Chris Winkel

Identification of glucosides in green beans of Vanilla planifolia Andrews and kinetics of vanilla β-glucosidase

Natural vanilla is extracted from the fruits of Vanilla planifolia. In the overall vanilla aroma, minor compounds p-cresol, creosol, guaiacol and 2-phenylethanol have a high impact. This is shown by GC-Olfactometry analysis of cured vanilla beans. The presence of β-D-glucosides of these compounds was investigated, in order to determine if these compounds are derived from glucosides or if they are formed during the curing process via different pathways. Glucosides of vanillin, vanillic acid, p-hydroxy benzaldehyde, vanillyl alcohol, p-cresol, creosol and bis[4-(β-d-glucopyranosyloxy)-benzyl]-2-isopropyltartrate and bis[4-(β-d-glucopyranosyloxy)-benzyl]-2-(2-butyl)tartrate have been identified in a green bean extract. The kinetics of the β-glucosidase activity from green vanilla beans towards eight glucosides naturally occurring in vanilla and towards p-nitrophenol were investigated. For glucosides of p-nitrophenol, vanillin and ferulic acid the enzyme had a Km of about 5 mM. For other glucosides (vanillic acid, guaiacol and creosol) the Km-values were higher (>20 mM). The Vmax was between 5 and 10 IU mg−1 protein for all glucosides tested. Glucosides of 2-phenylethanol and p-cresol were not hydrolysed. β-Glucosidase does not have a high substrate specificity for the naturally occurring glucosides compared to the synthetic p-nitrophenol glucoside (Km 3.3 mM, Vmax 11.5 IU mg−1 protein).

New Developments in Umami (Enhancing) Molecules

As health has become one of the main drivers in nutrition, the scientific interest in taste receptors and taste molecules has increased considerably. Academia as well as flavor and food companies are searching for molecules that make food more healthy but not less appetizing. In the savory area, salt and umami taste are being investigated. This review deals with the progress made in umami tasting molecules. Umami taste has been known as a separate taste for a long time in Asian countries and has been generally accepted as the fifth basic taste in the last decade of the previous century. In this review, first the current level of understanding of the umami receptors will be described. The main part of the paper will deal with the umami‐tasting molecules that have been published recently, including the work that has been performed within Givaudan itself. Lactoyl amides of GMP (guanosine monophosphate) appeared to have remarkably strong umami‐tasting properties.

Method for the enzymatic preparation of flavours rich in C6-C10 aldehydes

Abstract Raw materials previously used as reagents for production of C6-C10 aldehydes were refined unsaturated fatty acids or fatty acid mixtures obtained by fat hydrolysis. For some oils and fats (like butter fat) undesirable compounds, like butyric acid, would be formed in the hydrolysis treatment. Therefore, a new method was developed in which aldehydes were prepared directly from oils and fats without hydrolysis. In a first step, the oil or fat was reacted with lipoxygenase in a multiphase system in the presence of air. The obtained mixture was heated, preferably under acidic conditions, resulting in an aldehyde-containing product. Aldehydes could be further isolated by distillation.