High-Hydrostatic-Pressure-Stabilized White Grape Pomace to Improve the Oxidative Stability of Dry-Cured Sausages ("Salchichón").

White grape pomace (winery by-product) stabilized by blanching and high hydrostatic pressure has recently been successful at delaying lipid oxidation in burgers. The aim of this study was to investigate whether it can also delay lipid oxidation in dry-cured sausages, and to compare its effect when added at 0.5 and 3% with those of synthetic additives (sodium nitrite and ascorbic acid) and no additives (Control) in lipid and protein oxidation, the instrumental color, the sensory characteristics, and the volatile compounds. The pomace (68.7 ± 7.4 mmol Trolox g-1) was as effective as the additives at preventing lipid oxidation, resulting in values 3.2-3.8 times lower than the Control sausages. However, the pomace was not effective at decreasing the microbial counts, improving the instrumental and sensory color and the volatile compound profile, and decreasing the off-odor and off-flavor developed in the Control sausages. The lack of a detrimental effect of the pomace at 0.5% on the volatile compounds and the sensory characteristics and its benefits to delay lipid oxidation suggest that it might be useful to improve the oxidative stability. Conversely, at 3%, with a detrimental effect on some sensory characteristics and no benefits over the lower dosage, is not advisable.

Variability within L. albus and L. angustifolius Seeds in Dietary Fiber Components.

Lupin seeds have received increased attention due to their applications in the nutrition of humans and livestock. One of their special features is their high content of dietary fiber, which is influenced by the lupin species. No previous studies have focused on the variability in dietary fiber and its fractions within species so far. The aim of this study was to investigate the variability within L. albus and L. angustifolius (eight cultivars each) in the dietary fiber composition expressed as low-molecular-weight soluble dietary fiber (LMWSDF), soluble and insoluble non-cellulosic polysaccharides, cellulose, and Klason lignin. Additionally, we analyzed the proximate composition and the composition of amino acids and fatty acids. The results showed noticeable variability within both species not only in the total dietary fiber but also in all its fractions, especially in LMWSDF, cellulose, non-starch polysaccharides, and Klason lignin within L. angustifolius. This indicates that the cultivar choice should be based on the application for which it is used. Even though important nutrients, such as the most indispensable amino acids, are not highly variable within L. albus, dietary fiber variations can still have a marked influence on the nutritional value because of their influence on the digestibility of other nutrients.

Effect of a Chitosan Coating Enriched with an Olive Leaf Extract on the Characteristics of Pork Burgers.

Chitosan coatings have been investigated for improving food shelf-life. The addition of an olive leaf extract could enhance its beneficial effect. The aim of this study was to evaluate the effectiveness of an olive leaf extract added to a chitosan coating in delaying deterioration in refrigerated pork burgers without additives packaged under a 40% oxygen and 60% carbon dioxide modified atmosphere. Some general parameters (microbial counts, instrumental color and texture, and lipid and protein oxidation) were measured over the storage of pork burgers without coating (Control), with a chitosan-based coating (Chitosan) and with a chitosan-based coating enriched with an olive leaf extract (Chitoex). The coating impacted the effect of the storage time on most parameters. Both coatings were especially effective at limiting the changes that occur over time in the headspace gases, some texture parameters (hardness, gumminess, and chewiness) and lipid oxidation, although the effect on the microbial counts was weak. Chitoex was more effective than Chitosan at preventing changes in the headspace gases on day 11 and in lipid oxidation on all the sampling days. In conclusion, the Chitoex coating could be useful for prolonging the storage of pork burgers by preventing changes in texture and reducing lipid oxidation.

High-pressure processing applied to sliced dry-cured Iberian loin: Effect of category, company, and storage temperature.

The main purpose of this study was to evaluate the effect of high-pressure processing (HPP) and storage temperature on the microbial counts, the instrumental color, and the oxidation stability of sliced dry-cured Iberian loin from two categories and two leading companies. 600 MPa for 8 min was sufficient to decrease all the microbial counts without affecting the color and the oxidation status, the effect being modulated by the loin category and company, whose effect on those variables was marked. However, the subsequent 90-day storage softened the initial effect of HPP on microorganisms and allowed a significant effect of HPP to develop on color and oxidation. In addition, the coliform counts were higher after storage at 20°C than at 4°C, suggesting that refrigeration may be needed during long-term storage to ensure loin safety.

New Insights into the Application of High-Pressure Processing and Storage Time and Temperature to Sliced Iberian Chorizo.

Producing dry-cured meats with relatively high aw and pH allows companies to cut costs to the detriment of microbial control. The purpose of this study was to evaluate for the first time the effect of High Processing Pressure (HPP) and storage temperature on the microbial counts, instrumental color, oxidation and sensory characteristics of sliced Iberian chorizo with high aw and pH. First, 600 MPa was applied for 480 s to sliced chorizo with aw: 0.88 and pH: 6.01, and the treated and untreated samples were stored at 4 or 20 °C for 90 or 180 days. HPP, storage time and storage at 20 °C were successful at decreasing the microbial counts that were initially high. HPP and the storage temperature had a limited detrimental effect, whereas the storage time had a marked adverse effect on oxidation and some sensory traits. Despite the high aw and pH, no safety issues arose initially or during the storage at 4 or 20 °C. In conclusion, for chorizo with high aw and pH favoring high microbial counts, HPP may be an effective hurdle without a noticeable detrimental effect, and the economically convenient storage at 20 °C might be beneficial despite causing moderate quality loss.

The Effect of Deep Frying French Fries and Two Types of Iberian Pork on the Characteristics of Extra Virgin Olive Oil and the Fried Products.

Although deep frying is widely used, little is known about the effect of frying different meats on the frying oil. The aims of this study were to investigate whether the pork type influences the characteristics of the frying oil, to compare any effects with those of French fries, and to research whether the use of thermally damaged oil differentially affects those products. French fries and pork from pigs reared outdoors on acorns and grass (outdoor) or indoors on a concentrated feed (indoor) were deep-fried in either raw or previously heated olive oil. The type of product affected most color parameters, K268 and the α-tocopherol content of the oil. The frying of outdoor pork hardly affected the α-tocopherol content, whereas the frying of indoor pork and especially French fries caused a significant decrease. This suggests that the meat type should be considered when setting the frying lifespan of olive oil. Regarding the fried products, L*, moisture (only French fries) and the malondialdehyde (MDA) content (only indoor pork) were the only parameters affected by the previous oil damage. The outdoor pork was less susceptible to oxidation than the indoor pork when the oil was severely damaged. Therefore, pig outdoor-based systems based on antioxidant-rich diets might be convenient to maintain oxidation at the lowest level after frying.

Effect of a rice bran extract-based active packaging, high pressure processing and storage temperature on the volatile compounds of sliced dry-cured high quality (Montanera) Iberian ham.

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.

Effect of the Organic Production and the Harvesting Method on the Chemical Quality and the Volatile Compounds of Virgin Olive Oil Over the Harvesting Season.

Organic production has increasing importance in the food industry. However, its effect on the olive oil characteristics remains unclear. The purpose of this study was to research into the effect of organic production without irrigation, the traditional harvesting methods (tree vs. ground picked fruits), and the harvesting time (over a six-week period) on the oil characteristics. Free acidity, peroxide value, K232, K270, ΔK, total phenols, oxidative stability and the volatile compound profile (by SPME extraction, gas chromatography and mass detection) of olive oils from the Verdial de Badajoz cultivar were analysed. The organic production affected the peroxide value, total phenols, oxidative stability and 34 out of 145 volatile compounds. Its effect was much less strong than that of the harvesting method, which affected severely all the chemical and physical-chemical parameters and 105 out of 145 volatile compounds. Conversely, the harvesting time was revealed as a factor with little repercussion, on the chemical and physical-chemical parameters (only peroxide value was influenced), although it affected 83 out of 145 volatile compounds. The larger content in total phenols in the organic oils than in the conventional ones could explain the increase in oil stability and the differences in the volatile compounds.

Effect of the genetic line and oleic acid-enriched mixed diets on the subcutaneous fatty acid composition and sensory characteristics of dry-cured shoulders from Iberian pig.

The aim of this study was to research the effect of the genetic background (Retinto, Torbiscal, and their reciprocal crosses) on the subcutaneous fatty acids and the sensory characteristics of dry-cured shoulders from Iberian pig, and also to investigate whether there is some interaction between genotype and diet composition when pigs are reared indoors, to obtain information to improve the selection strategies for purebred Iberian pig. The genetic background affected both the fatty acid composition (C17:0, C17:1 n-7, C18:3 n-3 and C20:0 were significantly different) and the sensory characteristics (marbling, lean fibrousness, and flavour intensity and persistence were significantly influenced), which indicates that they should be taken into account in the selection strategies for purebred Iberian pig. In a similar way, the genotype × diet composition interaction also should be taken into account when selecting a genetic line or cross to be fed indoors on a particular diet because of its repercussion on the sensory characteristics.

Malondialdehyde interferes with the formation and detection of primary carbonyls in oxidized proteins.

Carbonylation is one of the most remarkable expressions of the oxidative damage to proteins and the DNPH method the most common procedure to assess protein oxidation in biological samples. The present study was elicited by two hypotheses: i) is malondialdehyde, as a reactive dicarbonyl, able to induce the formation of allysine through a Maillard-type reaction? and ii) to which extent does the attachment of MDA to proteins interfere in the assessment of protein carbonyls using the DNPH method? Human serum albumin (HSA), human hemoglobin (HEM) and ß-lactoglobulin (LAC) (5 mg/mL) were incubated with MDA (0.25 mM) for 24 h at 37 °C (HSA and HEM) or 80 °C (LAC). Results showed that MDA was unable to induce oxidative deamination of lysine residues and instead, formed stable and fluorescent adducts with proteins. Such adducts were tagged by the DNPH method, accounting for most of the protein hydrazones quantified. This interfering effect was observed in a wide range of MDA concentrations (0.05-1 mM). Being aware of its limitations, protein scientists should accurately interpret results from the DNPH method, and apply, when required, other methodologies such as chromatographic methods to detect specific primary oxidation products such as allysine.

SIFT-MS analysis of Iberian hams from pigs reared under different conditions.

The aim of this study was to investigate the usefulness of a Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) equipment to tentatively quantify relevant volatile compounds of dry-cured Iberian ham, and to differentiate Iberian hams from pigs reared at four different conditions yielding different commercial grades. The SIFT-MS analysis allowed the rapid quantification of 39 Iberian ham volatile compounds, 16 of them being significantly affected by the rearing conditions of pigs. The full spectra SIFT-MS data allowed the correct classification of 79.2% of hams according to diet, which is a smaller percentage than that obtained using intramuscular fatty acid data (95.8%) obtained by using a gas chromatograph-flame ionization detector after lipid extraction and transesterification. Therefore, the SIFT-MS analysis would be a rapid tool to tentatively quantify some relevant volatile compounds, and also would provide a rapid but rough classification of Iberian ham according to the rearing conditions of pigs.

Study of the volatile compounds and odor-active compounds of dry-cured Iberian ham extracted by SPME.

The volatile compounds and the most odor-active compounds of dry-cured Iberian ham were investigated by extracting them using a solid phase microextraction technique with a 2 cm Carboxen/PDMS/DVB fiber. The detection frequency method was applied to estimate the potential contribution of each compound to the odor of hams. Twenty-one volatile compounds were tentatively identified for the first time in dry-cured ham by gas chromatography-mass spectrometry, and eight in dry-cured Iberian ham. Gas chromatography-olfactometry allowed the identification for the first time of six compounds not previously reported as odorants of Iberian ham, and also two odorants were newly identified in dry-cured ham. According to the detection frequency method, the most odor active compounds found were 3-methylbutanoic acid (dirty sock-like smelling), hexanal (cut grass-like odor), 3-methylbutanal (sweaty and bitter almond-like odor), 2-methyl-3-furanthiol (toasted nuts-like odor) and 1-octen-3-one (mushroom-like odor).

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.

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.

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).

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.

Odor-active compounds of Iberian hams with different aroma characteristics.

The odor-active compounds of different commercial types of Iberian hams (Montanera and Pienso) were researched by gas chromatography-olfactometry based on a detection frequency method. The hams (long- and short-Montanera and Pienso Iberian hams) showed different sensory profiles, differences being significant for Montanera ham typical odor, aroma intensity and persistence, and cured and moldy aroma. Significant differences were also found for some odorants. The largest differences appeared in 2-acetyl-1-pyrroline, hexanal, (Z)-3-hexenal, ethyl 2-methylbutyrate, (E)-2-hexenal, 1-octen-3-one, 1-octen-3-ol, 2-propionyl-1-pyrroline, octanal, and an unknown odorant. Sensory characteristics and olfactometric profiles were significantly different between Montanera and Pienso hams. Significant differences also appeared between long- and short-Montanera hams, which shows great variability in this commercial type. Otherwise, the largest scores for moldy aroma in long-Montanera hams matched with the largest detection frequency of 1-octen-3-one and 1-octen-3-ol in this group.

Characterization of the most odor-active compounds of Iberian ham headspace.

Gas chromatography-olfactometry (GC-O) based on detection frequency (DF) was used to characterize the most odor-active compounds from the headspace of Iberian ham. Twenty-eight odorants were identified by GC-O on two capillary columns, including aldehydes (11), sulfur-containing compounds (7), ketones (5), nitrogen-containing compounds (2), esters (2), and an alcohol. Among them, the highest odor potencies (DF values) were found for 2-methyl-3-furanthiol, 2-heptanone, 3-methylbutanal, methanethiol, hexanal, hydrogen sulfide, 1-penten-3-one, 2-methylpropanal, ethyl 2-methylbutyrate, and (E)-2-hexenal. Nine of the 28 most odor-active compounds were identified for the first time as aroma components of dry-cured ham, including hydrogen sulfide, 1-penten-3-one, (Z)-3-hexenal, 1-octen-3-one, and the meaty-smelling compounds 2-methyl-3-furanthiol, 2-furfurylthiol, 3-mercapto-2-pentanone, 2-acetyl-1-pyrroline, and 2-propionyl-1-pyrroline.