Influence of Blackberry Plants on the Aroma Profile of Vitis vinifera L. cv. Pinot Noir

V. vinifera cv. Pinot noir vines were grown in pots together with blackberry plants and the effect of this association on the grape aroma was assessed. Preliminary data showed that vines that cohabited with blackberry had a different aroma profile compared to vine grown alone. The association with blackberry increased the concentration of 30 out 74 free aroma compounds and of 24 out 95 bound ones. No aroma compound was identified exclusively in the treated grapes

Relationships between volatile compounds and sensory characteristics in virgin olive oil by analytical and chemometric approaches

BACKGROUND: The volatile fraction of virgin olive oil is characterised by low molecular weight compounds that vaporise at room temperature. In order to obtain an aroma profile similar to natural olfactory perception, the composition of the volatile compounds was determined by applying dynamic headspace gas chromatography, performed at room temperature, with a cryogenic trap directly connected to a gas chromatograph\u2013mass spectrometer system. Samples were also evaluated according to European Union and International Olive Council official methods for sensory evaluation. In this paper, the composition of the volatile fraction of 25 extra virgin olive oils fromdifferent regions of Italywas analysed and some preliminary considerations on relationships between chemical composition of volatile fraction and sensory characteristics are reported. RESULTS: Forty-two compounds were identified bymeans of the particular analytical technique used. All the analysed samples, classified as extra virgin by the panel test, never present peaks whose magnitude is important enough in defected oils. The study was focused on the evaluation of volatile compounds responsible for the positive impact on olive odour properties (\u2018green\u2013fruity\u2019 and \u2018sweet\u2019) and olfactory perception. CONCLUSION: Chemometric evaluation of data, obtained through headspace analysis and the panel test evaluation, showed a correlation between chemical compounds and sensory properties. On the basis of the results, the positive attributes of virgin olive oil are divided into two separated groups: sweet types or green types. Sixteen volatile compounds with known positive impact on odour properties were extracted and identified. In particular, eight compounds seem correlated with sweet properties whereas the green sensation appears to be correlated with eight other different substances. The content of the compounds at six carbon atoms proves to be very important in defining positive attributes of extra virgin olive oils and sensory evaluation

Prediction of bulk milk fatty acid composition based on farming practices collected through on-farm surveys

International audience; The aim of this study was to predict the fatty acid (FA) composition of bulk milk using data describing farming practices collected via on-farm surveys. The FA composition of 1,248 bulk cow milk samples and the related farming practices were collected from 20 experiments led in 10 different European countries at 44 degrees N to 60 degrees N latitude and sea level to 2,000 m altitude. Farming practice-based FA predictions [coefficient of determination (R-2) >0.50] were good for C16:0, C17:0, saturated FA, polyunsaturated FA, and odd-chain FA, and very good (R-2 >= 0.60) for trans-11 C18:1, trans-10 + trans-11 C18:1, cis-9,trans-11 conjugated linoleic acid, total trans FA, C18:3n-3, n-6:n-3 ratio, and branched-chain FA. Fatty acids were predicted by cow diet composition and by the altitude at which milk was produced, whereas animal-related factors (i.e., lactation stage, breed, milk yield, and proportion of primiparous cows in the herd) were not significant in any of the models. Proportion of fresh herbage in the cow diet was the main predictor, with the highest effect in almost all FA models. However, models built solely on conserved forage-derived samples gave good predictions for odd-chain FA, branched-chain FA, trans-10 C18:1 and C18:3n-3 (R-2 >= 0.46, 0.54, 0.52, and 0.70, respectively). These prediction models could offer farmers a valuable tool to help improve the nutritional quality of the milk they produce

Effect of raw milk sonication on volatile compounds production

Introduction Among new technologies used to improve milk sanitization and shelf life, the treatment with ultrasounds (US) showed positive effects on bacterial inactivation, although it resulted responsible of some changes on milk sensory properties. The aim of this study was to evaluate the influence of different sonication parameters on volatile compounds production. Methods Ten combination of US wave amplitude (A: 70, 100%) and treatment duration (D: 0 (control), 50, 100, 200 and 300s) were applied to raw milk using a 400W ultrasonic processor, mounted with a 22 mm diameter horn. Solid-phase microextraction (SPME) was performed with a 100 \ub5m Polydimethylsiloxane (PDMS) fibre and GC/MS analysis of volatile compounds adsorbed onto the SPME fibre was carried out taking into account spectra from M/Z 29 to M/Z 500. The experiment was replicated twice and three determinations were carried out per replicate. Data were subjected to analysis of variance using the software PAWS Statistic 18.0. Results Given that the detector response factor for each compound was not determined, the amounts of the 34 volatiles detected are only semi-quantitative and will be therefore used only to discriminate the treatments. Among detected substances, 10 belonged only to sonicated milk, while 13 showed significantly different concentrations (P<0.05) according to the treatment. Discussion Sonication led to changes in the composition of volatile compounds and in particular to the increase of several esters, ketones and aldehydes that could be responsible of milk organoleptic modification. Compounds such as nonanal, n-octyl ether and 2-nonanone increased in concentration with duration of sonication treatment, while the others showed non linear variations. The increment of nonanal, that is formed only in the auto-oxidation of oleic acid, suggests that sonication favours lipid oxidation, probably through the free radical mechanism. Further research is needed to predict sensory properties from volatiles composition

Rapid dioxin-like polychlorinated biphenyls (DL-PCBs) and hexachlorobenzene (HCB) determination in fish by HPLC-GC-MS negative chemical ionization mode

The correct identification and quantification of mono-ortho and coplanar congeners allows the attribution of the WHO-TEFs (Van den Berg et al., 1998) and to calculate the TEQs. A rapid analytical method for PCBs and hexachlorobenzene determination was tuned. Briefly it consisted of: a) sample previously lyophilized was submitted in a ratio 1/10 (w/v) to solvent fat extraction (hexane/acetone, 50/50 v/v); b) the fat recovered was diluted 1/5 with 13C HCB and PCBs isotopes; c) to remove fat and other source of interference, HPLC pre-separation was achieved using a silica column and a three way valve; d) the GC separation was conducted by on-column injection into ZB5MS column (Zebron, 60 m, 0.25 mm i.d., 0.25 \u3bcm film thickness) while detection operated in negative chemical ionization SIM mode using methane as reagent gas. As regard quality analysis percent recovery was nearly 100%, repeatability was <10% (as relative standard deviation) and LOQ was 0.2 pg g-1 (w.w.). Farm reared and wild fish, coming from several areas of Mediterranean Sea, were analyzed. The sum of total DL-PCBs ranged from 0.22 to 6.33 ng g-1 (w.w.) for farm reared fish and from 0.04 to 12.96 ng g-1 (w.w.) for wild fish

Impiego di una metodologia analitica rapida e sensibile (HPLC/ECD) per la determinazione dei bifenili policlorurati (PCBs) nel pesce. Risultati preliminari

Milk and cheese production is a typical activity of several mountain areas with economic and historical implications. The guarantee of hygienic and sanitary traits is mandatory for legislative reasons and for the survive of this kind of food maker. E. coli and S. aureus are two powerfull indicator of hygienic and sanitary conditions respectively. Milk, Morlacco and Asiago allevo cheeses made in eight different places in the mountains areas of the province of Vicenza were submitted to microbiological and molecular analysis. Half of places investigated by plate analysis evidenced counts of S. aureus quite high, both in milk and cheese. The same result were confirmed by molecular analysis; the finding of enterotoxin A gene determinant was positive in the case of only one colony on 101 tested; the application of RAPD-PCR afforded to distinguish the same positive strain from all the others