Dry-cured Loin Research Articles

Fatty acids and sensory characteristics of Spanish dry-cured loin enriched in acid α-linolenic and α-tocopherol

The effects of using α-linolenic and α-tocopherol acid-enriched pork on the fatty acids and sensory characteristics of Spanish dry-cured loins were investigated. For the study, five batches of Spanish dry-cured loins were manufactured using pork loin enriched in polyunsaturated n − 3 fatty acids and α-tocopherol. Tissues were obtained from pigs fed on diets with the same ingredients, except for the oil source which corresponded to: [sunflower (C), linseed (L) and linseed and olive (1/1, w/w) (LO)] and two different amounts of α-tocopheryl acetate [20 (C, L and LO) or 200 (LOE and LE) mg/kg diet]. Dry-cured loins with polyunsaturated fatty acid n6/ n3 ratios below 4 were obtained from linseed and linseed/olive oil-enriched batches. Dry-cured loin manufactured with pork from animals fed on diets enriched only with linseed oil presented the worst sensory characteristics and higher TBAR values than did dry-cured loins from animals fed on diets enriched with linseed and olive oil and linseed oil plus tocopheryl acetate.

Protein and lipid oxidation in Longissimus dorsi and dry cured loin from Iberian pigs as affected by crossbreeding and diet

Lipid and protein oxidation in Longissimus dorsi (LD) and dry-cured loins from pigs with different genetic (pure Iberian (IBP), Iberian female × Duroc male (IB × D) and Duroc female × Iberian male (D × IB)) and feeding backgrounds (free rearing on acorn and pasture (MON), concentrates high in oleic acid and supplemented with 250 ppm of vitamin E(HOVE) and control concentrates (CON)) were investigated. Diet influenced the fatty acids profile from PL and α- and γ-tocopherol contents of LD. IBP–MON pigs showed the lowest malonaldehyde (MDA) values at 200 min of iron induced muscle oxidation. Dry-cured loins from IBP–HOVE pigs had significantly ( p < 0.05) higher values of TBARS than those from the other batches. Neither the diet nor crossbreeding affected hexanal counts in dry-cured loins. Protein carbonyl content showed a similar trend to that observed for MDA values in LD, suggesting a protective role of tocopherol against lipid and protein oxidation. The positive and significant correlations between iron induced lipid oxidation in LD (200 min) and carbonyl content in LD and dry-cured loin ( R 2: 0.55 and R 2: 0.52, respectively, p < 0.01) support the relationship between lipid and protein oxidation.

Colour and lipid oxidation changes in dry-cured loins from free-range reared and intensively reared pigs as affected by ionizing radiation dose level

The effect of irradiation (0, 5 and 10 kGy) of vacuum-packaged Iberian dry-cured loin slices from pigs fed on concentrate (CON) or free-range reared (FRG) was studied in relation to colour changes, TBA-RS and hexanal content. Both, ionizing radiation and type of loin had a significant effect on the instrumental colour parameters of the samples. Irradiation resulted in significantly higher a*-values in both sets of loins, indicating a redder colour. Numerically calculated total colour difference (Δ E) changes were significantly less intense in CON vacuum-packaged dry-cured loin slices than in FRG samples and changed significantly at 10 kGy dose levels in both types of samples. TBA-RS numbers were significantly affected by irradiation dose and type of loin and increased linearly with dose in both types of slices. Increments in TBA-RS numbers in FRG loin slices was dose-dependent and was closely related to the type of dry-cured loin. Irradiation of dry-cured loin slices significantly increased hexanal contents in both groups of loins and the increases were dose-dependent and greater in FRG samples than in CON samples. Differences in the characteristics of the raw material and initial lipid oxidation level could play an important role in the irradiation-induced changes in vacuum-packaged dry-cured loin slices.

Analyzing magnetic resonance images of Iberian pork loin to predict its sensorial characteristics

Iberian pork comes from genuinely bred Southwest Iberian Peninsula pigs traditionally fattened with acorns and pasture in an extensive production system. Dry-cured loins and hams constitute the main uncooked pork products with high sensorial quality and a first rate consumer acceptance, leading to high prices in the market. Several aspects related to quality in Iberian products have been examined by using chemical and sensorial procedures to provide quality. However, all these approaches are tedious and destroy the item. In addition, food science has shown little interest in MRI to explore meat products in a non-invasive way. Therefore, this paper introduce an objective and non-destructive methodology to classify Iberian loins consistently. It is based on texture analysis of MRI images displaying dry-cured pork loins. A statistical evaluation is provided for a set of 47 loins to predict three levels of different sensorial characteristics.

Profiles of water content, water activity and texture in crusted dry-cured loin and in non-crusted dry-cured loin

This study compares the profiles of water activity (aw), water content (X) and texture in loin with crusted surface versus those profiles in loin without crust, and establishes a mathematical model able to describe hardness based on aw and/or X. Two loins (m. longissimus dorsi) were dry-cured, aged and then each one was divided into four pieces. Two of them were dried at 15±2 °C, 50±3% RH (CL treatment) and the other two were dried at 2±2 °C, 80±3% RH (NCL treatment). The pieces of CL were dried under more severe conditions in order to develop a crust on the surface. Three-millimetre thick slices were taken from the most external part towards the inner part. The slices were prepared (10×10×3 mm) for texture profile analysis (TPA). Measurements of aw and X were carried out on each slice. Variance analyses and non-linear regression analyses were performed to create a model for loin hardness prediction through X and/or aw and a linear regression model for cohesiveness and springiness. CL loins showed a higher hardness and chewiness and lower cohesiveness at the surface (3-mm thickness) than the NCL loins. Hardness and chewiness, fitted with a non-linear model, were better described by X than by aw. Springiness showed a low relationship with X and aw. The on-line monitoring of X and aw at the surface of the product would enable an estimation of the profiles of water content, aw and texture and it could be, therefore, a useful tool to avoid crusting.

Volatile compounds on the surface and within Iberian dry-cured loin

The profile of volatile compounds from external and internal areas of Iberian dry-cured loin was studied by headspace solid-phase microextraction. Higher levels of 16 volatile compounds (hexane, decane, 3-methylbutanal, several sulphur compounds and some aromatic hydrocarbons) were detected in the outer part of the loins. These differences could be owing to several factors, such as greater exposure to oxygen and dehydration conditions in the surface of the product, which favour oxidation reactions and Strecker degradation of amino acids. Moreover, the addition of spices on the surface and the proximity of a mould layer growing on the surface of the product could also contribute to the higher levels of these compounds on the external layer. However, other sulphur compounds coming from spices showed similar levels on the surface and within the loins. This different behaviour could be a consequence of different diffusion rates depending on the features of the compound and the matrix.

Stereospecific analysis of fresh and dry-cured muscle phospholipids from Iberian pigs

A stereospecific analysis of phospholipids (PLs) from fresh and dry-cured Iberian loin was carried out in order to study the fatty acid and fatty alcohol composition of sn-1 and sn-2 positions as well as the changes in the profile of each position during the dry-cured processing. The profiles of fatty acids and alcohols in the sn-1 and sn-2 positions of PLs from fresh loin showed marked differences. Fatty alcohols were only detected in the sn-1 position. Saturated fatty acids (SFA) were located in the sn-1 position in a higher proportion ( P<0.001) than in the sn-2 one, while polyunsaturated fatty acids (PUFA) were mainly occupying the sn-2 position ( P<0.001). Dry-cured processing led to changes in the profile of each position. Thus, PUFA showed a marked decrease in the sn-2 position, monounsaturated fatty acids (MUFA) being the major family in this position in dry-cured loin PLs. Proportions of fatty alcohols in the sn-1 position increased during the processing, agreeing with the scarce or absent phospholipase (PLase) A 1 activity against the ether linkage. Moreover, no variation in the calculated amount of plasmalogens was detected between fresh and dry-cured samples, whereas there was a significant decrease ( P<0.001) in both total PLs and diacylglycerophospholipids. All these changes are most likely due to lipolytic processes rather than to lipid oxidative phenomena, although the latter could also be implied in the sn-2 PUFA decrease.

Volatile compounds in Iberian dry-cured loin

The volatile profile of Iberian dry-cured loin from four different Iberian pig lines (Entrepelado, Lampiño, Retinto and Torbiscal) and two feeding systems (OUT – fed on acorn and grass-vs.-IND – fed on high oleic acid concentrate) was studied using solid phase microextraction (SPME). 133 volatile compounds were identified and assigned to 16 chemical families. Alcohols were the major group, ethanol being the main compound. The high number of esters detected and the levels of ethanol and acetic acid found, points to an important role of microorganism activity in the formation of volatile compounds in Iberian dry-cured loin. Sulphur compounds, coming mostly from garlic, constituted an important group, with 14 compounds. Significant differences were found among loins from pigs reared in different feeding systems but not among Iberian pig lines. Dry-cured loins from OUT pigs showed higher levels of many compounds derived from lipid oxidation, such as octanoic acid ( P=0.000), decanoic acid ( P=0.018) or hexanal ( P=0.014).

Physico-Chemical and Sensory Characteristics of Dry-Cured Loin from Different Iberian Pig Lines

The influence of the line of Iberian pigs (Entrepelado, Lampino, Retinto and Torbiscal) on dry-cured loin sensory traits and its relationship with several physico-chemical characteristics were analysed. Entrepelado and Lampino lines showed a higher intramuscular fat content (P 1/4 0.034). These lines reached the highest 0.010) and flavour (P 1/4 scores for brightness (P 1/4 0.005), odour intensity (P 1/4 0.043), marbling (P 1/4 0.017). Weight losses showed a positive relationship with some texture features, as hardness and dryness, and a negative one with juiciness according to the principal component analysis (PCA). Marbling was positively linked to odour intensity, juiciness and flavour intensity. These latter sensory traits have been previously linked to dry-cured meat products acceptability. Thus, dry-cured loins from Entrepelado and Lampino Iberian pigs seem to have better sensory profiles, mainly due to their more intense marbling.

Lipolytic and oxidative changes in two Spanish pork loin products: dry-cured loin and pickled-cured loin

Lipolytic and oxidative changes were studied in two typical meat products from pork loin, dry-cured loin (DCL) and pickled-cured loin (PCL). Neither product registered changes in the percentages of the main lipid fractions: non polar lipids, phospholipids and cholesterol. However, in dry cured loin an important decrease was recorded in the main phospholipid classes, phosphatidyl choline and phosphatidyl ethanolamine. Muscle lipolytic enzymes were active in both products, and were accompanied by a significant increase in free fatty acids, from 0.580% (of total lipid) in fresh loin to 5.65 in DCL and 2.95% in PCL. With respect to oxidative changes, the peroxide value decreased in both products, and the TBA number only increased in PCL.

Feedback Inhibition of Porcine Muscle Alanyl and Arginyl Aminopeptidases in Cured Meat Products

Alanyl and arginyl aminopeptidases from porcine skeletal muscle were purified, and the effect of free amino acids on their activities was studied. Both aminopeptidases were inhibited by free amino acids via the competitive mode and were more strongly inhibited in the pure form than when they were in the meat extract. Arginyl aminopeptidase (RAP)was less susceptible to inhibition by free amino acids than alanyl aminopeptidase (AAP), as shown especially by the strong inhibitory effect of hydrophobic amino acids on AAP activity in the meat extract. The free amino acid concentration present in meat products such as dry-cured loin and dry-cured ham produced a strong inhibitory effect on AAP and RAP activity. The concentration of free amino acids in cooked ham mainly affected the activity of AAP. These facts can explain the differences obtained in free amino acid concentration depending on the kind of process or product. Keywords: Aminopeptidase; muscle exopeptidases; peptidase inhibitor; amino acid

Potassium chloride, potassium lactate and glycine as sodium chloride substitutes in fermented sausages and in dry-cured pork loin

Salt is essential in the elaboration of dry meat products, contributing to their texture and flavour development. The effect brought about by substituting NaCl with KCl (0–60%), potassium lactate (0–100%) and glycine (0–100%) on the texture, flavour and colour characteristics of fermented sausages and dry-cured pork loins was evaluated. Texture profile analysis and a sensory analysis were performed. Important flavour defects were detected with substitutions above 40% for the three substituents in both products, and with substitutions above 30% for glycine in dry-cured loin. A loss of cohesiveness was detected by the sensory analysis in fermented sausages at substitution levels higher than 30% with potassium lactate ( K-lactate) and higher than 50% with glycine. Although the instrumental analysis detected texture changes in dry-cured loin, the sensory analysis did not detect any substitution effect on texture.