Flavour retention and haze formation by chocolate polyphenols

Interactions of flavours and proteins with chocolate polyphenols were investigated. Flavour retention was measured by dynamic headspace gas chromatography. Relative recovery factors were calculated from standard addition experiments performed on polyphenol-containing model media. Aroma retention was found to depend on the (+)-catechin level, the aroma structure, and the temperature applied. Chocolate oligomeric procyanidins proved more active than monomers; catechin showed no significant interaction with proteins. Chocolate oligomers induced high colloidal instability at high temperature, especially with gliadin

Chocolate and cocoa: New sources of trans-resveratrol and trans-piceid

trans-Resveratrol and trans-piceid were found for the first time in dark chocolate (at least 0.4 ppm trans-resveratrol and 1 ppm trans-piceid) and cocoa liquor (at least 0.5 ppm trans-resveratrol and 1.2 ppm trans-piceid). Because these compounds are highly sensitive to light, a specific extraction procedure was required to recover them, involving delipidation with toluene and cyclohexane and ethanol/water (80/20, v/v) solid-liquid extraction at 60 degrees C before reverse-phase HPLC-MS/MS analysis (atmospheric pressure chemical ionization [APCI] in the positive mode). Thanks to an exceptionally high procyanidin content, chocolate products displayed higher antioxidant activity than much more concentrated commercial stilbene extracts. (c) 2005 Elsevier Ltd. All rights reserved

Bilinguisme et scolarité: une enquête sociolinguistique sur les enfants espagnols des écoles primaires liégeoises

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