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High-pressure treatment is useful for increasing the microbiological safety of ready-to-eat foods. With dry-cured hams, this treatment can be applied to the finished product after slicing and vacuum packaging. The effect of high-pressure treatment on the survival of inoculated Listeria monocytogenes Scott A and on the sensory characteristics of two Spanish dry-cured hams, Iberian and Serrano, was investigated. Ham slices were inoculated with L. monocytogenes at 6 × 106 CFU/g and held at 4°C for 20 h before high-pressure treatment. During this holding period, the population of the pathogen declined by 0.44 and 0.51 log CFU/g in Iberian and Serrano hams, respectively. Treatment at 450 MPa for 10 min at 12°C reduced L. monocytogenes populations by 1.50 and 1.16 log CFU/g in Iberian and Serrano hams, respectively. During the first week of storage at 4 or 8°C, L. monocytogenes populations declined by an average 0.89 log CFU/g in pressurized Iberian ham and 2.09 log CFU/g in pressurized Serrano ham. After 60 days at 4 or 8°C, the respective populations in pressurized and control hams were 3.24 and 4.70 log CFU/g for Iberian ham and 2.73 and 5.07 log CFU/g for Serrano ham. The color parameters L* and a* were not influenced by high-pressure treatment, and parameter b* was increased only in Iberian ham. Sensory characteristics of hams were not affected by high-pressure treatment. Treatment of Iberian and Serrano hams at 450 MPa for 10 min significantly reduced the population of L. monocytogenes Scott A without a detrimental effect on the sensory characteristics of the hams. Copyright ©, International Association for Food Protection.

This paper explores the use of MRI (Magnetic Resonance Imaging) in combination with a fully automated Image Analysis method for the recognition of Biceps Femoris and Semimembranosus muscles in Iberian ham. A quantitative description of volume and a study of moisture and weight relationships during the product’s ripening process are included. Three Active Contour methods (Variational Calculus, Dynamic Programming, and Greedy Algorithms) are used to recognize the Biceps Femoris and Semimembranosus muscles by means of Computer Vision techniques. The recognition of both muscles via MRI entails a low error rate (3–10%). A loss of weight in hams during the ripening process is related to a decrease in size ( r 2 = 0.992). The high correlation implies that the information obtained by means of Computer Vision techniques can be used as a non-invasive complement to the traditional processes of ham weighing and moisture estimation.

The influence of crossbreeding (Iberian vs Iberian×Duroc 50% pigs) and rearing system (Montanera vs Pienso) on the instrumental colour of Iberian ham (subcutaneous fat and biceps femoris muscle) and the relationships to sensory appearance and chemical composition were researched by using a factorial design. In subcutaneous fat, a significant effect (p

Active Contours constitute a widely used Pattern Recognition technique, consisting in curves to be moved by minimizing an energy function. Classical active contours are based on different methodologies. This paper proposes a new procedure using Genetic Algorithm to minimize the energy function of the Active Contour. Both techniques are combined to produce a new methodology, called Evolutionary Active Contours. An application has been developed in order to verify the validation of the proposed method. The valid performance of this approach has been demonstrated with both synthetic and real Magnetic Resonance images. Moreover, the algorithm has been used to recognize muscles from Magnetic Resonance images of Iberian ham at different maturation stages in order to calculate their volume change. Our main findings can be summarized as two: The feasible combination of genetic algorithms and active contours, and the automation of optimal ripening points for Iberian ham samples.

The production of dry-cured ham follows traditional processes that are based on a curing stage followed by a resting period, both at refrigeration temperature so that the salt reaches the inner part of the ham and stabilizes the product. The temperature is then gradually increased relative to the decrease in water activity, in order to facilitate drying and the development of the typical sensory characteristics. Over recent decades, a level of knowledge has been achieved and technology improved resulting in the production of safe, convenient, and highly flavored dry-cured hams.

Deformable Models are extensively used as a Pattern Recognition technique. They are curves defined within an image domain that can be moved under the influence of internal and external forces. Some trade-offs of standard deformable models algorithms are the selection of image energy function (external force), the location of initial snake and the attraction of contour points to local energy minima when the snake is being deformed. This paper proposes a new procedure using potential fields as external forces. In addition, standard Deformable Models algorithm has been enhanced with both this new external force and algorithmic improvements. The performance of the presented approach has been successfully proved to extract muscles from Magnetic Resonance Imaging (MRI) sequences of Iberian ham at different maturation stages in order to calculate their volume change. The main conclusions of this paper are the practical viability of potential fields used as external forces, as well as the validation of the algorithmic improvements developed. The feasibility of applying Computer Vision techniques, in conjunction with MRI, for determining automatically the optimal ripening time of the Iberian ham is a practical conclusion reached with the proposed approach.

Intermuscular Fat Content and its distribution during the ripening process of the Iberian ham is a relevant task from the point of view of technological interest. This paper attempts to study the Iberian ham during the ripening process with images obtained from a MRI (Magnetic Resonance Imaging) device using Pattern Recognition and Image Analysis algorithms, in particular Mathematical Morphology techniques. The main advantage of this method is the non-destructive nature. A concrete algorithm is proposed, which is based on the Watershed transformation. In addition, the results are compared with the Otsu thresholding algorithm. The decreases of the total volume in the ripening process are shown. Also the decrease of the meat percentage and intermuscular fat content are calculated. As a conclusion, the viability of these techniques is proved for the possible future utilization in the meat industries to discover new characteristics in the ripening process.

A semiconductor multisensorial system, based on tin oxide, to control the quality of dry-cured Iberian hams is described. Two types of ham (submitted to different drying temperatures) were selected. Good responses were obtained from the 12 elements forming the multisensor for different operating temperatures. Discrimination between the two types of ham was successfully realised through principal component analysis (PCA).

Fifty-five legs from Iberian pigs were traditionally processed into dry cured hams. Free amino acids and other non-volatile compounds in the water-soluble fraction from the biceps femoris muscle were analyzed by HPLC. At the drying stage and in the last months in the cellar the largest increases in these water-soluble compounds took place. There was a clear influence on free amino acid formation of salt content and on the formation of peptides of the temperature at each processing stage. As the amount of non-volatile compounds in the water-soluble fraction increases with processing time, their determination could provide a maturation index for Iberian ham.

Acoustic microscopy has been used for many years to image and measure the elastic properties of materials across a wide range of scientific disciplines. However the application of this technique in the food industry is scarce. In this paper we outline the operation of a reflection-mode acoustic microscope and discuss some of the issues relevant to its operation in the food sector. We then present two relevant case studies in which we employ acoustic microscopy to analyse potato cells and the fat structure in Iberian ham and chorizo.

[EN] The aim of this work was to evaluate the use of ultrasonic measurements to characterize the crystallization process and to assess the textural changes of Iberian fat and Iberian ham during cold storage. The ultrasonic velocity was measured in two types of Iberian fats (Montanera and Cebo) during cold storage (0, 2, 5, 7 and 10 ºC) and in vacuum packaged Iberian ham stored at 6ºC for 120 days. The fatty acid profile, thermal behaviour and textural properties of fat were determined. The ultrasonic velocity and textural measurements showed a two step increase during cold storage, which was related with the separate crystallization of two fractions of triglycerides. It was observed that the harder the fat, the higher the ultrasonic velocity. Likewise, Cebo fat resulted harder than Montanera due to a higher content of saturated triglycerides. The ultrasonic velocity in Iberian ham showed an average increase of 55 m/s after 120 days of cold storage due to fat crystallization. Thus, non-destructive ultrasonic technique could be a reliable method to follow the crystallization of fats and to monitor the changes in the textural properties of Iberian ham during cold storage.

This research evaluates the role of local technology institutions as an external source of ideas, information and knowledge that foster innovation and enhance the performance of firms. It is argued that firms that establish links with local technology institutions have access to valuable external information and knowledge flows, which in turn improve their export performance. We also examine differences in their absorptive capacity, which is their ability to recognise and assimilate information and knowledge spillovers, which depends on their existing internal knowledge stock. Empirical evidence from 106 exporting companies in the Iberian Ham cluster confirms that links with local technology institutions improve export performance. Contrary to expectations, the stock of internal knowledge does not increase a firm’s ability to absorb external knowledge. It appears that firms reduce the spillovers created around the technology institution network, either to protect their internal investments or to develop l...

A study was conducted to identify the volatile compounds in aged Iberian hams, processed in the traditional way. The volatiles from aged hams were entrained in cold traps after distillation under high vacuum. The distillate was collected with dichloromethane and analysed by gas-chromatography-mass-spectrometry (GC-MS). Seventy-seven compounds were tentatively identified in the volatile fraction. Alkanes (12), branched alkanes (14), aldehydes (13), and aliphatic alcohols (9) dominated the volatiles. Small amounts of lactones (5), esters (9) and ketones (7) and other miscellaneous compounds were also present. The possible origins of these compounds and their relationship with the characteristic flavour of this product are discussed.

Melting point, slip point, iodine value (fast analyses) and percentage contents of fatty acids were determined in subcutaneous fat of hams from Iberian pigs in order to study the possibilities of characterizing the type of pig feeding and the relationships between the results of fast analysis and fatty acid contents. Both types of analyses showed important differences between samples from pigs fed on acorn and samples from pigs fed on mixed feeds. When a combination of feeding materials (acorn and mixed feeds) was used, the analyses gave intermediate results, closer to those obtained with mixed feeds only. On the other hand, generally high simple and multiple correlation coefficients (greater than 0·85) were obtained between fast analyses and fatty acid contents, which allows accurate predictions using regression and canonical correlation analyses.

Fifty-five hams from Iberian pigs were processed using two different dry-curing techniques, traditional and modern. Salt content, non-protein nitrogen and its fractions (peptide, amino acid and volatile basic nitrogen) from Biceps femoris muscles were quantified. The existence of an overlapping effect of both temperature and salt content on the general non-protein nitrogen production was observed. The most intense proteolytic breakdown took place when higher temperatures were reached during the drying stage. The difference in salt concentration seems to contribute to generating different quantities in the non-protein nitrogen fractions. The inclusion at the end of the cellar stage of a stuffing period would permit increasing the accumulation of free amino acid in high salted hams.

peer-reviewed The aim of this study was to investigate the sensory characteristics of dry-cured hams from confined Iberian pigs fed on a high oleic (HO) concentrate (HO-Pienso hams), and to study how different the characteristics of these hams are from those of Iberian hams from the best grade (Montanera hams, from extensively reared pigs). Nearly half of the fatty acids studied were similar in HO-Pienso and Montanera hams. No differences were found for 18:1, but some major fatty acids of subcutaneous fat of Iberian hams were different between the HO-Pienso and the Montanera hams (C16:0, C18:0, C18:2). The descriptive test revealed that 15 of the 23 sensory characteristics were not significantly different between both groups of hams. No sensory differences appeared for fat appearance or lean texture characteristics, but lean appearance, oiliness, saltiness and the most intensively perceived characteristics of odour and flavour were significantly different. These differences in the sensory traits between Montanera and Pienso hams were not as marked as found in previous studies. Therefore, the use of a concentrate high in oleic acid enables simulation, at least in part, of the sensory characteristics, especially texture. Ángela Jurado thanks the Junta de Extremadura for its support.

To evaluate the influence of the Iberian ham processing conditions in the evolution of volatile aldehydes, 35 hams were processed in two plants following different conditions of relative humidity and temperature. For this, free fatty acids, peroxide values and volatile aldehydes were quantified in the hams. The highest increases in free fatty acids were noted during the drying stage in both processing plants. The drying period also revealed the greatest increase in peroxide values, where the highest values were in those hams processed at higher temperatures. The temperature during post-salting and drying had a marked influence on the formation of volatile aldehydes, being responsible for the differences in volatile compounds of matured hams.

The aim of the present study was to obtain aroma extracts from Iberian ham using supercritical carbon dioxide as the extraction technique of volatile compounds. After extraction, it was concluded t...