Aqueous Integrated Process for the Recovery of Oil Bodies or Fatty Acid Emulsions from Sunflower Seeds

An aqueous integrated process was developed to obtain several valuable products from sunflower seeds. With a high-shear rate crusher, high-pressure homogenization and centrifugation, it is possible to process 600× g of seeds in 1400× g of water to obtain a concentrated cream phase with a dry matter (dm) content of 46%, consisting of 74 (w/w dm) lipids in the form of an oil-body dispersion (droplet size d(0.5): 2.0 µm) rich in proteins (13% w/w dm, with membranous and extraneous proteins). The inclusion of an enzymatic step mediated by a lipase made possible the total hydrolysis of trigylcerides into fatty acids. The resulting cream had a slightly higher lipid concentration, a ratio lipid/water closer to 1, with a dry matter content of 57% consisting of 69% (w/w) lipids, a more complex structure, as observed on Cryo-SEM, with a droplet size slightly greater (d(0.5): 2.5 µm) than that of native oil bodies and a conserved protein concentration (12% w/w dm) but an almost vanished phospholipid content (17.1 ± 4.4 mg/g lipids compared to 144.6 ± 6 mg/g lipids in the oil-body dispersion and 1811.2 ± 122.2 mg/g lipids in the seed). The aqueous phases and pellets were also characterized, and their mineral, lipid and protein contents provide new possibilities for valorization in food or technical applications.

Theoretical and Kinetic Analysis of the Esterification of Undecylenic Acid with Glycerol

The synthesis of undecylenic acid partial esters can be performed at mild temperature with a classical esterification reaction catalyzed by dodecylbenzene sulfonic acid (DBSA). A semi-empirical molecular modeling on the different reaction intermediates indicates that DBSA can strongly decrease their heats of formation through hydrogen bonding. Diester formation seems to be thermodynamically favored with a selectivity for alpha, alpha, or alpha, beta forms that depend on the geometry of the catalyst-intermediate configuration. Triesters are not favored but a high selectivity for monoesters requires a kinetic control. Experimental approach, considering different DBSA concentrations and temperature partially confirms the theoretical predictions but surfactant properties of DBSA and monoesters may induce nonpredicted geometries. Global apparent activation energies are calculated, corresponding to the formation and hydrolysis of mono and diesters. If water trapping allows the decrease of hydrolysis reaction constants, the presence of water and subsequent phase separation may explain differences between theoretical and experimental results and could help increasing monoester selectivity.

Self-Assembling Behavior of Glycerol Monoundecenoate in Water

The self-assembling properties of glycerol esters in water are well known. Still, few data on glycerol monoesters of undecylenic acid are available. The aim of this study was to highlight the behavior of glycerol monoundecenoate (GM-C11:1) in different diluted and concentrated states. Its self-assembling properties in water and upon solid inorganic surfaces were investigated in the diluted state using surface tension experiments, atomic force microscopy, and cryogenic transmission electron microscopy studies. In the concentrated state, the gelling properties in the presence of water were investigated using polarized light microscopy, differential scanning calorimetry (DSC), and small-angle X-ray scattering (SAXS) experiments. GM-C11:1 at 100 mg/L self-assembles at the liquid/air interfaces as aggregates of approximately 20 nm in diameter, organized into concentric forms. These aggregates are spherical globules composed of several molecules of GM-C11:1. At higher concentrations (1000 and 10⁴ mg/L), GM-C11:1 is able to uniformly coat liquid/air and liquid/solid interfaces. In bulk, GM-C11:1 forms spontaneously aggregates and vesicles. In a more concentrated state, GM-C11:1 assembles into lamellar L_β and L_α forms in water. By cross-referencing SAXS and DSC findings, we were able to distinguish between interlamellar water molecules strongly bound to GM-C11:1 and other molecules remaining unbound and considered to be "mobile" water. The percentage of water strongly bound was proportional to the percentage of GM-C11:1 in the system. In this case, GM-C11:1 appears to be an effective molecule for surface treatments for which water retention is important.

Esters of oligo-(glycerol carbonate-glycerol): New biobased oligomeric surfactants

Glycerol carbonate is one of the most potentially multifunction glycerol-derived compounds. Glycerol is an important by-product of the oleochemical industry. The oligomerization of glycerol carbonate, assisted by the glycerol, results in the production of polyhydroxylated oligomers rich in linear carbonate groups. The polar moieties of these oligomers (M_w<1000Da) were supplied by glycerol and glycerol carbonate rather than ethylene oxide as in most commercial surfactants. The insertion of linear carbonate groups into the glycerol-based skeleton rendered the oligomers amphiphilic, resulting in a decrease in air/water surface tension to 57mN/m. We improved the physical and chemical properties of the oligomers, by altering the type of acylation reaction and the nature of the acyl donor. The polar head is constituted of homo-oligomers and hetero-oligomers. Homo-oligomers are oligoglycerol and/or oligocarbonate, hetero-oligomers are oligo(glycerol-glycerol carbonate). Coprah oligoesters had the best surfactant properties (CMC<1mg/mL, π_cmc<30mN/m), outperforming molecules of fossil origin, such as ethylene glycol monododecyl ether, glycol ethers and fatty acid esters of sorbitan polyethoxylates. The self-assembling properties of oligocarbonate esters were highlighted by their ability to stabilize inverse and multiple emulsions. The oligo-(glycerol carbonate-glycerol ether) with relatively low molecular weights showed properties of relatively high-molecular weight molecules, and constitute a viable "green" alternative to ethoxylated surfactants.

Elaboration of extensin-pectin thin film model of primary plant cell wall

With the aim of mimicking the plant cell wall, a layer by layer approach was used to build a thin film consisting of successive adsorption of pectin and extensin. Elaboration of the thin film was monitored by surface plasmon resonance, quartz crystal microbalance, and ellipsometry. All data indicate that formation of the film was successful and that growth occurred according to a nonuniform growth. It is likely that diffusion of the polymers occurred within the multilayer structure and that the final structure is not constituted by layered individual pectin and extensin films. Polymer rearrangements were also supported by the atomic force microscopy images that show a smoother surface after extensin adsorption than after pectin deposition.

Accessibility of the Functional Groups of Chitosan Aerogel Probed by FT-IR-Monitored Deuteration

Transmission FT-IR spectroscopy allowed us to monitor the deuteration of wafers of chitosan aerogel and xerogel by D2O vapor at room temperature. The complete deuteration of the alcohol and amine groups of the aerogel (surface area 175 m2 g(-1) as measured by N2 volumetry) confirmed the high accessibility of the functional groups of the polymer. The xerogel (surface area 5 m2 g(-1)) was only partially deuterated in more severe conditions. The isotopic shift of the deuterated groups allowed us to confirm or revise some attributions of infrared bands of chitosan.

FTIR Spectroscopy of NH3 on Acidic and Ionotropic Alginate Aerogels

The acidity of alginate aerogel films has been investigated by infrared spectroscopy of adsorbed NH(3). Supercritical drying of the alginate provided samples with a surface area of several hundred square meters per gram, in which the probe molecule could reach all acidic sites. Free carboxylic groups were studied on acid-gelled alginates and were found to behave as effective Brønsted acid sites. Ionotropic alginate gels formed by alkaline earth cations presented only the Lewis acidity of the cations. Ionotropic gels formed by transition metal cations presented both Lewis and Brønsted sites, because of the presence of a fraction of free carboxylic groups. The incomplete salification was correlated to the pH of the gelling solutions.

From Hydrocolloids to High Specific Surface Area Porous Supports for Catalysis

Polysaccharide hydrogels are effective supports for heterogeneous catalysts. Their use in solvents different from water has been hampered by their instability upon drying. While the freeze-drying process or air-drying of hydrocolloid gels led to compact solids with a low surface area, drying the gel in CO2 beyond the critical point provided mesoporous materials with a high specific surface area. Their effectiveness as a support for catalysis was exemplified in the reaction of substitution of an allyl carbonate with morpholine catalyzed by the hydrosoluble Pd(TPPTS)3 complex. The influence of water on the catalytic activity and the properties of the support was evidenced.

Attenuation of the near-infrared and red photoplethysmographic signal by different depth of tissues

Photoplethysmography enables non-invasive investigation of the volume pulse in the microvasculature of patients. We previously have shown that time-discrete analysis enables identification of highly reproducible characteristics of the volume pulse in absolute values. The method would be of particular interest, if the perfusion of deeper tissue layers like the skeletal muscle can be assessed. The aim of the current study was to investigate the attenuation of the photoplethysmographic signal by different tissues and up to which depth of tissue a time-discrete analysis of the photoplethysmographic signal would be possible. For the recordings we used the time-discrete near-infra-red photoplethysmography (NIRP), a reflection photoplethysmograph measuring at wavelengths of 840 nm and 640 nm. In an in vitro circuit filled with bovine blood we generated a typical and exactly reproducible volume pulse. On a platform the NIRP sensor probe was placed above the artificial vessel and recordings of the volume pulse were obtained by varying the sensor-vessel-distance with increasing layers of water, blood-agar or bovine skeletal muscle tissue. - The amplitude of the NIR signal was attenuated to 50% by each layer of 2.01 mm of water, 1.42 mm of blood-agar and 1.05 mm of bovine skeletal muscle tissue. A time-discrete analysis could be performed up to a depth of 15 mm of water, 6 mm of blood-agar and 5 mm of bovine skeletal muscle tissue. - As the photoplethysmographic curve is strongly attenuated even by a few millimetres of water we suggest that the NIRP signal mirrors the perfusion of the superficial tissue layer and mainly originates from the subpapillary capacious plexus. - We conclude that with the equipment used in this study volume pulsations in deeper layers of tissue like skeletal musculature can not be assessed.

Family support for heterosexual partners in HIV-serodiscordant couples

OBJECTIVE

To ascertain the extent of family member support to heterosexual HIV-serodiscordant couples, and to identify associated sociodemographic and clinical characteristics.

DESIGN

Discordant couples enrolled in a cohort study of heterosexual HIV transmission were interviewed with structured questionnaires to obtain sociodemographic data, family member awareness of HIV and perceived support from family members. Clinical characteristics were established by medical history, physical examination and laboratory tests.

RESULTS

Awareness and support of family members were associated with sex of family member and HIV seropositivity, sex, education, and race of the partner. HIV-seropositive partners were more likely to have a sister aware than were HIV-negative partners (P = 0.01). More educated HIV-positive partners had fewer aware family members than less educated HIV-positive individuals (P = 0.02). Mothers of HIV-positive women were more often aware than mothers of all other partners (P = 0.04). Black HIV-negative partners had fewer aware family members than whites or Hispanics (P = 0.02).

CONCLUSION

This research shows both encouraging and disturbing patterns of family awareness of HIV and support to serodiscordant partners.

Association of ethylene-oxide-induced IgE antibodies with symptoms in dialysis patients

IgE-type antibodies to human serum albumin/ethylene oxide conjugates were determined in 153 patients (140 unselected, 13 selected for presence of eosinophilia) on regular dialysis treatment by radioallergosorbent test (RAST) techniques. In 10.7% of unselected patients and 30.8% of selected patients, RAST values suggested ethylene oxide sensitisation. High RAST values were commonly associated with anaphylactoid reactions during dialysis and with chronic asthma. Ethylene oxide antibodies should be sought routinely in patients presenting with these symptoms and the necessity of ethylene oxide sterilisation of disposable dialysis equipment should be re-evaluated.

Low molecular weight heparin in hemodialysis and hemofiltration patients

Low molecular weight (LMW)-heparin was used as the sole anticoagulant during hemodialysis and hemofiltration in a pilot study on 32 patients. A LMW-heparin dose corresponding to 50% of the patients usual unfractionated, standard (UF)-heparin dose was found to produce comparable plasma heparin levels (anti-FXa-activity). No thrombosis of the extracorporal system and no bleeding complications occurred at this LMW-heparin dose. In contrast to UF-heparin, LMW-heparin produced only slight increases in PTT and thrombin time in all patients. Lipoprotein lipase was stimulated only marginally by LMW-heparin, with a correspondingly reduced release of free fatty acids. Both heparin species caused similar elevations in factor VIII and fibrin monomers, thus excluding a difference in coagulation activation. On the basis of these results, long-term studies have been started at four nephrology centers. To date, 26 patients have been treated with LMW-heparin for 6 months. A LMW-heparin dose was used that produced plasma anti-FXa-activity of 0.5 to 0.9 U/ml (initial dose: 30 to 40; dose/hr: 8 to 15 anti-FXa-units/kg body wt). PTT and thrombin time were only increased by 5 sec on average. Surprisingly, the elevated pre-dialysis levels of factor VIII and fibrin monomers decreased during this 6-month period. Bleeding complications did not occur and thrombotic complications were not observed when the anti-FXa levels were above 0.5 U/ml. LMW-heparin, therefore, appears to be a good alternative to UF-heparin for dialysis patients and may present less risk of bleeding because of its reduced effect on PTT, thrombin time, and thrombocytes.

[Hypersensitivity phenomena in dialysis patients. Incidence of eosinophilia, raised IgE and ethyleneoxide-induced antibodies]

The hypersensitivity parameters eosinophil count, serum IgE and IgE-type antibodies to ethylene oxide-albumin conjugates (ETO-antibodies), were determined in 182 dialysis patients. Eosinophilia was seen in 21.7% of patients, IgE elevation in 21.4% and ETO-antibodies in 12.4%. A pathological change in at least one of the measured parameters was present in 33.1%. The appearance of ETO-antibodies was frequently associated with severe clinical symptoms, especially asthma and anaphylactic shock. Sensitisation is apparently common in dialysis patients. Since ETO-antibodies are often associated with severe clinical symptoms, their presence should be sought in those dialysis patients showing incompatibility reactions or asthma.

Characterization of an ATPase on the inside of rat-liver nuclear envelopes by affinity labeling

Nuclear envelope membranes from rat liver cells contain ATPases, one of which can be inhibited and irreversibly labeled by (S-dinitrophenyl)-6-mercaptopurine riboside triphosphate. Inhibition and covalent substitution of the ATPase are achieved only after disruption of the nuclei, the ATP analogue is inactive on the ATPase activity of whole nuclei or on vesicles of the membrane prepared after a modified heparin method of Bornens and Courvalin. Electron micrographs and scanning micrographs helped to establish the characterization of closed vesicles and intact nuclei. With the aid of (alpha-32P)-labeled, and of the (beta, gamma-32P)-labeled analogue, it was possible to demonstrate the incorporation of the nucleotide into a few protein regions of the nuclear membrane disc electrophoresis pattern.