Accumulation and evolution of tocopherols in dry-cured hams from Iberian pigs as affected by their feeding and rearing system

A non-destructive sampling method for food authentication using gas chromatography coupled to mass spectrometry or ion mobility spectrometry

The study of volatile compounds obtained by gas chromatography (GC) coupled to mass spectrometry (MS) or ion mobility spectrometry (IMS) may be very useful to protect food quality, especially when using a non-destructive sampling method. In this work, the authentication of the highly appreciated dry-cured Iberian ham by those techniques was studied and compared. The results obtained show the suitability of a non-destructive sampling method coupled to headspace sampling (HS)-GC-IMS or HS-GC-MS to determine volatile markers in the feeding Iberian pig regime. Although both methods were suitable to differentiate the ham categories, HS-GC-IMS was more sensitive detecting a higher number of compounds than HS-GC-MS, which provided accurate qualitative results. The results of principal component analysis showed that ethanol, 2-propanol and 3-methylbutanol, identified by HS-GC-IMS, and 3-methylbutanal and heptane, identified by HS-GC-MS, could be considered potential markers to identify ham from different feeding regimes.

Quality Traits of Dry-Cured Loins from Iberian Pigs Reared in Montanera System as Affected by Pre-Freezing Cure

Iberian dry-cured loins from pigs fattened in Montanera are usually subjected to seasonal production, which could be overcome through freezing the loin before the curing process. Hence, three homogeneous batches (n = 15 per batch) were established to evaluate the effect of different pre-freezing cure (−20 ± 2 °C) times (three and six months) of raw material on main quality characteristics of dry-cured loins in comparison to those elaborated from unfrozen meat. All samples were subjected to similar seasoning and same curing length to obtain dry-cured loins. Results showed a decrease in lightness, redness, chrome and hue values, polyunsaturated fatty acids (PUFA), higher oxidative phenomena, and changes in rheological properties in fresh loins on account on freezing (p ≤ 0.05). Some quality parameters of dry-cured loins were affected by freezing, weight loss, and hardness being higher as well as salt content being lower. PUFA and Warner–Braztler Shear Force (p ≤ 0.05) also showed higher values in dry-cured loins from frozen meat than those elaborated from unfrozen counterparts.

Quality traits of fresh and dry-cured loin from Iberian x Duroc crossbred pig in the Montanera system according to slaughtering age

Iberian x Duroc cross grower pigs of similar weight, but 12, 10 and 8 months of age, were finished using the Montanera system to study effects on fresh and dry cured loin quality. Pigs were slaughtered simultaneously at 16, 14 and 12 months of age (IBxD16, IBxD14 and IBxD12) and longissimus thoracis et lumborum were removed and processed into dry-cured loin. Fresh and dry cured loins from the oldest animals (IBxD16) had higher tocopherols, C18:2 n-6 and PUFA as well as higher insoluble collagen, which led to greater hardness. Fresh loin from the youngest animals (IBxD12) had the lowest myoglobin content, redness (a*), chroma and hue angle. No differences in proximate composition or instrumental colour were found in dry-cured loins.

Effect of dietary selenium source (organic vs. mineral) and muscle pH on meat quality characteristics of pigs

This study evaluates the effect of organic (Se‐enriched yeast; SeY) versus inorganic selenium (sodium selenite; SeS) supplementation and the different response of selenium source according to muscle pH on pork meat quality characteristics. Pigs (n = 30) were fed the Se‐supplemented diets (0.3 mg/kg) for 65 days. Neither electric conductivity (EC) nor drip loss were affected by the selenium source. The SeY group had lower TBARS in muscle samples after day 7 of refrigerated storage and higher a* values on days 1 and 7 than the SeS group. The effect of dietary selenium source on some meat quality characteristics was affected by muscle pH. Hence, as the muscle pH increases, the drip loss decreases but this effect is more marked with the dietary organic Se enrichment. Muscle pH seems to modulate the action of selenium in pork, especially some meat characteristics such as drip loss.

Quantification of γ- and α-tocopherol isomers in combination with pattern recognition model as a tool for differentiating dry-cured shoulders of Iberian pigs raised on different feeding systems

BACKGROUND

Quantification of γ- and α-tocopherol in dry-cured shoulders of Iberian pigs was evaluated as a tool for differentiating feeding backgrounds or regimens. Samples (n = 115) were obtained over two different seasons from the four categories of pigs described in the Industry Quality Policy, i.e. pigs fed in free-range conditions (FREE-RANGE), pigs fed in free-range conditions and provided feed supplements (FREE-FEED), pigs fed outdoors with feed and with access to grass (FEED-OUT) and pigs fed in intensive conditions with feed (FEED). Linear discriminant functions were calculated and validated.

RESULTS

The validation results showed that 20% of the muscle samples were not correctly classified into the four feeding categories, giving an 80% success rate. The FEED group had the lowest proportion of errors, with 100% of samples correctly classified. For the FREE-RANGE group, 87% of samples were assigned to the correct feeding system by cross-validation; however, 13% were considered as FREE-FEED. A higher rate of correct classification can be obtained when using three categories or by calculating the weight gain in free-range conditions using regression equations.

CONCLUSION

Taking into account the high variability of the samples and the high success in classification, these results are of interest and may be applied in practical situations.

Alpha-tocopherol stereoisomer analysis as discriminant method for distinguishing Iberian pig feed intake during the fattening phase

The use of stereoisomers of α-tocopherol to correctly classify Iberian pig fat samples according to their feeding system was investigated. Samples were obtained over two different seasons in controlled farms from the four categories of pigs described in the Industry Quality Policy (FREE-RANGE: pigs fed exclusively under free-range conditions; FREE-FEED: pigs fed free-range and supplemented with feed; FEED-OUT: pigs fed outdoors with access to grass and a mixed diet; and FEED: pigs fed exclusively a mixed diet). A higher presence of RRR-stereoisomer indicated a greater consumption of the natural form of tocopherol provided by acorns or grass, whereas a higher proportion of S forms were related to a higher mixed diet intake. Validation results showed 90% success in fat sample classification. Analysis of the RRR-stereoisomer together with γ- and α-tocopherol determination can be considered as a potent tool for distinguishing fat from pigs fed under free-range conditions or exclusively with acorns and grass from those receiving a supplemented diet at any time of their fattening phase.