Sensory characteristics and volatile compounds of dry cured ham Speck are affected by pig dietary supplementation with antioxidant mixture.

BACKGROUND: Dry cured ham named Speck is a typical Italian product, with consolidated processing techniques and specific quality parameters. It has gained importance in the international market after obtaining the Protected Geographical Indication. Recent studies indicate that dietary plant extracts in pig may affect quality of processed meats but there are no data on their effect on Speck. Consequently, the effects of dietary supplementation with antioxidant mixture (AOX), containing vitamin E and polyphenols, in pigs on the nutritional characteristics, volatile compounds, sensory properties and consumers' preference of Speck were evaluated. RESULTS: The Speck weight loss during seasoning was lower in the AOX group, while products quality parameters were not affected by dietary treatments. Alcohol and terpenes concentrations were lower (P < 0.05) in the AOX samples than the control. Sensory profile revealed slight differences (P < 0.05) in Speck salty and sweet taste, whereas the consumer tests showed a higher (P < 0.05) preference, with mean score of seven, for Speck from pigs fed AOX. CONCLUSION: Our results provide new insights on the quality parameters of Speck. Dietary integration with antioxidant mixture decreased Speck weight losses during seasoning. Volatile compounds concentrations and sensory profile were slightly affected by dietary treatment. The consumer test revealed that dietary antioxidants, increased the overall preference for Speck, and can potentially increase its consumption. © 2020 Society of Chemical Industry.

Authentication of farmed and wild turbot (Psetta maxima) by fatty acid and isotopic analyses combined with chemometrics.

Fatty acid composition and stable isotope ratios of carbon (delta(13)C) and nitrogen (delta(15)N) were determined in muscle tissue of turbot (Psetta maxima). The multivariate analysis of the data was performed to evaluate their utility in discriminating wild and farmed fish. Wild (n=30) and farmed (n=30) turbot of different geographical origins (Denmark, The Netherlands, and Spain) were sampled from March 2006 to February 2007. The application of linear discriminant analysis (LDA) and soft independent modeling of class analogy (SIMCA) to analytical data demonstrated the combination of fatty acids and isotopic measurements to be a promising method to discriminate between wild and farmed fish and between wild fish of different geographical origin. In particular, IRMS (Isotope Ratio Mass Spectrometry) alone did not permit us to separate completely farmed from wild samples, resulting in some overlaps between Danish wild and Spanish farmed turbot. On the other hand, fatty acids alone differentiated between farmed and wild samples by 18:2n-6 but were not able to distinguish between the two groups of wild turbot. When applying LDA isotope ratios, 18:2n-6, 18:3n-3, and 20:4n-6 fatty acids were decisive to distinguish farmed from wild turbot of different geographical origin, while delta(15)N, 18:2n-6, and 20:1n-11 were chosen to classify wild samples from different fishing zones. In both cases, 18:2n-6 and delta(15)N were determinant for classification purposes. We would like to emphasize that IRMS produces rapid results and could be the most promising technique to distinguish wild fish of different origin. Similarly, fatty acid composition could be used to easily distinguish farmed from wild samples.

Classification of gilthead sea bream (Sparus aurata) from 1H NMR lipid profiling combined with principal component and linear discriminant analysis.

The combination of (1)H NMR fingerprinting of lipids from gilthead sea bream (Sparus aurata) with nonsupervised and supervised multivariate analysis was applied to differentiate wild and farmed fish and to classify farmed specimen according to their areas of production belonging to the Mediterranean basin. Principal component analysis (PCA) applied on processed (1)H NMR profiles made a clear distinction between wild and farmed samples. Linear discriminant analysis (LDA) allowed classification of samples according to the geographic origin, as well as for the wild and farmed status using both PCA scores and NMR data as variables. Variable selection for LDA was achieved with forward selection (stepwise) with a predefined 5% error level. The methods allowed the classification of 100% of the samples according to their wild and farmed status and 85-97% to geographic origin. Probabilistic neural network (PNN) analyses provided complementary means for the successful discrimination among classes investigated.

The use of stable isotope ratio analyses to discriminate wild and farmed gilthead sea bream (Sparus aurata).

Continuous flow isotope ratio mass spectrometry (CF-IRMS) has been used to analyze samples of gilthead sea bream (g.s.b.) (Sparus aurata) of known geographical origin (four countries on the Mediterranean Sea) from wild and farmed sources (40 farmed and 10 wild). delta(13)C and delta(15)N values have been measured on muscle samples as these are the most informative parameters of the diet of the animals. Both stable isotopes are indicators of the origin of the fish: delta(13)C giving a tool to distinguish between wild and farmed g.s.b. and delta(15)N being more informative on the geographical origin of the fish (this fact could be related more to differences in feed mixtures given to farmed fish than to geographical reasons). The proposed methodology offers a cost- and time-effective alternative to other analytical techniques in identifying wild and farmed fish.

Application of quantitative real-time PCR in the detection of prion-protein gene species-specific DNA sequences in animal meals and feedstuffs.

This study describes a method for quantitative and species-specific detection of animal DNA from different species (cattle, sheep, goat, swine, and chicken) in animal feed and feed ingredients, including fish meals. A quantitative real-time PCR approach was carried out to characterize species-specific sequences based on the amplification of prion-protein sequence. Prion-protein species-specific primers and TaqMan probes were designed, and amplification protocols were optimized in order to discriminate the different species with short PCR amplicons. The real-time quantitative PCR approach was also compared to conventional species-specific PCR assays. The real-time quantitative assay allowed the detection of 10 pg of ruminant, swine, and poultry DNA extracted from meat samples processed at 130 degrees C for 40 min, 200 kPa. The origin of analyzed animal meals was characterized by the quantitative estimation of ruminant, swine, and poultry DNA. The TaqMan assay was used to quantify ruminant DNA in feedstuffs with 0.1% of meat and bone meal. In conclusion, the proposed molecular approach allowed the detection of species-specific DNA in animal meals and feedstuffs.

Polymerase chain reaction-based analysis to detect terrestrial animal protein in fish meal.

The recent European bovine spongiform encephalopathy crisis has focused attention on the importance of adopting stringent control measures to avoid the risk of the diffusion of mad cow disease through meat meal-based animal feedstuffs. Potential adulteration of such feedstuffs with bone particles from terrestrial animals is determined by microscopic examination by law before the release of these feedstuffs for free circulation in the European Community. This study describes a DNA monitoring method to examine fish meal for contamination with mammalian and poultry products. A polymerase chain reaction (PCR) method based on the nucleotide sequence variation in the 12S ribosomal RNA gene of mitochondrial DNA was developed and evaluated. Three species-specific primer pairs were designed for the identification of ruminant, pig, and poultry DNA. The specificity of the primers used in the PCR was tested by comparison with DNA samples for several vertebrate species and confirmed. The PCR specifically detected mammalian and poultry adulteration in fish meals containing 0.125% beef, 0.125% sheep, 0.125% pig, 0.125% chicken, and 0.5% goat. A multiplex PCR assay for ruminant and pig adulteration was optimized and had a detection limit of 0.25%.