1,721,135 research outputs found
Suscettibilità alla fotossidazione del formaggio DOP Asiago d’allevo vecchio. Risultati preliminari
No full textGli alimenti sono potenzialmente esposti all’azione degradativa della luce durante tutta la loro vita commerciale. I fenomeni foto-ossidativi causano lo scadimento organolettico del prodotto, la perdita del valore nutrizionale e lo sviluppo di composti potenzialmente nocivi per la salute del consumatore. La presenza del packaging limita solo parzialmente tale fenomeno.
Si è valutata la suscettibilità alla fotossidazione del formaggio Asiago d’allevo D.O.P. porzionato in preincarto mantenuto in condizioni di conservazione commerciale. La valutazione ha preso in considerazione l’effetto dell’origine (formaggio di montagna vs. formaggio di pianura), dell’esposizione (buio vs. luce) e del tempo di conservazione (0÷336 ore) nei confronti del colore (misurato strumentalmente), contenuto di riboflavina e formazione di composti secondari dell’ossidazione lipidica. Il formaggio di montagna presentava un maggior valore dell’indice del giallo (P<0,001) e del rosso (P<0,001) mentre il contenuto dei riboflavina era significativamente maggiore in quello di pianura (P<0,001) che presentava anche una minore ossidazione dei lipidi (P<0,01). Luce e tempo di conservazione hanno comportato la progressiva riduzione dell’indice del giallo (P<0,001 per entrambi gli effetti) e del rosso (P<0,001 per entrambi gli effetti) e la riduzione del contenuto di riboflavina (P<0,01 e P<0,001 rispettivamente). Lo sviluppo dei prodotti secondari dell’ossidazione, invece, non sembra essere condizionato dall’esposizione alla radiazione luminosa ma dalla presenza di ossigeno all’interno della confezione (P<0,001). Il prodotto di montagna sembra essere maggiormente suscettibile.
Ulteriori analisi dovranno essere condotte per valutare l’effetto della radiazione luminosa e della presenza di ossigeno a carico delle vitamine liposolubili
XXVI Convegno Nazionale Associazione Italiana Veterinari Igienisti
No full textSul packaging degli alimenti sono frequenti i termini “naturale”, “100% naturale” o simili. Sovente tali indicazioni inducono il consumatore all’acquisto nella convinzione di scegliere un prodotto più sano, più fresco o, in generale, con caratteristiche peculiari.
Il lavoro analizza il significato attribuito dai giovani ai concetti di naturale e genuino nell’ambito degli alimenti quotidianamente consumati.
La raccolta dei dati è avvenuta somministrando un questionario a un campione di studenti (maschi: n. 314; femmine: n. 349) delle scuole secondarie di secondo grado (Licei, Istituti Tecnici e Professionali) presenti nel territorio di pertinenza dell’ASL 6 in provincia di Vicenza.
Gli studenti intervistati hanno affermato di essere abbastanza interessati a temi collegati agli alimenti come dieta e salute, bellezza, ricette e sicurezza alimentare. Il reperimento delle informazioni in merito avviene spesso su siti web e a volte attraverso la televisione. Un terzo degli intervistati ha dichiarato di scegliere e acquistare un alimento soprattutto perché fa bene alla salute ma forma e il colore della confezione rappresentano il secondo motivo di scelta. L’attenzione all’etichetta è soprattutto verso la data di scadenza e l’elenco degli ingredienti mentre origine geografica, produttore o indicazioni di uso e consumo sembrano essere meno considerate. Non vi sono differenze significative tra maschi e femmine.
Le definizioni più frequenti di alimento genuino riguardavano gli effetti sulla salute (“non fa male”, “fa bene”, “sano”), l’assenza di prodotti chimici, OGM, trattamenti o grassi e zuccheri ma anche l’individuazione di una categoria merceologica (frutta e verdura). Meno frequenti sono i riferimenti alla produzione domestica o biologica. Inoltre molti studenti non sono stati in grado di dare una definizione di alimento genuino. Alimento naturale è stato invece definito tale se privo di conservanti e coloranti, pesticidi e sostanze chimiche in generale; e chiaramente connotato come prodotto proveniente dalla terra.
Le associazioni spontanee al concetto di alimento naturale hanno riguardato il tema della salute (sano, salutare), il metodo di produzione e la provenienza (biologico, biodinamico, km zero, prodotto nel proprio orto); la sicurezza della produzione viene richiamata da pochi intervistati.
I dati confermano quanto riportato in letteratura. In generale ciò che è descritto come naturale appare migliore e il consumatore sceglie quel prodotto rispetto ad un altro in cui il richiamo alla genuinità o alla natura non è presente anche quando è identico. Gli studenti però, almeno in modo diretto, non vi attribuiscono una maggior sicurezza igienico-sanitaria. È importante conoscere la rappresentazione che il consumatore ha verso alcuni concetti in quanto possono portare a comportamenti non corretti dal punto di vista igienico che potrebbero essere prevenuti
Foodstuff authentication from spectral data: toward a species-independent discrimination between fresh and frozen-thawed fish samples
No full textThe substitution of fresh fish with frozen–thawed fish is a typical fraud that can damage consumers for
several reasons. In fact, not only the quality of thawed meat can be negatively affected during freezing,
but also safety issues can arise, as thawed meat is more susceptible to microbial growth. Though several
strategies have been proposed for fresh fish authentication, their classification ability is strongly affected
by the fish species being considered.
In this paper, we propose three different strategies based on latent variable modeling techniques in
order to develop a multi-species classifier of the fresh/frozen–thawed status of fish samples using
near-infrared spectra. Whereas the first two strategies model the information related to the species
and to the fish together (either jointly or sequentially), the third strategy aims at explicitly separating
them to improve the classification performance.
The proposed strategies were validated over a database of more than 1200 samples of several different
species, with near-infrared spectra collected with two different instruments. The overall classification
accuracies ranged between 80% and 91%, according to the strategy and the instrument used. We believe
that this study can contribute to the development of a species-independent approach to foodstuff
classification
Valutazione dell’antibiogramma mediante un sistema inpiastra di isolati di Lactococcus garvieae da trote iridea(Oncorhynchus mykiss) allevate nel Nord Italia
No full textSUMMARY – Lactococcosis due to Lactococcus garvieae is presently the most important bacterial disease in
rainbow trout (Oncorhynchus mykiss) reared in Italy. Although good results have been obtained with
vaccination, it is often necessary to use pharmaceuticals. Howere unsatisfactory results are often obtained as a
result of the increasing resistance of this pathogen to antibiotic therapy. The aim of this work was to antibiogram
evaluation by a plate system of some veterinarian chemotherapeutics (Enrofloxacin, Gentamicin, Ceftiofur,
Neomycin, Erythromycin, Oxytetracycline, Tetracycline, Amoxicillin, Spectinomycin, Sulphadimetoxin,
Sulphamethoxazole + Trimethoprim, Sarafloxacin, Sulphathiazole, Penicillin, Streptomycin, Novobiocin,
Tylosine, Clindamycin) against 50 L. garvieae isolates obtained from North Italian trout farms from 1993 to
2004. All isolates were resistant to Sulphonamides, Tylosine and Sarafloxacin, while good results were obtained
with Erythromycin and beta lactams (Amoxicillin and Penicillin). Our results offer some indications about the
best chemotherapeutics most likely to be efficient feed when a disease outbreak is occurs
Effect of the partial replacement of fish meal and oil by vegetable products on performance and quality traits of juvenile shi drum (Umbrina cirrosa L.)
No full textA four-month growth trial was carried out in order to evaluate performance and quality traits of juvenile shi drum fedwith two isonitrogenous and isoenergetic diets having different amounts of vegetable products (Vegetable diet vs. Control diet). Compared to the Control diet, the Vegetable diet was formulated by increasing the replacement of fish meal (14%) with soybean and cereal products, and fish oil (12%) with a mixture of vegetable oil. On June, 4 groups of 225 fish (2 replicates per dietary treatment) were sorted according to live weight and reared in fibreglass tanks over a four- month long experimental period. Fish were hand fed to apparent satiety. Offered feed, growth parameters and feed efficiency were recorded as productive performance. At the end of the trial (October) biometric, chemical and reological traits were examined to assess fish quality. The dietary treatments showed similar productive performance. The relatively high inclusion of vegetable sources led to a significant modification of body shape, mesenteric fat and viscera weight. Among quality traits, Vegetable diet-fed fish demonstrated a significantly lower whole body and fillet crude protein content. Yellowness value of the cooked fillet was significantly lower in the Control diet-fed fish, whereas fillet texture was similar. The results of this research showed that shi drum is a suitable candidate for Mediterranean marine aquaculture and its dietary formulation might include at least the amount of vegetable sources used in this trial
Multispectral data classification using similarity factors
No full textThe problem of classification through spectral information can be addressed using many different techniques,
from traditional k-nearest neighbor or linear (or quadratic) discriminant analysis to partial least-squares discriminant
analysis, or more sophisticated approaches such as support vector machines or wavelet-based
methods. In many cases the available spectra, independently from their origin (e.g. mass spectroscopy,
light spectroscopy, hyperspectral imaging), require several pretreatments before any classification method
can be applied, and typically the most appropriate preprocessing of raw spectra is determined by
trial-and-error. In this paper, we propose the use of similarity factors based on principal component analysis
to classify different types of spectral datasets. The proposed classification technique has a very intuitive
graphical interpretation and works through an assigned sequence of pretreatment steps on the raw signals,
which avoids the trial-and-error selection of the most appropriate preprocessing method. The proposed
strategy is successfully validated through two food engineering case studies. A third case study illustrates
how the similarity factor-based strategy can be extended to the classification of multi/hyper spectral images
Cold chain and consumers’ practices: exploratory results of focus group interviews
Full text linkThe aim of this qualitative survey was to gain an insight into the ways consumers purchase, transport and storage fresh and frozen food. In particular, this paper considered consumers’ behaviour and the knowledge they have about cold chain. An explorative study was held using focus group interviews (n. 4) as the method for data collection. The sampling group was composed of 24 consumers (4 males and 20 females) and the age ranged from 33 to 78. Data revealed that food safety knowledge is at a fairly good level, however consumer practices in certain cases were inappropriate particularly with respect to transport from the store to home, storage and thaw. Consumers were particularly concerned about frozen food that should not be thawed during shopping or transportation. Knowledge about eggs storage seemed to be dodgy as well. Due to the restricted extent of the sample survey the results cannot be generalized to the whole Italian population; still, this method is particularly useful for discovering not only what people think but why they think that way
Valutazione del profilo aminoacidico corporeo in ombrine (Umbrina cirrosa L.) alimentate con diete a diverso rapporto lipidi/carboidrati
No full textthe objective of the study was to determine by HPLC whole body aminoacid compositions of shi drum after a 4 months long period according with two lipid/carbohydrate ratio (EE/NFE):1.0 vs !.5. Total and essential AA amount were found significantly higher in EE/NFE 1.0 fed fish as well as LYS and LEU content resulting in an higher crude protein retention. Results suggest that low dietary EE/NFE ratio increases protein feed efficiency by reduction of catabolic oxidation of almost two essential amino acid
Effect of the replacement of fish meal and oil by vegetable products juvenile shi drum (Umbrina cirrosa L.) performance and quality traits
No full textFood fraud and mislabeling: development of a Real-Time PCR for rapid identification of Octopus vulgaris
No full textThe consumption of seafood products, in particular cephalopods, and their worldwide commercialization is increasing in last decade. The excessive exploitation of this type of resources is going to deplete seas and oceans, moreover the most appreciated species like Octopus vulgaris are widely substituted with others ( e.g. other Octopus and Amphioctopus species). The aim of this work was the comparison among barcoding (COI) and an in-house Real-Time PCR approaches for the identification of this fraud on products sold in north east Italy. The identification method was developed through an EvaGreen Real-Time PCR, as faster and cheaper technique in comparison of the classical barcoding approach (2 day vs. 4-5 day). One hundred of samples from different FAO areas (46 Octopus vulgaris and 56 non-O. vulgaris) were applied for the experimental set-up.
This method can distinguish between Octopus vulgaris and other cephalopods species through the study of the amplification curves. Sensitivity and specificity tests on all samples showed two different clusters according to the ct (cycle threshold); the 20 ≥ Ct ≤ 30 levels identified O. vulgaris samples, while a 30) need a subsequent barcoding analysis for a detailed identification of genus and species using the same DNA extracts. After the method optimization, a market survey was conducted in order to collect data about commercial fraud. Seventy-seven prepared (e.g. cooked in oil) and unprepared products from different markets of 4 provinces (north-east Italy) were analyzed with both methods.
Survey data shown that 51.2% of products labeled as Octopus vulgaris were substituted with non-Octopus vulgaris species (commercial fraud), 36.2% of products declared as other octopus species are mislabeled for a total of fraud/mislabeling estimated at 44.15%. The EvaGreen Real-Time PCR showed a specificity and sensitivity of 100% and 80% respectively. Furthermore there was a substantial agreement between Real-Time PCR and barcode methods (K Cohen value = 0.86).
In conclusion, this technique allowed a simple and economic method to confirm Octopus vulgaris (< 48 h ) according to the variability of the samples tested and their different provenience areas. The EvaGreen Real-Time PCR could be a routinely system in diagnostic laboratories
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