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RESEARCH PRODUCT

L'intégration multisensorielle comme stratégie pour compenser la réduction en sodium et matière grasse dans les aliments

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In recent years;health authorities worldwide advise for a reduction of salt and fat in daily food consumption. However;foods with reduced salt and fat content are often not appreciated by consumers;Therefore;the formulation of low-salt-fat foods that maintain acceptability is a major concern in food research. In this thesis;the multi-sensory integration and release kinetics of flavor compounds were explored as strategies to compensate for salt and fat reduction in cheese products (model cheeses and real cheeses). The objective was to better understand the mechanisms leading to aroma and salt release during mastication and to evaluate how the matrix composition and structure influence salt and aroma release profile. Multisensory integration approach to compensate for salt and fat reduction was studied in a first step. The structure and sensory perception of 24 cheese models varying in composition (2 levels of fat;2 salt;2 pH at renneting) and flavored with either a sardine aroma (associated to salt);a butter aroma (associated to fat) or not flavoured (control) were characterised by rheological measurements (uniaxial compression) and sensory evaluation (descriptive analysis). The results demonstrated an influence of the composition on the products structure and perceived texture. Furthermore;a significant saltiness enhancement was induced by sardine aroma while significant fat perception enhancement was induced by butter aroma. However;this influence of the aroma on other sensory dimensions depends on the texture of the products thus on their composition and structure. These results have been extended to real cheeses but with specificities. If the sardine flavor enhanced the perception of salt;only butter-sardine-flavor enhanced the perception of fat. In a second step;a physico-chemical approach was developed to explore the release kinetic of flavor compounds during in vitro breakdown using a chewing simulator. The aim was to use these data to explain the influence of the structure of model cheeses and real cheeses and their breakdown during chewing on sensory effects observed in the first step. Volatile compounds release was monitored by connecting the chewing simulator to a proton transfer reaction-mass spectrometry (PTR-MS);while salt release was monitored using a conductivity probe. Results showed that product composition and structure (fat;salt and pH at renneting) influenced aroma release;which however depends on the nature of the aroma: the more hydrophobic compounds are less sensitive to variations in fat content and more sensitive to variations in pH and therefore to the products structure. The salt release kinetic during in vitro chewing was also influenced by the composition and structure of the products. Indeed;beyond salt content which determined the amount of salt released;fat content and the pH at renneting modulated the release kinetic. In conclusion;this work showed a significant impact of the flavor compounds release kinetic and probably of temporality of sensations on the overall perception of salt and fat when consuming a complex food.