Ana I. Carrapiso

Effect of crossbreeding and rearing system on sensory characteristics of Iberian ham

The aim of this work was to study the influence of crossbreeding (Iberian and Iberian×Duroc 50% pigs) and rearing system (outdoors and indoors) on the sensory characteristics of Iberian ham [using descriptive analysis], and to investigate the relationships among sensory data and subcutaneous fat composition. Crossbreeding had a slight effect on sensory and fatty acid profile (only the bitter taste and some low-content fatty acids were significantly affected), but rearing system had a marked effect on subcutaneous fat composition (most fatty acids were affected) and sensory characteristics (texture characteristics being the most affected together with lean appearance and aroma). Palmitic, stearic and oleic acids were closely correlated to some sensory traits, not only lipid-related characteristics (brightness, fat oiliness) but also to aroma.

In situ transesterification of fatty acids from Iberian pig subcutaneous adipose tissue.

The purpose of this study was to optimize a rapid method for fatty acid analysis in Iberian pig subcutaneous adipose tissue. An in situ transesterification method was used to avoid the lengthy lipid extraction step. Samples were in situ transesterified with 5% HCl/methanol at 70°C, and toluene was used to help dissolve lipids. The method had advantages over other in situ methods since only 45 min were required to completely transesterify the fatty acids, and 10 min to obtain the fatty acid profile. A sample size of 25 mg of adipose tissue was suitable. The in situ transesterification gave higher fatty acid concentrations than conventional lipid extraction and transesterification, the differences being significant for all the fatty acids. Relative fatty acid contents were similar to those found by the conventional method.

Effect of ripening time and rearing system on amino acid-related flavour compounds of Iberian ham

The evolution of free amino acids and amino acid-derived volatile compounds during the ripening of Iberian ham from pigs reared in a Montanera system (outdoor-based, with acorn and pasture available) and a Pienso system (indoor-based, with a high oleic acid concentrate) was studied. Ripening time influenced significantly all the free amino acids detected (p<0.05) except for threonine and tyrosine. The total free amino acid content increased significantly from day 120 to day 230 (drying stage) and then the concentration remained almost steady. This marked increase in the free amino acid content matched an increase in the amino acid-derived volatile compounds. The volatile compounds also increased after day 230. Conversely, rearing system had a weak effect on the free amino acid content and on the amino acid-derived volatile compounds. Only glutamic acid was significantly influenced (p=0.027), and a slight effect on proline and aspartic acid was found (p=0.051 and p=0.084, respectively), concentrations being larger in Montanera hams than in Pienso ones. With regard to the amino acid derived volatile compounds, only a significant influence of rearing system on acetaldehyde and on the coelution of 2,6-dimethylpyrazine+dihidro-2(3H)furanone was found. The small differences caused by rearing system confirm the great importance of concentrate formulation.

Instrumental colour of Iberian ham subcutaneous fat and lean (biceps femoris): Influence of crossbreeding and rearing system.

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<0.05) of crossbreeding and rearing system was found: b* and chroma were larger in hams from Iberian pigs than from Iberian×Duroc (50%) pigs, and L*, a* and chroma were larger in Pienso hams than in Montanera hams. CIEL*a*b* variables of subcutaneous fat were closely related to subcutaneous fatty acid composition, the largest correlationships involving L* (L* and 18:0, 0.652, p<0.001; L* and 18:1, -0.616, p<0.001). Instrumental colour variables and sensory appearance were also correlated (L* and fat pinkness, -0.539, p<0.001). In lean (biceps femoris), instrumental colour data was not affected by crossbreeding and rearing system. CIEL*a*b* variables were not related to chemical composition (moisture, NaCl, intramuscular fat and pigment content), although they were correlated to sensory appearance (L* and marbling, 0.419, p=0.014).

Subcutaneous and intermuscular fat characterisation of dry-cured Iberian hams.

The fatty acid composition of the triacylglycerols and free fatty acids of subcutaneous (internal and superficial layers) and intermuscular fat and the contribution of these fatty acids to the formation of volatile compounds were determined in dry-cured Iberian ham. The profile of the fatty acids and volatile compounds showed that lipolytic and oxidative processes occur more intensively in subcutaneous than intermuscular fat, however, few differences were found compared to those found in ham lean.

Effect of the Iberian pig line on dry-cured ham characteristics

The purpose of this study was to compare the characteristics (chemical composition, instrumental colour, sensory characteristics and acceptance) of dry-cured hams obtained form three genetic lines of Iberian pig (Censyra, Torbiscal and Entrepelado). The instrumental colour of fat was affected by the genetic line (b(∗), p=0.008; and h°, p=0.024), the Censyra group having the largest values. The genetic line did not affect the chemical composition of the subcutaneous fat and lean of the dry-cured hams or the instrumental colour of the lean. Data from a descriptive analysis showed that the only characteristic significantly affected was the toasted flavour (p=0.004), and juiciness and sweetness were slightly affected (p=0.062 and 0.061, respectively). In spite of the slight effect on the physical-chemical and sensory characteristics, acceptance was significantly different, Torbiscal hams having the highest scores.

Note: Effect of Crossbreeding and Rearing System on Iberian Ham Volatile Compounds

Several volatile compounds from Iberian ham trapped from the headspace were analysed to research the effect of crossbreeding (Iberian vs. Iberian Duroc 50% pigs) and rearing system (Montanera system vs. Pienso system) on them. Thirty-four Iberian hams grouped following a factorial treatment structure were analysed. A two-way analysis of variance with interaction was applied to the data from 46 volatile compounds identified. The effect of crossbreeding was negligible on the studied volatile compounds, which was in agreement with the effect on fatty acid percentages of subcutaneous fat. On the contrary, the effect of rearing system was significant in most of the fatty acid percentages used to classify the hams into the current commercial grades of Iberian ham (16:0, 18:0 and 18:1, p<0.001). However, a slight effect on the volatile compounds was found, and only a limited number of compounds were significantly affected. Results for the effect of crossbreeding and rearing system on headspace volatile compounds agreed with the sensory data for odour of hams.

Characterisation of the most odour-active compounds of bone tainted dry-cured Iberian ham.

The most odour-active compounds of different bone tainted dry-cured Iberian hams were researched using the detection frequency method. Most of the odourants identified were found in all the Iberian hams (spoiled and unspoiled). Some compounds (ethyl butanoate, dimethyl disulfide, phenylacetaldehyde, acetic, propanoic, butanoic, 3-methylbutanoic and pentanoic acids) were identified in the spoiled hams as Iberian ham odourants for the first time. The detection frequency (DF) values for the spoiled and the unspoiled hams were markedly different. The main differences were found for 2-methylpropanal, ethyl-2-methylpropanoate, ethyl-2-methylbutanoate, phenylacetaldehyde and methional (the lowest DF values were found in the unspoiled ham) and hexanal (the largest DF value was found in the unspoiled ham). Spoiled hams with a different global odour had different DF values.

Sensory Characteristics and Consumer Preference of Smoked Dry-Cured Iberian Salchichon

The aim of the study was to investigate the effect of applying a traditional-like mild-smoking treatment on the sensory characteristics and the consumer preference of small and medium diameter dry-cured Iberian Salchichons. A paired comparison test revealed a significant effect of the smoking treatment, but the descriptive test showed just a slight effect on the characteristics of the small diameter sausage (i.e., smoked flavor and cohesiveness) and no effect on the medium diameter sausages. Smoking affected consumer response. The consumer segmentation was found to be, the preference of the younger people increased with sausage smoking, but not those of older people.

MADURACIÓN DEL JAMÓN IBÉRICO: EVOLUCIÓN DE ÍNDICES BASADOS EN COMPUESTOS VOLÁTILES IBERIAN HAM RIPENING: EVOLUTION OF VOLATILE COMPOUND-BASED INDICES

Abstract The aim of this work was to know the evolution of several summatories and indices (calculated using volatile compound data) during the ripening stage of Iberian ham. Several summatories and indices experienced significant changes through ripening, and therefore they could be used as indicators of the ripening time of Iberian ham. Furthermore, for most variables a significant equation of simple linear regression (including one variable and ripening time) was found, which could help to predict ripening time. With regard to the summatories, the best result was found for the equation including time and the sum of 2-methylpropanal, 2-methylbutanal, 2-methyl-1-butanol and dimethyldisulfide (R2 = 0.610). With regard to the indices, the best result was found for the equation including time and the percentage of lipid oxidation-derived compounds (R2 = 0.632). Resumen El objetivo de este trabajo fue conocer la evolución de distintos sumatorios e índices (calculados a partir de los compuestos volátiles) durante la maduración del jamón ibérico. Distintos sumatorios e índices experimentaron cambios significativos durante la maduración, por lo que podrían ser utilizados como indicadores del grado de maduración del jamón ibérico. Además, en la mayoría de los casos se obtuvo una ecuación de regresión lineal simple significativa incluyendo uno de los índices y el tiempo, lo cual podría permitir predecir el tiempo de maduración. En cuanto a los sumatorios, el mejor ajuste se obtuvo con la suma de 2-metilpropanal, 2-metilbutanal, 2-metil-1-butanol y dimetildisulfuro (R2 = 0,610). En cuanto a los índices, el mejor ajuste se consiguió con el porcentaje de compuestos volátiles procedentes de la oxidación respecto al total (R2 = 0,632). Palabras clave: Jamón Ibérico, maduración, compuestos volátiles