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The purpose of this study was to evaluate for the first time the effect of a rice bran extract based-active packaging with antioxidant and antimicrobial activity, high pressure processing (HPP) (600 MPa, 7 min), storage time (1, 90, and 180 days) and temperature (4 vs 20 °C) on the volatile compounds of sliced “Montanera” Iberian ham. The active packaging affected a quarter of the compounds, with a trend similar (although to a greater extent) to the one resulting from the HPP. The active packaging provided no clear advantages or serious drawbacks. The slight effect of the high pressure processing indicates that “Montanera” products might be more resistant to HPP-induced changes than other dry-cured hams. Regarding storage, despite the marked effect of time (30 out of 38 compounds), the temperature only influenced two compounds. This weak effect raises the possibility of storing and distributing this vacuum-packaged sliced product at room temperature.

The data obtained with a polar or non-polar gas chromatography (GC) column coupled to ion mobility spectrometry (IMS) has been explored to classify Iberian ham, to detect possible frauds in their labelling. GC-IMS was used to detect the volatile compound profile of dry-cured Iberian ham from pigs fattened on acorn and pasture or on feed. Due to the two-dimensional nature of GC-IMS measurements, great quantities of data are obtained and an exhaustive chemometric processing is required. A first approach was based on the processing of the complete spectral fingerprint, while the second consisted of the selection of individual markers that appeared throughout the spectra. A classification rate of 90% was obtained with the first strategy, and the second approach correctly classified all Iberian ham samples according to the pigs' diet (classification rate of 100%). No significant differences were found between the GC columns tested in terms of classification rate.

This paper describes the Magnetic Resonance Imaging (MRI) contrastive analysis of Iberian hams from pigs that have been fattened only with acorns and grass (AG) and those that have been fattened with high oleic acid concentrates (HO). Based on computer vision techniques, the implemented methods of image processing allowed for the automatic recognition of the Biceps femoris muscle as well as for computational texture feature detection in the muscle. The data collected was then checked against physical–chemical composition. The MRI sequence obtained displayed markedly visual differences in terms of the grey hue for both muscle (darker in AG-fed hams) and inter-muscular and intra-muscular fat (darker in HO hams). Most computational texture characteristics proved to be statistically different between the AG and HO image sets. Two groups (G1 and G2) of texture features were derived. G1 was closely related to linolenic acid (C18:3 n-3) and γ-tocopherol, defining Iberian ham of AG pigs, while G2 was associated with HO pigs. Thus MRI-based analyses enable visual distinction of Iberian hams according to the feeding background. This distinction is also achieved computationally via the examination of the texture features in the muscles.

One hundred and seventeen yeast strains isolated from dry-cured Iberian ham from the four different protected designations of origin of Spain were investigated for their volatile compound production. The yeast strains were grouped into the two main yeast species usually found in this product ( Debaryomyces hansenii and Candida zeylanoides ) and 10 different biotypes by restriction mitochondrial DNA analysis. Yeast strains were grown in a designed model culture medium under conditions representative of dry-cured ham processing. Volatile compounds were extracted from this medium using solid-phase micro-extraction and were analysed by gas chromatography/mass spectrometry. Marked differences in volatile compound production were found between D. hansenii and C. zeylanoides and between the mitochondrial DNA patterns of these species . Two of the mitochondrial DNA patterns of D. hansenii exhibited the highest production of the volatile compounds involved in the dry-cured flavour. Consequently, these patterns of D. hansenii should be proposed as starter cultures for dry-cured ham.

An analytical method which offers accurate determination and identification of eight α-keto acids (α-ketoglutaric acid, pyruvic acid, 4-hydroxyphenylpyruvic acid, 3-methyl-2-oxobutyric acid, α-keto-γ-methylthiobutyric acid, 4-methyl-2-oxovaleric acid, 3-methyl-2-oxovaleric acid, and phenylpyruvic acid) in pork meat and Iberian ham samples is reported. The method utilises a highly selective and sensitive method of multiple reaction monitoring (MRM) by mass spectrometry. The analytical method is simple (although the chemical derivatisation of the α-keto acids with dansylhydrazine is required), precise (18% RSD), accurate (90-110%), sensitive (0.01-0.34 mg/kg of defatted and freeze-dried meat depending on the α-keto acid) and linear (R0.99) over several orders of magnitude (until 0.01-146.1 mg/kg of defatted and freeze-dried meat depending on the α-keto acid). Using this methodology, α-keto acids were found to be present in pork meat to a low extent, and their concentration increased when they were determined in Iberian ham. This is the first report of the presence of α-keto acids in both pork meats and Iberian hams.