Untreated Control Fruit Research Articles

Effect of ethrel spray on the ripening behaviour of mango (Mangifera indica L.) variety 'Dashehari'

An experiment was carried out to investigate the effect of post harvest spray of different concentrations (100, 200, 400, 600 and 800 ppm) of ethrel (2-chloroethyl phosphonic acid) on ripening and colour development in ‘Dashehari’ mango fruits harvested in second week of June, 2015. The treated fruits were assessed for physico-chemical parameters such as physiological loss in weight (%), firmness (Kg/cm2), TSS (°Brix), titrable acidity (%), total carotenoids (mg/100g) and peel chlorophyll (mg/100g) and observations were recorded at 2 days interval during 8 days storage at ambient temperature. Changes in total soluble solids (8.5 to 23.23° Brix), total carotenoids (0.807 to 7.12 mg/100g) and PLW (14.58%) showed increasing trends up to 8 days during storage whereas fruit firmness (8.5 to 0.68 Kg/cm2), titrable acidity (1.26 to 0.08%) and total peel chlorophyll (5.2 to 0.14 mg/100g) showed decreasing trends. At the end of the storage period for 8 days, Ethrel spray at 600 ppm induced uniform ripening with attractive yellow colour within 4 days while untreated control fruits failed to ripen uniformly and remain light green even after 8 days of storage. Ripening advances by 4 days in fruits sprayed with 600 ppm ethrel com-pared to unsprayed control fruits.

Effect of Vector Control and Foliar Nutrition on the Quality of Orange Juice Affected by Huanglongbing: Sensory Evaluation

A 3-year study was undertaken to establish the effect of field nutritional sprays, combined with insecticide treatments or not against Asian Citrus psyllid, on the fruit quality of ‘Valencia’ orange trees affected by the greening disease Huanglongbing (HLB). Four replicated plots were harvested, juiced, and pasteurized. Nine to twelve trained panelists evaluated the juice using seven flavor, five taste, four mouthfeel and three aftertaste descriptors. There was little difference between treatments in 2013; only orange peel flavor and bitterness were significantly lower for the insecticide treatment. In 2014, positive attributes, such as orange and fruity flavor, sweetness and mouthfeel body, were significantly higher in the insecticide treatment. Sourness was highest in untreated control, and there were no differences between treatments for bitterness. In 2015, negative attributes, such as grapefruit, orange peel and typical HLB flavor, sourness, bitterness, and astringency, were significantly higher in untreated control fruit, suggesting perhaps that the beneficial effect of nutritional and insecticide treatments was cumulative, only manifesting on the 3rd year of the study, and or because of the progression of the disease affecting untreated controls. Data are discussed in relation to juice chemical composition, including volatiles, sugars, acids, limonoids, and flavonoids, adding to the fundamental knowledge concerning chemical drivers of orange flavor.

Ultrasonic fog application of organic acids delays postharvest decay in red bayberry

Red bayberry (Morella rubra Lour.) has attractive fruit with appealing flavour and global market potential. However, its fresh fruit are highly susceptible to mechanical damage and postharvest fungal decay. The objective of the current study was to assess the efficacy of weak organic acids in delaying decay when applied to the fruit as an ultrasonic fog. Preliminary screening identified genotypes with acceptable postharvest longevity for use in the experiments. Fruit of genotype N1MR06 that received a 1h ultrasonic fog treatment with acetic acid exhibited a significantly (P<0.05) lower decay incidence of 18% after 10 d at 5°C as compared with 70% for untreated control fruit. However, the decay incidence in fruit treated with citric acid (55%) did not significantly (P>0.05) differ from the control. Subsequent experiments using fruit of genotypes N1MR06 and N1MR09 confirmed that ultrasonic fogging with acetic acid was an effective measure for delaying postharvest decay in red bayberry. Sensory evaluation along with total soluble solids and titratable acidity measurements showed that the acetic acid treatment had no adverse effect on the organoleptic quality of red bayberry. Overall, the study determined that genotype selection has an impact on red bayberry shelf life and that further shelf life gains can be achieved through ultrasonic fogging of safe, natural and inexpensive acetic acid.

In vitro and In vivo Antifungal Activity of Culture Filtrates and Organic Extracts of Penicillium sp. and Gliocladium spp. against Botrytis cinerea

Eight isolates of Penicillium sp. and two isolates of Gliocladium spp. were tested in vitro and in vivo for their inhibitory effects against Botrytis cinerea, causal agent of tomato fruit grey mold. The biocontrol essays conducted in vitro revealed that the culture filtrates of the isolates tested have significantly reduced the mycelial growth of the pathogen. The filtrates of the isolate CH6 of Penicillium sp. applied at different concentrations (10, 15 and 20% v/v), was most effective in reducing B. cinerea colony diameter. The ethyl acetate and chloroform extracts of the isolates CH6 of Penicillium sp., Gc1 of G. catenulatum and Gv1 of G. virens have shown an inhibitory effect of the pathogen radial growth, at the concentrations used (1, 2.5 and 5% v/v). In addition to the reduction of the mycelial growth of B. cinerea, these antagonistic agents have induced important morphological alterations to the mycelium of the pathogen. These antagonists were applied to tomato fruits 2 hours before their inoculation with the pathogen. Tested as culture filtrates, the most effective isolates CH11 and MC1 of Penicillium sp. and Gv1 of G. virens had significantly reduced the severity of the disease compared to the inoculated and untreated control fruits. Similar effects were recorded using the ethyl acetate and chloroform extracts of the tested antagonists; those of CH6 and CH5 of Penicillium sp. and Gc1 of G. catenulatum were found to be the most effective in reducing severity grey mold. Thus, this study showed the presence of bioactive molecules in the culture filtrates of the antagonistic agents used and also allowed the selection of effective isolates for grey mold disease control.

Physico-Chemical changes in pear fruits in response to post harvest applications of oxalic acid

To study the effect of oxalic acid (OA) on storage behaviour of ‘Nijisseiki ’pear, fruits were dipped in aqueous solutions of oxalic acid @ 2, 4 and 6 m mol L−1 for 4–5 mins. Treated as well as untreated (control) fruits were packed in corrugated fibre board (CFB) boxes and stored at low temperature conditions (0–1°C and 90–95% RH) for 70 days. Fruits were analyzed for various physical and chemical changes after 30, 50 and 70 days of storage. Oxalic acid treatments were found effective in decreasing physiological loss in weight (PLW), spoilage and maintained the fruit firmness, sensory quality, total soluble solids (TSS), titratable acidity (TA), total sugars content and pectin methyl esterase (PME) activity as compared to control fruits under cold storage conditions. Postharvest application of oxalic acid delayed the ripening process of fruits. Among all the treatments, oxalic acid @ 6mmolL-1 was most effective in retaining postharvest quality and reducing physio-chemical losses of pear fruits. From the present investigations, it can be inferred that oxalic acid treatment could be a promising way for extending the shelf life of pear under low temperature conditions.

Physico-chemical and enzymatic changes in peach (Prunus persica (L.) Batsch) fruit in response to sodium salts during low temperature storage

‘Shan-i-Punjab’ is a leading cultivar of peach (Prunus persica (L.) Batsch) in Punjab. After harvesting peach fruits cannot be stored for a longer period under ambient conditions. To prolong the post-harvest life of fruits, an experiment was conducted during the year 2014. Physiological mature fruits of peach cv. Shan-i-Punjab were harvested and subjected to various post-harvest dip treatments viz. sodium bicarbonate (@ 0.5 and 1%), sodium benzoate (@ 0.5 and 1%) for 5 mins. Treated and untreated (control) fruits were packed in Corrugated fibre board CFB boxes and kept under low temperature storage conditions (0-10 C and 90-95% RH) for 6 weeks. Stored fruits were analyzed for various physico-chemical characteristics after 2, 4, 5 and 6 weeks of storage. Fruits treated with 0.5% sodium bicarbonate showed better results in terms low PLW (5.05%), high palatability rating (7.66), TSS (11.26%), acidity (0.70%) and PME activity (1.28 ml of 0.02N NaOH used) upto 4 weeks of storage as compared to control. It can be concluded that peach fruits of the cultivar Shan-i-Punjab treated with sodium bicarbonate @ 0.5% can be safely stored upto 4 weeks with acceptable quality under low temperature conditions.

Xylem, phloem, and transpiration flows in developing sweet cherry fruit

Flow in the phloem increased in developing sweet cherry, whereas xylem flow continuously decreased resulting in a fruit water potential that was independent from the tree at fruit maturity. Rain cracking of sweet cherry fruit is associated with water uptake through the skin, but probably also through the vasculature of the pedicel. The aim of this study was to quantify the xylem, phloem, and transpiration contributions to the overall water balance of developing sweet cherry fruit. Using linear variable displacement transducers, changes in fruit diameter were monitored in untreated control fruit, fruit whose pedicels had been steam-girdled, and fruit whose pedicels had been cut through (these fruits were detached, but remained in situ in the canopy). Fruit volume changes with time were inferred from the measured diameter changes. Pedicel xylem and phloem sap-flow rates, and fruit transpiration rates, were inferred from fruit volume changes. Daily phloem flows were low during stage II (phase of pit development), but markedly increased in stage III (phase of cell enlargement in flesh). Xylem flows exceeded phloem flows in stage II, but decreased continuously in stage III to nearly zero at harvest. Transpiration flow essentially mirrored xylem flow in stage II, but exceeded xylem flow in stage III. Transpiration flow was closely related to the water vapour pressure deficit. Phloem flow was linearly related to the increase in fruit dry mass per-unit time. The data reveal a decrease in xylem sap flow throughout stage III resulting in a water-potential isolation of the mature fruit from the tree. Such isolation would prevent uncontrolled osmotic uptake of xylem water by the sugary flesh and a putative backflow in the xylem from fruit to tree.

Uses of an innovative ethylene-α-cyclodextrin inclusion complex powder for ripening of mango fruit

A novel ethylene-α-cyclodextrin (α-CD) inclusion complex (IC) powder was investigated to ripen Calypso mango fruit. Modulated release of ethylene gas from the IC powder was achieved by admixture with deliquescent salt CaCl2 at RHs of 75.5% and 93.6%. The IC powder was tested in the laboratory and for in-transit ripening of mango fruit over two seasons. In the laboratory experiment, ethylene gas started to release from the IC powder in 2h and complete release was achieved in 24h. Assessments of fruit colour and firmness showed that encapsulated ethylene and commercial grade ethylene from pressurised cylinder similarly shortened the ripening time to 9–10 days (after harvest) for treated fruit as compared with 15 days for untreated mango. Mango fruit treated in both ways with ethylene showed more uniform ripening than the control. For the in-transit ripening using the IC powder, ethylene was found to be between 4.9 and 10.5μLL−1 in the headspace of the truck containers over 48h. Mango fruit from the treated containers shortened the ripening time by 3–6 days as compared to the untreated control fruit. Thus, the safe and convenient IC powder has demonstrated promise for in-transit fruit ripening.

A LIQUID FORMULATION FOR BIOLOGICAL CONTROL OF ANTHRACNOSE IN RAMBUTAN

The anthracnose pathogen Colletotrichum gloeosporioides, is a major cause of postharvest loss of rambutan in Sri Lanka. Results of our investigation demonstrated antagonistic activity of Trichoderma asperellum against a rambutan isolate of C. gloeosporioides. The antagonistic activity was mainly due to coil formation around the pathogen hyphae by T. asperellum. Fungicidal activity was observed when rambutan fruit inoculated with 105 conidia/ml of C. gloeosporioides, were treated with the formulation containing spores of T. asperellum within 10 and 30 min after inoculation. Treated fruit were observed to be free of disease when stored at 28±2°C for 7 days. Fruit treated with the control formulation (formulation without conidia) and untreated control fruit showed characteristic symptoms of anthracnose disease. Anthracnose symptoms were also observed on fruit that were inoculated with C. gloeosporioides and held as inoculated controls under similar storage conditions. Chemical parameters including pH and titratable acidity among treated, untreated (controls) and fruit treated with the control formulation showed no significant differences. The formulation was observed to be effective when stored at ambient temperature of 28±2°C for a period of up to 6 months. The data suggest that a formulation of T. asperellum might be an alternate, eco-friendly method for the control of anthracnose disease of rambutan.

Combining an antagonistic yeast with harpin treatment to control postharvest decay of kiwifruit

Integrated management, utilizing different non-chemical methods, is an approach to controlling postharvest losses that is being actively investigated. In the present study, the use of an antagonistic yeast, Candida diversa, combined with harpin (a hypersensitive response elicitor) treatment was evaluated for their ability to prevent infection of kiwifruit after they were artificially inoculated with Botrytis cinerea or Penicillium expansum. Natural infection of treated fruit was also assessed. As a standalone treatment, C. diversa or harpin significantly reduced gray (B. cinerea) and blue mold (P. expansum) infections on kiwifruit, relative to the untreated control fruit, and also reduced the level of natural infection. The combination of C. diversa and harpin treatment, however, provided a superior level of control on fruit, relative to either treatment alone. Harpin did not negatively impact C. diversa growth in kiwifruit wounds. Treatment of kiwifruit with C. diversa and harpin alone or in combination also induced the activity of enzymes involved in defense response, such as polyphenol oxidase, peroxidase and superoxide dismutase. Harpin alone or in combination with C. diversa enhanced accumulation of lignin content in kiwifruit as well. The mode of action by which harpin enhanced biocontrol efficacy of C. diversa may be partially attributed to the elicitation of defense response in kiwifruit. Integrating the use of antagonistic yeast with harpin treatment has potential as an effective method for the control of postharvest decay in kiwifruit.

Lysophosphatidylethanolamine (LPE) Improves Fruit Size, Color, Quality and Phytochemical Contents of Sweet Cherry c.v. ‘0900 Ziraat’

Lysophosphatidylethanolamine (LPE) affects the quality of flowers, fruits, and other horticultural products. Studies have provided evidence that LPE can accelerate ripening of fruits and prolong shelf-life at the same time. In this study, the influence of LPE on anthocyanin accumulation and phytochemical characteristics of sweet cherry was investigated. LPE (10 ㎎·L -1 ) was applied to a commercial sweet cherry c.v. ‘0900 Ziraat’ orchard two and four weeks before harvest for two treatment years (2011 and 2012). Preharvest applications of LPE resulted in significant improvement in both pomological and phytochemical attributes at harvest. LPE treatment led to a 17% increase in fruit weight and a 6% increase in soluble solid content when averaged over two experimental years. Fruit phytochemical content and antioxidant capacity were increased significantly. The average total phenolic content of LPE-treated fruits for the two years was 703 ㎍ gallic acid equivalent (GAE)/g fresh weight (g FW) compared to 569 ㎍ GAE/g FW in the untreated control. Fruits treated with LPE had a 27% and 16% more anthocyanin than the control fruits in 2011 and 2012. Antioxidant capacity of fruits, as measured by TEAC (Trolox equivalent antioxidant capacity) assay, was 12.5 and 11.4 μ㏖ TE/g FW in LPE-treated and untreated control fruits, respectively, when averaged over two experimental years. Our results suggest that preharvest application of LPE may have the potential to increase anthocyanin accumulation, improve fruit quality and enhance phytochemical characteristics of sweet cherries.

EFFECT OF EDIBLE COATING ON ASCORBIC ACID, BETALAINS, ORGANIC ACIDS, SUGAR, POLYPHENOL CONTENT AND ANTIOXIDANT ACTIVITY IN MINIMALLY PROCESSED CACTUS PEAR (OPUNTIA FICUS-INDICA)

The quality and nutraceutical traits of minimally processed cactus pear fruits were investigated after application of the following edible coatings: “Food coat” (composed of fatty acids derivatives and polysaccharides in alcohol solution) and “Pomfresh” (composed of a mixture of organic acids and antioxidant compounds). Fruit were manually peeled, dipped for 3 s in water emulsions containing each coating alone or in combination and placed on a sterile adsorbent material, in number of three, inside easy-to-open polylactic acid (a biodegradable polymer) tray. Fruits were stored at 4°C and inspected after 4, 8 or 12 days. Concentration of ascorbic acid, polyphenol, indicaxanthin and antioxidant activity were positively affected by “Pomfresh”, in contrast “Food coat” both applied alone or in combination with “Pomfresh” increased fruit degradation rate. Both coatings did not significantly affect in-package gas composition with respect to untreated control fruit: in-package CO2 partial pressure amongst treatments ranged between 4.8 and 5.7 kPa, while in-package O2 partial pressure never dropped below 14 kPa. Taste and firmness were little affected by treatments and showed that control fruit and those treated with Pomfresh coating alone were better than the other treatments. Results indicate that “Pomfresh” could be applied as edible coating to preserve the nutraceutical traits and prolong the shelf life of minimally processed cactus pear fruit.

Benzyladenine and gibberellin treatment of developing "Pink Lady" apples results in mature fruits with a thicker cuticle comprising clusters of epidermal cells.

A mixture of 6-benzyladenine (BA) and gibberellins GA4 plus GA7 applied to "Pink Lady" apple at early phenological stages was previously shown to result in an immediate increase in epidermal cell density and associated reduction in calyx-end cracking disorder in the mature fruit, implying a long-term effect of the BA + GA4+7 mixture. Here, we analyzed the anatomical changes in the mature peel at the calyx end 210days after full bloom (DAFB), following application of the plant growth regulators (PGRs) at the cell-division phase of fruit development, 21-50 DAFB. Experiments were conducted in northern Israel, and the PGRs were applied as the commercial formulation Superlon™ (Fine Agrochemicals Ltd.), composed of 19gl(-1) BA and 19gl(-1) GA4+7. Trees were sprayed with 0.025, 0.1, or 0.2% (v/v) Superlon™. The most obvious phenomenon was the presence of epidermal cell clusters within the cuticular matrix that were detached from the native epidermal layer located at the bottom of the cuticle and which could not be detected in the untreated control fruits. Treatment with 20mgl(-1) BA + GA4+7 (0.1% Superlon™) resulted in a markedly thicker cuticle, a higher percentage of detached epidermal cells within the cuticular membrane and a significant reduction in calyx-end cracking at harvest. The presence of cuticle-embedded epidermal cell clusters may have contributed to strengthening the peel by adding more cell-wall components, thickening the cuticle layer and possibly enhancing crack repair.

Late-season Surface Water Induces Skin Spot in Apple

Skin spot is a commercially important disorder of the fruit skin of ‘Elstar’ apples (Malus ×domestica Borkh.). The disorder is characterized by patches of small brownish dots (“skin spots”) that usually appear on the skin after fruit are removed from storage. Water-induced cuticular microcracks are implicated in the etiology of skin spot. The objectives of our study were 1) to establish the effect of surface wetness on the severity of skin spot; and 2) to identify possible relationships between meteorological records of rainfall over a number of seasons and the severity of skin spot in those seasons. Surface wetness treatments were imposed on fruit using overhead sprinklers installed above trees grown under a plastic rain shelter. During early fruit development [14 to 44 days after full bloom (DAFB)], surface wetness did not affect the severity of skin spot. However, during the later part of the growing season (greater than 44 DAFB), increased surface wetness increased the incidence and severity of skin spot and also the severity of cuticular microcracking. Most skin spots and microcracks were already present at harvest before storage, but skin spots and microcracking did increase slightly during subsequent controlled atmosphere (CA) storage. Over a 9-year period, the severity of skin spot in ‘Elstar’ apples grown and stored locally under standard orchard and storage conditions was positively correlated to the number of rainy days. This correlation was greater for the period between 1 Aug. to harvest than for periods 1 June to harvest or 1 July to harvest. Fruit treated with 1-methylcyclopropene (1-MCP) were more susceptible to skin spot than untreated control fruit. Calculating regression equations for the relationship between the severity of skin spot and the number of rainy days (period 1 Aug. and harvest) revealed that the (commercially important) threshold score for skin spot of 2 is predicted to occur after 44 rainy days for control fruit and after 34 rainy days for 1-MCP-treated fruit. Our data demonstrate that skin spot arises from cuticular microcracks, which in turn result from numerous exposures to surface wetness (rain, dew), especially those occurring during later stages of fruit development.

Effect of ethylene and temperature conditioning on sensory attributes and chemical composition of ‘Bartlett’ pears

‘Bartlett’ pears are resistant to ripening after harvest. Ethylene and temperature conditioning have been successfully used to stimulate fruit ripening with improved eating quality over non-conditioned fruit. However, few studies have evaluated the effect of different conditioning treatments on the sensory attributes of the fruit. In this study, we compared a descriptive sensory evaluation with the chemical composition of ‘Bartlett’ pears after the fruit were exposed to the following conditioning treatments: 2d 100μlL−1 ethylene, 14 or 7d at 0°C, 7 or 3d at 10°C, or untreated control at 20°C. Fruit were softened to 27, 18 and 9N firmness before evaluation. At 9N, fruit conditioned at 0°C produced high levels of esters, and fruit conditioned at 0°C for 14d also were high in sweet taste and fruity flavor attributes. Fruit treated at 10°C had lower concentrations of esters, but fruit treated at 10°C for 3d was high in sweet taste perception. Ethylene treated fruit produced low levels of esters and high levels of aldehydes and were associated with apple aroma, similar to the untreated control fruit. Water soluble pectin levels were highly and positively correlated with juiciness and sweetness and negatively correlated with firmness, crunchiness, and grittiness. Future studies should determine whether consumer liking of ‘Bartlett’ pear fruit is also influenced by conditioning treatment.

Preharvest calcium chloride sprays affect ripening of Eksotika II’papaya fruits during cold storage

The effects of preharvest application of calcium chloride on ripening, activity patterns of pectin modifying enzymes and overall quality of papaya (Carica papaya L. cv. ‘Eksotika II’) fruits have been investigated. Foliar sprays of 0, 0.5%, 1%, 1.5% and 2% (w/v) calcium chloride were applied six times during the growing season. After harvest, fruits were stored at 12°C for up to three weeks. Higher calcium concentrations in the sprays coincided with increasing calcium concentrations in peel and pulp tissues, higher firmness and titratable acidity, and reduced respiration rate, ethylene production and soluble solids concentrations, compared with those of the untreated control fruits. The overall quality of fruits treated with calcium was greater than the control fruits. Also, fruits sprayed with calcium had decreased activities of polygalacturonase (PG) and pectin methyl esterase (PME) during storage. Microscopic results confirmed that the middle lamallae of cell walls was more intact in calcium chloride-treated fruits.

PREVENTION OF SWEET CHERRY FRUIT CRACKING USING SURESEAL, AN ORGANIC BIOFILM

Rain-induced fruit cracking in sweet cherries can be a major problem. In the Pacific Northwest United States, due to high labor costs, when fruit cracking exceeds 25% at harvest, fruit are not picked. Oregon State University Horticulture and Pharmacy Faculty have collaborated in producing and patenting a novel, elastic, organic biofilm, SureSeal, which significantly reduced sweet cherry fruit cracking by up to 250% in Milton Freewater, Oregon and Loftus, Norway. Formulations of SureSeal are hydrophobic and consist of a copolymer of complex carbohydrates, phospholipids and calcium. Collaborative research undertaken over three years throughout the Pacific Northwest and overseas found that two applications of 1% SureSeal applied at straw color, and again ten days later, reduced fruit cracking con-sistently when compared to untreated control fruit. In Norway, fruit cracking was reduced from 24.6 to 9.8% when trees were treated with SureSeal in combination with plastic ground covers and a preharvest fungicide (fenhexamid). Furthermore, studies throughout Oregon and Idaho found that SureSeal resulted in significantly (P<0.001) higher total soluble solids (TSS) and increased Stem Pull Force (g) (retention force between the pedicel and the fruit) than untreated control fruit. In 2008, ‘Bing’ fruit had higher TSS both before (18.5°Brix) and after (18.9°Brix) two weeks of regular atmosphere storage at 2°C than untreated control fruit (17.4 and 17.2°Brix, respectively). In Norway, 1% Biofilm increased TSS to 21.4°Brix compared to untreated control fruit (18.6°Brix). Two applications of 1% Biofilm applied at straw color and again ten days later has the potential to significantly reduce fruit cracking, accelerate maturity by significantly increasing TSS levels, and increase stem pull force. The concurrent reduction in fruit firmness observed may be a function of maturity but, in all instances, fruit firmness still exceeded the minimum standard of 250 g mm-1.

Foliar application of calcium plus boron reduces the incidence of sunburn in ‘Golden Delicious’ apple

SummaryLosses of apple fruit due to sunburn damage under South African climatic conditions can reach up to 40% per annum for specific cultivars in certain years. Various approaches to reduce the incidence and severity of sunburn resulted in temporary effects but, at present, no single remedy is available to provide a significant and consistent reduction in sunburn damage on a commercial scale. ‘Golden Delicious’ apple trees that received both calcium (Ca) and boron (B) as foliar applications on a weekly basis, when applied from approx. 21 – 70 d after full bloom (DAFB), showed significantly less sunburn in two consecutive seasons (P = 0.0500 and P = 0.0247 respectively) than untreated control fruit, or treatments based on Ca alone. The minerals were applied as supplements of sugar-alcohol complexed with Ca and B, trading as Manni-Plex® Ca [10% (w/w) Ca] and Manni-Plex® B [3.3% (w/w) B], respectively. The mode of action by which the incidence of sunburn was reduced using combined sprays of Manni-Plex® Ca plus Manni-Plex® B remains to be elucidated.

Low oxygen pre-storage treatment is effective in reducing chilling injuries of deciduous fruit

Apple and pear fruits stored at low temperatures may suffer from chilling injury symptoms, caused by oxidative stress. Application of a low-oxygen (LO2) atmosphere (0.5%) for 10 d at 20°C or 500 ppb 1-methylcyclopropene (1-MCP) at 20°C for 24 h, prior to cold storage at 0°C, were equally effective in reducing superficial scald on ‘Granny Smith’ apples, after six months of cold storage at 0°C plus seven days at 20°C. Compared to untreated control fruit, the LO2 and 1-MCP-treated fruit produced less ethylene, a-farnesene and its oxidation product, 6-methyl-5-hepten-2-one (MHO), as determined by SPME/GC-MS technique. In addition, LO2 pretreatment applied to Californian ‘Bartlett’ or Israeli ‘Spadona’ pears, was effective in reducing superficial scald, senescent scald and internal breakdown, after 4–4.5 months of cold storage at –1°C or 0°C, respectively, plus five to seven days at 20°C. We assume that LO2 and 1-MCP pretreated fruit remained free of physiological disorders, due to the reduced production of ethylene and the oxidation product MHO during cold storage.

Effects of ozone on major antioxidants and microbial populations of fresh-cut papaya

The problems that are usually associated with fresh-cut commodities are the rapid depletion of nutritional value and the presence of high microbial populations. Ozone is a strong oxidant that can elicit physiological, chemical and microbial changes in fresh produce. Therefore, fresh-cut papaya was treated with ozone (9.2±0.2μl/L) at 10, 20 and 30min to investigate its effect on phytochemicals and microbial load. Following a 20min ozone treatment, the total phenolic content of fresh-cut papaya increased by 10.3% while the ascorbic acid content decreased by 2.3% compared to that of untreated control fruit. Also, gaseous ozone reduced microbial counts being more effective on coliforms (0.39–1.12log10CFU/g) than on mesophilic (0.22–0.33log10CFU/g) bacteria. The results suggest that microbial populations on fresh-cut papaya can be reduced without depleting its major antioxidants except for ascorbic acid when subjected to 9.2±0.2μl/L gaseous ozone for 20min.