Filippo M. Pirisi

Composition and Antimicrobial Properties of Sardinian Juniperus Essential Oils against Foodborne Pathogens and Spoilage Microorganisms

In this work, the chemical compositions and antimicrobial properties of Juniperus essential oils and of their main components were determined. Five berry essential oils obtained from different species of Juniperus growing wild in Sardinia were analyzed. The components of the essential oils were identified by gas chromatography-mass spectrometry (GC-MS) analysis. The antimicrobial activities of the oils and their components against food spoilage and pathogenic microorganisms were determined by a broth microdilution method. The GC-MS analysis showed a certain variability in the concentrations of the main constituents of the oils. Alpha-pinene was largely predominant in the oils of the species J. phoenicea subsp. turbinata and J. oxycedrus. Alpha-pinene and myrcene constituted the bulk (67.56%) of the essential oil of J. communis. Significant quantitative differences were observed for myrcene, delta-3-carene, and D-germacrene. The results of the antimicrobial assay show that the oils of J. communis and J. oxycedrus failed to inhibit any of the microorganisms at the highest concentrations tested (MLC > or = 900 microg/ml), while the oils extracted from J. turbinata specimens were active against fungi, particularly against a strain of Aspergillus flavus (an aflatoxin B1 producer). Of the single compounds tested, delta-3-carene was found to possess the broadest spectrum of activity and appeared to contribute significantly to the antifungal activity observed for J. turbinata oils. This activity may be helpful in the prevention of aflatoxin contamination for many foods.

Phenolic compounds in virgin olive oils I. Low-wavelength quantitative determination of complex phenols by high-performance liquid chromatography under isocratic elution

Abstract An HPLC method that allows the determination of complex phenolic compounds at low λ (225 nm) after solid-phase extraction from virgin olive oils is reported. The separation was achieved on ODS-2, ODS-1 and C8 columns in eluting mixtures 10−3 M H2SO4CH3CN employed with different ratios. The method was employed for the quantitative determination of phenolic compounds in oils. It allows the presence of some new unknown compounds to be shown. The preliminary spectroscopic data of these compounds, probably phenolic, are reported. The reactivity with protic solvents of the deacetoxy oleuropeine aglycon is discussed.

Simplified multiresidue method for the determination of organophosphorus insecticides in olive oil

Abstract A simple and rapid method for the determination of 13 organophosphorus insecticides and theie metabolites in olive oil by GC is described. The pesticide was extracted from oil with acetonitrile and no cleanup was needed. GC-nitrogen-phosphorus detection response factors of pesticides were affected by solvents and coextractive substances. Pesticides in hexane showed on average higher response factors. Standards were prepared in the residue-free oil extract solubilized in hexane to handle effects of matrix and solvent. The low amount of coextractive substances does not decrease the column efficiency, even after a few hundred analyses. Recovery at three fortification levels (ca. 0.1, 1.0 and 3.0 mg/kg) ranged from 74 to 118%, with coefficients of variation ranging from 1 to 16.

Antioxidant capacity and vasodilatory properties of Mediterranean food: The case of Cannonau wine, myrtle berries liqueur and strawberry-tree honey

The aim of this work was to use different assays to evaluate the antioxidant and vasodilatory properties of three typical food products from the Mediterranean area and to correlate these activities with their phenolic content. For this purpose, red wines Cannonau, liqueurs obtained by cold maceration of myrtle (Myrtus communis L.) berries and bitter honeys obtained from strawberry-tree flowers (Arbutus unedo L.) were analysed. The total phenolic (TP) content was measured spectrophotometrically with a modified Folin-Ciocalteau method and phenolic compounds were identified and dosed by HPLC-DAD and LC-MS/MS. Antioxidant activities were evaluated with DPPH, FRAP and ABTS assays and the in vitro vasodilatory effects were assessed using norepinephrine precontracted rat aortic rings. Cannonau wines and myrtle liqueurs showed high levels of TP (1978±279 and 1741±150mg GAE/L, respectively), linearly correlated to the results of FRAP, ABTS, and DPPH assays. Their maximal vasodilatory activity was 61.7±4.1% and 53.0±3.0%, respectively. Although strawberry-tree honey contained relatively high levels of phenolic compounds (922±38mg GAE/kg), it did not induce vasodilation, even at the highest dose tested (0.206g/L). These results indicate that foods with high levels of phenolic compounds should be studied using several different biological assays before being recommended to the general public as functional foods.

Fenhexamid residues in grapes and wine

The behaviour of the fungicide, fenhexamid, on grapes, and during wine-making, as well as its effect on the microflora of alcoholic and malolactic fermentation has been studied. After treatment, the residue on grapes decreased rapidly to one-third of the initial level after the first week, while it remained constant during the following two weeks. At harvest, in the wine obtained by vinification without skins, the fungicide residue decreased on average by 49%, while in the wine obtained by vinification with skins, the decrease was on average 62%. The presence of this fungicide on grapes and in the wine did not affect alcoholic and malolactic fermentation, nor did fermentation cause any degradation of the fungicide. A simple and rapid gas chromatograhic method (GC-NPD) for the determination of fenhexamid residues in grapes, must and wine is described.

Synthesis and Inhibitory Activity of 7-Geranoxycoumarin against Penicillium Species in Citrus Fruit.

Abstract A naturally occurring compound with strong antifungal activity was isolated from the flavedo tissue of “Star Ruby” grapefruits (Citrus paradisi) and identified as 7-geranoxycoumarin. A high yield strategy for its synthesis was found and its antifungal activity against Penicillium italicum and P. digitatum assessed by in vivo and in vitro test.

A gas chromatography-mass spectrometry-based metabolomic approach for the characterization of goat milk compared with cow milk

In this work, the polar metabolite pool of commercial caprine milk was studied by gas chromatography-mass spectrometry and multivariate statistical data analysis. Experimental data were compared with those of cow milk and the discriminant analysis correctly classified milk. By the same means, differences due to heat treatments (UHT or pasteurization) on milk samples were also investigated. Results of the 2 discriminant analyses were combined, with the aim of finding the discriminant metabolites unique for each class and shared by 2 classes. Valine and glycine were specific to goat milk, talose and malic acid to cow milk, and hydroxyglutaric acid to pasteurized samples. Glucose and fructose were shared by cow milk and UHT-treated samples, whereas ribose was shared by pasteurized and goat milk. Other discriminant variables were not attributed to specific metabolites. Furthermore, with the aim to reduce food fraud, the issue of adulteration of caprine milk by addition of cheaper bovine milk has been also addressed. To this goal, mixtures of goat and cow milk were prepared by adding the latter in a range from 0 to 100% (vol/vol) and studied by multivariate regression analysis. The error in the level of cow milk detectable was approximately 5%. These overall results demonstrated that, through the combined approach of gas chromatography-mass spectrometry and multivariate statistical data analysis, we were able to discriminate between milk typologies on the basis of their polar metabolite profiles and to propose a new analytical method to easily discover food fraud and to protect goat milk uniqueness. The use of appropriate visualization tools improved the interpretation of multivariate model results.

THE EFFECT OF SIMULATED RAIN ON FOLPET AND MANCOZEB RESIDUES ON GRAPES AND ON VINE LEAVES

Artificial rainfalls were used to determine the effect of the amount of the rainfall and the time interval between pesticide application and rainfall event, on folpet and mancozeb residues on grapes and vine leaves. Forty-five mm of rain were administered to the vineyard in different amounts (45; 30+15; + 15 15+15 mm). Folpet showed good rainfastness on the grapes and on the leaves. A modest decrease was observed only in the experiments that had received 45 mm of rain at one go. Mancozeb showed a lower rainfastness, since a portion of the deposit was easily washed off also by a modest rainfall. The percentage of this portion was higher in the grapes (38%) than in the leaves (20%). The data obtained in these experiments show that, in the case of folpet, it is not necessary to repeat the treatment when it rains the day after, while it is recommendable to repeat it in the case of mancozeb.

Residues of the fungicide famoxadone in grapes and its fate during wine production

Abstract Famoxadone is a recently applied fungicide to vines that belongs to the oxazolidinedione family. The fate of famoxadone was studied by considering the decay ratio of this fungicide during the maturation of grapes and wine production. The main factors affecting the presence of fungicide residues such as fruit growth, photodegradation, evaporation, thermodegradation and co-distillation were studied with model systems. An experimental field was treated with a commercial product containing famoxadone at the recommended dose. After this application, residues of famoxadone were found in grapes at 0.27 ± 0.06 mg kg–1. In this field experiment, the half-life (t 1/2;) of famoxadone, which is described by pseudo-first-order kinetics (R 2 = 0.74), was 18 ± 6 days, resulting from the photodegradation. The famoxadone residue levels in grapes were below the established maximum residues level for Europe (2 mg kg–1), whilst levels in wine, carried out with and without maceration, were below the calculated limit of detection of the method.

Analysis of the Essential Oil of Helichrysum italicum G.Don ssp. microphyllum (Willd) Nym.

Abstract The chemical composition of Sardinian dwarf curry plant (Helichrysum italicum G.Don ssp. microphyllum (Willd.) Nym.) essential oils was studied. Oil samples were isolated by water and steam distillation of flowering tops collected at different locations. The constituents of the oils were analyzed by GC/MS. Since both the chemical composition and physicochemical characteristics of the oils obtained during these trials were significantly different, they were divided into two groups. One oil was rich in nerol (10.7%), neryl acetate (28.9%), neryl propionate (11.4%) and γ-curcumene (11.4%), while the other was rich in linalool (14.9%) and γ-curcumene (18.2%).