Effect of pre-slaughter physiological conditions on the oxidative stability of colour and lipid during chill storage of pork

The physiological condition of the live animal was found to significantly affect colour, lipid oxidation and water holding capacity of chill stored pork chops (M. Longissimus dorsi) in a study, where various pre-slaughter conditions were achieved by the following four treatments: (A) control; (B) subjected to treadmill exercise immediately prior to stunning; (C) given epinephrine injection 15 h prior to slaughter; and (D) given epinephrine injection 15 h before slaughter and further subjected to treadmill exercise immediately before stunning. The treatments resulted in variations in energy metabolites (glycogen, lactate, creatine phosphate, ATP) and ultimate pH (pH_u), with the lowest pH_u in chops from treatments A and B, and in significantly different tristimulus colour L^*-, a^*- and b^*-parameters, although the effect of treatment on colour was not consistent during the chill storage period of 6 days. Overall, chops from treatments A and B had significantly higher L^*- and b^*-values (were paler and less blue) than chops from C and D during storage under conditions typical for retail trade. The initial a^*-values were higher (redder) in chops from treatments A and B, but the colour, as judged by the a^*-values, was less stable in meat from these treatments compared with treatments C and D. Lipid oxidation, evaluated by thiobarbituric acid reactive substances (TBARS) in the fresh meat, and drip loss, measured after 6 days of storage, were both significantly higher in chops from treatments A and B compared to chops obtained from treatments C and D. Statistical analysis relating the pH and the level of various energy metabolites post-mortem in the individual animals to the measured quality parameters, revealed that pH_u was the most important factor affecting product quality. In conclusion, over all product quality depends on obtaining a pH_u in the narrow range where both meat quality parameters such as colour, lipid oxidation and drip loss as well as microbiological aspects have to be considered.     

Quantification of aroma vapours sorbed in polyethene films using supercritical carbon dioxide

Extraction with supercritical carbon dioxide was used to quantity the amounts of seven different aroma vapours sorbed in polyethene films. The method was found to completely extract all aroma compounds from the films. The solution of aroma compounds in the polymer films decreased with increasing polymer density. Monoterpenes were always completely sorbed in the films, whereas aldehydes and ketones had a much lower affinity for the films. The sulphur-containing compound, thiophene, was difficult to analyse due to its adsorption on metal surfaces.     

Involvement of yeast YOL151W/GRE2 in ergosterol metabolism

The Saccharomyces cerevisiae gene YOL151W/GRE2 is widely used as a model gene in studies on yeast regulatory responses to osmotic and oxidative stress. Nevertheless, information concerning the physiological role of this enzyme, a distant homologue of mammalian 3-beta-hydroxysteroid dehydrogenases, is scarce. Combining quantitative phenotypic profiling and protein expression analysis studies, we here report the involvement of yeast Gre2p in ergosterol metabolism. Growth was significantly and exclusively reduced in gre2Delta strains subjected to environmental stress straining the cell membrane. Furthermore, whereas no compensatory mechanisms were activated due to loss of Gre2p during growth in favourable conditions (synthetic defined media, no stress), a striking and highly specific induction of the ergosterol biosynthesis pathway, represented by the enzymes Erg10p, Erg19p and Erg6p, was observed in gre2Delta during growth in a stress condition in which lack of Gre2p significantly affects growth. Involvement of Gre2p in ergosterol metabolism was confirmed by application of an array of selective inhibitors of lipid biosynthesis, as gre2Delta displayed vastly impaired tolerance exclusively to agents targeting the ergosterol biosynthesis. The approach outlined here, combining broad-spectrum phenotypic profiling, expression analysis during conditions reducing the growth of the mutant and functional confirmation by application of highly selective inhibitors, may prove a valuable tool in gene functional analysis.     

The analysis and occurrence of hydrazine toxins in fresh and processed false morel,Gyromitra esculenta

Summary Two methods for the extraction and determination of hydrazines in false morel,Gyromitra esculenta, were compared. Extraction under acid hydrolysis yielded much higher levels of the hydrazines, measured as monomethylhydrazine (MMH), than a direct solvent extraction. This shows that the greater part of the hydrazines in the false morel is chemically bound. Further studies are required to reveal the extent to which these stable hydrazine compounds are liberated in the human stomach after ingestion of false morels. The total amounts of MMH in Swedish fresh false morels varied from 40 to 150 mg/kg. Boiling the fungus in large amounts of water for 2 x 5 min effectively reduced the levels to 10% of the original amounts. After drying in the open air at room temperature for 3 months, as much as 30%-71 % of MMH remained in the fungus. These results suggest that the drying of false morels is an inadequate method of detoxication.

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Analyse und Vorkommen der Hydrazintoxine in frischen und eingedosten Lorcheln,Gyromitra esculenta

Zusammenfassung Zwei Methoden zur Extraktion und Bestimmung von Hydrazinen in der Frühjahrslorchel,Gyromitra esculenta, wurden miteinander verglichen. Die Extraktion unter sauren hydrolytischen Bedingungen ergibt viel mehr Hydrazine, bestimmt als Monomethylhydrazin (MMH), als durch eine direkte Lösungsmittelextraktion. Dieses Verhältnis zeigt, daß der größte Teil des Hydrazins in der Frühjahrslorchel chemisch gebunden ist. Weitere Untersuchungen sind nötig, um klarzulegen, ob größere Anteile dieser stabilen Verbindungen im Magen des Menschen nach dem Verzehr von Frühjahrslorcheln freigesetzt werden können. Die totale Menge von MMH in schwedischen frischen Frühjahrslorcheln variierte von 40 bis 150 mg/kg. Das Kochen der Pilze in großen Mengen Wasser für 2 x 5 min reduziert den Gehalt bis zu 10% der ursprünglichen Menge. Nach dem Trocknen an der Luft bei Zimmertemperatur während drei Monaten blieb etwa 30–71% von MMH in dem Pilz zurück. Diese Ergebnisse deuten daraufhin, daß das Trocknen von Frühjahrslorcheln eine ungenügende Methode zur Entfernung des Giftes ist.

     

Consumer preferences and willingness to pay for value-added chicken product attributes

A growing demand for convenient and ready-to-eat products has increased poultry processors' interest in developing consumer-oriented value-added chicken products. In this study, a conjoint analysis survey of 276 chicken consumers in Edmonton was conducted during the summer of 2009 to assess the importance of the chicken part, production method, processing method, storage method, the presence of added flavor, and cooking method on consumer preferences for different value-added chicken product attributes. Estimates of consumer willingness to pay (WTP) premium prices for different combinations of value-added chicken attributes were also determined. Participants'"ideal" chicken product was a refrigerated product made with free-range chicken breast, produced with no additives or preservatives and no added flavor, which could be oven heated or pan heated. Half of all participants on average were willing to pay 30% more for a value-added chicken product over the price of a conventional product. Overall, young consumers, individuals who shop at Farmers' Markets and those who prefer free-range or organic products were more likely to pay a premium for value-added chicken products. As expected, consumers' WTP was affected negatively by product price. Combined knowledge of consumer product attribute preferences and consumer WTP for value-added chicken products can help the poultry industry design innovative value-added chicken products. Practical Application: An optimum combination of product attributes desired by consumers for the development of a new value-added chicken product, as well as the WTP for this product, have been identified in this study. This information is relevant to the poultry industry to enhance consumer satisfaction of future value-added chicken products and provide the tools for future profit growth.     

Effect of acid deposition on quantity and quality of dissolved organic matter in soil-water

The aim of this study was to explore how acid deposition may affect the concentration and quality of dissolved organic matter (DOM) in soil-water. This was done by a small-scale acidification experiment during two years where 0.5 × 0.5 m(2) plots were artificially irrigated with water with different sulfuric acid content, and soil-water was sampled using zero-tension lysimeters under the O-horizon. The DOM was characterized using absorbance, fluorescence, and size exclusion chromatography analyses. Our results showed lower mobility of DOM in the high acid treatment. At the same time, there was a significant change in the DOM quality. Soil-water in the high acid treatment exhibited DOM that was less colored, less hydrophobic, less aromatic, and of lower molecular weight, compared to the low acid treatment. This supports the hypothesis that reduction in sulfur deposition is an important driver behind the ongoing brownification of surface waters in many regions.     

Temporal trends of synthetic musk compounds in mother's milk and associations with personal use of perfumed products

We analyzed two nitro musks (musk xylene and musk ketone) and five polycyclic musks (HHCB, AHTN, ADBI, ATII, and AHDI) in mother's milk from primiparae women (N = 101) living in Uppsala County, Sweden, 1996-2003. Possible temporal trends in musk concentrations and associations with lifestyle/medical factors, such as use of perfumed products during pregnancy were studied. HHCB showed the highest median concentration (63.9 ng/g lipid) followed by AHTN (10.4 ng/g) and musk xylene (MX) (9.5 ng/g). Concentrations of the other substances were, in most cases, below the quantification limit (2.0-3.0 ng/g). Women with a high use of perfume during pregnancy had elevated milk concentrations of HHCB, and elevated concentrations of AHTN were observed among women reporting use of perfumed laundry detergent. This strongly suggests that perfumed products are important sources of musk exposure both among the mothers and the nursed infants. Concentrations of AHTN and MX declined significantly between 1996 and 2003, suggesting a decline in the industrial use of the compounds in consumer products, or alterations in the consumer use pattern of perfumed products. No temporal trend in HHCB concentrations was seen. The lack of toxicity data makes it difficult to generalize about the safety of musk exposure of breast-fed infants.     

Calcium sulphide formation in fluidized bed boilers

Analyses of samples of bed ash from a stationary fluidized bed boiler show the presence of calcium sulphide. In some samples, half of the total sulphur was present as sulphide. The samples containing CaS were obtained under unstaged conditions and with a high excess air ratio, 1.3 to 1.4. The samples were taken after a stop in the limestone addition, i.e. at high SO₂ emissions of about 1000 mL/m³ (ppm). No CaS was found during limestone addition when the SO₂ emission was 300–400 mL/m³. This indicates that formation of large amounts of CaS may be initiated as the SO₂ concentration exceeds some critical level.