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This study aimed to evaluate a pomegranate peel extract (PPE), selected for its level of phytochemical compounds and antioxidant activities, as a nitrite substitute in dry sausages, as well as its effect on lipid and protein oxidative changes and instrumental colour during the drying period (28 days). Of the extraction solvents screened, water: acetone 3:7 (v/v) was the most effective extraction solvent, yielding extracts with the highest content of phenolic compounds, flavonoids and condensed tannins and antioxidant activities (ABTS, DPPH and FRAP). Four batches of dry sausages were produced with different incoming amounts of sodium nitrite (NaNO 2 ) and PPE: 1) 150 ppm NaNO 2 ; 2) 0 ppm NaNO 2 ; 3) 0 ppm NaNO 2  + 1% PPE (v/w) and 4) 0 ppm NaNO 2  + 2% PPE (v/w). Nitrite removal increased lipid oxidation in uncured dry sausages, while nitrite and PPE caused lower TBA-RS values in cured and PPE treated sausages. During drying, both nitrite and PPE addition significantly decreased carbonyl and thiol contents compared to the uncured dry sausages. A dose-response was found for PPE, with lower carbonyl and thiol concentrations, the higher the level of PPE added. PPE significantly modified instrumental colour coordinates L*a*b* producing significant total colour changes compared to cured dry sausages., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ramon Cava Lopez reports financial support and administrative support were provided by FEDER and JUNTA DE EXTREMADURA., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Dry-cured loins from three different pig genotypes were studied: GEN1: ♂ Iberian×♀ Duroc1, GEN2: ♂ Duroc1×♀ Iberian; GEN3: ♂ Duroc2×♀ Iberian. GEN1 and GEN2 are reciprocal crosses, while the difference between GEN2 and GEN3 is the Duroc sire line. The genotype of pigs Duroc1 was selected for the manufacture of dry-cured meat products, while the genotype Duroc2 was selected for meat production. The chemical composition of the dry-cured loins was significantly different, especially the intramuscular fat (IMF) content which was highest in GEN2. Dry-cured loins from GEN3 showed lower CIE a(∗) and chroma values. IMF from GEN2 was more saturated whereas GEN3 had higher percentages of PUFA and MUFA. Loins from GEN3 had higher TBA-RS values (p>0.05) and hexanal contents. Loins from GEN3 had higher Warner-Bratzler shear force (p>0.05) and instrumental hardness than those from GEN2, being intermediate in GEN1. Panellists considered that loins from GEN2 were more marbled, more odorous, juicier, sweeter and less salty than loins from GEN3. Therefore, loins from GEN2 had the best quality, followed by GEN1, while GEN3 had the worst quality.

The aim of this study was to investigate the effect of the Iberian×Duroc reciprocal cross on: (i) productive parameters, (ii) physico-chemical traits of three muscles with different oxidative patterns (Longissimus dorsi, Biceps femoris and Psoas maior) and (iii) lipogenic enzyme activities (glucose-6-phosphate dehydrogenase and malic enzyme) in subcutaneous adipose and muscle tissues. Fourteen Duroc-sired (Duroc♂×Iberian♀) and 14 Iberian-sired castrate male pigs (Iberian♂×Duroc♀) were selected at weaning and were reared until 235 days of age. Iberian-sired pigs had significantly higher weight at slaughter (147.7kg vs. 138.8kg, p<0.05) as well as a greater ham and foreleg weight than Duroc-sired pigs. The fatty acid composition of subcutaneous adipose tissue of Duroc-sired pigs showed a higher percentage of C18:0 (13.21% vs. 14.34%, p<0.05) and a lower percentage of monounsaturated fatty acids (47.79% vs. 46.73%, p<0.05) compared to that from Iberian-sired pigs. Contrary to productive parameters, there were no noticeable differences between reciprocal cross in parameters defining meat quality, although there was a clear muscle effect on such parameters with this effect being significant for most of the traits. No differences were found between reciprocal crosses for glucose-6-phosphate dehydrogenase and malic enzymes activities in both muscular and subcutaneous adipose tissues. Lipogenic enzyme activities were considerably higher in subcutaneous adipose tissue compared to muscles. Glucose-6-phosphate dehydrogenase activity did not differ (p>0.05) between muscles, whereas malic enzyme activity was higher (p<0.05) in Psoas maior compared to Biceps femoris and those were higher than in Longissimus dorsi, which was consistent with the positive correlations (p<0.05) found between malic enzyme activity and traits defining oxidative metabolic type. On the contrary, negative correlations (p<0.05) were found between malic enzyme activity and intramuscular fat content, which could suggest that there are differences among muscles in the ability of depositing fatty acids from other tissues.

The antioxidant effect of two plant essential oils (sage and rosemary) and one synthetic antioxidant (BHT) on refrigerated stored porcine liver pâté (4°C/90 days) was evaluated. Pâtés with no added antioxidants were used as controls. Liver pâtés were analysed for protein oxidation, modification of heme (HI) and non-heme iron (NHI) concentrations, and colour and texture characteristics at days 0, 30, 60 and 90 of refrigerated storage. The amount of carbonyls from protein oxidation significantly (p<0.05) increased during refrigerated storage, and this increase was significantly higher in the control pâtés than in their treated counterparts. Antioxidants successfully protected heme molecules from degradation and significantly inhibited the increase of NHI in refrigerated stored liver pâtés. Colour changes seemed not to be directly related to oxidative processes since pâtés with added antioxidants suffered greater colour modifications than the controls. The addition of rosemary essential oil significantly reduced hardness of liver pâtés. Sage and rosemary essential oils exhibited similar antioxidant properties to BHT denoting their suitability as alternatives to synthetic antioxidants.

The effect of increasing levels (150, 300 and 600ppm) of rosemary essential oil on lipid and protein oxidation and the increase of non-heme iron (NHI) content during refrigeration (+4°C/60 days) of frankfurters produced with tissues from Iberian pigs (IF) or white pigs (WF), was studied. Frankfurters with no added essential oil were used as controls. Iberian pigs were free-range reared and fed on acorns and pasture whereas white pigs (Large-white×Landrance) were intensively reared and fed on a mixed diet. Large differences were detected between types of frankfurters (Iberian vs white) in terms of fatty acid composition and tocopherols content due to the different feeding background of the animals. The effect of the addition of rosemary essential oil on the oxidative stability of frankfurters depended on the level of added essential oil and the characteristic of the frankfurter. The rosemary essential oil successfully inhibited the development of lipid and protein oxidation in IF with that antioxidant effect being more intense at higher concentrations of essential oil. In WF, 150ppm rosemary essential oil showed an antioxidant effect, significantly reducing the generation of lipid and protein oxidation products. At higher levels (300 and 600ppm) the essential oil had, in general, no effect on lipid oxidation while significantly enhanced the oxidation of proteins and the release of iron from myoglobin. The presence of certain amounts of tocopherols in the frankfurters could have influenced the activity displayed by the added essential oil leading to antioxidant or prooxidants effects though the different fatty acid composition and oxidative status between frankfurters could also have had an effect.

Physico-chemical characteristics and different quality traits of the raw material (meat and adipose tissue) and the frankfurters elaborated from extensively reared Iberian pigs (IF) and intensively reared white pigs (WF) were evaluated. Hybrid frankfurters (HF) made with meat from white pigs and adipose tissue from Iberian pigs were also studied. The differences found between muscles and adipose tissues from Iberian and white pigs largely influenced the characteristics displayed by the frankfurters. Particularly remarkable are the higher amounts of substances with proven antioxidant activity such as tocopherols and phenolic compounds in tissues from Iberian pigs than in those from white pigs. No significant differences were found amongst frankfurters for their proximate composition though IF presented a higher iron content than WF and HF. IF exhibited a redder and darker colour than WF and HF. The latter were paler and showed higher hue values than IF. Concerning their fatty acid composition, IF had higher proportions of oleic acid and MUFA and smaller proportions of SFA and PUFA than WF. From a nutritional point of view, IF had a lower n-6/n-3 value than WF. The addition of adipose tissue from Iberian pigs to the HF modified its fatty acid composition compared to that of WF, significantly increasing the percentages of MUFA and reducing the proportions of PUFA, SFA and the n-6/n-3 value. Though no significant differences were found amongst frankfurters for their texture profile, a clear trend was detected, with the HF showing intermediate texture characteristics between IF and WF.

The physico-chemical characteristics of a traditional Finnish liver sausage (FLS) and different types of Spanish porcine liver pâtés (commercial, home-made and experimental) were studied. The characteristic recipes and different protocols of manufacture influenced the chemical composition and oxidative stability of the liver products. FLS showed, amongst the liver products, the smallest percentage of monounsaturated fatty acids (MUFAs) and the highest of polyunsaturated fatty acids (PUFAs) acids, including long-chain PUFAs. From a nutritional point of view, the FLS showed the smallest n-6/n-3 value whereas the experimental liver pâté (ELP) presented the smallest ratio between hyper- (lauric, myristic and palmitic acids) and hypocholesterolemic fatty acids (oleic and linoleic acids). A large variety of volatile compounds were isolated from the liver products including lipid-derived volatiles, Strecker aldehydes and alcohols, sulphur and nitrogen containing compounds and volatile terpenes, providing information on their oxidative stability and aroma characteristics. The FLS presented a balanced profile between lipid-derived volatiles and volatile terpenes from spices. The presence of potent odorants from added flavourings in the commercial liver pâté (CLP) could mask undesirable aroma odours from a large variety of lipid-derived volatiles. The home-made liver pâté (HMLP) also presented large amounts of lipid-derived volatiles as a likely consequence of strong thermal treatment during cooking, the presence of high amounts of iron and the absence of sodium nitrites and ascorbate in its composition. The ELP showed the simplest profile due to its high oxidative stability and the absence of added spices.

In the present work, lipid and protein oxidation, increase of non-heme iron (NHI) content and colour changes occurring during refrigerated storage (90 days/4 °C) of liver pâtés from Iberian and white pigs were studied. Iberian pigs were reared outdoors and fed on natural resources (grass, acorns) while white pigs were intensively reared and fed on a mixed diet. Lipid and protein oxidation were, respectively, measured by determining TBA reactive substances (TBARS) and protein carbonyl groups. Pâtés from Iberian pigs had better oxidative stability at all stages of storage, having lower amounts of TBARS and carbonyls compared to those from white pigs (p<0.05). NHI increased during refrigerated storage of liver pâtés, with those from white pigs having a higher amount of NHI at all stages of storage (p<0.05). During refrigerated storage, L(*)-values tended to increase while the evolution of a(*) and b(*) depended on the group and did not seem to be related to the oxidative processes.

The oxidative stability and colour evolution during refrigerated storage (10 days at +4 °C) of Longissimus dorsi muscle from three lines of Iberian pigs and industrial genotype pigs were studied. The Iberian pigs were reared in an extensive system and fed on a commercial feed with access to pasture grazing, while industrial genotype pigs were reared in an intensive system. Fresh Longissimus dorsi of Iberian pig lines showed a more intense and redder colour, with a statistically significant higher CIE chroma and a*-value as well as a lower L*-value (P<0.05) compared with those of industrial genotype pigs. Pig genotype significantly affected the colour and lipid oxidation changes of m. Longissimus dorsi during refrigerated storage. The decrease in L*-value during the refrigerated storage was more intense in industrial pig's Longissimus dorsi than in those from Iberian pig lines. CIE a*-value decrease was more intense in 'Lampiño' Iberian line and industrial Longissimus dorsi than in the other two Iberian pig lines, however CIE a*-value was significantly higher in muscles from Iberian pig lines than in muscle of industrial genotype (P<0.05) at the end of refrigerated storage. The Iberian and industrial pig's Longissimus dorsi did not show statistically significant differences in TBA-RS values (mg MDA/kg meat) at the end of the refrigerated storage period (P>0.05). To establish relationships between parameters measured in fresh meat and oxidation and colour changes during refrigerated storage, correlations and multiple regression models were calculated. CIE a*-values at day 10 were positively correlated with values of fresh muscles for a*, C18:1 percentages and negatively correlated with polyunsaturated fatty acids percentages of neutral and polar lipids. Inversely, TBA-RS values at day 10 showed a positive correlation with initial values for phospholipid content and polyunsaturated fatty acids of neutral and polar lipid fractions, while C18:1 percentage were negatively correlated.

Three different type of muscles, two glicolytic (Serratus ventralis and Longissimus dorsi) and one oxidative (Masseter) were displayed under refrigeration at +4 °C during 10 days to evaluate differences in lipolytic and oxidative changes of different muscles with different metabolic pattern. Thiobarbituric acid reactive substances (TBARS), phospholipid content, hexanal content and fatty acid profiles of neutral and polar lipid fractions were analysed at day 0 and day 10. Phospholipid content (g phospholipids/g intramuscular fat) significantly (P<0.035) decreased from day 0 to day 10 in m. Masseter (0.33 vs. 0.25, respectively), but not in m. L. dorsi (0.12 vs. 0.09, respectively) and m. S. ventralis (0.19 vs. 0.14, respectively). Changes in fatty acid profiles of neutral and polar lipids significantly differed among muscles after storage. Slight differences were found in neutral lipids from m. L. dorsi and m. S. ventralis, while neutral lipids from m. Masseter were highly altered. Great changes affected fatty acid profiles from polar lipids in the three muscles. m. Masseter muscle showed significantly higher (P<0.000) TBARS values (1.13, 0.65 and 0.60 mg MDA/kg meat, respectively) and hexanal content (689.2, 241.2 and 355.8 μg/g meat, respectively) than m. L. dorsi and m. S. ventralis. In conclusion, oxidative meat is more prone to oxidative and lipolytic deterioration than glycolytic muscles during refrigerated storage and as a consequence of that a lower shelf-life.

Three muscles from free-range reared pigs with different metabolic pattern were studied. m. Masseter (M), m. Longissimus dorsi (LD) and m. Serratus ventralis (SV) the first having an oxidative metabolism and the other two an intermediate and glycolytic metabolism. m. Masseter contained the highest content of myoglobin (M: 6.65 mg/g, LD: 3.00 mg/g and SV: 3.64 mg/g; P<0.001) and exhibited the highest CIE a* (M:17.10, LD: 14.83, SV:15.34, P<0.001) and C* (M: 17.95, LD: 15.61, SV: 15.54, P<0.001) values. m. L. dorsi and S. ventralis contained a higher intramuscular fat content than m. Masseter (M: 2.26 g/100 g muscle, LD: 4.79 g/100 g muscle, SV: 3.52 g/100 g muscle, P=0.001) and lower amounts of phospholipids (M: 0.33 g/g imf, LD: 0.12 g/g imf, SV: 0.19 g/g imf; P<0.001). Fatty acid profiles from total intramuscular fat and lipid fractions, neutral lipids and polar lipids, significantly differed among muscles, there being a higher content of unsaturated fats (especially in the C18:2 and C20:4 percentages) in the m. Masseter than in the other two muscles analysed. Comparatively, muscles from 90 kg live weight Iberian pigs contained more fat and heme pigments and were redder than those from the commercial pig crosses usually produced.