Effect of dietary vitamin E on physicochemical and fatty acid stability of fresh and thawed lamb.

This study evaluated the effect of dietary vitamin E supplementation (1000mg of DL-α-tocopheryl acetate/kg of basal diet) on physicochemical and fatty acid stability of fresh and thawed lamb leg chops, frozen stored for 3, 6 and 9months. Legs were chopped, modified atmosphere packaged (70%O2/30%CO2) and maintained under retail conditions (4±0.5°C, with 14h fluorescent light) for 9days. Muscle α-tocopherol concentration was over 3.5-fold higher in supplemented samples than in control lambs. The effect of dietary vitamin E was independent of frozen storage, so these effects were analysed separately. Vitamin E supplementation reduced lipid oxidation (P≤0.001) and decreased metmyoglobin formation, leading to a more attractive colour of meat. Moreover, supplementation led to a higher percentage of polyunsaturated fatty acids. Therefore, vitamin E supplementation could be recommended for preserving either fresh or thawed lamb.

The combined effects of superchilling and packaging on the shelf life of lamb.

The aim of this study was to evaluate the effect of superchilled storage at -1° on the shelf life of lamb slices packaged in an O2 enriched (40% O2/30% CO2/30% Ar) or in an anaerobic atmosphere (vacuum skin packaging). Physicochemical, microbial and sensory analyses were performed. The effect of superchilled storage on lamb stability differed depending on the atmosphere surrounding the product. Superchilled (-1°C) slices of lamb showed lower microbial counts than those refrigerated at 4°C in both packaging conditions. Moreover, meat stored at -1°C had a higher colour stability under vacuum. Superchilled storage combined with an O2 enriched atmosphere increased the rate of lipid oxidation, which reduced the shelf life reached by refrigerating at 4°C. Vacuum skin packaging strongly inhibited lipid oxidation independently of storage temperature. Thus, superchilled storage extended the shelf life at least twice compared to storage at 4°C under anaerobic conditions while it was disadvantageous when an O2 enriched atmosphere was used.

Effect of borage and green tea aqueous extracts on the quality of lamb leg chops displayed under retail conditions.

Different concentrations of two aqueous extracts from green tea leaves and borage seeds with potential antioxidant activity were evaluated in lamb leg chops. Chops were sprayed with 0.005, 0.05, 0.5, 5% (p/v) green tea extracts (T) and 0.5, 5 and 10% (p/v) borage seed extracts (B) and displayed under retail conditions for 13days. Total polyphenols, TBARS, colour, microbial and sensory analyses were performed. The extracts showed a concentration-dependent action; the minimum concentration of polyphenols which significantly reduced lipid oxidation was 2.08mgGAE/100cm2 of meat. Both 0.5% T and 10% B limited colour deterioration, reducing also metmyoglobin formation. The extracts showed no antimicrobial effect, exceeding microbial counts of 7logCFU/cm2 at 13days of display. Sensory analyses determined that none of the extracts added herb odours or flavours to lamb. In conclusion, 0.5% T or 10% B extracts extended lamb shelf life from 8 to 11days, so both would be recommended for lamb chops preservation.

Peptic Ulcer Bleeding Risk. The Role of Helicobacter Pylori Infection in NSAID/Low-Dose Aspirin Users.

OBJECTIVES: Helicobacter pylori (H. pylori) infection and NSAID/low-dose aspirin (ASA) use are associated with peptic ulcer disease. The risk of peptic ulcer bleeding (PUB) associated with the interaction of these factors remains unclear. The objective of this study was to determine the risk of PUB associated with the interaction between H. pylori infection and current nonsteroidal anti-inflammatory drugs (NSAIDs) or low-dose ASA use. METHODS: This was a case-control study of consecutive patients hospitalized because of PUB. Controls were matched by age, sex, and month of admission. H. pylori infection status was determined in all cases and controls by serology. Drug use was determined by structured questionnaire. Adjusted relative risk (RR) associated with different factors, and the interaction between NSAID/ASA and H. pylori infection was estimated by logistic regression analysis. RESULTS: The study included 666 cases of PUB and 666 controls; 74.3% cases and 54.8% controls (RR: 2.6; 95% confidence interval (CI): 2.0-3.3) tested positive for H. pylori infection; 34.5% of cases had current NSAID use compared with 13.4% of controls (RR: 4.0; 95% CI: 3.0-5.4). Respective proportions for low-dose ASA use were 15.8 and 12%, respectively (RR: 1.9; 95% CI: 1.3-2.7). The RR of PUB for concomitant NSAID use and H. pylori infection suggested an additive effect (RR: 8.0; 95% CI: 5.0-12.8), whereas no interaction was observed with ASA use (RR: 3.5; 95% CI: 2.0-6.1). CONCLUSIONS: NSAID, low-dose ASA use, and H. pylori infection are three independent risk factors for the development of PUB, but there were differences in the interaction effect between low-dose ASA (no interaction) or NSAID (addition) use and H. pylori infection, which may have implications for clinical practice in prevention strategies.

Chemical composition and antimicrobial effects of essential oils of Eucalyptus globulus, Myrtus communis and Satureja hortensis against Escherichia coli O157:H7 and Staphylococcus aureus in minced beef.

Essential oils (EOs) extracted by hydrodistillation from leaf parts of Algerian Eucalyptus globulus, Myrtus communis and Satureja hortensis were analyzed by gas chromatography/mass spectrometry (GC/MS). The main components of EOs obtained were γ-terpinene (94.48%), 1,8-cineole (46.98%) and carvacrol (46.10%), respectively, for E. globulus, M. communis and S. hortensis. The in vitro antimicrobial activity of the EOs was evaluated against Staphylococcus aureus CECT 4459 and Escherichia coli O157:H7 CECT 4267 using the agar diffusion technique. Results revealed that E. globulus and S. hortensis EOs had more antibacterial effects than that from M. communis. Minimal inhibitory concentrations (MIC) showed a range of 0.05-0.22% (volume by volume [v/v]). Sensitivity of gram-positive S. aureus was much higher than that of gram-negative E. coli. Plant EOs were added to minced beef (two-fold MIC value) at 0.10-0.44%, experimentally inoculated with the same pathogens at a level of 5 × 10(5) colony forming units (cfu)/g and stored at 5 ± 2 °C. Results showed that the EOs of E. globulus and S. hortensis had remarkable antibacterial properties, higher than that of M. communis, against S. aureus and E. coli. Indeed, a reduction of 5.8 log cfu/g (70.74% of reduction) was recorded after 7 days of storage for S. hortensis against E. coli. However, regarding S. aureus, both S. hortensis and E. globulus caused a highly significant (p < 0.05) decrease of microbial counts, most evident after 5 days of storage; S. aureus numbers were 3.50 and 2.50 cfu/g, respectively, corresponding to a reduction of 2.20 and 3.20 log cfu/g (38.60 and 56.14% of reduction) after 1 week of storage. Sensory evaluation revealed that the aroma of minced beef meat treated with EOs was acceptable by panelists at the levels used.

Risk factors for advanced lesions undetected at prior colonoscopy: not always poor preparation.

BACKGROUND AND STUDY AIM: Colonoscopy is regarded as the gold standard for diagnosis of colonic lesions. However, adenoma miss rates in tandem colonoscopy studies vary from 2 % to 26 %. We aimed to investigate the rates of advanced neoplasia in patients with a prior normal colonoscopy in an outpatient endoscopy unit. METHODS: Review of reports for colonoscopies performed in our Endoscopy Unit from 2000 to 2005. Undetected lesions were defined as advanced adenoma or colorectal cancer (CRC) not reported in a colonoscopy performed in the previous 2 or 3 years, respectively. Patients with hereditary nonpolyposis CRC (HNPCC) and familial adenomatous polyposis (FAP) were excluded. RESULTS: Between 2002 and 2005, 795 patients were diagnosed with at least one advanced adenoma and 386 with CRC. Among these, 107/795 patients (13.5 %) had advanced adenoma that had been undetected in a previous colonoscopy (39 % [53/135 lesions] in the right colon); 92/107 (86 %) had an undetected advanced adenoma ≥ 10 mm. Previously undetected CRCs were found in 27/386 patients (6.7 %), located in the left colon in 21/27 (78 %); in 7 the area had not been reached in the previous colonoscopy. Risk factors for undetected advanced adenoma were advanced age, male gender, the presence of another advanced adenoma at first colonoscopy, and history of advanced neoplasia. CONCLUSIONS: Failure to detect advanced neoplasia is common in a community-based endoscopy facility. Previously undetected advanced lesions are more frequently found in the left colon and rectum. Risk factors for non-detection of advanced adenoma are similar to those for advanced neoplasia recurrence. Lowering non-detection rates is crucial for correct follow-up recommendations. Patients should be aware of rates of detection of advanced neoplasia after previous normal colonoscopic findings.

Sensory attributes that drive consumer acceptability of dry-cured ham and convergence with trained sensory data.

The paper investigates the degree of convergence between trained panelists and consumers with regard to overall quality assessment and acceptability, respectively. In particular, the main sensory drivers used by both groups of assessors in their valuations, are investigated: first, a Principal Component Analysis (PCA) is applied to identify main dimensions underlying sensory data, and second, the external preference mapping (PREFMAP) technique, that regress consumers' hedonic valuations on the PCA sensory dimensions, is applied. A total of eight samples of dry-cured ham was analysed by 14 trained panelists and 213 consumers in a northern city of Spain (Zaragoza). The results showed that both, consumers and trained panelists make use of the same sensory attributes to elicit their assessments, which are crumbliness, softness, flavour and sweetness. However, trained assessors are able to discriminate better the quality across ham samples, as we would expect, according to a higher degree of expertise. Interestingly, the PREFMAP technique showed a certain degree of heterogeneity in consumers' preferences, highlighting clusters with opposite liking trends.

Investigación translacional en patología digestiva: del laboratorio a la clínica y viceversa beneficiario: el paciente / No disponible

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Preservation of the proteolytic activity of a bovine spleen lysosomal-enriched extract using various freezing conditions.

The preservation of the proteolytic activity of a bovine spleen lysosomal-enriched (BSLE) extract was investigated. The BSLE extract (pH = 5.8), was subjected to storage under different conditions: refrigeration at 0 degrees C for 60 days; freezing at -20 degrees C -either directly or previously frozen in liquid nitrogen-, -80 degrees C and in liquid nitrogen; freeze-drying and stored at 0 degrees C; and freezing at -20 degrees C or in liquid nitrogen in the presence of glycerol and sorbitol as cryoprotectants. Freezing at low temperatures (-80 degrees C and in liquid nitrogen) was most effective for preserving about 100% of the initial activity of all cathepsins (B, B+L and D), as well as the activity of the extract on myofibrils, for two years. Freezing at -20 degrees C, on the contrary, led to significant (P < 0.01) losses of activity. Freeze-drying was able to preserve cathepsin activity, while it failed to maintain activity on myofibrils. Both cryoprotectants sorbitol and glycerol significantly (P < 0.01) enhanced enzyme preservation, particularly cathepsin D and the activity on myofibrils, even at a freezing temperature of -20 degrees C.

The effects of ascorbic acid, taurine, carnosine and rosemary powder on colour and lipid stability of beef patties packaged in modified atmosphere.

This research was aimed at evaluating the inhibition of oxidative changes of beef patties packaged in modified atmosphere (70% O(2)+20% CO(2)+10% N(2)) by natural antioxidants: ascorbic acid (500 ppm), taurine (50 mM), carnosine (50 mM), rosemary powder (1000 ppm) and their combinations with the first. Beef patties stored at 2±1°C for 20 days were evaluated for colour (L*, a*, b*, C* and H*), TBARS, metmyoglobin formation (% of total myoglobin), psychrotrophic microbial counts and sensory odour and discolouration. Rosemary, either alone or with ascorbic acid, was highly effective in inhibiting both metmyoglobin formation and lipid oxidation; sensory analysis was in agreement with these results. Ascorbic acid, ascorbic acid+taurine and ascorbic acid+carnosine treatments showed a limited inhibitory effect of myoglobin oxidation, while carnosine and carnosine+ascorbic acid were effective in inhibiting lipid oxidation. Taurine alone failed to exert any antioxidant effect. Principal components analysis confirmed these results.

Direct and highly species-specific detection of pork meat and fat in meat products by PCR amplification of mitochondrial DNA.

Highly species-specific primers for pork D-loop mtDNA have been designed. Use of these and restrictive PCR amplification conditions has improved a reliable and rapid method for detecting a PCR-amplified 531 bp band from pork. It has been proved useful for detecting both pork meat and fat in meat mixtures, including those dry-cured and heated by cooking. Absence of response in PCR-amplified samples or mixtures from bovine, ovine, chicken, and human was also demonstrated. Furthermore, wild boar and pork samples can be also easily distinguished by a simple AvaII restriction analysis.

Beef shelf life in low O(2) and high CO(2) atmospheres containing different low CO concentrations.

The use of atmospheres with low concentrations of CO (0.1 to 1%), in combination with O(2) (24%), high CO(2) (50%) and N(2) (25 to 25.9%), for preserving chilled beef steaks was investigated. The atmosphere used as reference contained 70% O(2)+20% CO(2)+10% N(2). Bacterial counts showed that all atmospheres containing CO greatly reduced total aerobic population numbers, including Brochothrix thermosphacta. Lactic acid bacteria, however, were not affected. CO concentrations of 0.5-0.75% were able to extend shelf life by 5-10 days at 1±1°C, as demonstrated by delayed metmyoglobin formation (less than 40% of total myoglobin after 29 days of storage), stabilisation of red colour (no change of CIE a* and hue angle after 23 days), maintenance of fresh meat odour (no variation of sensory score after 24 days) and significant (P<0.01) slowing of oxidative reactions (TBARS).

Textural assessment of clenbuterol treatment in beef.

Eight Charolais heifers (ca. 300 kg) were fed a diet containing either 0 (control) or 1 ppm clenbuterol during 5 weeks. Daily live weight gain was higher (p<0.01), by about 34%, in treated animals. They were slaughtered after a week of withdrawal. Activity of µ-calpain of meat from clenbuterol-fed heifers was lower (p<0.01) immediately post mortem, while activity of calpastatin was higher (p<0.05) than in meat from controls. According to sensory and instrumental data, meat from clenbuterol-fed heifers did not tenderise during aging, and was tougher (p<0.05) than control meat at 8th day post mortem. Both principal component analysis and multivariate discriminant analysis of a pool of data of the textural profile showed differences due to clenbuterol treatment at 24 h. The slope after yield (calculated from the Warner-Bratzler shearing force-deformation curve), was the only textural parameter affected (p<0.05) at 24 h by the treatment.

Shelf-life extension and colour stabilisation of beef packaged in a low O(2) atmosphere containing CO: Loin steaks and ground meat.

A combination of low O(2), high CO(2) and very low CO was investigated for packaging fresh beef steaks and ground meat. The following atmospheres were used: 70% O(2) + 20% CO(2) + 10% N(2) (CMA); 70% O(2) + 20% CO(2) + 9% N(2) + 1% CO (HOCO) and 24% O(2) + 50% CO(2) + 25% N(2) + 1% CO (LOCO). Bacterial counts showed that LOCO atmosphere greatly reduced psychrotrophic population, so that log cfu cm(-2) was under 7.5 at 29 days of storage at 1 °C. All the objective measurements related to meat colour (a(∗), hue, Chroma and metmyoglobin concentration) revealed that the bright-red colour was more stable in both HOCO and LOCO atmospheres, reaching 29 days of storage without appreciable signs of oxidation. Sensory analysis confirmed these results.

Effect of stress-induced high post-mortem pH on protease activity and tenderness of beef.

Forty-four Swiss Brown young bulls were stressed by regrouping unfamiliar animals before slaughter. M. longissimus thoracis (6-9th ribs) of carcasses were analysed for post-mortem pH, protease activities (m- and α-calpain, calpastatin and cathepsin B + L), Warner-Bratzler shear force and sensory tenderness and juiciness. Muscles were classified into three groups, according to ultimate pH values: > 6.3, 6.3-5.8 and < 5.8. The most significant difference related to high pH was a higher activity of m-calpain at 7th day post mortem. It was also found that meat showing the highest pH was significantly more tender and juicy. Sensory tenderness was highly correlated with activity of m-calpain at 7th day post mortem (r = 0.776) and with ultimate pH (r = 0.708). It is concluded that high ultimate pH induced by stress significantly increases m-calpain activity, and this results in a greatly enhanced tenderisation of beef meat.

Ultrasonication of lamb skeletal muscle fibres enhances postmortem proteolysis.

The effect of ultrasound upon the postmortem proteolytic activity of muscle fibres was investigated. As a preliminary result it was demonstrated that ultrasonication released lysosomal enzymes from liver cells while cell membranes suffered little damage. Proteolysis brought about by endogenous proteinases after 2 days of fibre storage at 4 degrees C was assessed by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Ultrasonic treatment of fibres enhanced proteolytic activity, as shown by the increased intensity of 30-kDa region degradation bands. A distinct change featuring sonicated fibres was the degradation of an 87-kDa protein and the appearance of an 83-kDa peptide. Cell damage was not very extensive, although it depended upon ultrasonication and fibre conditions.

Proteolytic activity of isolated lamb calpains on myofibrils under the conditions of pH, Ca2+ concentration and temperature existing in postmortem muscle.

The two calcium-activated neutral proteinases (calpains I and II) and their specific inhibitor were isolated by ion exchange chromatography in DEAE-Sephacel from lamb skeletal muscle (longissimus dorsi). Their proteolytic activities were then determined using myofibrils as substrate. The Ca2+ requirements were different for each form of the enzyme: calpain I needed only 50 mumol Ca2+ for half-maximal activity, while the other isoenzyme, calpain II, needed 1,000 mumol Ca2+ for reaching 50% of its maximum activity. Both calpains showed a relevant activity in the pH range 5.5-6.5 (over 40% of maximum activity found at pH 7.5). With regard to the effect of temperature, both isoenzymes retained about 25% of their activity at 25 degrees C with a temperature reduction down to 4 degrees C. It is concluded that calpain I is an active protease under conditions similar to that prevalent in lamb meat during postmortem storage.

Tenderisation of lamb meat: Effect of rapid postmortem temperature drop on muscle conditioning and aging.

Lamb Longissimus dorsi muscles were excised from carcasses of 9-12 kg and 16-20 kg weight and brought to internal temperatures of either 0°C, 4°C, 10°C, 15°C, 20°C or 36°C within 3-4h post mortem. After rigor completion they were allowed to age at 4°C for 7 days. Sensory panel scores obtained on the first day of post-rigor aging showed that meat from heavier animals was tougher than that of lighter ones at any temperature. In all cases aging for 7 days had a marked tenderising effect which was similar at all studied temperatures, and greater in heavier animals. Tenderness was also dependent on the temperature at conditioning, as shortening caused by either high or low temperature resulted in meat toughening. The sole and surprising exception to this fact was, however, the high sensory scores obtained in 0°C experiments, even though shortening occurred as expected. In fact, a more intense proteolysis was evident in this case, which was already apparent on the first day of aging. The effect of a rapid drop of muscle temperature to 0°C on the fast and intense proteolysis, capable of even overcoming toughness due to cold shortening, was explained by the higher pH and the dramatic increase of the sarcoplasmic Ca(++) level induced early post mortem by chilling and which might result in the activation of calpain.

Sarcomere shortening of prerigor muscles and its influence on drip loss.

Detailed studies of muscle shortening post mortem at incubation temperatures between -2°C and +38°C revealed that the sarcomeres in unrestrained, excised red bovine muscle (M. sternomandibularis) shortened less than 10 % in the prerigor state between 6°C and 18°C. Below 6°C, sarcomeres contracted up to 70%. Between 20°C and 38°C sarcomere shortening of 40% was observed. In the red porcine M. cleidooccipitalis the minimum of shortening was measured at about 10°C, a higher degree of shortening-up to 50%-being obtained above and below this temperature. The drip loss of both muscle types increased linearly with increasing prerigor shortening. This latter relationship is discussed with regard to changes within the muscle post mortem. The influence of three events on water movement from the interfilamental space into the interfibrillar fluid and from there into the extracellular space is critically evaluated. These events are: (1) the prerigor contraction of sarcomeres depending on the temperature of storage, (2) the changes due to the falling pH post mortem and (3) the onset of rigor mortis, with its irreversible association of actin and myosin.

Bisphosphoglycerate synthase activity in cells of the erythrocytic line of rat.

The specific activity of bisphosphoglycerate synthase (EC 2.7.5.4) is significantly higher in rat mature erythrocytes than in reticulocytes from phenylhydrazine treated animals, while 2,3-bisphosphoglycerate levels do not differ between them. The enzyme specific activity and the concentration of 2,3-bisphosphoglycerate are both negligible in the erythroid cell pool from the bone marrow of anaemic animals. Thus, a cellular specialization in the last stages of erythropoiesis is confirmed. Human bisphosphoglycerate synthase shows a lower specific activity than that of rat without a parallel decrease in 2,3-bisphosphoglycerate levels.