Search

The influence of temperature on the formation of high molecular weight poly(lactic acid) (PLA) stereocomplex was studied by evaluation of the precipitates from dioxane solutions of PLA enantiomers (PLLA and PDLA). The racemic mixtures were characterized by Gel Permeation Chromatography, Infrared Spectroscopy, Differential Scanning Calorimetry, Scanning Electronic Microscopy, Wide-Angle X-ray Scattering and Vicat Softening Temperature. Precipitation was carried out under different solution temperatures, keeping constant the mixing ratio (XD), the molecular weight, the optical purity of both PLA enantiomers and the stirring rate. It was found that the precipitates contained only pure stereocomplex crystallites (racemic crystallites), without observing crystal phase separation between both homocrystals. The kinetics of the insoluble phase formation could be adjusted with the Avrami model, classically used for polymer crystallization in molten state. It was observed that the maximum PLA stereocomplex production rate was at about 40 °C. However, more thermally stable racemic crystallites were formed at high solution temperatures. It was found that all the precipitates were sphere-like at 10 g·dl-1 at the solution temperature of 25, 40, 60 and 80 °C. [ABSTRACT FROM AUTHOR]

The objectives of this study were to evaluate the influence of different pure pig breeds and muscle types on the expression of muscle proteins, as well as their interactions, and second, to find biomarkers for breed and muscle types. A total of 126 male pigs, including 43 Landrace, 21 Duroc, 43 Large White, 13 Pietrain, and 6 Belgian Landrace, were slaughtered at the age of 174 ± 6 d. Samples from the semimembranosus muscle (SM) and LM were collected 24 h postmortem. Proteomic spectra were generated on an anion exchanger (Q10), a cation exchanger (CM10), and on immobilized metal affinity capture (IJVIAC3O) ProteinChip arrays and analyzed using surface-enhanced laser desorption/ionization time-of-flight inass spectrometry ProteinChip techniques. Breed and muscle type did not affect the number of peaks per spectrum but, interestingly, affected the average intensity of the peaks. Of these peaks, a total of 4 proved to be potential protein biomarkers to differentiate LM or SM muscles, and 2 to classify specific breed types. Additionally, several peaks influenced by the interaction between muscle and breed types could correctly classify pig muscles according to their breed. Further studies need to be carried out to validate and identify these potential protein biomarkers for breed and muscle types in finishing pigs. [ABSTRACT FROM AUTHOR]

The gene (Cbg) encoding cortisol-binding globulin (CBG) has been proposed as a candidate gene to explain genetic variation in cortisol secretion and carcass composition in pigs. The objective of this study was to evaluate the association between CBG and pork quality in 5 European breeding lines, Piétrain, Large White (LW), and Landrace purebred lines, a Duroc synthetic line, and a Meishan (MS) × LW advanced intercros s. Cortisol-binding globulin maximum binding capacity (CBG-Bmax) was twice as high (P < 0.05) in MS × LW pigs compared with the other lines. There was no (P ≥ 0.364) association between CBG-Bmax and carcass quality traits in Piétrain gilts, but CBG-Bmax was associated with increased loin yields in LW (P = 0.010) and Landrace (P = 0.103) gilts, decreased ham yields (P = 0.082) in Duroc guts, and increased fat depth (P = 0.064) and leaf fat (P = 0.001) in MS × LW guts. There was no association between CBG-Bmax and pork quality traits in Piétrain (P ≥ 0.269) and Duroc (P ≥ 0.114) gilts. Conversely, CBG-Bmax was associated with lighter (higher L* values; P < 0.05) pork in Land-race guts, as well as lower (P ≤ 0.055) ultimate pH in the LM and semimembranosus, and a tendency for lower (P = 0.095) L* values of pork from LW gilts. Within MS × LW pigs, CBG-Bmax was associated with increased drip loss (P = 0.001) and decreased i.m. fat in the semimembranosus (P = 0.005). Because drip loss is an economically important pork quality trait, results of this study could be used in the selection of improved water-holding capacity of pork from synthetic lines involving the MS breed. [ABSTRACT FROM AUTHOR]

Abstract: Dynamic Head Space methodology was applied to evaluate the possible contribution of some volatile compounds to the development of boar taint in pig backfat samples with low concentrations of skatole and androstenone, but which had previously been classified as tainted by a trained test panel. Volatile compounds were collected in a trap of graphited charcoal and analysed by GC–MS in Scan mode. Aldehydes and short chain fatty acids, compounds that play a significant role in the development of undesirable aromas in food products, were the main classes of compounds identified in this study, although the possible contribution of other compounds that were detected in a minor proportion – such as alcohols and ketones – was evaluated. Styrene and 1,4-dichlorobenzene, compounds that may have come from an external contamination, showed a high concentration in the samples classified with boar taint, so these compounds could have been responsible for the development of some off-flavours in the fat samples studied in this work. In the same study, skatole and androstenone were also determined by normal phase HPLC and GCMS, respectively. [Copyright &y& Elsevier]

Abstract: The effect of high pressure (at 600 and 900MPa) on the levels of purines and pyrimidines was evaluated in dry-cured and cooked ham. Pressurization of dry-cured ham did not modify purines and pyrimidines contents. On the contrary, treatment at 600 MPa and 900MPa caused a decrease in guanosine and an increase in adenosine respectively. [Copyright &y& Elsevier]

Abstract: The functional single polymorphisms identified in the calpastatin (CAST) gene have been related to the rate of meat tenderization and the protein turnover after slaughter, and the Ile199Val polymorphism identified in the coding region of the protein kinase AMP-activated (PRKAG3) gene has been proven to affect ultimate pH in muscle. The aim of the present study was to show the effects of these genetic polymorphisms on the quality traits of Spanish dry-cured ham Jamón Serrano. A tissue sample from 665 crossbreed pigs were genotyped for PRKAG3 Ile199Val, CAST Arg249Lys and CAST Ser638Arg polymorphisms, and a subsample of 120 dry cured hams was selected to perform physico-chemical, rheological, instrumental colour and sensory analyses. Associations between the polymorphisms and several quality traits of dry-cured ham, mainly related to flavour and texture, were found. The genotypes PRKAG3 Ile/Ile, CAST249 Arg/Arg and CAST638 Arg/Arg, and the haplotype CAST 249Arg–638Arg were the most favourable for Jamón Serrano production. [Copyright &y& Elsevier]

Abstract: Expression of water soluble proteins of fresh pork Longissimus thoracis from 4 pure breed pigs (Duroc, Large White, Landrace, and Piétrain) was studied to identify candidate protein markers for meat quality. Surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry (SELDI-TOF-MS) was used to obtain the soluble protein profiles of Longissimus thoracis muscles. The pure breeds showed differences among the studied meat quality traits (pHu, drip loss, androstenone, marbling, intramuscular fat, texture, and moisture), but no significant differences were detected in sensory analysis. Associations between protein peaks obtained with SELDI-TOF-MS and meat quality traits, mainly water holding capacity, texture and skatole were observed. Of these peaks, a total of 10 peaks from CM10 array and 6 peaks from Q10 array were candidate soluble protein markers for pork loin quality. The developed models explained a limited proportion of the variability, however they point out interesting relationships between protein expression and meat quality. [Copyright &y& Elsevier]

Abstract: The relationship between protein profiles of Gluteus medius (GM) muscles of raw hams obtained from 4 pure breed pigs (Duroc, Large White, Landrace, and Piétrain) with the final quality of the Semimembranosus and Biceps femoris muscles of dry-cured hams was investigated. As expected, Duroc hams showed higher levels of marbling and intramuscular fat content than the other breeds. Piétrain hams were the leanest and most conformed, and presented the lowest salt content in dry-cured hams. Even if differences in the quality traits (colour, water activity, texture, composition, intramuscular fat, and marbling) of dry-cured hams were observed among the studied breeds, only small differences in the sensory attributes were detected. Surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry (SELDI-TOF-MS) was used to obtain the soluble protein profiles of GM muscles. Some associations between protein peaks obtained with SELDI-TOF-MS and quality traits, mainly colour (b*) and texture (F0, Y2, Y90) were observed. Candidate protein markers for the quality of processed dry-cured hams were identified. [Copyright &y& Elsevier]

Abstract: This study aimed to evaluate the effects of PRKAG3 Ile199Val and CAST Arg249Lys and CAST Ser638Arg polymorphisms on the quality traits of the French dry-cured ham Jambon de Bayonne and their interaction with salt reduction. Significant (p<0.05) and suggestive associations (p<0.10) between the polymorphisms and several quality traits of dry-cured ham, mainly related to processing and textural properties, were found. PRKAG3 Ile/Val and CAST 249Lys/638Arg presented the highest scores for sensory and processing properties, whatever the salt content. [Copyright &y& Elsevier]

Abstract: This study aimed at evaluating the effect of housing system (HS), slaughter weight (SW) and strategy (SS) on carcass a nd meat quality, sexual organ development and boar taint in entire males. Twelve pens of 10 pigs were used (two trials). Half of male pens were allowed visual contact with females (MF) and half with males (MM). Half MM or MF were slaughtered at 105 or 130kg in trial 1, or penwise or by split marketing in trial 2 at 120kg. Housing system showed no significant effect on carcass or meat quality. MF presented significantly longer testicles and heavier bulbourethral glands compared to MM. The distribution of androstenone and skatole levels was affected by SW but not by HS or SS, samples with androstenone >1μg/g of the different groups falling within the range of 16 to 22%. All correlations between androstenone and sex organs were significant. Housing system and slaughter strategy did not reduce the risk of boar tainted carcasses. [Copyright &y& Elsevier]

Abstract: Boar taint is a sensory defect mainly due to androstenone and skatole. The most common method to control boar taint is surgical castration at an early age. Vaccination against gonadotropin releasing factor (also known as immunocastration) is an alternative to surgical castration to reduce androstenone content. In this experiment, loins from 24 female (FE), 24 entire male (EM), 24 vaccinated males (IM) and 23 surgically castrated males (CM) were evaluated by eight trained panellists in 24 sessions. Loins were cooked in an oven at 180°C for 10min. Furthermore loins were evaluated by consumers and its androstenone and skatole content were also chemically determined. Meat from EM had higher androstenone and skatole odour and flavour than meat from FE, IM and CM and lower sweetness odour scores. High correlations were found between androstenone and skatole levels assessed by trained panelists, chemical analysis and consumers’ acceptability. Moreover meat from EM is mainly related to androstenone and skatole attributes. [Copyright &y& Elsevier]

Abstract: Boar taint is the off-odour or off flavour of cooked pork. Currently, the most common method of controlling boar taint is surgical castration. However, immunocastration has been used in some parts of the world as an alternative to surgical castration. The aim of this study was to evaluate the sensory acceptability of meat from immunocastrated pigs (IM) compared with meat from females (FE), surgically castrated (CM) and entire males (EM). Twenty animals of each type were evaluated by 201 consumers in 20 sessions. Longissimus thoracis muscle of the different animals was cooked in an oven at 180°C for 10min. Consumers scored the odour and the flavour of the meat in a 9-point category scale without an intermediate level. There were no significant differences in consumer’s evaluation of meat from IM, CM, and FE. In contrast, EM meat presented a higher percentage of dissatisfied scores and was significantly (P <0.05) less accepted than meat from CM, IM and FE. Consumers’ acceptability of EM meat was always lower, independently of its androstenone levels. However meat with low levels of androstenone was more accepted that meat with medium or high levels of this substance. It can be concluded that immunocastration produced pork that was accepted by the consumers, and was indistinguishable from pork from CM or FE. [Copyright &y& Elsevier]

Abstract: Functional genomics, including analysis of the transcriptome and proteome, provides new opportunities for understanding the molecular processes in muscle and how these influence its conversion to meat. The Quality Pork Genes project was established to identify genes associated with variation in different aspects of raw material (muscle) quality and to then develop genetic tools that could be utilized to improve this quality. DNA polymorphisms identified in the porcine PRKAG3 and CAST genes illustrate the impact that such tools can have in improving meat quality. The resources developed in Quality Pork Genes provide the basis for identifying more of these tools. [Copyright &y& Elsevier]

The search for new sources of antimicrobial compounds has become an urgent need, due to the threat that the spread of bacterial resistance represents for global health and food safety. Brown macroalgae have been proposed as a great reservoir in the search for novel antimicrobial compounds. In this study, mid-polarity extracts were performed with a selection of 20 brown macroalgae species from northern Spain. The total polyphenol, carbohydrate and protein contents were quantified by spectrophotometry. The volatile organic compounds (VOCs) of whole macroalgae were also studied as a biomarker of their metabolic state in the representative species of the tested families by gas chromatography-mass spectrometry (GC-MS). The antimicrobial potential of the extracts was assessed by a disk diffusion assay against 20 target bacteria and further determinations of the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) were performed by a microdilution assay for the active extracts. Ericaria selaginoides , Bifurcaria bifurcata and Dictyota dichotoma showed an antimicrobial effect against six Gram-positive strains: Bacillus cereus , Bacillus subtilis , Geobacillus stearothermophilus , Listeria monocytogenes , Staphylococcus aureus and Staphylococcus haemolyticus . The phenolic content was generally higher in the extracts that showed antimicrobial activity, followed by carbohydrates and low contents of proteins. The results obtained in this study reveal the potential of brown macroalgae as a promising alternative source of antimicrobial compounds as functional ingredients for the application in industrial fields.

Prevention and control of diseases and delaying the signs of ageing are nowadays one of the major goals of biomedicine. Sirtuins, a family of NAD + dependent deacylase enzymes, could be pivotal targets of novel preventive and therapeutic strategies to achieve such aims. SIRT1 activating and inhibiting compounds, such as polyphenols and bioactive peptides, have been proposed to be involved in the development of many human diseases. The objective of this work was to assess and compare the antioxidant and SIRT1 modulation activities of enzymatic protein hydrolysates (EPHs) from a wide number of algae species (24 commercial samples and 12 samples harvested off the Atlantic coast of northern Spain). High antioxidant activities were observed in EPHs from red and green seaweed species. Moreover, 19 samples exhibited SIRT1 activation, while EPHs from the 16 samples were SIRT1 inhibitors. Pearson's correlation test and Principal Component Analysis revealed significant correlations between (1) total peptide and hydrophobic amino acid content in EPHs and their antioxidant activities, and (2) concentrations of taurine, homotaurine, and amino acid gamma aminobutyric acid in EPHs and their SIRT1 modulation activity., (© 2022. The Author(s).)

The aim of this study was to investigate the aroma and sensory profiles of various types of peaches (Prunus persica L. Batsch.). Forty-three commercial cultivars comprising peaches, flat peaches, nectarines, and canning peaches (pavías) were grown over two consecutive harvest years. Fruits were assessed for chemical aroma and sensory profiles. Chemical aroma profile was obtained by proton transfer reaction-mass spectrometry (PTR-MS) and spectral masses were tentatively identified with PTR-Time of Flight-MS (PTR-Tof-MS). Sensory analysis was performed at commercial maturity considering seven aroma/flavor attributes. The four types of peaches showed both distinct chemical aroma and sensory profiles. Flat peaches and canning peaches showed most distinct patterns according to discriminant analysis. The sensory data were related to the volatile compounds by partial least square regression. γ-Hexalactone, γ-octalactone, hotrienol, acetic acid and ethyl acetate correlated positively, and benzeneacetaldehyde, trimethylbenzene and acetaldehyde negatively to the intensities of aroma and ripe fruit sensory scores., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Meat quality traits have low heritability and large environmental influences. To predict, improve and manage meat quality, proteomic biomarkers are superior to genetic markers. The objectives of this research were (1) to find associations between proteome profiles of longissimus muscle at slaughter and meat quality accuracies of prediction of traits ranged from 20 up to 80%. Differentially expressed proteins related to drip loss and ultimate pH were identified by NanoLC-FTMSMS. The proteins highlight biological mechanisms that may explain how these traits develop biologically and how they are related to each other., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Effect of tetracycline (TC) administration on the proteomic profile of pig muscle was evaluated by 2D electrophoresis and MALDI-TOF mass spectrometry. The TC content at slaughter was determined in L. dorsi samples by HPLC-DAD. Mean residual concentration of TC in the muscle of treated animals, calculated as the sum of TC and epi-TC was 126.3 microg/kg, indicating a rapid elimination of TC in this tissue. Several differential spots (n = 54, p < 0.05) were observed in protein profiles from control and treated animals. MALDI-TOF identification gave a positive match for 5 differential spots, that is, glycerol-3-phosphate dehydrogenase 1 (G3PD1), phosphoglycerate kinase 1, novelprotein (0610037L13Rik), leucine aminopeptidase 3 (LAP), and hypothetical protein isoform 2. Results show that proteomics could be a useful tool to reveal pharmacological treatments with TC, even if the possible uses of differential spots as biomarkers to detect illegal administration of TC require further studies. Different spot patterns as a consequence of TC treatments seem to be another interesting issue for the consequences on tissue metabolism and meat quality.

The day after slaughter, six chops of Longissimus lumborum from each of 10 Large White pigs and six Piétrain pigs were packed individually under vacuum and kept at 3-4 °C in the dark. At 1, 5 and 9 days after slaughter, two chops were used for analysis of lipids, thiobarbituric acid reactive substances (TBARS), sarcoplasmic Ca(2+) and sarcoplasm and mitochondria phospholipase A(2) activity. Free fatty acid content was higher in Piétrains than in Large Whites and increased with keeping time. Total lipids of Large White pigs contained more saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) and less polyunsaturated fatty acid (PUFA). Large Whites had less dioleoyl-linoleyl-glycerol (OOL) and Palmitoyl-oleoyl-linoleyl-glycerol (POL) and more Palmitoyl-oleoyl-stearyl-glycerol (POS) than Piétrains. The percentages of SFA and MUFA decreased and the percentage of PUFA increased with time in FFA of Large White pigs. In Piétrains, similar changes were observed between days 1 and 5, but later the percentages of SFA increased and the percentage of PUFA decreased again. TBARS tended to increase with time particularly in Piétrains. Sarcoplasmic phospholipase A(2) decreased between days 5 and 9 in both breeds. Sarcoplasmic calcium was markedly higher at day 1 in Piétrains than in Large Whites then the difference decreased. These breed differences in lipid composition differences and lipid changes during storage are considered too small to be of practical importance, for instance in influencing the choice of a breed for pork production.