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Nathalie Martin

Publications and source records attributed to Nathalie Martin.

8 recordsLinked to original sources
PubMed2006

Flavored yogurt complex viscosity influences real-time aroma release in the mouth and sensory properties.

The influence of flavored yogurt texture on aroma perception and in-nose aroma release measured by atmospheric pressure chemical ionization mass spectrometry analysis was investigated. The study was carried out on six yogurts varied by protein composition and mechanical treatment. For the same matrix composition, the complex viscosity of yogurts influenced in-nose release and perception. After swallowing, aroma release and intensity of olfactory perception were stronger in low-viscosity yogurts than in high-viscosity yogurts. Moreover, the protein composition influenced aroma release only when yogurts exhibited wide variations of complex viscosity and consequently texture. In mouth, aroma release and perception were influenced more by yogurt mechanical treatment than by protein composition. On the basis of mass transfer analysis, the main physical mechanism which could explain the difference in aroma release would be the surface exchange area developed in the mouth and in the throat.

Dietary Proteins↗
PubMed2006

Complex viscosity induced by protein composition variation influences the aroma release of flavored stirred yogurt.

Dairy protein composition is known to influence the structure and the texture characteristics of yogurt. The objective of the present work was therefore to investigate the impact of protein composition, at a constant protein level, on the physicochemical properties of 4% fat flavored stirred yogurt and, more specifically, on the rheological properties, the microstructure, and the aroma release. The results showed that caseinate-enriched yogurt generally presented changes in their microstructure network and had a higher complex viscosity than whey protein-enriched yogurt. To a lesser extent, the release of the majority of aroma compounds was lower in caseinate-enriched yogurt. It was therefore possible to quantify physicochemical interactions between aroma compounds and proteins. The influence of gel structure on the flavor release was observed and was in agreement with sensory characteristics previously studied for these products.

Chemical Phenomena↗
PubMed2006

Sensitivity to allyl isothiocyanate, dimethyl trisulfide, sinigrin, and cooked cauliflower consumption.

The consumption of cauliflower consumers has been related to the olfactory and gustatory sensitivities to potentially objectionable flavor compounds in this vegetable. Based on the ascending concentration series method of limits, a first experiment was designed to develop rapid tests dedicated to estimate individuals' olfactory thresholds for allyl isothiocyanate (AITC) and dimethyl trisulfide (DMTS) and gustatory thresholds for sinigrin (SIN). The best compromise between rapidity and reliability was obtained with two replications of a four-alternative forced choice (AFC) at six ascending concentrations (6x2x4-AFC) for both AITC and DMTS, and with a 6x1x4-AFC for SIN. In a second experiment, sensitivity to SIN, AITC and DMTS was determined on 267 participants divided into three cauliflower consumer target groups: non-, medium- or high consumers. The non-consumers were significantly more sensitive to SIN and AITC than were the medium and high consumers. No effect of consumer's sensitivity to DMTS was observed.

Adolescent↗
PubMed2006

Airway inflammation in cadmium-exposed rats is associated with pulmonary oxidative stress and emphysema.

The aim of this study was to test the hypothesis that pulmonary inflammation and emphysema induced by cadmium (Cd) inhalation are associated with pulmonary oxidative stress. Two groups of Sprague Dawley rats were used: one vehicle-exposed group undergoing inhalation of NaCl (0.9%, n = 24) and one Cd-exposed group undergoing inhalation of CdCl(2) (0.1%, n = 24). The animals in the vehicle-and Cd-exposed groups were divided into 4 subgroups (n = 6 per group), which underwent either a single exposure (D2) of 1H or repeated exposures 3 times/week for 1H for a period of 3 weeks (3W), 5 weeks (5W) or 5 weeks followed by 2 weeks without exposure (5W + 2). At sacrifice, the left lung was fixed for histomorphometric analysis (median inter-wall distance, MIWD), whilst bronchoalveolar lavage fluid (BALF) was collected from the right lung. Cytological analysis of BALF was performed and BALF was analysed for oxidant markers 8-iso-PGF(2a), uric acid (UA), reduced (AA) and oxidised ascorbic acid (DHA) and reduced (GSH) and oxidised glutathione (GSSG). Cd-exposure induced a significant increase of BALF macrophages and neutrophils. 8-iso-PGF(2a), UA, GSH and GSSG were significantly increased at D2. At 5W and 5W + 2, AA and GSH were significantly lower in Cd-exposed rats, indicating antioxidant depletion. MIWD significantly increased in all repeatedly Cd-exposed groups, suggesting development of pulmonary emphysema. 8-iso-PGF(2a) and UA were positively correlated with macrophage and neutrophil counts. GSH, GSSG and 8-iso-PGF(2a) were negatively correlated with MIWD, indicating that Cd-induced emphysema could be associated with pulmonary oxidative stress.

Animals↗
PubMed2004

Composition rather than viscosity modifies the aroma compound retention of flavored stirred yogurt.

The influence of thickening agents (modified starch/pectin mixture 0 and 7 g/L) and mechanical treatment (low, medium, and high) on the retention of esters (pentyl acetate and ethyl pentanoate), aldehydes (hexanal and (E)-2-hexenal), and a lactone (gamma-octalactone) in low-fat flavored stirred yogurts were investigated under equilibrium conditions. In the range studied, the thickening agent and mechanical treatment had little influence on aroma compound retention compared to the decreasing effect of increasing dairy protein concentration on aldehyde retention and the "salting out" effect of carbohydrates on esters. Moreover, experiments in dynamic mode (study of the release of hexanal when yogurts were heated) showed, in the conditions studied, that heat and mass transfer coefficients were not influenced by any of the studied factors (thickening agents and mechanical treatment). These results under static and dynamic conditions are not related to the significant decreasing effect of thickening agents on apple sensory scores associated with hexanal, observed in a previous sensory study. Thus, this sensory effect of thickening agents may be due to sensory interactions between perceptions rather than physicochemical interactions.

Chemical Phenomena↗
PubMed2002

Flavor-active compounds potentially implicated in cooked cauliflower acceptance.

The aim of the present study was to determine the flavor-active compounds responsible for the "sulfur" and "bitter" flavors of cooked cauliflower potentially implicated in cauliflower rejection by consumers. Eleven varieties of cauliflower were cooked and assessed by a trained sensory panel for flavor profile determination. Among the 13 attributes, the varieties differed mainly according to their "cauliflower odor note" and their "bitterness". Various glucosinolates were quantified by HPLC and correlated with bitterness intensity. The results showed that neoglucobrassicin and sinigrin were responsible for the bitterness of cooked cauliflower. Application of Dynamic Headspace GC-Olfactometry and DH-GC-MS showed that allyl isothiocyanate (AITC), dimethyl trisulfide (DMTS), dimethyl sulfide (DMS), and methanethiol (MT) were the key odorants of cooked cauliflower "sulfur" odors. Moreover, these volatile compounds corresponded to the main compositional differences observed between varieties. Finally, AITC, DMTS, DMS, MT, sinigrin, and neoglucobrassicin were shown to be potential physicochemical determinants of cooked cauliflower acceptance.

Brassica↗
PubMedDate not supplied

Level of endogenous formaldehyde in maple syrup as determined by spectrofluorimetry.

The level of endogenous formaldehyde in maple syrup was established from a large number (n = 300) of authentic maple syrup samples collected during 2000 and 2001 in the province of Quebec, Canada. The average level of formaldehyde from these authentic samples was measured at 0.18 mg/kg in 2000 and 0.28 mg/kg in 2001, which is lower than previously published. These average values can be attributed to the improved spectrofluorimetric method used for the determination. However, the formaldehyde values obtained demonstrate a relatively large distribution with maximums observed at 1.04 and 1.54 mg/kg. These values are still under the maximum tolerance level of 2.0 mg/kg paraformaldehyde pesticide residue. Extensive heat treatment of maple syrup samples greatly enhanced the formaldehyde concentration of the samples, suggesting that extensive heat degradation of the sap constituents during evaporation could be responsible for the highest formaldehyde values in maple syrup.

Acer↗