Using of Volatile Release Measurements to Understand Polysaccharide Molecular Interactions: An Example with Guar Gum Study Y. Aguni, C. Jouquand, C. Malhiac, M. Grisel * Summary: It is well establishment that polysaccharides are commonly used in many fields of formulation such as food and cosmetic industries as viscosity modifiers or gelling agents. Among the different impacts on the mixture properties, these materials are also known to affect the aroma release or retention thus its sensory perception; the effect depends whether polysaccharide structure induces specific retention or release phenomena from the complex media. Present study deals with studying aroma compounds behaviour from dilute and semi-dilute aqueous poly- saccharide solutions consisting of different guar gum samples. Results allow stating that the whole polymer characteristics as determined by means of structural analysis, protein content determination, rheological and surface tension measurements play a major role on the polysaccharide/aroma compound interaction mechanisms. In particular, results evidence a strong Mannose to Galactose (M/G) ratio effect, thus allowing stating the occurrence of hydrophobic intra and inter- molecular mechanism. In addition to that, proteins are demonstrated to only slightly affect the volatile retention. More generally, such an original study allows new highlights concerning macromol- ecular organisation and interactions in solution. Keywords: aroma release; guar; molecular interactions; structural properties Introduction Thickeners and stabilizers are commonly used as formulation aids in food industry mainly for their ability to increase viscosity or to lead to gelled mixtures. Among the numerous polysaccharides employed in the food industry, galactomannans gums as extracted from plant seeds are some of the most commonly employed ones. As visible below, the chemical structure of galactomannans consists of a linear backbone of b-D-mannose residues (M) attached by (1 ! 4) linkages, this main backbone being substituted with a-D- galactose residues (G) attached through (1 ! 6) linkages. Guar gums belong a low M/G ratio (1.6) while locust bean gums are less substituted (M/G  3.5–4.0). Due to the large industrial utilization of galactomannan polysaccharides, most of it have been extensively studied to elucidate first their chemical and structural charac- teristics but also to better understand their tendency to self associate in aqueous media through intra and/or intermolecular mechanisms; [1,2] unfortunately, in spite of numerous studies dealing with many experimental approaches, many questions still remain unanswered. Otherwise, guar and locust bean gums, the most used galactomannans in food applications, have been demonstrated to markedly influence the aroma compounds Macromol. Symp. 2007, 251, 96–102 DOI: 10.1002/masy.200750513 96 Unite ´ de Recherche en Chimie Organique et Macro- mole ´ culaire, Universite ´ du Havre, 25 rue Philippe Lebon, 76058 Le Havre Cedex, France Fax: (þ33)232744391 E-mail: michel.grisel@univ-lehavre.fr Copyright ß 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim