Redox processes in pressurised smoked salmon studied by resonance Raman spectroscopy

Non-thermal food preservation technology is based on the application of high pressures up to 600 MPa. Here we report a resonance Raman (RR) spectroscopic analysis of smoked salmon meat after high pressure processing. High quality spectra, which can be obtained even from packed salmon without spectral interference of the packing foil, allow determining pressure-dependent irreversible changes of the main RR-active components of salmon meat, astaxanthin and myoglobin/haemoglobin. High pressure-treatment causes a decrease of the relative RR intensities of astaxanthin as probed with 514 nm excitation which is in line with a slight attenuation of the originally intense red colour of the salmon meat. 413-nm excited RR spectra indicate a heterogeneous broadening of astaxanthin bands accompanied by the formation of deoxy-myoglobin or deoxy-haemoglobin. The results suggest that pressure-treatment facilitates the oxidative degradation of astaxanthin coupled to the reduction of metmyoglobin (methaemoglobin).     

Assessment of dietary and genetic factors influencing serum and adipose fatty acid composition in obese female identical twins

Fourteen pairs of obese female monozygotic twins were recruited for a study of genetic influences on serum and adipose fatty acid (FA) composition. Following 1 wk of inpatient stabilization, fasting serum and adipose tissue obtained by surgical excision were analyzed by thin-layer and gas chromatography. Intrapair resemblances (IPR) for individual FA were assessed by Spearman rank correlation and by analysis of variance and were found in serum cholesteryl esters (CE), triglycerides (TG), and adipose TG. With two exceptions (CE linoleate and adipose eicosapentaenoate), these IPR were limited to the nonessential FA. Palmitate had significant IPR in four lipid fractions; in serum CE and adipose TG palmitate was strongly correlated with multiple measures of adiposity. In contrast to other lipid fractions, serum phosphatidylcholine (PC) FA had 12 IPR, of which 6 were essential FA including arachidonate (r=0.76, P<0.0005), eicosapentaenoate (r=0.78, P<0.0005), and docosahexaenoate (r=0.86, P<0.0001). The PC IPR could not be explained by analysis of preadmission 7-d food records. After dividing the pairs into two groups differing and nondiffering according to fat intake of individuals in the pair, there was no evidence of a gene-environment interaction between fat intake and FA composition. The IPR for nonessential FA indicate that there is active genetic control of either food choices or postabsorptive metabolic processing. The high level of IPR in the PC fraction in contrast to the other lipid fractions suggests strong genetic influence over selection of specific FA for this membrane fraction independent of diet.     

Implementation of substrates for surface-enhanced Raman spectroscopy for continuous analysis in an optofluidic device

The fabrication of substrates for surface-enhanced Raman spectroscopy (SERS), which offer high enhancement factors as well as spatially homogeneous distribution of the enhancement, plays an important role for expanding the surface-enhanced Raman spectroscopy to a powerful quantitative and non-invasive measurement technique. In this paper, a method for the fabrication of capable SERS-active substrates by laser treatment of gold films supported on glass with single 351?nm UV-laser pulses is presented. Resulting nanometer scaled structures show enhancement factors of up to 10⁶ with very high spatial reproducibility for a monolayer of benzenethiol. A method for integration of these substrates into PDMS microchannels is shown. A technique for the generation of a simple mold master for PDMS replication is presented. Rhodamine 6G is used as model system to demonstrate continuous measurements on a solid SERS-active substrate in a microchannel. The label-free detection of the biological molecule albumin is improved by an order of magnitude.     

Carotenoid–protein interaction as an approach for the formulation of functional food emulsions

Functional foods represent an emerging market of growing economic importance. The formulation of carotene fortified food emulsions involves the difficulty to transfer the carotenoids into the lipid phase. Usually, undesirable organic solvents are used to dissolve the carotenoid in the lipid phase, in particular astaxanthin and β-carotene. Here, we present a novel approach in which the carotenoid is first bound to bovine serum albumin (BSA) and then the carotenoid–protein complex is used to prepare an emulsion. Absorbance spectroscopy indicates the formation of the complex in the aqueous phase and provides first results of the carotenoid load, which is supported by the colour of the cream phase. The droplets in the emulsion are visualized by confocal laser scanning spectroscopy, indicating the protein layer. The laser diffraction spectroscopy and confocal laser scanning spectroscopy provide the particle size distribution and insight of the stability of emulsion interface.     

Symptoms of depression in residents: a South Carolina Family Practice Research Consortium study

OBJECTIVES: To test the hypothesis that loss of polymorphonuclear neutrophil tumor necrosis factor alpha (TNF-alpha) receptors during transmigration renders the exudate neutrophil refractory to TNF-alpha-mediated stimulation of apoptosis; and to investigate the surface expression of Fas on both circulating and exudate neutrophils. DESIGN: A prospective cohort study. SETTING: Surgical laboratory of a tertiary care hospital. PARTICIPANTS: Twenty-one healthy human volunteers. INTERVENTIONS: All subjects had circulating neutrophils and exudate neutrophils collected by venipuncture and skin window methods, respectively. MAIN OUTCOME MEASURES: Circulating and exudate neutrophils were incubated in culture medium (1.0x10(6) neutrophils per milliliter) alone or with TNF-alpha (100 ng/mL). Apoptosis was evaluated by flow cytometry (annexin V-fluorescein isothiocyanate and propidium iodide). Tumor necrosis factor alpha-phycoerythrin and anti-human Fas-fluorescein isothiocyanate were used to evaluate neutrophil TNF-alpha receptors and surface expression of Fas. RESULTS: Exudate neutrophils had a significant delay in apoptosis rates when compared with circulating neutrophils. The percentage of neutrophils expressing TNF-alpha receptors was significantly diminished after exudation (80%+/-15% vs 33%+/-9%; P<.001), as was the median channel number of TNF-alpha phycoerythrin fluorescence (8.1+/-1.6 vs 5.2+/-0.5; P=.001). However, the expression of Fas was unchanged after transmigration (percentage positive for Fas: 98.7%+/-0.7% vs 92.8%+/-3.4%, P=.89; Fas antibody-fluorescein isothiocyanate median channel fluorescence: 12.2+/-1.1 vs 13.1+/-1.2; P=.80). Exposure of exudate neutrophils to TNF-alpha failed to increase their rate of apoptosis. CONCLUSIONS: Exudate polymorphonuclear neutrophils are confirmed to have delayed apoptosis. Loss of TNF-alpha receptors during transmigration is necessary for neutrophil survival in the extravascular inflammatory milieu.