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Storage behaviour of 'Core', 'Core Columbu', 'Fradis' and 'Meloni' white prunes, and a black one ('Sighera') of Sardinian germplasm were evaluated following immersion for 0 (control), 15, 30, 45 or 60 sec in water at 20, 50, 55 or 60 degrees C with or without 2% (w/v) NaHCO3 (SBC). As international varieties, fruit from one white plum ('Shiro') and one black prune ('Stanly') were subjected to the same treatments. Fruit was harvested at commercial maturity, treated and then stored for 1 month at 5 degrees C and 90% RH followed by a simulated marketing period at 20 degrees C and 80% RH for 6 days. Fruit appearance, external damage, firmness and decay percentage were monitored after storage and SMP. Treatments did not induce rind damage (browning or discoloration) to any variety. SBC at 20, 45, 50 or 55 degrees C for 15 or 30 sec was not effective in controlling decay and compared to controls no improvement was observed. Immersion for 45 or 60 sec with SBC at all temperatures improved decay control with respect to controls and best results were obtained at 50 or 55 degrees C. Immersions at 60 degrees C improved decay control, but differences were not significant compared to the control attained with solutions of SBC heated at 55 degrees C. The overall appearance of 'Core', 'Core Columbu', 'Fradis' and 'Shiro' decreased significantly after the SMP period, especially when treated at 55 or 60 degrees C for 60 sec. Fruit shrivel was the main cause of the low rating. SBC did not affect shrivel indicating that heat treatment may be the probable cause. In general, local varieties were less affected by decay than other varieties and they performed well during stora

The influence of the immersion of lemon fruit in aqueous imazalil (IMZ) mixtures at 25 or 50 °C on the deposition and persistence of IMZ within the fruit rind and its effectiveness in controlling postharvest green mold, caused by Penicillium digitatum, was investigated. Concentrations of IMZ in the albedo tissue surrounding deep wounds in the rind were higher than the mean EC50 values for IMZ-resistant strains (1.0 ?g ·mL-1) after immersion of fruit into IMZ mixtures containing 25, 50, or 75 mg· L-1 heated to 50 °C, but not those at 25 °C, where fungicide deposition was insufficient. IMZ residue, one day after treatment with 25, 50, or 75 mg· L-1, was 3, 5, or 7 times higher after treatment at 50 °C compared to treatment at 25 °C. IMZ residues within the albedo of unwounded fruit treated with 25, 50, or 75 mg· L-1 at 50 °C were 0.8, 1.3, or 2.0 ?g · g-1, respectively, while those similarly treated at 25 °C had negligible residues. Residues following treatment at 50 °C in the albedo did not decline during storage at 10 °C after 60 days. IMZ residues in the flavedo were higher than those in the albedo: after treatment with 25, 50, or 75 mg· L-1 IMZ, they averaged 1.0, 1.2, or 2.7 ?g · g-1, respectively, after treatment at 25 °C, and 5.5, 7.9, or 16.2 ?g · g-1, respectively, after treatment at 50 °C. IMZ effectiveness as an eradicant to control green mold improved when it was heated. Green mold was reduced by 22 or 95% after treatment of lemons inoculated 1 h before immersion of lemons in IMZ at 50 mg· L-1 at 25 or 50 °C, respectively. Green mold was reduced by 18 or 61% after treatment of lemons inoculated 1 day after immersion of lemons in IMZ at 50 mg· L-1 at 25 or 50 °C, respectively. Scanning electron microscopy of the rind surface indicated that treatment at 50 °C for 2 min also caused ruptures in the cuticle.

The toxic activity of 2-deoxy-D-glucose (2-DG) alone or combined with the biocontrol yeast Candida saitoana strain 8C was evaluated in vitro and in vivo against the postharvest fungal pathogen Penicillium digitatum. In order to assess the effect of the 2-DG on both the biocontrol yeast and fungal pathogen, in vitro tests were performed in Petri dishes containing potato dextrose agar amended with different concentrations (1.5, 3.0, 6.0, 15.0, 30.0, 60.0 mM) of the sugar. The plates were then seeded with 25 microl of a P. digitatum conidial suspension at 10(5) conidia/mL. Result of the assays showed an enhanced inhibitory activity as concentration increased from 15.0 to 60.0 mM. Corroborated by SEM observations showing a reduced growth and the appearance of damaged hyphae were found. At 60 mM of 2-DG, a total inhibition occurred while concentrations from 1.5 to 6.0 mM resulted ineffective. The same tests evidenced no adverse effects on the yeast 8C at all tested concentrations. In vivo assays were carried out on orange fruit cv 'Biondo comune', wounded in 5 sites around the calyx. Each wound (2.5 wide and 3.4 mm depth) was first filled with 25 microl of a 0, 3.0, 6.0, 15.0, 30.0 or 60.0 mM 2-DG-water solution alone or combined with the yeast 8C at 10(8) cells/mL and then a 25 microl of the P. digitatum conidial suspension was added. Each treatment consisted of 3 replicates of 8 fruit (5 wounds/fruit) for a total 120 wounds per treatment. Oranges were maintained at 20 degrees C and high RH (95-98%) for up to 5 days, during which infection was monitored and the inhibitory activity calculated. The tests in vitro evedenced a significant slowing of the pathogen growth with the highest concentrations of 2-DG (15.0, 30.0 and 60.0 mM) with respect to the control; while at lower concentrations (1.5, 3.0, 6.0 mM) the development of the fungi was not significantly reduced. C. saitoana was resistant to all the doses employed to the abovementioned compound. In vivo the yeast alone was more effective compared to the sugar alone up to 6.0 mM while, at higher concentrations an additive effect was founded.

A method for the inclusion of imazalil (IMZ) in the ‚Beta-cyclodextrin (Beta‚CD), structural characterization of the inclusion complex and its antifungal activity against Penicillium digitatumand P. italicumassessed by in vitro and in vivo tests are reported. According to the starting stoichiometry of BetaCD with respect to IMZ, an equimolar ratio ‚Beta-cyclodextrin-IMZ (BetaCD-IMZ) was detected by 1H NMR. In vitro assays showed that the freshly prepared BetaCD-IMZ was as effective as IMZ, although 1- and 4-day-old BetaCD-IMZ mixtures were more effective. Studies on Star Ruby grapefruit showed no significant differences in residue uptake between treatments with an IMZ commercially available fungicide (Deccozil) or BetaCD-IMZ when equal active ingredient (a.i.) concentrations (250 mg/L) and dip temperatures (20 or 50 °C) were used. By contrast, treatments of Tarocco oranges and Di Massa lemons with 250 mg/L BetaCD-IMZ at 50 °C produced significant differences in residue uptake in comparison with 250 mg/L Deccozil treatments at 50 °C. The a.i. degradation rate in grapefruit during postquarantine and simulated marketing period (SMP) at 20 °C was not affected by the type of formulation used, whether at 20 or 50 °C. Conversely, IMZ in oranges and lemons had greater persistence when applied at 50 °C. All fungicide treatments showed a comparable efficacy against decay in grapefruit and oranges, whereas treatment in lemons at 250 mg/L a.i. of heated fungicides had higher suppressive effects against decay than unheated chemicals having equal a.i. concentrations and comparable activity at 1200 mg/L IMZ at 20 °C.

Among the alternatives to synthetic postharvest fungicides encouraging results have been reported with biocontrol agents, and on Citrus fruits, their efficacy was improved when co-applied with GRAS compounds or with physical means. Still, the reason for this increased efficacy has not been explained and therefore a study was performed using orange fruit (Citrus sinensis Osbec. cv 'Washington navel') as host, P. digitatum as the pathogen, a yeast (Pichia guiliermondii, isolate 5A) as the biocontrol agent, white 2% Na2CO3 (SC) and 1% CaCl2 were employed as GRAS compounds. When treatments were combined salts were applied sequentially, and SC preceded CaCl2 followed by the yeast. As a result of large scale trait with inoculated and un-inoculated fruit a clear beneficial interaction occurred when treatments were combined. SC exerted a direct fungistatic activity and an indirect one by inducing scoparone in host tissue. Also the isolate A5 induced the phytoalexin accumulation and when combined with SC a greater accumulation occurred within the first 7 days post-treatment. The application of CaCl2 alone had no effect on pathogenesis, while when combined with SC or with the yeast, decay was towered. The yeast growth on an amended medium was negatively affected by the addition of SC; while in vivo this effect was missing. The antagonist growth in vivo was enhanced when applied together with 1% CaCl2 also when applied with SC. The results reported improve our knowledge on the complex interactions among host, pathogen and the antagonist as affected by SC and CaCl2.

As a non destructive analysis method, Nuclear Magnetic Resonance Imaging (MRI) may provide helpful information on water movement and physiological effects of transpiration in senescing tissues. In the past decade, the use of MRI has provided a better understanding of some physiological disorders in horticultural product (e.g., internal breakdown) and on quality changes during storage. Here we report on MRI techniques used to study the movement of water into the rind (flavedo and albedo) following fruit immersion in hot water containing imazalil (IMZ). Pummelo hybrid (Citrus paradisi × Citrus grandis 'Oroblanco') was used to study in a completely non-invasive mode the water-IMZ motion and permeation within unwounded or wounded rind following immersion at 25 or 50°C for 2 min. Fruit was harvested in the experimental orchard, graded, rinsed in distilled water and wounded (3×3 mm; Ø, depth) in the equatorial area. The 2 min treatment was performed 30 min after wounding by immersing the fruit in the mixture at 25 or 50°C. Then, 'Oroblanco' fruit were gently surface wiped with a paper towel, marked (position reference for analysis) and immediately subjected to MRI. Twenty-four hours after immersion, measurements were repeated on the same fruit placed in the identical position based upon the position reference. Comparing resolved spatial information concerning the distribution of free-water, a clear and fast motion of the IMZ mixture into wounded rind occurred only with immersion at 50°C, and permeation in the neighbouring parenchyma cells took place within the subsequent 24h. In wounded fruit immersed at 25°C changes of free-water inside the wounds were insignificant and in unwounded fruit, no differences were found between the two immersion temperatures. From the results of MRI and the residue data it is likely that the fungicide in the albedo is acquired mainly at the time of treatment, while during storage permeation from the flavedo seems to be negligible, independently from the immersion temperature.

The keeping quality of three early ripening pear (Pyrus communis) cultivars, two belonging to the local biodiversity ('San Domenico' and 'San Giovanni Migliorata') and a National one ('Coscia') was evaluated, during the postharvest life, as affected by two hydrocooling temperatures. Fruit of 'S. Domenico' and 'S. Giovanni Migliorata' were harvested in the middle of June and 'Coscia' in July, when they reached their optimal stage for consumption and before the internal breakdown started in the local cultivars. Harvest took place in the morning, and then in the laboratory all fruit was heat conditioned until the core reached 25°C. One third of the fruit was immediately cold-stored for 7 days at 5°C and 95±2% RH followed by a 3 day simulated marketing period (SMP) at 17°C and 75% RH. Half of the remaining fruit was hydrocooled with water at 0°C to reach 5°C inside the fruit (HC-5C) and the other half to reach 2°C (HC-2C). Then, fruit was cold-stored as reported above. Both hydrocooling temperatures improved the keeping quality of the pears, during storage and SMP. Compared to the control fruit, pulp of hydrocooled fruit remained more firm and in 'Coscia', handling blemishes were less evident. During the SMP most of the fruit of local cultivars that were not hydrocooled became un-marketable due to the internal breakdown and in 'Coscia' to the development of molds. With both hydrocooling temperatures the internal breakdown was completely inhibited during the whole experiment in 'S. Giovanni Migliorata', while in 'S. Domenico' the internal breakdown started during the SMP when fruit was hydrocooled up to 5°C. The results evidenced a strong effect of hydrocooling on the delay of internal breakdown in local early ripening pear cultivars.

The activity of 2-deoxy-D-gLucose (2-DG) alone or in combination with a biocontrol yeast (Candida saitoana, strain 8C) was evaluated in vitro and in vivo against citrus green mould (Penicillium digitatum Sacc.). The in vitro assays were performed on amended potato dextrose agar (PDA) containing 0, 1.5, 3.0, 6.0, 15.0, 30.0 or 60.0 mM of 2-DG. P. digitatum conidia were sown on the amended media and growth inhibition occurred starting from 6.0 mM. A nearly total inhibition of the growth and spore germination occurred with 60.0 mM of 2-DG. The antagonist was not affected by any of the 2-DG concentrations employed and the amended plates resulted well colonized within 2 d post-treatment. In vivo assays were carried out with 'Hamlin' oranges, inoculated with P. digitatum 24 h before treating with: the antagonist; the above reported concentrations of 2-DG, or by combining the two treatments. Seven days post-treatment the inhibition activity exerted by 3.0, 6.0, 15.0, 30.0 and 60.0 mM of 2-DG combined with the yeast was 15, 37, 42, 63 and 84%, respectively. While that exerted by the antagonist was 22% and that by the different concentrations of 2-DG were 7, 11, 27, 42 and 57%, respectively. Compared to single treatments, the co-application significantly and in a synergic mode improved the control of decay. Alterations to the hyphae were observed by SEM when the pathogen was cultured on amended media and into the wounds of inoculated oranges.

Citrus fruit are susceptible to many postharvest diseases and disorders, but Penicillium digitatum and Penicillium italicum are the most common and serious pathogens during storage and marketing. The continuous employ in packing houses of synthetic fungicides such as imazalil (IMZ) or thiabendazote for the control of these pathogens is promoting the selection of resistant biotypes. These considerations together with an increased attention for human health and the environment have multiplied the studies on new ecological technologies. In recent years researchers studies focused on alternatives to the chemical control of post-harvest decay, such as the utilization of GRAS compounds as well as physical methods. In the present study is reported the sequential use of acetic acid (AAC) followed by curing. The lemon variety "Verna" and the orange variety "Jaffa", naturally inoculated, were treated with vapors of AAC performed at three different concentration (15, 25 and 50 ?L/L) for 15 minutes, after an incubation period of 24 hours at 27 °C and 90% relative humidity (RH). After treatments fruits were cured at 36 °C for 36 hours with 90% RH and subsequently stored at 8 °C and 90% of RH for eight weeks. Both citrus varieties were also treated with IMZ at a concentration of 200 mL/HL. At the end of the experiment decay and weight loss were evaluated. After 8 weeks of storage, in the lemon variety, the lowest percentage of infected wounds was 1.5% for both the fruit treated with IMZ or with AAC at 25 ?/L. Fruit treated with 15 ?L/L or untreated (control) showed similar results with 13.6% and 16.6% of rotted fruit respectively. Different results were obtained with the orange variety, in this case the synthetic fungicide was the most effective at the end of the storage period, with 18.0% of decay. AAC treatments were not as successful as on lemons, the best result was achieved even in this case with AAC performed at 25 ?L/L, but with 39.9% of decay. In both species the weight loss was not affected by the treatments. These results show that a good control of postharvest decay could be achieved, on lemon fruit, by combining the effect of a GRAS compound such as AAC with curing. Conversely the results obtained, by applying this control method to the orange variety were not so promising. Further researches are needed to shed light on the different behavior between the two species.

Storage behaviour of 'Core', 'Core Columbu', 'Fradis' and 'Meloni' white prunes, and a black one ('Sighera') of Sardinian germplasm were evaluated following immersion for 0 (control), 15, 30, 45 or 60 sec in water at 20, 50, 55 or 60 degrees C with or without 2% (w/v) NaHCO3 (SBC). As international varieties, fruit from one white plum ('Shiro') and one black prune ('Stanly') were subjected to the same treatments. Fruit was harvested at commercial maturity, treated and then stored for 1 month at 5 degrees C and 90% RH followed by a simulated marketing period at 20 degrees C and 80% RH for 6 days. Fruit appearance, external damage, firmness and decay percentage were monitored after storage and SMP. Treatments did not induce rind damage (browning or discoloration) to any variety. SBC at 20, 45, 50 or 55 degrees C for 15 or 30 sec was not effective in controlling decay and compared to controls no improvement was observed. Immersion for 45 or 60 sec with SBC at all temperatures improved decay control with respect to controls and best results were obtained at 50 or 55 degrees C. Immersions at 60 degrees C improved decay control, but differences were not significant compared to the control attained with solutions of SBC heated at 55 degrees C. The overall appearance of 'Core', 'Core Columbu', 'Fradis' and 'Shiro' decreased significantly after the SMP period, especially when treated at 55 or 60 degrees C for 60 sec. Fruit shrivel was the main cause of the low rating. SBC did not affect shrivel indicating that heat treatment may be the probable cause. In general, local varieties were less affected by decay than other varieties and they performed well during storage.

The trade of fresh fig fruit is restricted by its high perishability and numerous attempts have been done to extend the postharvest life. The main difficulties can be found in the fast ripening and the easiness of pathogen spread. Although the ripening can be slowed by low storage temperatures (close to 0 degrees C) the control of pathogens remains still unsolved since no pesticide treatments are allowed. Generally Recognized As Save Compounds (G.R.A.S.) are possible candidates to fulfil this void. Sodium carbonate (SC) solutions (0.5, 1, 2 and 3%) and acetic acid (AAC) vapours (25, 50 and 100 ppm) have been used as postharvest treatments to control Botrytis cinerea on black (Craxiou de Porcu) and white (Rampelina) fig varieties. Fruit was subsequently stored at 2 or 8 °C and 90% relative humidity for two weeks. At the end of the experiment decay, weight loss, pH, acidity, total soluble solids and visual assessment were performed. SC treatment at 1% reduced significantly the decay while, lower and higher concentrations did not. Between the two studied varieties the lowest decay percentage (9.8%) was found for the "Craxiou de Porcu". Using AAC a good efficacy was achieved only with 100 ppm, this treatment decrease to 2.4% the incidence of decay irrespective to storage temperature. Lower concentrations were lesser effective and the efficacy was strictly dependent on the storage temperature, being higher at 2 °C. No treatment damages were observed following SC or AAC applications. Regarding fruit weight loss all treatments did not affect this parameter that was 10.1% and 16.9% at 2 and 8 °C, respectively. Chemical analyses performed at the end of the storage period did not evidenced differences among the treatments and slight ones if compared to initial values. Visual score of the fruit at the end of storage evidenced a better keeping quality for "Craxiou de Porcu" especially when stored at 2 °C. Both G.R.A.S. compounds are promising, but in the reported experiments AAC was the most effective

The feasibility to restrain citrus green mould (Penicillium digitatum Sacc.) during storage, by means of induced natural resistance, was investigated following combined heat and ultravioLet light C (254 nm, UV-C) treatments. Heat treatment (HT) was performed by keeping Citrus fruits in a humid saturated room at 36 degrees C for 36 h while, the UV-C light treatment (254 nm) was carried out by illuminating the fruits with 3 or 6 kJm(-2). Physical treatments were sequential and reversely applied to un-inoculated or to 24 h-old inoculated lemons or oranges. Then, fruits were stored for 30 days at 8 or 5 degrees C with 95% relative humidity (RH) followed by a 6 day simulated marketing period at 20 degrees C and 75% RH. Constitutive (cuticle and epicuticular wax) and induced resistance (scoparone biosynthesis) were monitored and the variation in natural resistance was correlated to the decay development. HT influenced positively the constitutive factors of resistance by reducing or delaying cuticular cracking and by remodelling the epicuticular wax layer. Following HT the synthesis of scoparone took place only in the albedo of wounds and was greater when fruits were inoculated. Following UV-C illumination, scoparone accumulated rapidly in the outer rind (flavedo) but, particularly with 6 kJm(-2), favoured cuticular fracturing during storage. Sequential treatments resulted significantly more effective in controlling decay on either, inoculated and non inoculated fruit. The best control of green mould during storage of lemons and oranges was obtained when HT preceded 6 kJm(-2) UV-C illumination with 52 and 45% reduction of natural decay in fruit stored at 8 degrees C compared to the control, respectively.