Interactions of bile salts with a dietary fibre, methylcellulose, and impact on lipolysis

Methylcellulose (MC) has a demonstrated capacity to reduce fat absorption, hypothetically through bile salt (BS) activity inhibition. We investigated MC cholesterol-lowering mechanism, and compared the influence of two BS, sodium taurocholate (NaTC) and sodium taurodeoxycholate (NaTDC), which differ slightly by their architecture and exhibit contrasting functions during lipolysis. BS/MC bulk interactions were investigated by rheology, and BS behaviour at the MC/water interface studied with surface pressure and ellipsometry measurements. In vitro lipolysis studies were performed to evaluate the effect of BS on MC-stabilised emulsion droplets microstructure, with confocal microscopy, and free fatty acids release, with the pH-stat method. Our results demonstrate that BS structure dictates their interactions with MC, which, in turn, impact lipolysis. Compared to NaTC, NaTDC alters MC viscoelasticity more significantly, which may correlate with its weaker ability to promote lipolysis, and desorbs from the interface at lower concentrations, which may explain its higher propensity to destabilise emulsions

A calorimetric study of methylcellulose gelation

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Physical properties of methylcelluloses in relation with the conditions for cellulose modification

cited By 75International audienceWater-soluble methylcellulose (MC) samples were synthesized by a new homogeneous reaction using DMAc/LiCl as solvent, a dimsyl sodium solution as activator and CH3′ as alkylating reagent. Different degrees of substitution were obtained (0.9 < DS < 2.2). A commercial MC (D̄S̄ =1.7) was also studied. The structural characterization of the samples was carried out using 13C-NMR and h.p.l.c. measurements. Rheological and steric exclusion chromatography studies in the dilute regime were performed as a function of the temperature and the properties of the samples were compared. According to the DS value, two different behaviours were observed. For DS > 1.5, interactions occur for T>45°C. If D̄S̄ < 1.5 there is no clear evidence for aggregation. © 1997 Elsevier Science Ltd. All rights reserved

Erratum: Thermogelation of methylcellulose: Rheological considerations (Polymer 41 (2000) (2451-61) PII S0032386199004139)

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Thermogelation of methylcellulose: rheological considerations

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Thermogelation of methylcelluloses: new evidence for understanding the gelation mechanism

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A microfluidic gel valve device using reversible sol-gel transition of methyl cellulose for biomedical application

We have fabricated a microfluidic gel valve device that used reversible sol-gel transition of methyl cellulose (MC). A microheater and a microtemperature sensor were implemented in each microchannel in the gel valve device. Before evaluating the performance of the gel valve device, various properties of the MC solution were investigated using viscometer, spectrophotometer, and NMR. Gelation temperature was increased as the MC concentration was increased. Clear gel, an intermediate state between clear sol and turbid gel, was found at the temperature range from 30-40??C to 50-60??C. Temperature at each microchannel of the device was measured and the effect of the temperature difference on the valve operation was elucidated. In order to have normal operation of the gel valve, it was important to keep the temperature of the heated microchannel around 60??C while keeping the temperature of the flowing microchannel below 35??C. The temperature difference between two microchannels was about 23 K when fan forced cooling (FFC) method was used. For normal performance of the gel valve device, a temporary pause of fluid flow for at least 5 s was required to complete the local gelation in the microchannel. Stable gel valve performance was obtained at the flow rates larger than 5 ??l/min. The gel valve device showed no leakage up to 2.07??104 Pa.close6