EFFECT OF PHORONE ON ACCUMULATION AND FATTY ACID COMPOSITION OF SURFACE LIPID OF APPLE DURING STORAGE

Phorone added to apples after harvest stimulated the rate of accumulation of surface lipid and decreased the rate of water loss when fruit were stored at 0°C but had the opposite effect in fruit stored at 5, 10 or 20°C where lipid accumulation was inhibited and water loss enhanced. The fatty acid composition of surface lipid from phorone-treated fruit showed a higher proportion of linoleic acid at all temperatures. For oleic and linolenic acids, a differential effect of storage temperature occurred with phorone-treated fruit at 0°C developing a lower proportion of oleic acid and a higher proportion of linolenic acid compared to control fruit whereas at 5° and 20°C the reverse occurred.     

RIPENING AND QUALITY CHANGES IN MANGO FRUIT AS AFFECTED BY COATING WITH AN EDIBLE FILM

Mango fruit has a relatively short storage life of about 2 to 3 weeks at 13C. In order to prolong the storage life of ‘Haden’ mangoes, fruit were coated with 3 concentrations (8,16 and 24 g.L^?1) of the edible coating film “Semperfresh” and then stored at 13C and 85% RH. Fruit were then evaluated every 4 days for up to 32 days for total soluble solids (TSS), titratable acidity (TA), pH, firmness, weight loss, color of the skin, and ascorbic acid content. All 3 concentrations applied to the fruit affected fruit ripening. TA, firmness, and green color were higher in coated fruit, and weight loss, SST, and pH were lower compared with the noncoated fruit. “Semperfresh” had no effect on decay development. Ascorbic acid decreased in all stored fruit, but this decrease was slower in coated fruit, and there were no significant differences between the different “Semperfresh” concentrations.     

RESPONSE OF 1-METHYLCYCLOPROPENE TREATED "GRANNY SMITH" APPLE FRUIT TO AIR AND CONTROLLED ATMOSPHERE STORAGE CONDITIONS

ABSTRACT

In the study, the efficacy of 1‐Methylcyclopropene (1‐MCP) on the quality of apples cv. “Granny Smith” was examined. Fruits were stored for 120 and 180 days at 0 ± 0.5C and 90 ± 5% relative humidity (RH) under normal (NA) and controlled atmosphere (CA), and samples taken at 120 and 180 days of storage were kept at 20 ± 2C and 60 ± 5% RH for 7 days. Weight loss was higher in fruits stored under NA. The lowest respiration rates were in CA while the highest rates were found in NA‐stored fruits without pretreated. 1‐MCP + CA reduced the internal ethylene concentration from 10.63 µL/L to 0.60 µL. The incidence and severity of superficial scald was 68.10 and 77.00% in fruits stored in NA. 1‐MCP consistently suppressed the expression of superficial scald. 1‐MCP maintained the quality fruit kept in CA and NA environments to a higher degree than nontreated apples over a 180‐day storage period. The results indicated that cv. “Granny Smith” could be stored successfully under 1‐MCP + CA conditions and that 1‐MCP + NA may be a viable alternative to CA for optimal eating quality.

PRACTICAL APPLICATIONS

1‐Methylcyclopropene (1‐MCP) is an effective inhibitor of ethylene action and it binds irreversibly to ethylene receptors. 1‐MCP delays the onset of the climacteric ripening of fruits. Recently research has been conducted on the effects of 1‐MCP on postharvest behavior of fruits and vegetables with the objective of reducing physiological disorders and quality losses to prolong their commercial life. The use of 1‐MCP is easy. It is important that the fruit treated with 1‐MCP reach a good sensory quality at the commercial level. Superficial scald of apples is a physiological disorder, which following long‐term storage has the potential to destroy the market value and utility of millions of tons of fresh apples annually. The present work evaluated a prestorage conditioning treatment to protect against this physiological disorder. Results will allow the long storage of apple cv. “Granny Smith,” benefiting growers, exporters, shippers and distributors of this horticultural product.     

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     

Biocontrol of Postharvest Anthracnose of Mango Fruit with Debaryomyces Nepalensis and Effects on Storage Quality and Postharvest Physiology

Anthracnose is presently recognized as one of the most important postharvest disease of mango worldwide. To control the disease, chemical fungicides for a long time was widely used among fruit farmers, but recently found that pathogen had developed increasingly resistance to it. With people's growing desire of healthy and green food, finding new and environmentally friendly biological control approach was very necessary. In this paper, we provided a kind of new antagonistic yeast which enriched the strain resources and the efficacy of Debaryomyces nepalensis against postharvest anthracnose of mango fruit and the influence on quality parameters were investigated. The results showed that the decay incidence and lesion diameter of postharvest anthracnose of mango treated by D. nepalensis were significantly reduced compared with the control fruit stored at 25 °C for 30 d or at 15 °C for 40 d, and the higher concentration of D. nepalensis was, the better the efficacy of the biocontrol was. Study also found that 1 h was the best treatment duration and antagonistic yeast inoculated earlier had good biocontrol effect on anthracnose. Meanwhile, treatment by D. nepalensis could significantly reduce postharvest anthracnose of mango, delay the decrease in firmness, TSS, TA, and ascorbic acid value, and do not impair surface color during postharvest storage. Moreover, the increase in MDA (malondialdehyde) content and increase in cell membrane permeability of fruit treated by D. nepalensis was highly inhibited. The results suggested D. nepalensis treatment could not only maintain storage quality of mango fruit, but also decrease the decay incidence to anthracnose disease. All these results indicated that D. nepalensis has great potential for development of commercial formulations to control postharvest pathogens of mango fruit.     

MICROBIOLOGICAL AND CHEMICAL PROPERTIES OF IRRADIATED MANGO

Fourteen fungal species belonging to five genera , Aspergillus, Cladosporium, Penicillium, Fusarium and Scoplariopsis were isolated from the surface of mango fruits , (Mangifera indica L.) variety "Zebda". Mycotoxin production by isolated molds was tested in Czapek-Dox broth as well as mango pulp. The irradiation decimal reduction doses (D₁₀ values) of the molds were determined in either physiological saline solution or mango pulp. The effects of ionizing radiation in combination with hot water-dipping (55C/5 min) on shelf-life extension and the microbiological, chemical, rheological and organoleptic properties of mango fruit (at mature green stage) stored at 12°C and 80–85% relative humidity were determined. Results showed that Zebda mango irradiated with doses of 1.0 kGy can be stored 50 days at 12°C without any undesirable changes to measured nutrient and sensory quality when compared to unirradiated mangoes refrigerated for 25 days.     

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.     

BEHAVIOR OF LISTERIA MONOCYTOGENES AND ESCHERICHIA COLI O157:H7 IN FRESH-SLICED CACTUS-PEAR FRUIT

Storage experiments were conducted to follow the behavior of Listeria monocytogenes and Escherichia coli O157:H7, deliberately inoculated on fresh‐cut cactus‐pear fruits before packaging under modified and control atmosphere and stored at four different temperatures (4, 8, 12 and 20C). L. monocytogenes was able to proliferate during storage at different temperature both in control and modified atmosphere. By comparing the sanitary‐risk values with those of shelf life, it is possible to conclude that the storage of cactus‐pear samples at temperatures greater than 4C, both in control and in modified atmospheres, could lead to a significant health‐time risk, and that this is strictly affected by temperature. E. coli O157:H7 was able to proliferate only in the sample stored at 4 and 8C in both package atmospheres. On the contrary, this species was completely suppressed at the higher temperatures. In our study, E. coli O157:H7 appeared to be much less suited for survival on the surface of the fruit than L. monocytogenes.     

THE EFFECT OF ULTRAVIOLET IRRADIATION ON SHELF-LIFE AND RIPENING OF PEACHES AND APPLES

“Loring” and “Elberta” peaches and “Golden Delicious” apples were irradiated with UV (254nm) to doses of 0.84 × 10⁴ to 40 × 10⁴ erg/mm² then stored. “Loring” were stored 10 days and “Elberta” 20 days at 12°C. “Golden Delicious” were stored 30 days at 20–25°C in a dark room. Fruit were examined and differences in percentage rot and in physical-chemical properties determined. Percentage rot decreased with increasing UV dose. Fruit were firmer, pH and soluble solids lower and acidity higher for UV-treated than for nontreated peaches; pH was lower and acidity and ascorbic acid higher in UV treated than in nontreated apples. Percentage weight loss was less for UV-treated apples. The results indicated that UV treatment not only reduced storage rots but also delayed ripening of peaches and apples.     

ACCELERATED STORAGE, SHELF LIFE AND COLOR OF MANGO POWDER

Vacuum‐dried mango powder was produced from mango pulp through the addition of glycerol monostearate and tricalcium phosphate at 0.015 kg each per kg mango solids and maltodextrin at 0.62 kg per kg dry mango solids. The mango powder was packed in aluminum foil‐laminated pouches and stored in an accelerated storage environment maintained at 90% relative humidity (RH) and 38 ± 2C. The sticky‐point moisture content at 38 ± 2C was considered as the maximum moisture content to which the mango powder would remain stable. The shelf life of the powder predicted from this consideration and the Guggenheim‐Anderson‐de Boer (GAB) model for the water activity moisture content relationship was 114.68 days, whereas the actual shelf life was 105 days. The color change of the powder during storage followed first‐order reaction kinetics with a rate constant of 0.038 per day.     

THE STORAGE LIFE OF FRUITS AND VEGETABLES

Exponential curves have been fitted to published temperature/time/quality data for both fresh and frozen fruits and vegetables. The two constants in the exponential equation are used as measures of the relative storage life of the product and of its sensitivity to temperature change. Of these 2 constants, 1 is analogous to the “Q₁₀” value often used to express temperature sensitivity, but it is independent of actual temperature. The two constants are used to provide an index of “storability” of different fruits and vegetables and a tentative classification of produce according to this “storability” is presented. Fitting curves to temperature/time/quality data also allows prediction of the effects on storage life of fluctuating product temperatures, such as are experienced during normal transport and storage.     

ETHYLENE CAPSULE PROMOTES EARLY RIPENING OF 'd'ANJOU' PEARS PACKED IN MODIFIED ATMOSPHERE BAGS

‘d'Anjou’ pears (Pyrus communis, L.) harvested commercially with flesh firmness of 64.5 N were incapable of ripening normally at 20C within 60 days of air storage at ‐1C (denoted as “under‐chilled” fruits). When under‐chilled ‘d'Anjou’ fruits (8 fruits, total fruit weight of 1.8 kg) were packed in a 3.8‐liter perforated bag inserted with an ethylene capsule, fruit would ripen normally at 20C. The ethylene concentration in the packed bag maintained no less than 100 ppm after 4 days at 20C, and declined to about 25 ppm on day 7. Regardless of the storage length, ripened fruit induced by the ethylene capsule developed high buttery and juicy texture. If ‘d’ Anjou’ fruit had been stored at ‐1C for less than 30 days, ripened fruit lacked high flavor quality. Flavor quality of ripened fruit improved rapidly when the fruit had been stored for longer than 30 days.     

Optimum Postmortem Chilled Storage Temperature for Summer and Winter Acclimated, Rested, Chinook Salmon (Oncorhynchus tshawytscha) White Muscle

Chemical anaesthesia (AQUI‐S^TM) was used to harvest 2 groups of tank‐reared chinook salmon (Oncorhynchus tshawytscha), naturally acclimated to summer (18.8 °C) and winter (10.7 and 12.4 °C) temperatures, in a “rested”state. Carcasses were stored in 35% seawater at temperatures between approximately 2 and 19 °C to investigate the effects of acclimation and storage temperature on the postmortem metabolic rate of rested epaxial white muscle tissue. Muscle pH, [lactate], and adenosine triphosphate/inosine monophosphate measurements made 20 h postharvest indicated that winter acclimated fish were 2.2 times more sensitive to temperature than summer fish. A 3^rd group of winter acclimated fish, stored between –1.2 and 6 °C, indicated that significant cold injury only occurred on freezing.     

PROLONGING THE SHELF-LIFE OF FRESH GREEN CHILE PEPPERS THROUGH MODIFIED ATMOSPHERE PACKAGING AND LOW TEMPERATURE STORAGE

The postharvest quality of green chile fruit was compared after storage in 3 types of packages at 2 temperatures (24C and 8C). Package types were corrugated cardboard boxes, pressed cardboard trays overwrapped with VF-71 polyethylene, or low-density polyethylene (LDPE) bags. Fruit packaged in boxes or overwrapped trays had 24.8% and 10.1% weight loss, respectively, after 1 week of storage at 24C. Fruit packaged in polyethylene bags lost 0.3% weight and remained green. After 1 week at 8C, the weight losses were 3.8%, 1.8% and 0% for the boxed, overwrapped and bagged treatments, respectively. Postharvest quality was maintained up to 4 weeks when fruit were packaged in LDPE bags and stored at 8C. In a second study, steady state O₂ and CO₂ levels were determined inside the LDPE packages as fruit weight and temperature were varied. Storage temperatures were 24C, 16C and 8C. At 8C, steady state O₂ levels ranged from 12.0 kPa to 0.9 kPa, and CO₂ levels ranged from 2.0 kPa to 4.6 kPa as fruit weight was increased from 120 to 480 g. At 24C and 16C, fruit packaged in 480 g units had slower ripening rates than fruit packaged in smaller units; however, fruit stored at 8C remained green the longest, regardless of fruit weight.     

EFFECT OF WAX APPLICATION ON THE QUALITY,LYCOPENE CONTENT AND CHILLING INJURY OF TOMATO FRUIT

ABSTRACT

Waxed and nonwaxed mature green tomato fruits were stored at 12C (nonchilled) or 5C (chilled) for 5, 10, 15 and 20 days before being transferred to 22C for 3, 6, 9 and 12 days, were evaluated for weight loss, chemical composition, skin color, chilling injury (CI) index and pigment content. Waxed fruits showed a delay in weight loss, color development and ripening. The sensitivity of tomato fruit to CI was reduced in waxed fruits, which showed a delay in the appearance of symptoms. A delay in chlorophyll degradation and lycopene synthesis was observed as a result of the use of wax and low temperature. Waxing of tomato fruits allowed their storage at temperatures below critical reducing CI sensitivity and maintaining quality giving more time for marketing.

PRACTICAL APPLICATIONS

Nowadays, local tomato producers use wax on fruits as an everyday practice to carry postharvest fungicides and to improve brightness. They store tomato fruits at nonchilling temperature (12C) because lower temperatures would cause chilling injury and irregular ripening. In this way, it is interesting that waxing tomato fruits allow reducing their storage temperature, protecting them from chilling injury and maintaining their quality and correct color change and ripening; thereby producers and sellers have more days to position their fruits with no extra cost.     

ISOLATION and CHARACTERIZATION of MANGO PEEL PECTINS

An efficient method for manufacture of pectin from Totapuri mango peels was standardized by studying various factors that govern the recovery and quality of pectin. Among the different organic and inorganic acids, 0.05 N HCl was found to be the best for recovery of pectin from mango peels. Optimum yield of pectin was obtained by taking two extractions each for one-hour duration employing a peel: extractant ratio of 1:2 and by alcohol precipitation method. Dried mango peels could be stored for six months at ambient conditions (14.5–33.9C) without any significant effect on the recovery of pectin. Pectin extract, an intermediate product in the manufacture of pectin, could be stored for one month either at low temperature (6C±2) or at ambient conditions (24.5–33.0C) by the addition of 700 ppm SO₂ with minimum loss in the recovery of pectin. Using the optimum extracting conditions about 20.8% (DWB) of purified pectin was obtained from mango peels. the powdered pectin could be stored for over 6 months without any deterioration in quality when packed in airtight containers at ambient conditions.     

Mango film coated for fresh‐cut mango in modified atmosphere packaging

Mango puree is known to have good oxygen barrier properties. Therefore, mango film on its own might be useful to extend the shelf life of fresh‐cut mango. In this study, fresh‐cut mango was wrapped with mango film and packed in modified atmosphere packaging (MAP). Each package was stored at 30 °C or 5 °C and sensory evaluation was performed to determine its quality and shelf life. The shelf life of uncoated and coated fresh‐cut mango pieces was 6 days for each at 5 °C and was 3 and 4 days, respectively, at 30 °C. The sensory evaluation indicated that coated fresh‐cut mango was slower to produce an off‐flavour and maintained better visual quality than uncoated mango at 30 °C. Nonetheless, coated fresh‐cut mango was softer than uncoated mango because of the hydrophilic nature of the mango film. No significant difference in the oxygen and carbon dioxide concentrations was observed between coated and uncoated fresh‐cut mango. Coating fresh‐cut mango with mango film showed a similar effect to MAP in prolonging the shelf life of the fresh produce. The use of the coating will enhance fruit quality and lead to better acceptance by consumers.     

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.     

EFFECTS OF SHRINK FILM WRAP ON INTERNAL GAS CONCENTRATIONS, CHILLING INJURY, AND RIPENING OF HONEYDEW MELONS

Honeydew muskmelons (Cucumis melo L.) were individually wrapped with polyvinyl chloride (PVC) shrink film and stored at 2.5° or 7.5 °C for 21 days and examined, then held an additional 2 or 3 days at 20°C and examined again. Nonwrapped melons were the control. The concentration of CO₂ in the cavity of wrapped melons stored 21 days was 5.6% at 2.5°C, 9.1% at 7.5°C, but only 1.1% and 1.5% in the nonwrapped held at 2.5°C or 7.5°C, respectively. Wrapped fruit ripened slower than nonwrapped fruit during storage and subsequent holding at 20°C, after which time 70% of the wrapped melons were rated eating ripe, but 62% of the controls were overripe. Wrapped melons exhibited 30% less chilling injury (CI) symptoms than nonwrapped fruit stored at 2.5°C. The CI symptoms ranged from reddish-brown to dark-brown surface discolorations and sometimes included dry sunken areas of skin. Fresh weight loss was about 1 % in wrapped melons, but 5% in nonwrapped fruit, regardless of storage temperature. Decay incidence was about equal in wrapped and nonwrapped melons after storage at 2.5°C, but was greater for wrapped than nonwrapped melons after storage at 7.5°C. Soluble solids content was about 12.5% in wrapped and nonwrapped melons stored at either temperature.