Applicazione dell'MRI ai prodotti agroalimentari: analisi del profilo dell'acqua durante la conservazione

In questo lavoro, un modello di diffusione basato su legge del Fick secondo è stato usato per simulare il trasporto dell'acqua in pere in varie condizioni (20° C e RH di 75%; 1°C e RH di 60%). Il metodo degli elementi finiti è stato usato per la definizione delle equazioni differenziali che modellano il comportamento dell’acqua applicato alla geometria 3D della pera. Per la prima volta, il trasporto dell'acqua nella pera di cultivar Conference è stato descritto al livello della mesoscala incorporando i differenti tessuti ( corteccia, interna ed esterna, e cuticola) con differenti proprietà di diffusione

Functionalization of Screen-Printed Sensors with a High Reactivity Carbonaceous Material for Ascorbic Acid Detection in Fresh-Cut Fruit with Low Vitamin C Content

In this study, carbon screen-printed sensors (C-SPEs) were functionalized with a high reactivity carbonaceous material (HRCM) to measure the ascorbic acid (AA) concentration in fresh-cut fruit (i.e., watermelon and apple) with a low content of vitamin C. HRCM and the functionalized working electrodes (WEs) were characterized by SEM and TEM. The increases in the electroactive area and in the diffusion of AA molecules towards the WE surface were evaluated by cyclic voltammetry (CV) and chronoamperometry. The performance of HRCM-SPEs were evaluated by CV and constant potential amperometry compared with the non-functionalized C-SPEs and MW-SPEs nanostructured with multi-walled carbon nanotubes. The results indicated that SPEs functionalized with 5 mg/mL of HRCM and 10 mg/mL of MWCNTs had the best performances. HRCM and MWCNTs increased the electroactive area by 1.2 and 1.4 times, respectively, whereas, after functionalization, the AA diffusion rate towards the electrode surface increased by an order of 10. The calibration slopes of HRCM and MWCNTs improved from 1.9 to 3.7 times, thus reducing the LOD of C-SPE from 0.55 to 0.15 and 0.28 μM, respectively. Finally, the functionalization of the SPEs proved to be indispensable for determining the AA concentration in the watermelon and apple samples

Effect of different pretreatments on drying of green table olives (<i>Ascolana tenera</i> var.)

Mature green olives (Olea europea L.) were dried in a forced air oven at 50°C, after being subject 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 hot brine (50°C) followed by 32 hours dehydration. The latter product reached 20% residual humidity and did not rotted for one year

An Integrated Caco-2TC7cells/biosensors Device for the Real Time Monitoring of Intestinal Glucose and Polyphenols Absorption and Hypoglycemic Effect of Phytochemicals

Abstract An integrated device, for real-time monitoring of glucose and phenols absorption, that consists of a sensors/biosensors system (SB) and a Caco-2TC7 human intestinal cell culture, is shown here. The SB was made of a glucose oxidase-based biosensor, a sentinel platinum sensor, a laccase/tyrosinase-based biosensor and a sentinel carbon sensor located in the basolateral compartment (BC) of a cell culture plate. This system was able to monitor the glucose absorption and the hypoglycemic effect induced by different polyphenols and could be proposed to provide an effective strategy to manage postprandial hyperglycemia with natural compounds

Effectiveness of <i>Thymus capitatus</i> aerosol application at subatmospheric pressure to control green mold on "avana" mandarin fruit

A trial was carried out to compare the effectiveness of Thymus capitatus essential oil and thiabendazole (TBZ) on postharvest disease control of cv. "Avana" mandarin fruit. Fruits were sprayed with a 106 conidia/ml suspension of Penicillium digitatum and exposed to subatmospheric pressure (0.8 bar) in 250 litre containers. After 24 hours, atmospheric pressure was re-estabilished and fruits were stored at 8°C, 90 % R.H. While TBZ was used as a 1000 ppm water suspension before applying subatmospheric pressure, T. capitatus essential oil was fumigated as an ethanolic solution (20 ppm) immediately after. Fruits sprayed and treated with T. capitatus vapour compared to those sprayed, not treated, at subatmospheric pressure showed a 30.1 % reduction in green mold, while TBZ application gave a 39.1 % reduction. Thymus capitatus essential oil caused no injury in flavedo of ripe fruits. In vitro assays showed the minimum inhibiting concentration (MIC) and fungicide rate were 100 and 200 ppm respectively, for PDA cultures and wounded peels, both inoculated with 10 μl of a 106 conidia/ml suspension of P. digitatum

The Use of <i>Thymus capitatus</i> essential oil under vacuum conditions to control <i>Penicillium digitatum</i> development on citrus fruit

Lemon and satsuma fruit were sprayed with a 105 spore solution of Penicillium digitatum Sacc. and placed in 10-liter jars at constant temperature (20°C). Vacuum (10-1 bar) was created and the essential oil of Thymus capitatus was applied by aerosol at 5 different concentrations (50, 100, 200, and 300 μl/10lt) in order to delay P. digitatum development. Viability of P. digitatum spores was checked 24 hours after treatment by plating 100 ml of fruit rinse water on Petri dishes. Penicillium growth was observed in 80% of the dishes containing untreated fruit rinse water. A significantly lower percentage of growth (10% with 300 ml/10lt) was observed in dishes containing rinse water from treated fruit

Potential use of seed morpho-colourimetric analysis for Sardinian apple cultivar characterisation

Linear discriminant analysis (LDA) of morpho-colourimetric features, obtained through scanned images of apple (Malus domestica Borhk.) seeds from 25 Sardinian native cultivars, was employed to validate this approach as an easy and fast method to discriminate apple cultivars. Digital images of seeds were acquired using a flatbed scanner that measured 154 morpho-colourimetric features using ImageJ software. The data were used to build a database and statistically processed by LDA in order to identify and investigate phenotypic characteristics of apple cultivars. Afterwards, LDA of the database was used to investigate skin colour differences according to the apple variety colour descriptors established by the International Union for the Protection of New Varieties of Plants (UPOV) and the International Board for Plant Genetic Resources (IBPGR). The results evidence that by LDA it is possible to classify apple cultivars and highlight the presence of three possible synonymy groups. Moreover, when considering skin colour, LDA correctly classified a high percentage of both ground and over colour, as described by the IBPGR; in particular, using LDA it was possible to correctly identify 90.5% and 93.5% of green-yellow and red apple groups, respectively. The results of this investigation prove that image analysis of apple seeds is a valuable approach to study and characterise cultivars, as well as to identify important trade characteristics of fruit, such as skin colour, resulting in a useful tool for early selection of fruit characteristics in breeding programmes

Reducing decay of Avana mandarin fruit by the use of UV, heat and thiabendazole treatments

The use of heat and UV treatments on "Avana" mandarin fruit are shown to be promising alternatives for postharvest treatments. Heat delayed fruit softening and quality was better at the end of storage. Thiabendazole treatment imparted the lowest percentage decay, but was not significantly different from the percentage decay in the heat treated fruit. The weight loss was the highest in the thiabendazole treated fruit. External appearance was negatively influenced by the UV treatment leanding to a loss in quality, while decay was significantly less than in the non-treated fruit

Rooting of <i>Opuntia ficus</i>-indica Mill. young cladodes

The results of rooting tests with young shoots of the 'Gialla' prickly pear cultivar (Opuntia ficus-indica Mill.) are reported. The growth regulators IAA, IBA and NAA at concentrations of 100 and 200 ppm were tested. The young cladodes were cut in June, July and August 1989, soaked in one of the growth regulator solutions, and planted in pots for four months. The cladodes cut in June showed the lowest survival rate. Samples treated with NAA showed the best performance in the number of roots and their weight per cladode