Search

Angiotensin I-converting enzyme (ACE) inhibitory peptides have been searched in thornback ray (Raja clavata) muscle hydrolysed with Bacillus subtilis A26 proteases until a hydrolysis degree of 18.35%. The hydrolysate showed an IC50 of 0.83 mg mL−1. To identify peptides responsible for this activity, the extract was eluted through size-exclusion chromatography and fractions collected. The highest ACE inhibitory activity was found for fractions F2 and F3 which had IC50 of 0.42 and 0.51 mg mL−1, respectively. These fractions were analysed by nano-liquid chromatography coupled to tandem mass spectrometry (nLC-MS/MS). A total of 131 and 108 peptide sequences mainly derived from actin, myosin heavy chain and procollagen alpha 1 chain proteins were identified in fractions F2 and F3, respectively. FQPSF and LKYPI showed the best results with an IC50 of 12.56 and 27.07 μM, respectively. These results prove the potential of thornback ray muscle hydrolysate as a source of ACE inhibitory peptides., This work was funded by a grant from the Ministry of Higher Education and Scientific Research of Tunisia and grant Prometeo/2012/001 from Conselleria d´Educació Cultura i Sport of Generalitat Valenciana, both are acknowledged. JAEDOC- CSIC postdoctoral contract cofounded by ESF to L.M. is also acknowledged

Summary The objective of this research was to study the entire visible spectra evolution during meat ageing in different pork meat quality classes (PSE, DFD and RFN). The potential use of the visible spectra for discriminating low meat quality classes during the 24 hours postmortem (hpm) was also analysed. For these purposes, 26 pork loins were used: 3 PSE (pale, soft and exudative), 3 DFD (dark, firm and dry) and 20 RFN (red, firm and non-exudative). At 12, 24, 48 h and 7 days postmortem, reflectance spectra (400–700 nm) were obtained by a spectrocolorimeter Minolta CM-3600D after one and a half hour of blooming time. It was demonstrated that the ageing time has an influence in colour parameters and in blooming ability of RFN loins. The evolution of visible spectra was influenced by ageing time in PSE and RFN loins, while the visible spectra of DFD loins showed no variation with postmortem time. The results showed the possibility of separating PSE meats from the other classes by using visible reflectance spectra at 24 hpm.

Glucoamylase has been successfully immobilized in controlled pore glass fibers by a silane-glutaraldehyde coupling method. Enzyme solution was continuously recycled through the glass fibers held in a fixed bed reactor. Different process parameters were tested. Reservoir volume and initial enzyme concentration both had a strong influence on final glucoamylase loading. The recycle rate affected the rate of loading but not the final amount of loaded enzyme. Glucoamylase was found to be nonuniformly distributed within the fibers with penetration depths never higher than 5.75 μm, half of the fiber radius. This factor could be important in improving the immobilized glucoamylase hydrolysis of dextrin syrups.

Solid phase microextraction (SPME) has been shown to be an effective tool for analysing volatile compounds. The aim of this study was to optimise the conditions for the application of SPME in the analysis of volatile compounds in dry-cured ham. The effects of exposure time and fibre coating were investigated while maintaining the dry-cured ham at 30 °C to avoid artefact generation due to possible temperature effects. A divinylbenzene/Carboxen on polydimethylsiloxane (DVB/CAR/PDMS) coating showed the best extraction performance for medium- and high-molecular-weight analytes, whilst a Carboxen on polydimethylsiloxane (CAR/PDMS) coating gave the best results for low-molecular-weight compounds. A total of 70 different compounds were extracted by the two fibre coatings and identified. Sixty compounds were extracted by the DVB/CAR/PDMS fibre, whilst only 41 of these were found with the CAR/PDMS fibre. On the other hand, 10 additional volatile compounds were extracted by the CAR/PDMS coating, all of them being of low molecular weight. Two of the major compounds extracted, hexanal and 2-pentanone, were found in high proportion in both fibre coatings. The extraction yields of dry-cured ham volatile compounds varied according to the fibre coating used and the time of exposure. Therefore extraction conditions should be selected depending on the objective of the study. © 2002 Society of Chemical Industry

The content of nucleotide metabolites in the muscle L.dorsi from 9 exudative and 9 acceptable quality pork carcasses was determined during 7 d of aging in order to establish a period postmortem for detecting exudative meats. Hypoxanthine and inosine levels in exudative meats were different (p < 0.05) from those of normal meats up to 3 days of aging, while 5′-inosine monophosphate (IMP) and 5′-adenosine triphosphate (ATP) contents only differed during the 1st 4 and 6 h postmortem, respectively. The IMP/ATP ratio was only different (p < 0.05) at 2 h. Thus, 2 h postmortem is proposed as the optimal sampling time for the detection of exudative pork meats.

The content of nucleotide metabolites in the muscle L. dorsi was analyzed for the detection of pale, soft and exudative (PSE) pork meats at just 2 h postmortem. PSE meat was characterized by significantly lower (p < 0.05) amounts of adenosine 5′-triphosphate (ATP) and higher adenosine 5′-monophosphate (AMP), inosine 5′-monophosphate (IMP), inosine (ino) and hypoxanthine (hyp) than normal meat. IMP and ino classified all the samples from both groups with statistical significance (p < 0.05). The K0 value, R′ value and IMP/ATP ratios were also useful indicators for full distinction of PSE meats. Thus, the assay of any of these nucleotide metabolites may allow a good detection of PSE meats at very short, only 2 h, postmortem time.

Five sire types, namely Danish Duroc (DU), Dutch Large White (LWD), English Large White (LWE), Belgian Landrace × Landrace (BL × LR) and Belgian Landrace (BL), were mated with LR × LW crossbred sows. Dipeptidylpeptidase and aminopeptidase activities and free amino acid and natural dipeptide contents were compared between the offspring of each sire type. Regarding the sire type effect, significant differences were detected in dipeptidylpeptidase I and IV and alanyl and pyroglutamyl aminopeptidase activities, with activity being lowest in the offspring of BL sires. Significant differences were also observed between sire types in the content of aspartic acid, glutamic acid, serine, glycine, glutamine, histidine and arginine. Taking into account the role of exopeptidases and free amino acids in taste development, the meat from BL-sired pigs may be considered as inferior in generating flavour precursors and thus not appropriate to undergo a dry-curing process. © 1999 Society of Chemical Industry

Five different sire types, Danish Duroc (DU), Dutch Large White (LWD), English Large White (LWE), Belgian Landrace × Landrace (BL × LR) and Belgian Landrace (BL), were mated with LR × LW crossbred sows. Their offspring were compared on carcass traits, meat quality measurements and sensory characteristics of dry-cured ham. An animal mixed model was used to analyse these traits. BL-sired pigs had the worst score for meat quality but the highest killing out proportion and the best carcass conformation, with a higher percentage of ham and shoulder. On the other hand, DU-sired pigs had a good score on meat quality measurements as well as low subcutaneous fat and a good carcass conformation. Sensory analysis of dry-cured ham revealed that the BL-sired pigs showed a high ‘rancid’ aroma, although this sire type presented a low ‘marbling’ appearance. Dry-cured ham from BL × LR-sired pigs was characterised by a high ‘fat complex’ aroma and a low level of ‘tyrosine crystals’, and from DU-sired pigs by high ‘marbling’ and ‘tyrosine crystals’ and a low aroma content. The females produced a higher percentage of ham and dry-cured ham with a higher ‘overall quality’ than the males. It can be concluded that the appropriate genetic type for dry-cured ham processing is the DU sire because of its high desirable ‘marbling’ descriptor. © 1999 Society of Chemical Industry

This scientific opinion of EFSA deals with the risk assessment of the substance 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n-octyloxyphenyl)-1,3,5-triazine, CAS No. 2725-22-6, REF. No. 38885 for which the CEF Panel concluded that there is no safety concern for the consumer if its migration does not exceed 5 mg/kg food

The activities of cathepsins B, D, H and L have been assayed at various stages in the slow processing (15 months) of dry-cured ham. Cathepsins B, H and L showed low recovered activity (5–10% of the initial activity) at the end of the process. However, cathepsin D almost disappeared after 5–10 months. Water-soluble protein extractability decreased throughout the process while myofibrillar protein extractability was constant. There was a progressive disappearance of myosin heavy chain, myosin light chains 1 and 2, and troponins I and C, a marked increase of three breakdown products with molecular weights of about 150, 95 and 16 kDa and some minor products in the ranges 50–100 kDa and 20–45 kDa. Cathepsins B and L could be particularly active in the observed proteolysis which had a special relevance when the drying started. Actin, actinin, troponin T and tropomyosin did not seem to change.

Scanning Electron Microscopy (SEM) has become a routine technique for the characterization of inert support materials for biocatalyst immobilization as well as for the observation of immobilized cells, especially cell colonization and cell-support interaction. SEM is expected to have important future applications in the observation of immobilized enzymes and will prove a useful technique in the engineering design and scale-up of immobilized biocatalyst systems.

Glucoamylase has been covalently immobilized in controlled pore glass fibers packed parallel to the axis of a tubular reactor. Flow kinetic studies have been carried out for a range of flow rates and substrate concentrations at 50°C and pH 4.5. Diffusion control has been found negligible with high flow rates and substrate concentrations. The apparent Michaelis constant was three orders of magnitude higher than that of the free enzyme. As flow rate and substrate concentration decrease, the extent of diffusion control increased up to a moderate degree. The immobilized glucoamylase was more stable than the free enzyme when incubated at 50°C.

The effects of polyamines (agmatine, cadaverine, putrescine, spermidine and spermine) on the activity of the main aminopeptidases (AP I and AP II) from Lactobacillus sake were determined. Concentrations in the range of 1 mM caused 6–25% inhibition of AP I except for spermine (45% inhibition). Higher polyamine levels (5–10 mM), except for putrescine, exerted a stronger inhibition (20–60%) on AP I. Agmatine and putrescine also reduced AP II activity (6–25%) at concentrations of 0.1–10 mM while cadaverine did not have a notable effect. Spermidine and spermine stimulated (15–70%) the activity of AP II at concentrations >1 mM. Thus, control of polyamine levels is important because they are a potential hazard for human health and also because of their effects on aminopeptidase activity.

A fluorimetric assay has been developed using several aminoacyl-7-amido-4-methyl coumarin (AMC) substrates (L-leucine-, L-alanine-, L-arginine-, L-tyrosine-, L-phenylalanine-, L-serine- and L-valine-AMC) in black multi-well plates to measure microbial aminopeptidase activity in lactobacilli intact cell suspensions (10 9 -10 10 CFU/mL). The fluorescence emission was visually evaluated by panelists and showed that substrate concentrations of 0.01 mM were optimal for visual detection and thus useful for rapid screening of many strains. The different ratios of activities quantitated in a multiscan fluorimeter showed a potential for differentiation among strains.

An initial freezing/thawing treatment of raw hams prior to dry-curing was compared to the standard process (refrigerated hams) by assaying free fatty acid generation and carbonyl index in both biceps femoris muscle and adipose tissues throughout curing. More intense lipolysis occurred between 0 and 5 mo for muscle, and 0 and 10 mo for adipose tissue. Lipid oxidation in adipose tissue was higher than in muscle. No significant differences (p

The effect of common curing agents (salt, nitrate, nitrite, ascorbic acid and glucose) on porcine muscle leucyl, arginyl, alanyl, pyroglu-tamyl and tyrosyl hydrolyzing activities was studied. Salt, ascorbate and nitrite had inhibitory effects on most enzyme activities. All activities decreased as salt increased (to 1.25 M) and/or water activity decreased (from 1.00 to 0.81). Nitrite inhibited only alanyl, pyroglu-tamyl and tyrosyl hydrolyzing activities. An in-vitro study using model conditions of three stages of dry-curing of ham, revealed that leucyl hydrolyzing activity may be important through the complete process. Other enzymes may also be involved in later stages of curing but are less important.

Different assays were tested for the detection of proteolytic activity in both Pediococcus pentosaceus and Staphylococcus xylosus, two major microorganisms isolated from dry-cured ham. Absence of endopeptidase activity was found even when using raw sarcoplasmic and myofibrillar proteins. However, P. pentosaceus showed strong leucine and valine arylamidase activities while St. xylosus showed a very weak leucine arylamidase activity.

Free amino acids have been analyzed in biceps femoris muscle and adipose tissue from raw and dry-cured ham. A high increase was observed for all amino acids except glutamine and taurine. Major increases were in glutamic acid, arginine, alanine, valine, leucine, and lysine. A survey of five aminopeptidase activities of muscle and adipose tissue from raw and dry-cured ham was performed by using 7-amino-4-methylcoumarin derivatives of five amino acids (Leu, Arg, Ala, Tyr and pGlu) as substrates. Optimum activity was found at neutral pH and around 37°C, except the leucyl hydrolyzing activity which was 45°C. High recoveries of activity (25–75%) were obtained in the dry-cured ham. These enzymes might be responsible for free amino acids increasing during dry-curing.

Scanning electron microscopy of the white film developed on the cut surface of some vacuum-packed dry-cured ham slices showed a fibrous structure composed of protein materials. Gradient SDS-PAGE revealed the main components in the film were proteins with molecular weight in the range 26000–87000, but especially 37000, 41000, 56000, and 65000. Free amino acids were also in the film in low proportions (250 μg total free amino acids per mg of protein). The main amino acids were proline methionine, isoleucine, leucine, phenylalanine, histidine and tyrosine. 11.7% of the total free amino acids was tyrosine, thus indicating its minor role in formation of white film.

EFSA has been asked to provide scientific advice in relation to possible divergences between the conclusions of the EFSA Scientific Opinion on Bisphenol A of September 2010 and those in the ANSES reports on BPA published in September 2011. The EFSA CEF Panel has analysed whether the ANSES report "Effets sanitaires du bisphenol A" contains any elements that would necessitate a revision of the EFSA opinion. The approach of the ANSES report is that of hazard identification, comprising also elements which could be relevant for the safety assessment of non-dietary exposure to BPA, whereas the EFSA opinion of 2010 addresses the assessment of risk from dietary exposure to BPA. This is the main reason for divergences between the ANSES and EFSA conclusions on BPA. The Panel overall considers that the information in the ANSES report does not change the views that the Panel expressed in 2010. To further investigate the divergences between the conclusions of ANSES in 2011 and those of EFSA in 2010 and to identify the relevant uncertainties in the data, the CEF Panel has undertaken a preliminary review of the new literature emerging on BPA. For most endpoints, the Panel considers that there is no new information that would change the views of the Panel of 2010. In 2010 the Panel noted that some studies conducted on developing animals suggest certain BPA-related effects which were not sufficiently convincing to use as pivotal effects for risk assessment, but which the Panel considered could be of possible toxicological relevance. Since then, additional studies related to these effects have become available, indicating effects of BPA in rodents at dose levels below the current NOAEL of 5 mg/kg bw/day. Uncertainties regarding the relevance to humans of these toxicological effects remain to be clarified. The Panel would need more time to review in depth these new studies. The Panel will reconsider its opinion following further evaluations of new studies and of new data from ongoing low dose studies.EFSA has been asked to provide scientific advice in relation to possible divergences between the conclusions of the EFSA Scientific Opinion on Bisphenol A of September 2010 and those in the ANSES reports on BPA published in September 2011. The EFSA CEF Panel has analysed whether the ANSES report "Effets sanitaires du bisphenol A" contains any elements that would necessitate a revision of the EFSA opinion. The approach of the ANSES report is that of hazard identification, comprising also elements which could be relevant for the safety assessment of non-dietary exposure to BPA, whereas the EFSA opinion of 2010 addresses the assessment of risk from dietary exposure to BPA. This is the main reason for divergences between the ANSES and EFSA conclusions on BPA. The Panel overall considers that the information in the ANSES report does not change the views that the Panel expressed in 2010. To further investigate the divergences between the conclusions of ANSES in 2011 and those of EFSA in 2010 and to identify the relevant uncertainties in the data, the CEF Panel has undertaken a preliminary review of the new literature emerging on BPA. For most endpoints, the Panel considers that there is no new information that would change the views of the Panel of 2010. In 2010 the Panel noted that some studies conducted on developing animals suggest certain BPA-related effects which were not sufficiently convincing to use as pivotal effects for risk assessment, but which the Panel considered could be of possible toxicological relevance. Since then, additional studies related to these effects have become available, indicating effects of BPA in rodents at dose levels below the current NOAEL of 5 mg/kg bw/day. Uncertainties regarding the relevance to humans of these toxicological effects remain to be clarified. The Panel would need more time to review in depth these new studies. The Panel will reconsider its opinion following further evaluations of new studies and of new data from ongoing low dose studies.EFSA has been asked to provide scientific advice in relation to possible divergences between the conclusions of the EFSA Scientific Opinion on Bisphenol A of September 2010 and those in the ANSES reports on BPA published in September 2011. The EFSA CEF Panel has analysed whether the ANSES report "Effets sanitaires du bisphenol A" contains any elements that would necessitate a revision of the EFSA opinion. The approach of the ANSES report is that of hazard identification, comprising also elements which could be relevant for the safety assessment of non-dietary exposure to BPA, whereas the EFSA opinion of 2010 addresses the assessment of risk from dietary exposure to BPA. This is the main reason for divergences between the ANSES and EFSA conclusions on BPA. The Panel overall considers that the information in the ANSES report does not change the views that the Panel expressed in 2010. To further investigate the divergences between the conclusions of ANSES in 2011 and those of EFSA in 2010 and to identify the relevant uncertainties in the data, the CEF Panel has undertaken a preliminary review of the new literature emerging on BPA. For most endpoints, the Panel considers that there is no new information that would change the views of the Panel of 2010. In 2010 the Panel noted that some studies conducted on developing animals suggest certain BPA-related effects which were not sufficiently convincing to use as pivotal effects for risk assessment, but which the Panel considered could be of possible toxicological relevance. Since then, additional studies related to these effects have become available, indicating effects of BPA in rodents at dose levels below the current NOAEL of 5 mg/kg bw/day. Uncertainties regarding the relevance to humans of these toxicological effects remain to be clarified. The Panel would need more time to review in depth these new studies. The Panel will reconsider its opinion following further evaluations of new studies and of new data from ongoing low dose studies.

This scientific opinion of EFSA deals with the risk assessment of the monomer a-dimethyl-3-(4'-hydroxy-3'-methoxyphenyl)propylsilyloxy,u-3-dimethyl-3-(4'-hydroxy-3'-methoxyphenyl)propylsilyl polydimethylsiloxane, n=26-50, CAS No. 156065-00-8, REF. No. 16265, FCM substance No. 874, for which the CEF Panel concluded that there is no safety concern for the consumer if the substance is only used as comonomer in siloxane modified polycarbonate,and its migration is up to 0.05 mg/kg food. The end-capper eugenol must comply with the restriction on migration set in Commission Regulation (EU) No 10/2011

This scientific opinion of EFSA deals with the risk assessment of the substance perfluoro[(2-ethyloxy-ethoxy)acetic acid], ammonium salt, CAS No. 908020-52-0, REF. No. 71955, FCM substance No. 926 for which the CEF Panel concluded that there is no safety concern for the consumer if the substance is only used in the polymerisation of fluoropolymers that are processed at temperatures higher than 300°C for at least 10 minutes.

This scientific opinion of EFSA deals with the risk assessment of the substance 3H-perfluoro-3-[(3-methoxypropoxy) propanoic acid], ammonium salt, CAS No. 958445-44-8, REF. No. 71958, FCM Substance No. 896 for which the CEF Panel concluded that there is no safety concern for the consumer if the substance is used only: a) in the polymerisation of fluoropolymers processed at temperatures higher than 280°C for at least 10 minutes and b) in the polymerisation of fluoropolymers for being processed at levels up to 30% and temperatures higherthan 190°C into polyoxymethylene polymer for repeated use articles only

This scientific opinion of EFSA deals with the risk assessment of the polymeric additive (butadiene, styrene, methyl methacrylate) copolymer cross-linked with 1,3-butanediol dimethacrylate, REF. No. 40560 for which the CEF Panel concluded that there is no safety concern for the consumer if the substance is used only up to 12% w/w in rigid poly(vinyl chloride) (PVC) materials at room temperature or below

This scientific opinion of EFSA deals with the risk assessment of the polymeric additive (butadiene, styrene, methyl methacrylate, butyl acrylate) copolymer cross-linked with divinylbenzene or 1,3-butanediol dimethacrylate, REF. No. 40563 for which the CEF Panel concluded that there is no safety concern for the consumer if the substance is used only up to 12% w/w in rigid poly(vinyl chloride) (PVC) materials at room temperature or below

This scientific opinion of EFSA deals with the risk assessment of the substance poly(12-hydroxystearic acid)-polyethyleneimine copolymer, CAS No. 124578-12-7, REF. No. 80350 for which the CEF Panel concluded that there is no safety concern for the consumer if the substance is prepared by the reaction of poly(12-hydroxystearic acid) with polyethyleneimine and used up to 0.1% w/w in plastics