Marcel-Alexandre Juillerat

Lipid deposition on the tongue after oral processing of medium-chain triglycerides and impact on the perception of mouthfeel.

Lipids between the tongue and palate strongly contribute to the sensory impact of a product. Mouthfeel is a sensory attribute responsible for distinguishing reduced fat from full fat food products. The aim of this work was to quantify the distribution, deposition, and retention of lipids on the tongue and palate upon oral processing and relate this to texture. The thickness of lipid deposition was measured in mouth by fluorescence. A trained panel evaluated the perceived intensity of samples to describe lipid Mouthfeel. The thickness of lipid deposition on the tongue shows spatial variation (10-100 microm) and stopped increasing after intakes higher than 8 mL of medium-chain triglycerides (MCTs). After 2 min, only 25% of the lipid deposition was retained on oral surfaces. A difference in the thickness of lipid deposition of 25 microm resulted in significantly different perception. This work describes the in-mouth behavior of food lipids and its influence on texture perception.

Generation of Bioactive Peptides Derived from Caseins Using a Lactobacillus helveticus Strain

Bovine milk is known to contain a number of peptide fractions that can affect physiological functions. Bioactive peptides have to be hydrolytically derived from native proteins. Various biological effects of peptides generated upon in vitro enzymatic or in vivo gastrointestinal digests have been demonstrated [1].

UV degradation of sesquiterpene lactones in chicory extract: Kinetics and identification of reaction products by HPLC-MS

Inulin, a valuable food ingredient, can be extracted from chicory roots (Cichorium intybus L.). However, the direct use of this material is limited, because of the presence of extremely bitter, co-extracted sesquiterpene lactones. Lactucin, a major component, has been degraded by UV irradiation, a process which showed neither temperature (293- 313 K) nor initial concentration dependence. An overall half life time of ca. 45 min was determined. The degradation product was identified by HPLC-MS and 1 H NMR and was the result of the addition of a water molecule on the lactucin C(1)-C(10) double bond, with the OH group located at the C(10) position.

Biogeneration of 2-(1-hydroxyethyl)-4,5-dihydrothiazole as precursor of roasted and popcorn-like aroma for bakery products

Abstract Bread aroma is one of the most important criteria of the quality of bakery product. Molecules exhibiting roasted notes largely contribute to this flavour and 2-acetyl-2-thiazoline (2-AT) was identified as one of the strongest. We report here the formation of its precursor 2-(1-hydroxyethyl)-4,5-dihydrothiazole via the bioconversion of cysteamine, ethyl- l -lactate and d -glucose with baker’s yeast as biocatalyst. The microbial reduction of the carbonyl group of 2-acetyl-2-thiazoline using the same microorganism is an alternative to produce the target precursor in good yield (up to 60%). Heat treatment of 2-(1-hydroxyethyl)-4,5-dihydrothiazole generated attractive and intensely roasted, popcorn-like and bread crust-like notes. High amounts of 2-acetyl-2-thiazoline were detected in the heated samples. Finally, the addition of the precursor significantly enhanced the aroma of pizza bread when mixed into the dough.

Effect of saliva on physical food properties in fat texture perception

ABSTRACT Sensory properties of food drive our food choices and it is generally accepted that lipids greatly contribute to the sensory properties of many foods and consequently to eating pleasure. Many studies have investigated the mechanisms of the fat perception. Unfortunately they used a variety of methods and products, thereby making generalization very difficult. The mechanism of fat perception in oral cavity is combined of several processes. Lipid composition and its properties strongly influence food structure. During consumption food is exposed to a range of in-mouth processing steps. Oral sensation of fat texture changes with time, from a first bite to chewing, while mixing with saliva, up to swallowing and even after swallowing. The present work reviews many aspects of fat texture perception from physical chemistry to physiology. Understanding the underlying mechanisms of in-mouth lipid processing would provide new concepts to produce low-fat food products with full-fat perception.