Search

Sintesi delle attività di ricerca svolte nel primo anno di attività dalle sedi di Bari, Lecce e Sassari nell'ambito degli OR 2-A: Utilizzo della diversità genetica di specie agrarie per l'adattamento ai cambiamenti climatici e - OR4 - A: Strategie innovative di adattamento ai cambiamenti globali.

Mature green olives (Olea europea L.) were dried in a forced air oven at 50ºC, after being subjected alternatively to four different pre-treatments. Results indicate the possibility to obtain bitter-free and high quality olives by combining a ten minutes dip in a 10 % hot brine (50ºC) followed by a 32 hours dehydration. The latter product reached 20 % of residual humidity and did not rotted for one year.Se han deshidratado aceitunas verdes de mesa en horno a temperatura de 50ºC tras ser sometidas, alternativamente, a cuatro pretratamientos diferentes para ayudar a su desecación. Los resultados mostraron que es posible obtener aceitunas exentas de amargor y de alta calidad combinando su inmersión en salmuera caliente (50ºC), a una concentración del 10 % en NaCl durante 10 minutos, seguida de una deshidratación durante 32 horas. Las aceitunas deshidratadas alcanzaron una humedad residual del 20 % y no manifestaron signos de putrefacción en un año.

Nell'ottica di valorizzare la biodiversità autoctone frutticola, non più come materiale genetico per la propagazione ma come fonte di salute, sono state avviate delle indagini per stabilire le proprietà funzionali delle accessioni di pero, melo e susino. Si riportano i risultati più interessanti al fine di promuovere l'interesse per la coltivazione e il consumo di 'vecchie varietà. Al fine di diversificare la commercializzazione sono stati esposti anche alcuni prodotti trasformati ottenuti con le susine autoctone.

Il germoplasma del susino (25 accessioni) presente presso il campo collezione sito ad Oristano (ISPA-CNR) è stato parzialmente caratterizzato dal punto di vista chimico-nutrizionale. Oltre ai parametri standard della qualità (acidità, pH, solidi solubili totali) sono state quantificati i contenuti di alcune classi chimiche caratterizzanti le proprietà funzionali quali: flavonoidi, polifenoli totali ed antociani (di cui è stato parzialmente determinato il profilo), contenuto vitaminico e la capacità antiossidante. Alla raccolta, il pH di tutte le accessioni era superiore a 3.0 ed inferiore a 4.0, l'acidità titolabile tra 0.4 e 1.1 (% acido malico) e i solidi solubili totali tra 14.4 e 19.5 °Brix. Nelle varietà pigmentate i fenoli totali erano presenti in prevalenza nell'esocarpo (tra 87 e 93% del totale) e raggiungevano i 550 mg di GAE per 100g di peso fresco (PF), mentre nelle accessioni chiare i valori erano decisamente più bassi (117 - 213 mg GAE per 100g di PF). L'acido ascorbico era presente in tracce e lo studio del profilo degli antociani ha evidenziato che l'antociano principale in tutte le varietà è la Cianidina 3-glucoside, seguito dalla Cianidina 3-rutinoside e dalla Cianidina 3-galactoside. La Delfinidina 3-rutinoside è quello meno rappresentato in tutte le accessioni e altri antociani di cui è tuttora in corso l'identificazione sono presenti in tracce. Tra le accessioni chiare la 'Meloni' è risultata quella con il più alto contenuto in fenoli e flavonoidi totali ed una attività antiossidante di 2.16 mmol/100g peso fresco (TAEC). Nella varietà 'Perdigone' il contenuto in polifenoli totali è risultato particolarmente elevato (545 mg di GAE/100g) nettamente superiore ai valori riportati in letteratura. In base ai risultati conseguiti sono state individuate alcune accessioni di particolare interesse su cui proseguiranno le indagini allo scopo di caratterizzare le classi chimica con proprietà funzionali e valutarene utilizzo nella preparazione di integratori alimentari.

Nella maggior parte delle accessioni di pere autoctone il contenuto in polifenoli totali risulta superiore ai valori riportati in letteratura e così anche l'attività antiossidante. Tali caratteristiche sono risultate molto importanti dal punto di vista funzionale in quanto il loro utilizzo ha protetto in vivo cellule epiteliali da stress ossidativi indotti artificialmente.

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.

Fresh fruits and vegetables had both an important nutrition-health and an economic value. According to the new dietary guidelines, fresh fruit and vegetables were at the fundament of the nutritional pyramid and were, within our global food package, the best carriers of bio-active substances such as vitamins, minerals, dietary fibres, phenolic antioxidants, glucosinolates and other bioactive components. The main objective of this Action was to enhance and preserve fruit quality, safety and the amount of nutritional and functional components in fresh fruits and vegetables in an integrated approach from orchard to consumer with special attention to organic growing.

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.

Treatments as hot water dips or high temperature conditioning have been proven to be effective to control postharvest decay on various horticultural crops. These treatments reduce chilling injury and rot losses without causing detrimental effects on fruit firmness, flavour, taste or peel appearance. These technologies, aimed to control postharvest pathogens, can be easily matched with the use of "Generally Recognized as Safe" (G.R.A.S.) compounds and employed alternatively to pesticides, known to be harmful to health and environment. In this respect we studied the combined effect of sodium carbonate (SC) and hot water on the storability of black fig fruit cultivar 'Niedda Longa' of Sardinian germplasm. Second crop fig fruit, harvested in the middle of September, was dipped for one minute in water solutions containing 0, 0.05, 0.5, and 1% (w/v) of SC at 25 or 60 degrees C and then stored at 5 degrees C and 90% relative humidity (RH) for two weeks. After one and two weeks of storage decay, weight loss were monitored and visual assessment was scored. Treatments with hot solutions were more effective in controlling decay compared to cold ones and the best results were achieved with 0.5% of SC at 60 degrees C. This combination reduced the decay rate from 26% (control) to 0% after 1 week and from 50% to 14% after two weeks of storage, respectively. Lower or higher SC concentrations applied at 60 degrees C were less effective and, after two weeks of storage, decay percentages were 38 and 43.6%, respectively. Water dip at 60 degrees C did not affect the weight loss as compared to dips at 25 degrees C either after one or two weeks of storage. At the same time, a significant reduction was found only with 1% of SC at 25 degrees C. The fruit treated with 0.5% of SC at 60 degrees C also had the best visual assessment up to two weeks of storage.

The combination of the yeast Candida oleophila strain '13L' with ultraviolet-C irradiation evidenced a synergistic effect in reducing A digitatum mould and only 11% of the artificially inoculated wounds were infected. Adversely, when the bacteria Bacillus subtilis strain 'B160' was combined with ultraviolet-C irradiation no synergistic effect was achieved. By using only yeast, bacteria or ultraviolet-C treatments the decay percentage was reduced by 79.6, 55 and 75%, respectively. The phytoalexin scoparone accumulation was high in all treatments where UV-C was applied but the highest values were found when combined with the yeast. Population growth of bacteria in vivo was halved when fruit was irradiated, whereas direct irradiation of bacteria did not affect their growth in vitro. An inhibitory effect of the phytoalexin toward the bacteria is suggested as the reason for the growth inhibition in vivo when the bacterial treatment was combined with UV-C irradiation.