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The objective of this study was to identify particular wine components as responsible for the bioactivities observed in marinated bovine muscle Longissimus lumborum during 7 days of refrigerated storage at 4 °C. Depending on the grape variety, four marinades were considered (300 mL dealcoholized wine/kg meat): Carbernet (CAB), Tempranillo (TEM) and Isabel (ISA), including a control group of samples. CAB and TEM, rich in procyanidins, were more effective against lipid oxidation while ISA, rich in hydroxycinnamic acids, protected proteins against oxidation more efficiently. The lower Warner Bratzler shear force values in beef stakes marinated with ISA could be explained by the inhibition of protein cross-linking. Caftaric acid, the most abundant hydroxycinnamic acid in ISA, was tentatively identified as responsible for this relevant bioactivity. The particular phenolic composition of ISA wine and its high content in organic acids, may explain its effects against Enterobacteriaceae while sugars may have promoted the growth of lactic-acid bacteria in beef marinated with CAB and TEM.

High-oxygen packaging atmosphere (High-Ox-MAP) promotes meat protein oxidation and leads to texture deterioration. This study was conceived to assess the extent to which sprayed fruit extracts could inhibit the oxidative damage to proteins in lamb cutlets subjected to High-Ox-MAP (10 days/4 &deg, C) and subsequent roasting (10 min/180 &deg, C). Extracts from oaknut (Quercus ilex subsp. ballota, QI), rose hips (Rosa canina L., RC), common hawthorn (Crataegus monogyna Jacq., CM) and strawberry tree (Arbutus unedo L., AU) were characterized for bioactive compounds (phenolic subclasses, tocopherols and ascorbic acid) and in vitro bioactivities. While the four fruits showed relevant antioxidant potential, CM had the highest phenolics and tocopherol content and that was reflected in efficient antiradical activity. The in vitro activity of this fruit to inhibit meat protein oxidation was, however, lower than that displayed by the other fruits. Taking the results altogether, CM was also found to be most efficient in protecting lamb cutlets from lipid oxidation. All fruits were able to inhibit thiols oxidation except RC, which seemed to reduce protein thiols. Among fruits, QI was the most efficient in protecting lamb cutlets against protein carbonylation as a plausible involvement of ellagitannins. The inhibition of protein oxidation by QI was reflected in significantly lower instrumental hardness in cooked lamb cutlets. Spraying lamb cutlets with extracts from QI, RC and CM improved consumers&rsquo, purchase intention after chilled storage. This antioxidant strategy seems to be a feasible and efficient solution to the pro-oxidative effects caused by High-Ox-MAP in red meat.

Sustainability of the Mediterranean forest is threatened by oak decline, a disease of holm oak and other Quercus species that is initiated by infection with the oomycete Phytophthora cinnamomi. Focusing on the role of tannins in the chemical defense of plants, this work investigated whether tannins content in Quercus ilex is regulated by biotic stress. Screening of published genomes allowed the identification of Quercus sequences encoding enzymes for early steps of the biosynthesis of phenolic compounds, like hydrolysable tannins and condensed tannins (CT) among others, plus genes involved in the late steps of CT biosynthesis. Four days after treatment of Q. ilex seedlings by mechanical defoliation, P. cinnamomi infection and both stressors simultaneously, mRNA concentrations for tannins biosynthesis enzymes were measured in leaves. Among the transcript amount for shikimate dehydrogenase (SDH, EC 1.1.1.25), anthocyanidin reductase (EC 1.3.1.77), anthocyanidin synthase (EC 1.14.11.19) and leucoanthocyanidine reductase (EC 1.17.1.3), defoliation induced gene expression for SDH2 isoenzyme. About 4 days after infection of roots by P. cinnamomi, this up-regulation was canceled and SDH enzyme activity decreased. Furthermore, during this late stage of biotrophic interaction the pathogen switched off the correlation engaged by defoliation between the expression of SDH1 and SDH2 encoding genes and chemical defenses corresponding to total tannins, which were down-regulated. Thus, tannins biosynthesis in seedlings of Q. ilex is induced after mechanical defoliation whereas infection by the pathogen interferes with this regulation, potentially increasing the susceptibility of plants to herbivory and aggravating the impact of biotic stress.

The aim of this study was to assess the effectiveness of sprayable essential oils for counteracting the pro-oxidant environment created during retail display of lamb cutlets packed under high-oxygen atmosphere. North-African essential oils from Pituranthos chloranthus (PC) and Teucrium ramosissimum (TR) were applied by spraying on the surface of whole-lamb cutlets. The bio-preservative treatment led to a significant increase of their shelf life in terms of protection against lipid and protein oxidative deterioration, discoloration of lean and bone and microbiological stability during 12days of chilled storage. Furthermore, the addition of TR and PC on the surface of lamb cutlets significantly improved their appearance, increasing hence the purchase intention and consumers' preferences towards treated retailed products. This study shows that the application of a high-oxygen active packaging in combination with natural sprayable extracts is a feasible and effective strategy for protecting whole-meat muscle foods against oxidation and microbial deterioration.

Spermatozoa contain polyunsaturated fatty acids (PUFA). Cryopreservation damages sperm membranes and they become less functional after thawing. We analysed the lipid composition of spermatozoa from Shetland stallions (n = 15) collected monthly from January to June and hypothesized that sperm lipid patterns change with season. In addition, one ejaculate per month was submitted to cryopreservation. Content of saturated palmytic and stearic acid decreased from January to March (p

This study evaluated the impact of a phenolic-rich acorn extract (200 ppm gallic acid equivalents) and the concentration of oxygen in the packaging system (low-oxygen modified atmosphere; 5% vs. normal-oxygen; 21%) on lipid and protein oxidation and consumers acceptance of the ready-to-eat chicken patties. Samples were subjected to cooking (electric oven, 170 °C/16 min), cold storage (14 d at 4 °C), and reheating (microwave, 600 mW/1 min). Samples treated with acorn extract kept thiobarbituric acid-reactive substances numbers and lipid-derived volatiles at basal levels throughout the whole processing irrespective of the oxygen concentration in the packaging atmosphere. Consistently, treated patties had lower protein carbonyls than control ones. The acorn extract also controlled color and texture deterioration during chilled storage and reheating and improved the color and odor acceptance of the products. Formulating with acorn extract is a feasible strategy to inhibit the oxidation-driven changes and preserve the quality of reheated samples as if there were freshly cooked. Compared to the effect of the antioxidant extract, the concentration of oxygen in the packaging system was negligible in terms of quality preservation.

Phytophthora cinnamomi (Pc) is a dangerous pathogen that causes root rot (ink disease) and threatens the production of chestnuts worldwide. Despite all the advances recently reported at molecular and physiological level, there are still gaps of knowledge that would help to unveil the defence mechanisms behind plant-Pc interactions. Bearing this in mind we quantified constitutive and Pc-induced stress-related signals (hormones and metabolites) complemented with changes in photosynthetic related parameters by exploring susceptible and resistant Castanea spp.-Pc interactions. In a greenhouse experiment, five days before and nine days after inoculation with Pc, leaves and fine roots from susceptible C. sativa and resistant C. sativa × C. crenata clonal 2-year-old plantlets were sampled (clones Cs14 and 111-1, respectively). In the resistant clone, stomatal conductance (gs) and net photosynthesis (A) decreased significantly and soluble sugars in leaves increased, while in the susceptible clone gs and A remained unchanged and proline levels in leaves increased. In the resistant clone, higher constitutive content of root SA and foliar ABA, JA and JA-Ile as compared to the susceptible clone were observed. Total phenolics and condensed tannins were highest in roots of the susceptible clone. In response to infection, a dynamic hormonal response in the resistant clone was observed, consisting of accumulation of JA, JA-Ile and ABA in roots and depletion of total phenolics in leaves. However, in the susceptible clone only JA diminished in leaves and increased in roots. Constitutive and Pc-induced levels of JA-Ile were only detectable in the resistant clone. From the hormonal profiles obtained in leaves and roots before and after infection, it is concluded that the lack of effective hormonal changes in C. sativa explains the lack of defence responses to Pc of this susceptible species. published

Organic contaminants, specifically contaminants of emerging concern (CECs), have a great environmental impact, since the removal of these pollutants is of great difficulty by conventional treatments and the presence of these pollutants in the aquatic medium, even at low concentrations, is extremely hazardous to human health. Advanced oxidation processes and, specifically, TiO2-photocatalytic process is considered an option with positive results for an efficient treatment. However, the photocatalyst must be accessible to the UV radiation, for the activation of the TiO2. For this reason, it is recommendable to use a floating photocatalyst (with lower density than water) if the UV light comes from the solar radiation, because it will be on the water surface. In addition, this characteristic of the catalyst can entail an increase of the process efficiency if the pollutant is mainly located on the surface of water. In this context, the goal of this work is the preparation of floating photocatalysts for the removal of CECs from wastewater. TiO2 is deposited in low-density-polyethylene (LDPE), support with lower density than water and high stability and resistance to degradation. LDPE-TiO2 mixtures were prepared by different methods: mixing TiO2 and LDPE in a hot-cylinder-mixer or using o-xylene or an anionic surfactant as dispersing agent, in order to increase the dispersion of TiO2 before extrusion. Filaments obtained were printed as meshes in a Fused-Deposition-Modelling 3D-printer. The printed photocatalysts improved the activity in comparison with the plate obtained in the cylinder, used as benchmark. Thus, this study opens the doors to the in-situ treatment of CECs, using floating photocatalysts and solar radiation as the sole reagent, a very economical, efficient, easily implantable and environmentally compatible process.

The effect of apple phenolics on the oxidative damage caused to myofibrillar proteins by an in vitro metal-catalyzed oxidation system was investigated. Three pure phenolic compounds (chlorogenic acid, (−)-epicatechin and phloridzin) and an apple peel extract were added to myofibrillar proteins in three concentrations (50, 100 and 200 μM), and a blank treatment was included as a control. All suspensions were subjected to Fe 3+ /H 2 O 2 oxidation at 37 °C during 10 days, and protein oxidation was evaluated as carbonylation (α-amino adipic and γ-glutamic semialdehydes) and Schiff base cross-links. Significant inhibition by apple phenolics was found as compared to the control treatment, with (−)-epicatechin being the most efficient antioxidant and phloridzin showing the weakest antioxidant effect. The higher concentrations of apple extract showed effective antioxidant activity against protein oxidation in myofibrillar proteins, emphasizing the potential of apple by-products as natural inhibitors of protein oxidation in meat products.

NaCl reduction remains a significant challenge for the food industry. The influence of NaCl reduction on the oxidative damage to meat proteins during processing of experimental fermented sausages was studied. Sausages with low (0.55%, LS), medium (1.1%, MS) and high (2.2%, HS) NaCl concentrations were produced and analyzed at fix times (days 1, 18, 42 and 54 of processing) for proteolysis, protein oxidation, volatiles and texture. NaCl reduction led to a 30% lower oxidation of TRP but promoted proteolysis (from 19.5 to 26.7 mg free amino acids/g sample in HS and LS, respectively at day 54), protein carbonylation (from 0.62 to 1.18 nmol carbonyl/mg protein in HS and LS, respectively at day 42) and formation of Schiff bases (from 119 to 179 fluorescence units in HS and LS, respectively at day 54). NaCl reduction led to a significantly lower detection of Strecker aldehydes (from 8.8 to 28.6 area units in LS and HS, respectively at day 42) and a significant increase of hardness (from 117 to 143 N in HS and LS, respectively at day 54) in fermented sausages. The redox state of proteins is affected by ionic-driven effects and proteolysis with this having consequences on relevant quality traits.

The effects of pre-cooking methods, namely, boiling (BL), roasting (RT) and grilling (GR), refrigerated storage (14 days/+4 °C) and microwave reheating on chicken patties were studied. Physical, chemical and sensory parameters were evaluated in order to correlate the chemical deterioration of ready-to-eat chicken patties with the acceptance of the odor. Chemical deterioration was evaluated through the chemical composition, Maillard compounds, Thiobarbituric acid-reactive substances (TBARS) and volatiles. Sensory deterioration (odor liking) was performed by an acceptance test with hedonic scale. According to the TBARS values and volatile compounds generated in the head space during the examined stages, the pre-cooking method and the storage time had a significant effect on lipid oxidation, whereas reheating in a microwave had a negligible impact. At each succeeding processing stage, panelists gave lower odor scores to all samples and no significant differences were found between treatments at any stage. RT and GR patties showed less intense chemical changes and presented higher acceptation scores by the sensory panel than BL patties. Thus, the choice of pre-cooking method and control of storage conditions plays a key role in the inhibition of oxidative changes in ready-to-eat chicken patties.

In response to the increasing consumers' mistrust in synthetic additives, the meat industry is focused on searching sources of natural antioxidants. Two different sources of natural antioxidants i) a mixture of garlic, cinnamon, cloves and rosemary essential oils and ii) a Rosa canina L. extract, were compared with a commercial antioxidant additive (Artinox®) for their ability to control protein and lipid oxidation in cooked hams after a settling period of 30 days and at the end of a chilled storage (150 days). The mixture of essential oils was the most effective against lipid oxidation while R. canina L. extracts were the most effective in controlling protein carbonylation at day 150. Accordingly, the use of these antioxidants via brine injection is a successful strategy to enhance the oxidative stability of cooked hams without modifying their physicochemical properties.

Chemical interactions between proteins and phenols affect the overall oxidative stability of a given biological system. To investigate the effect of protein-phenol adduct formation on the oxidative stability of β-lactoglobulin (β-LG), the protein was left to react with an equimolar concentration of 4-methylcatechol (4MC), catechin (Cat), or their respective quinone forms, 4-methylbenzoquinone (4MBQ) and catechin-quinone (CatQ), and subsequently subjected to metal-catalyzed oxidation by Fe(II)/H2O2 for 20 days at 37 °C. The reaction with 4MBQ resulted in 60% thiol loss and 22% loss of amino groups, whereas the addition of 4MC resulted in 12% thiol loss. The reaction with Cat or CatQ resulted in no apparent modification of β-LG. The oxidative stability of β-LG after reaction with each of 4MC, 4MBQ, Cat, or CatQ was impaired. Especially 4MC and 4MBQ were found to be pro-oxidative toward α-aminoadipic semialdehyde and γ-glutamic semialdehyde formation as well as the generation of fluorescent Schiff base products. The changes observed were ascribed to the redirection of oxidation as a result of the blocking of thiol groups but also to the oxidative deamination pathway, accelerating the production of semialdehydes and subsequently Schiff base structures.

Recent findings suggested that using frozen material for meat processing leads to products with increased protein oxidation rates and impaired quality traits. Therefore, the effects of frozen storage and the addition of a phenolic-rich dog rose extract (Rosa canina L.; RC), on lipid and protein oxidation, moisture losses, color stability, and hardness of beef patties were investigated. Protein oxidation was assessed by means of tryptophan loss and the formation of specific lysine oxidation products: α-aminoadipic semialdehyde (AAS), α-aminoadipic acid (AAA), and Schiff bases. Frozen storage increased proteins susceptibility towards oxidation during successive technological processes. The addition of the RC extract inhibited the formation of AAS, AAA, and had an antioxidant effect towards tryptophan oxidation, but promoted the formation of Schiff bases and incremented the hardness of beef patties. The antioxidant effect may be attributed to the phenolic compounds, mainly procyanidins, found on the RC extract. Further knowledge on the interactions between phenolics and proteins is needed to optimize the application of these antioxidants against meat protein oxidation.

The objective of this work was to study the effectiveness of extracts from hawberry (Crataegus monogyna Jacq.) to inhibit lipid oxidation and odor deterioration during processing of ready-to-eat (RTE) pork patties subjected to roasting (180 °C/16 min), chilling (10 days/+3 °C) and reheating in microwave (600 mW/1 min). Acetone extracts of hawberry were chosen based on their total phenolic content (1281.1 ± 84.8 mg gallic acid equivalent (GAE)/100 g fruit) and in vitro antiradical activity (DPPH) (53.33 ± 15.40 g equivalent Trolox per g of fruits). Pork patties treated with increasing concentrations of hawberry extract, 200 and 800 ppm GAE (T2 and T8, respectively) and a control group (T0) of samples, were analyzed for TBARS, volatile carbonyls and odor liking in a consumer test. Hawberry extracts significantly improved the oxidative stability of cooked pork patties keeping TBARS and hexanal counts at basal levels during the whole process. The addition of hawberry phenolic-rich extracts significantly improved the degree of consumer satisfaction regarding the odor of patties. In conclusion, the hawberry extract displayed potential usage as an ingredient with antioxidant properties for the manufacture of high-quality RTE meat products. © 2017, Association of Food Scientists & Technologists (India).

The aim of the present work was to characterization and compare acorns from selected Quercus spp. from the Mediterranean forest in Spain, namely, Portuguese oak (QF, Quercus faginea Lam.), Cork oak (QS, Quercus suber L.), Pyrenean oak (QP, Quercus pyrenaica Wild), Kermes oak (QC, Quercus coccifera L.), Holm oak (QB, Quercus ilex L. subsp. ballota [Desf.]). All physicochemical attributes varied significantly between species. Fat contents ranged from 1.30 to 4.70 g 100 g-1 fresh matter. The most abundant fatty acids were oleic (62.44, 56.25, 57.46, 48.02, 65.83%), followed by linoleic (16.42, 20.73, 21.30, 25.38, 14.17%) and palmitic (11.69, 14.27, 12.17, 16.22, 12.28) acids in QF, QS, QP, QC and QB species, respectively. The tocopherol content was high in the range of 31.83–45.25 mg kg-1, and ?-tocopherol constituted 67–78% of total tocopherols. Only an effect of the location on ?-tocopherol content in QB was observed. The present results show the potential of different species of acorn to be used as agricultural and food resources and that geographical location plays a secondary role. © 2017, Association of Food Scientists & Technologists (India).

UNLABELLED The effect of increasing concentrations of curing agents, ascorbate (0, 250, and 500 ppm), and nitrite (0, 75, and 150 ppm), on the oxidative and nitrosative damage to proteins during processing of fermented sausages was studied. The potential influence of these reactions on color and texture of the fermented sausages was also addressed. Nitrite had a pro-oxidant effect on tryptophan depletion and promoted the formation of protein carbonyls and Schiff bases. The nitration degree in the fermented sausages was also dependent on nitrite concentration. On the other hand, ascorbate acted as an efficient inhibitor of the oxidative and nitrosative damage to meat proteins. As expected, nitrite clearly favored the formation of the cured red color and ascorbate acted as an enhancer of color formation. Nitrite content was positively correlated with hardness. The chemistry behind the action of nitrite and ascorbate on muscle proteins during meat fermentation is thoroughly discussed. The results suggest that ascorbate (500 ppm) may be required to compensate the pro-oxidant impact of nitrite on meat proteins. PRACTICAL APPLICATION This study provides insight on the action of curing agents on meat proteins during processing of fermented sausages. This chemistry background provides understanding of the potential influence of the oxidative and nitrosative damage to proteins on the quality of processed muscle foods. The study provides novel information on the impact of the combination of nitrite and ascorbate on the chemical deterioration of proteins and the influence on particular quality traits of fermented sausages. These data may be of interest for the design of cured muscle foods of enhanced quality.

This study examined the relationship between protein and lipid oxidation and the impairment of water holding capacity (WHC), colour and texture after frozen storage (20 weeks/−18 °C) and subsequent processing (cooking, chilled storage) of beef patties with increasing fat content (3, 20 and 35%). Various manifestations of protein oxidation were found to occur during frozen storage and processing of patties including, loss of tryptophan fluorescence, carbonylation and formation of Schiff bases structures (SB). Patties with higher fat content underwent the more intense protein oxidation as assessed by formation of protein carbonyls and SB, highlighting the timely interaction between proteins and oxidizing lipids. Protein oxidation occurred concomitantly with loss of WHC and discolouration of beef patties. Mechanisms and consequences of the chemical modifications induced by oxidative stress in meat proteins are thoroughly discussed.

An extraction procedure of phenolics from Willowherb (Epilobium hirsutum L.) was optimized; extracts were characterized in terms of phenolic content, composition, and in vitro antioxidant activity. Additionally, the effect of 50, 200, and 800 ppm Willowherb extracts on the oxidative stability (formation of thiobarbituric acid-reactive substances, α-aminoadipic, and γ-glutamic semialdehydes) of beef patties was studied. Acetone (50 %) extract, rich in ellagic acid, myricetin, hydroxybenzoic, and hydroxycinnamic acids, had the highest phenolic content compared to methanol (25, 50, 75, and 100 %), acetone (100 %), or water extracts and displayed intense in vitro antioxidant properties. Lipid oxidation levels in processed beef patties with added Willowherb extract remained as similar to that of 100 ppm gallic acid. A dose-dependent effect of Willowherb extract was observed on protein carbonylation and myoglobin oxidation. The lack of correlation between lipid and myoglobin oxidation and the underlying mechanisms involved in the pro-oxidant action of phenolics on meat proteins are thoroughly discussed. © 2014 Springer-Verlag Berlin Heidelberg.

The efficiency of extracts from Arbutus unedo L. (AU), Crataegus monogyna L. (CM), Rosa canina L. (RC), and Rubus ulmifolius Schott. (RU) to inhibit lipid oxidation in raw, cooked and cooked and chilled (2°C/12 d) porcine burger patties, was investigated. The modification of the fatty acid profile during processing treatments (cooking and chilling), the quantitative measurements of thiobarbituric acid reactive substances (TBA-RS), and lipid-derived volatiles, were used as indicators of lipid oxidation. Polyunsaturated fatty acids (PUFA) gradually decreased during cooking and the subsequent storage of cooked burger patties with this decrease being significantly greater (P

The present study aimed to evaluate the influence of three serving temperatures (7 °C, 16 °C and 20 °C) and two different ham sections varying in the intramuscular fat (IMF) content on the sensory characteristics of sliced and vacuum-packaged Iberian dry-cured hams using the time-intensity (TI) method. Preceding the TI study, appearance and odour of dry-cured hams were evaluated using a descriptive profile. Fluidity and brightness of the external fat, brightness of lean and all odour attributes increased as serving temperature increased whereas the hardness of external fat decreased with temperature. Oral temperature would have disguised the effect of serving temperature over time as a consequence of a possible balance between both temperatures during samples' consumption. TI revealed that the effect of serving temperature on flavour and texture perception was more noticeable along the first seconds of chewing. Odour intensities increased with the IMF content and temporal perception of hardness, saltiness and rancid flavour were also significantly influenced by the IMF content.

Genetic variability of trees influences the chemical composition of tissues. This determines herbivore impact and, consequently, herbivore performance. We evaluated the independent effects of plant genotype and provenance on the tannin content of holm oak (Quercus ilex) and their consequences for herbivory and performance of gypsy moth (Lymantria dispar) larvae. Oak seedlings of 48 open-pollinated families from six populations were grown in a common garden in central Spain. Half the plants were subjected to defoliation by gypsy moth larvae and the other half were destructively sampled for chemical analysis. Tannin content of leaves did not differ significantly among populations but differed significantly among families. Estimates of heritability (h 2) and quantitative genetic differentiation among populations for tannin content (Q ST) were 0.83 and 0.12, respectively. Defoliation was not related to the tannin content of plants nor to spine and trichome densities of leaves, although positive family–mean associations were observed between defoliation and both seed weight and plant height (P

This study evaluated the impact of a phenolic-rich acorn extract (200 ppm gallic acid equivalents) and the concentration of oxygen in the packaging system (low-oxygen modified atmosphere; 5% vs. normal-oxygen; 21%) on lipid and protein oxidation and consumers acceptance of the ready-to-eat chicken patties. Samples were subjected to cooking (electric oven, 170 °C/16 min), cold storage (14 d at 4 °C), and reheating (microwave, 600 mW/1 min). Samples treated with acorn extract kept thiobarbituric acid-reactive substances numbers and lipid-derived volatiles at basal levels throughout the whole processing irrespective of the oxygen concentration in the packaging atmosphere. Consistently, treated patties had lower protein carbonyls than control ones. The acorn extract also controlled color and texture deterioration during chilled storage and reheating and improved the color and odor acceptance of the products. Formulating with acorn extract is a feasible strategy to inhibit the oxidation-driven changes and preserve the quality of reheated samples as if there were freshly cooked. Compared to the effect of the antioxidant extract, the concentration of oxygen in the packaging system was negligible in terms of quality preservation.

The effects of the addition of avocado oil and a phenolic-rich avocado peel extract on protein oxidation were studied in porcine patties subjected to cooking and chilled storage. Protein oxidation was assessed by means of tryptophan loss and the formation of specific lysine oxidation products, such as α-aminoadipic semialdehyde (AAS), α-aminoadipic acid (AAA), and Schiff bases. In the present paper, quantitative data of AAA are reported for the first time on a food matrix. The addition of the avocado extract inhibited the formation of AAS, AAA, and Schiff bases in patties during cooking and subsequent chilled storage. The antioxidant effect may respond to the protecting effect of phenolic compounds, mainly procyanidins, found on the avocado extract. Apparently, the combination of both strategies (back-fat replacement and addition of avocado extract) does not lead to an enhanced advantage on the oxidative stability of the product. The novel methodologies used in the present study enable a better comprehension of the mechanisms and consequences of protein oxidation in food systems.

The effect of phenolic-rich extracts from avocado peel on the formation of cholesterol oxidation products (COPs) in porcine patties subjected to cooking and chill storage was studied. Eight COPs (7α-hydroxycholesterol, 7β-hydroxycholesterol, 7-ketocholesterol, 20α-hydroxycholesterol, 25-hydroxycholesterol, cholestanetriol, 5,6β-epoxycholesterol, and 5,6α-epoxycholesterol) were identified and quantified by GC-MS. The addition of avocado extracts (∼600 GAE/kg patty) to patties significantly inhibited the formation of COPs during cooking. Cooked control (C) patties contained a larger variety and greater amounts of COPs than the avocado-treated (T) counterparts. COPs sharply increased in cooked patties during the subsequent chilled storage. This increase was significantly higher in C patties than in the T patties. Interestingly, the amount of COPs in cooked and chilled T patties was similar to those found in cooked C patties. The mechanisms implicated in cholesterol oxidation in a processed meat product, the protective effect of avocado phenolics, and the potential implication of lipid and protein oxidation are thoroughly described in the present paper.

Precise methodologies for the routine analysis of particular protein carbonyls are required in order to progress in this topic of increasing interest. The present paper originally describes the application of an improved method for the detection of α-aminoadipic and γ-glutamic semialdehydes in a meat system by using a derivatization procedure with p-amino-benzoic acid (ABA) followed by fluorescent high-performance liquid chromatography (HPLC). The method development comprises i) the description of a simple HPLC program which allows the efficient separation of the ABA and the key standard compounds and ii) the optimization of the procedure for the preparation of a meat sample in order to maximize the fluorescent signal for both protein carbonyls. Furthermore, the suitability of this method is evaluated by applying the technique to porcine burger patties. The present procedure enables an accurate and relatively fast analysis of both semialdehydes in meat samples in which they could play an interesting role as reliable indicators of protein oxidation.

Processing of avocados generates an important amount of by-products such as peels and seeds that are rich in bioactive substances with proven radical suppressing activities. The objective of this study was to evaluate the effectiveness of peel and seed extracts from two avocado varieties-'Hass' and 'Fuerte'-as inhibitors of lipid and protein oxidation and color deterioration of raw porcine patties during chilled storage (4 °C/15 days). Avocado extracts significantly (p

Numerous protocols and modifications of the thiobarbituric acid (TBA) test are available in the literature. The present paper compares the effectiveness of different TBA tests in minimizing the interferences caused by the addition of phenolic-rich materials (wild fruits) as antioxidants in cooked burger patties. The aqueous acid extraction procedure (EM) and a modified distilation TBA method (DM) were tested with different conditions of incubation – boiling (B) vs. room temperature (RT) – for monitoring lipid oxidation in cooked burger patties during refrigerated storage. DM-B and DM-RT were more suitable than EM procedures for assessing TBA-reactive substances (TBA-RS) in meat samples containing compounds such as anthocyanins, with similar spectral properties than that of the TBA–malondialdehyde (MDA) adduct. Additionally, interferences caused by browning development during incubation were avoided by DM procedures or by performing RT incubations. Correlations between TBA-RS numbers and hexanal contents in cooked pork burger patties were calculated in order to corroborate the suitability of the tested TBA procedures. The DM-RT procedure showed the highest correlation with hexanal content (R2 = 0.90; p

Contents: Lipids were extracted from ejaculated spermatozoa from seven individual stallions to distinguish neutral lipids (NL) and polar lipids (PL) and determine their variation among stallions and their relationship with sperm quality and sperm susceptibility to lipid peroxidation. The isolated fatty acids were correlated with sperm quality (membrane integrity, mitochondrial membrane potential (ΔΨm) and expression of active caspases) and the sensitivity of the sperm plasma membrane to LPO. The miristic (C14: 0), palmitic (C16: 0), stearic (C18: 0) and oleic (C18: 1n9) acids were predominant among the NLs. Within the phospholipid fraction, the docosapentanoic acid (C22: 5n6) was dominant, albeit varying among stallions. Surprisingly, the percentage of polyunsaturated fatty acids was positively correlated with sperm quality and a low propensity for LPO, probably because these particular fatty acids provide a higher fluidity of the plasma membrane. The stallion showing the poorest sperm membrane integrity plus a high level of LPO in his ejaculate had a lower percentage (p less than 0.05) of this fatty acid in his sperm plasma membranes. © 2010 Blackwell Verlag GmbH.

In the present study, water, ethanolic, and methanolic extracts from seven selected wild fruits originally from the Mediterranean area, namely, strawberry tree ( Arbutus unedo L., AU), azarole ( Crataegus azarolus L., CA), common hawthorn ( Crataegus monogyna L., CM), blackthorn ( Prunus spinosa L., PS), dog rose ( Rosa canina L., RC), elm-leaf blackberry ( Rubus ulmifolius Schott, RU), and rowan ( Sorbus aucuparia L., SA), were analyzed for the total amount and profile of phenolic compounds and for the in vitro antioxidant activity against the DPPH and ABTS radicals (study 1). The seven fruits showed different chemical compositions, which consequently led to different antioxidant potentials. Among the seven fruits initially analyzed, AU, CM, RC, and RU had the highest amount of phenolic compounds and displayed the greatest antioxidant activity in vitro. Extracts from these four fruits were tested as inhibitors of lipid oxidation in raw pork burger patties subjected to refrigerated storage at 2 degrees C for 12 days (study 2). The quantitative measurements of thiobarbituric acid reactive substances (TBA-RS), hexanal content, and color stability were used as indicators of oxidative reactions. The four selected fruits displayed intense antioxidant activity against lipid oxidation, which highlights the potential usage of these fruits as ingredients for the manufacture of healthy meat products. Among them, RC and AU were particularly efficient as their protective effect against lipid oxidation was more intense than that displayed by quercetin (230 mg/kg of burger patty).

The effect of HHP treatment (600 MPa) on the oxidative stability of lipids and proteins of vacuum-packaged Iberian dry-cured ham and the impact on the sensory characteristics of the product was investigated. In order to assess how different commercial presentations are affected by HHP treatment, three different presentations of vacuum-packaged Iberian dry-cured ham were considered, namely, (i) intact format (IF) corresponding to non-sliced vacuum-packaged dry-cured ham, (ii) conventional-sliced format (CSF) corresponding to dry-cured ham slices placed stretched out in the package and (iii) alternative-sliced format (ASF) corresponding to dry-cured ham slices piled up horizontally. The oxidation of dry-cured ham lipids and proteins was enhanced by HHP-treatment with the presentation being highly influential on these oxidative reactions. Pre-slicing dry-cured ham results in a more susceptible product to oxidative reactions during pressurisation and subsequent refrigerated storage. Possible mechanisms, by which HHP-induced oxidative reactions would affect particular sensory traits in vacuum-packaged Iberian dry-cured ham such as colour, texture and flavour attributes, are discussed.

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, p0.05) 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%, p0.05) and a lower percentage of monounsaturated fatty acids (47.79% vs. 46.73%, p0.05) 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 (p0.05) between muscles, whereas malic enzyme activity was higher (p0.05) in Psoas maior compared to Biceps femoris and those were higher than in Longissimus dorsi, which was consistent with the positive correlations (p0.05) found between malic enzyme activity and traits defining oxidative metabolic type. On the contrary, negative correlations (p0.05) 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 adipogenic potential of subcutaneous fat (SCF) and muscles Longissimus dorsi (LD) and Biceps femoris (BF) were evaluated in three different Iberian × Duroc pig genotypes: GEN1: ♂ Iberian × ♀ Duroc1; GEN2: ♂ Duroc1 × ♀ Iberian; GEN3: ♂ Duroc2 × ♀ Iberian. Reciprocal crosses (GEN1 vs. GEN2) showed similar traits, while the genotype of the Duroc sire line (GEN2 vs. GEN3) significantly influenced the adipogenic character. GEN3 had lower fat depths and a more unsaturated SCF than GEN2. The intramuscular fat (IMF) content of the LD was higher in GEN2 than in GEN3, while BF showed a similar trend. The fatty acid compositions of IMF and neutral lipid fraction (NL) in LD and BF were more unsaturated in GEN3 than in GEN2. Glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME) activities in SCF and in both muscles analysed were higher in GEN2 than in GEN3. The higher fat depths and IMF of GEN1 and GEN2 correspond to higher G6PDH and ME activities, which indicated that the lipid synthesis and deposition in muscles and in SCF were higher in GEN1 and GEN2 than in GEN3; these differences were associated with the Duroc sire line. Therefore, the use of Duroc selected genotypes reduced the adipogenic character of Iberian × Duroc crosses, which could have important repercussions on the quality of meat and dry-cured products.

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.

Changes in fatty acid profiles of pork loin chops fried in different culinary fats (olive oil, sunflower oil, butter and pig lard) during 10 days of refrigerated storage were studied. Olive oil-fried loin chops (OOLC) were significantly highest in monounsaturated fatty acids (MUFA) and C18:1. Sunflower oil-fried loin chops (SOLC) showed the highest polyunsaturated fatty acid (PUFA) proportions, mainly due to C18:2 contents. Butter-fried loin chops (BTLC) were significantly richer in saturated fatty acids (SFA), such as C12:0, C14:0 and C16:0, while pig lard-fried loin chops (PLLC) contained moderate proportions of SFA, MUFA and PUFA. Fatty acid profiles of neutral lipids (NL), free fatty acids (FFA) and polar lipids (PL) were slightly changed after refrigerated storage. After 10 days of refrigerated storage, differences among samples fried in different culinary fats were maintained or increased. NL from OOLC had the significantly largest percentages of C18:1 and MUFA, while SOLC had the significantly largest percentages of C18:2 and PUFA. The highest percentages of C12:0, C14:0, C16:0 and SFA were characteristic for pork loin chops fried in butter at the end of the storage period. Refrigerated pork loin chops fried in pig lard showed intermediate percentages of SFA, MUFA and PUFA. OOLC had a more desirable nutritional value than other fried pork loin chops after and before the refrigerated storage.

In this study, composition and fatty acid profiles of intramuscular lipid fractions, proteolytic and lipolytic muscle enzyme activities in muscle Longissimus dorsi have been determined in three lines of Iberian pigs (“Lampino”, “Retinto” and “Torbiscal”) reared under the free-range system and slaughtered at 90kg live weight and industrial genotype pigs (IGP) (Large White-Landrace × Large White) reared intensively. Intramuscular fat content was significantly higher (p 0.05) higher in IGP than in IPL. The ratio cathepsin B + L/B was significantly lower (p

The effects of different types of culinary frying fats and oils (olive oil -OO-, sunflower oil -SO-, butter -BT- and pig lard -PL-) were studied in relation to lipid oxidation and instrumental colour in fried pork loin chops during 10 days of refrigerated storage. At day 0, pork loin chops fried in butter showed significantly lower values of TBARS (0.37 mg MDA/kg, p

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 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 (P0.05) 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 (P0.05) 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 (P0.05). 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

The influence of feeding Iberian pigs with and without α-tocopheryl acetate (α-TAc) on fatty acid composition of intramuscular lipids, throughout dry-cured ham maturation was investigated. Supranutritional levels of α-TAc (100 mg α-TAc/kg) increased α-tocopherol content in m. Semimembranosus in comparison to a basal diet containing 5 mg α-TAc/kg (Control: 6.38 vs. E-supplemented: 10.31 μg/g muscle dry matter). Fatty acid composition of lipids in the raw hams was similar whatever the level of vitamin E in the diet. Fatty acid composition of neutral lipids did not change much during ham maturation. In contrast, fatty acid content of polar lipids decreased considerably (∼90%) after 700 days of maturation. At the end of ripening (700 days), the contents of polyunsaturated fatty acids from neutral and polar lipids were significantly higher in hams from Iberian pigs fed on α-TAc-enriched diet than those fed with a basal diet. This result indicates that α-tocopherol-enriched diets maintain polyunsaturated fatty acids in neutral and polar lipid fractions of intramuscular fat in dry-cured hams from Iberian pigs.

Muscle fibre type, fatty acid composition of phospholipids (PLs) and triacylglycerols (TGs) and susceptibility of muscle to lipid oxidation were studied in Biceps femoris (BF) and Tibialis cranialis (TC) muscles from Iberian and Iberian×Duroc pigs reared indoors and outdoors. Fatty acid composition of TGs was not affected by muscle fibre type and crossbreeding, but was strongly influenced by rearing system. In PLs crossbreeding slightly affected monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) content in BF muscle, whereas rearing system showed a great influence on fatty acid composition of PLs. Oxidative fibres showed a positive relationship with saturated fatty acid (SFA) and MUFA contents and a negative one with PUFA content of PLs. Susceptibility of muscle to lipid oxidation was strongly influenced by diet, animals reared indoors and fed on concentrates showing higher levels of 2-thiobarbituric acid reactive substances (TBARS). Iberian×Duroc pigs tended to show slightly higher values of lipid oxidation than pure Iberian pigs. With regards to muscle fibre type, BF had lower TBARS values than TC, although within muscle no relationship was found between muscle fibre type and lipid oxidation.

The effect of three frozen storage temperatures (-8, -18 and -80 °C) on protein oxidation in beef patties was studied through the analysis of novel oxidation markers. Additionally, the connection between lipid and protein oxidation and the impact of the latter on particular quality traits (water holding capacity, color and texture) of subsequently processed beef patties (cooking/cold-stored) were investigated. Protein oxidation was measured as the loss of tryptophan fluorescence and formation of diverse lysine oxidation products (α-aminoadipic semialdehyde, α-aminoadipic acid and Schiff bases). Lipid oxidation was assessed by levels of thiobarbituric acid reactive substances and hexanal. A significant effect of storage temperature on protein oxidation was detected. Frozen storage increased the susceptibility of meat proteins to undergo further oxidation during processing. Timely interactions were found between lipid and protein oxidation. Plausible mechanisms by which oxidative damage to proteins may have an impact in particular quality traits are thoroughly discussed.