperature and seal-packaging prolonged the ripening period but did not affect the firmness values at various color stages of tomatoes.     

EFFECT OF INTERMITTENT WARMING AND MODIFIED ATMOSPHERE PACKAGING ON COLOR DEVELOPMENT OF PEACHES

Peaches (Prunus persica L. Batsch cv. ‘Paraguayo’) at firm-breaker stage of maturity were stored at 0.5 C for 3 weeks. Intermittent warming (IW) for 1 day at 20C every 6 days of cold storage at 0.5C, modified atmosphere packaging (MAP) generated by 42 μm oriented polypropylene bags, and a combination of MAP and IW were applied. Changes in skin and flesh color (measured by CIELAB parameters and Chroma and Hue angle color indices) during normal postharvest ripening at 20C, during cold storage and after 3 days of post-storage ripening were studied. For commercial purposes, IW led to the same color level being reached as was found in normal postharvest ripened fruits. In contrast, the high carbon dioxide and low oxygen generated by MAP alone or combined with IW delayed color development even during post-storage ripening. Ground color measured by hue angle was the best index for monitoring color evolution during ripening and storage.     

Tocopherol Quantification by HPLC in Pecans and Relationship to Kernel Quality during Storage

Changes in tocopherols were followed in Stuart, Desirable and Schley cultivars during storage at 23.9°C and 60-70% RH and 0.6°C and 75% RH for 12 mo. Quality changes in the pecans were monitored using Hunter color measurements and conjugated diene measurement. α-, β-,γ- and 8-tocopherols were found in the three cultivars and γ-tocopherol was the primary form in each. Decreases of γ- and total tocopherols and L, hue angle and saturation index values were observed for pecans stored at 23.9°C (P < 0.05). Positive correlations (P < 0.05) were found between γ- and total tocopherols and Hunter color values for samples stored at 23.9°C. Conjugated diene levels did not correlate with tocopherol levels and Hunter values (P < 0.05). Pecans could be stored at 0.6°C and 75% RH for 12 mo without changes in kernel color, oil quality, tocopherols or conjugated diene levels.     

Postharvest Changes in Antioxidant Capacity,Enzymatic Activity,and Microbial Profile of Strawberry Fruits Treated with Enzymatic and Divalent Ions

Strawberry fruits are highly perishable and cannot be stored for more than 1–2 days at ambient condition. Therefore, it was thought desirable to enhance the shelf-life of harvested strawberry using pectin methyl esterase and divalent ions. The freshly harvested fruits of strawberry were treated with different concentrations of pectin methyl esterase (50–300 units) and divalent calcium ions (calcium chloride) for 5–30 min using response surface methodology—Box–Behnken design. The treated and untreated (control) fruits were packed in plastic punnets and stored at two different temperature conditions, viz., 7 °C with 80 % relative humidity (RH) and 25 °C with 60 % RH, for evaluating the shelf-life. Appropriate physico-chemical and microbiological parameters were determined at alternate days during their storage. Overall firmness and color values (L, a, b) decreased, while physiological weight loss (percent) increased during their storage. No food-borne pathogens, viz., Salmonella, Staphylococcus, and coliforms, were observed during storage. Total antioxidant capacity and ferric reducing antioxidant power decreased, while lipoxygenase and polyphenol oxidase activities increased during storage at 7 and 25 °C. The shelf-life of treated strawberry was found to be 10 days at 7 °C as against 6 days for control fruits under similar conditions. The treated strawberry had shelf-life of 2 days compared to 1 day for control maintained at 25 °C.     

Effect of 1-methylcyclopropene on tomato flavour components, shelf life and decay as influenced by harvest maturity and storage temperature

BACKGROUND: In Florida, tomatoes are harvested green (GR), which includes mature green (MG) and immature green (IG) fruits, and stored at low temperature (13 °C), resulting in poor flavour. Flavour improvement might be achieved if fruits were harvested with some colour (to eliminate IG fruits) and/or stored at higher temperature with the ripening inhibitor 1‐methylcyclopropene (1‐MCP). RESULTS: ‘Florida 47’ tomatoes were harvested at GR (MG + IG), breaker (BR), turning (TR) and pink (PK) stages, treated (+) or not (?) with 1‐MCP and stored at 13 and/or 18 °C. 1‐MCP treatment resulted in a gain of up to 6 days of shelf life depending on harvest maturity and storage temperature. Storage at 18 °C rather than 13 °C resulted in an increase in internal red colour, soluble solids (SS)/titratable acidity (TA) ratio and levels of many volatiles studied. The shelf life of BR (+) MCP fruits stored at 13 °C was similar to that of MG fruits. IG fruits exhibited lowest levels of SS, TA and ten volatiles compared with BR fruits. CONCLUSION: Harvesting tomatoes with colour (BR), thereby eliminating IG fruits, and treating with 1‐MCP resulted in better quality with adequate shelf life. Published 2011 by John Wiley & Sons, Ltd.     

EFFECT OF COLD STORAGE ON THE QUALITY CHARACTERISTICS OF ‘AU-RUBRUM’ PLUMS1

The effect of cold storage (0°C) and maturity on the physical, chemical and sensory characteristics of plums (cv. ‘AU-Rubrum’) was determined. The size, weight, soluble solids and total sugar contents of the more mature fruit were significantly higher (P<0.05) and the “L” and hue angle were significantly lower (P<0.05) than plums in the less mature class. ‘AU-Rubrum’ fruit contained glucose, fructose and sorbitol but had no sucrose. Artificially ripening fruit at 20°C had a significant effect (P<0.01) on all color values for both maturity 1 and 2 fruit. The titratable acidity and sugar contents of the fruit ripened at 20°C were lower for ripened than for unripened fruit. Storage of the plums at 0°C for 5 weeks followed by subsequent ripening at 20°C had no significant effect on physical, chemical or sensory characteristics. Data indicate that ‘A U-Rubrum’ plums which have one-half red ground color (maturity 1) will develop full color and complete the normal ripening process. Data also indicate that the plums can be stored for at least 5 weeks at O°C without loss of quality and that the cultivar has potential for shipping to distant markets.     

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 FILM PERFORATION ON THE QUALITY OF INDIVIDUALLY SEAL PACKAGED TOMATOES

Freshly harvested, ethylene treated, mature green tomatoes (Lycopersicon esculentum Mill. cv. ‘Flora-Dade’) were individually packaged in heat-shrinkable perforated films and stored at 21°C and 55% RH. The degree of film perforation (exposed surface area, A) was varied as 0, 1.4, 4.5, 11 and 100%, with the hole diameter, D, being constant at 8 mm or D was varied as 0.7, 4, 8 and 16 mm, while A was kept constant at 11%. Films with A = 0 or 1.4% drastically reduced weight loss and tissue softening resulting in tomatoes of good eating quality and bright red color. Off-flavor was detected when films with D = 0.7 mm were used. Large size holes (D = 16 mm) allowed free gas exchange between the fruit and the environment. Results indicated that fruits transpire throughout the entire skin surface area, but respire primarily through the stem scar.     

Physicochemical and sensory evolutions of the lactic goat cheese Picodon in relation to temperature and relative humidity used throughout ripening

To produce a wide variety of cheeses, it is necessary to control the ripening process. To do that, artisanal goat cheeses were ripened to evaluate the effects of temperature (10 and 14°C) and relative humidity (RH; 88 and 98%) on (1) 16 physicochemical characteristics throughout ripening and (2) 19 sensory characteristics at the end of ripening (d 12). Whatever the ripening time, the physicochemical characteristics were strongly dependent on the daily productions, which affected the sensory perception of the cheeses. Both physicochemical and sensory characteristics were strongly reliant on RH, whereas only a few of the characteristics were influenced by temperature changes. On d 12, whatever the ripening temperature, an RH increase from 88% to 98% modified many cheese characteristics (core pH, lactate consumption, underrind thickening, dry matter content, and hardness). As a result of these physicochemical properties, changes in perception were observed: the cheeses ripened under 88% RH were dry and hard compared with those ripened under 98% RH. An RH of 98% led to an acceleration of the ripening process, inducing a slightly ammonia and milky flavor and a sticky and creamy texture in the mouth. However, cheeses ripened under 14°C and 98% RH were also indicative of overripened cheeses: a temperature of 14°C induced an acceleration of the ripening process due to physicochemical modifications compared with a temperature of 10°C. Nevertheless, when the cheeses on d 0 were still very humid and soft, those ripened under 98% RH collapsed and were overripened with a liquid underrind. This study provides a means for achieving a better and more rational control of the ripening process in artisanal lactic goat cheeses.     

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.     

Quality Changes in Tomatoes and Resistance to Alternaria Infection as Influenced by Varying Storage Temperature

Tomato fruits were stored at 27°C continuously or at temperatures of 35°, 18°, and 27°C for 3, 2, and 4 days, respectively, before inoculation with Alternaria solani. Following inoculation, fruits were ripened at 27°C for 6 days and evaluated for quality changes and response to infection. Decreased resistance occurred in fruits stored at varying temperature, resulting in significantly larger lesions. Surface color was not significantly affected by storage and inoculation. Firmness was only significantly affected in noninoculated fruits. The pH and titratable acidity improved significantly in control fruits. Total soluble solids was only different in noninoculated fruits. Reducing sugars were lower in inoculated fruits.     

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.     

Storage studies of mango packed using biodegradable chitosan film

The effect on the quality of mango fruits (Mangifera indica) during modified atmosphere packaging was investigated. The fruits were kept in carton boxes whose top surface was covered with either chitosan film or with low-density polyethylene (positive control) or kept as such (control) and stored at room temperature (27ǃ °C at 65% RH). The CO₂ and O₂ levels measured on day 3 were 23-26% and 3-6%, and at the end of the storage period they were 19-21% and 5-6%, respectively. Various quality parameters such as colour, chlorophyll, acidity, vitamin C, carotenoid and sugar contents were studied. The fruits stored as such had a shelf-life of 9ǃ days, whereas those stored in low-density polyethylene showed off-flavour due to fermentation and fungal growth on the stalk and around the fruits, and were partially spoiled. On the other hand, fruits stored in chitosan-covered boxes showed an extension of shelf-life of up to 18 days and without any microbial growth and off-flavour. Being biodegradable and ecofriendly, chitosan films are useful as an alternative to synthetic packaging films in the storage of freshly harvested mangoes.     

Shelf Life of Mature Green Tomatoes Stored in Controlled Atmosphere and High Humidity

Freshly harvested mature green tomatoes were washed, sorted and treated with 125 ppm chlorine water. The treated tomatoes were stored at 85% or 98% RH under controlled atmosphere (CA) storage for periods up to 8 wk. The controlled atmosphere was 2.5% O₂, 5.0% CO₂, and N₂ as the balance gas at 12°C. After storing 40 days, the tomatoes were allowed to ripen in air at 23°C. Samples of tomatoes were tested every 3 days to examine changes in quality as determined by visual observation, weight loss, titratable acidity, pH, color and firmness. Weight loss was reduced significantly by CA storage of tomatoes at 98% RH. Tomatoes remained green up to 40 days of storage and changed in color gradually during consecutive storage in atmospheric conditions. Appearance of the tomatoes was acceptable after ripening.     

Effect of cold‐shock treatment on chilling injury in mango (Mangifera indica L. cv. ‘Wacheng’) fruit

To investigate how cold shock may affect chilling injury in mango fruit (Mangifera indica L. cv. ‘Wacheng’), the fruit were treated for 3, 4 or 5 h at 0 °C, or treated for 8, 10 or 12 h at 4 °C, respectively, then transferred to 20 °C for 20 h prior to being stored at 2 °C, 85–95% RH. The chilling injury index of mango treated at 0 °C for 4 h was 59.7% lower than that of the control fruit directly stored at 2 °C, 85–95% RH. Some attributes were assayed in the fruit treated at 0 °C for 4 h. Ion leakage of the cold‐shock fruit at 0 °C for 4 h was 16% or 10% lower than that of the control on day 9 or day 12 of storage, respectively. Malondialdehyde content of the cold‐shocked fruit was 70% or 50% lower than that of the control on day 6 or day 12 of storage at 2 °C, respectively. Activities of catalase, ascorbate peroxidase, and contents of glutathione and phenolic compounds in the fruit during storage were all markedly enhanced by the cold‐shock treatment, whereas activities of superoxide dismutase, glutathione reductase and content of ascorbic acid in the mango were slightly influenced by the cold‐shock treatment. These results suggest that cold‐shock treatment may hold promise as an alternative approach to reduce chilling injury in mango fruit during cold storage. Copyright © 2006 Society of Chemical Industry