Effect of konjac glucomannan addition on aroma release in gels containing potato starch.

International audience; The present study aimed to measure the retention of aroma compounds (ethyl acetate, ethyl hexanoate and carvacrol) in dispersions based on konjac glucomannan and/or potato starch, and to highlight the influence of konjac glucomannan on the mechanisms involved in aroma retention. Publications on the effect of konjac glucomannan on aroma release are scarce. Konjac glocomannan is a polysaccharide used as a food additive for its viscous and emulsifying properties. Retention of aroma compounds in dispersions was calculated from partition coefficients which were measured using the phase ratio variation method. This method, consisting of analyses of the headspace at equilib…

Effect of high hydrostatic pressure on extraction of B-phycoerythrin from Porphyridium cruentum: Use of confocal microscopy and image processing

International audience; The aim of the study was to extract B-phycoerythrin from Porphyridium cruentum while preserving its structure. The high hydrostatic pressure treatments were chosen as extraction technology. Different methods have been used to observe the effects of the treatment: spectrophotometry and confocal laser scanning microscopy followed by image processing analysis. Image processing led to the generation of masks used for the identification of three clusters: intra, extra and intercellular. All methods showed that high hydrostatic pressure treatments between 50 and 500 MPa failed to extract B-phycoerythrin from Porphyridium cruentum cells. The fluorescence emission was negati…

Impact of the structure of polysaccharide-based food gels on the release of aroma compounds: an APCI-MS approach

International audience

Antioxidant Properties of Ergosterol and Its Role in Yeast Resistance to Oxidation

International audience; Although the functions and structural roles of sterols have been the subject of numerous studies, the reasons for the diversity of sterols in the different eukaryotic kingdoms remain unclear. It is thought that the specificity of sterols is linked to unidentified supplementary functions that could enable organisms to be better adapted to their environment. Ergosterol is accumulated by late branching fungi that encounter oxidative perturbations in their interfacial habitats. Here, we investigated the antioxidant properties of ergosterol using in vivo, in vitro, and in silico approaches. The results showed that ergosterol is involved in yeast resistance to tert-butyl h…

The Potential Use of Raw and Deodorized Non-Conventional Protein Powder in Human Food

This study aimed to evaluate the potential use of a non-conventional protein source, a powder made from earthworms, as human food. Sensory analyses were done in order to assess the acceptability of cookies that were fortified with Eisenia foetida (Ef) protein powder. Cocoa and cinnamon were used as taste-masking agents. The acceptability of cookies fortified with deodorized Ef protein powder (off-flavor reduced) was also evaluated. We demonstrated that cocoa cookies can be fortified with 3.9% of raw Ef proteins and that cocoa/cinnamon cookies can be fortified with 5.2% of raw Ef proteins without any loss in their acceptability. Cookies fortified either with a raw protein powder or with a de…

Protein aggregation induced by phase separation in a pea proteins–sodium alginate–water ternary system

Abstract The physicochemical properties of a native, globular plant protein–linear anionic polysaccharide aqueous system at 20 °C were investigated in conditions where biopolymers carry a net negative charge (pH 7.2, 0.1 M NaCl). The pea proteins–sodium alginate mixtures showed a phase separation mainly by thermodynamic incompatibility, characterized at both the macroscopic and microscopic scale. Phase diagram was established and confocal laser scanning microscopy (CLSM) provided accurate data on the microstructure morphology of the system, regarding its phase behavior. In admixture, sodium alginate induced a protein aggregation, certainly by a local depletion of the polysaccharide. Protein…

Screening of lactic acid bacteria for fermentation of a mix of cow and pea protein

Screening of lactic acid bacteria for fermentation of a mix of cow and pea protein. Vitagora - 9. international taste-nutrition-health congress

Sensor and device for detecting an analyte in a liquid

Partition of volatile compounds in pea globulin–maltodextrin aqueous two-phase system

International audience; This study is based on the assumption that the off-flavour of pea proteins might be decreased using the retention of volatile compounds by a mixture with another biopolymer. The partition of volatile compounds in an aqueous system containing pea protein and maltodextrins was followed under thermodynamic incompatibility conditions. Firstly, the phase diagram of the system was established. Then, the partition of aroma compounds between the phase rich in protein and the phase rich in maltodextrin was measured by SPME–GC–MS. There was a transfer of volatile compounds during phase separation. Variations of pH were also used to vary the retention of volatile compounds by p…

The effects of sodium alginate and calcium levels on pea proteins cold-set gelation

Abstract A multi-scale investigation of pea proteins – alginate cold-set gels was proposed in this study. The gel preparation followed a two-steps procedure. Globular pea proteins were first denatured and aggregated by a pre-heating step. Sodium alginate was then added at different concentrations. Thereafter the in situ gelation process was induced at 20 °C using glucono-δ-lactone (GDL) and two calcium carbonate (CC) levels; calcium cations were released as the pH decreased. Small-amplitude rheology measurements (storage modulus G′) showed that stronger mixed gels were obtained than single-biopolymer solutions. Confocal laser scanning microscopy (CLSM) revealed phase-separating microstructu…

How Chemical and Sensorial Markers Reflect Gentian Geographic Origin in Chardonnay Wine Macerated with Gentiana lutea Roots?

A Burgundian Chardonnay wine was enriched with Gentiana lutea root powders originating from two French mountain sites (Massif Central and Jura) in order to prepare semi-dry gentian aromatized Chardonnay wine-based drinks. These novel alcoholic beverages were chemically and sensorially characterized for evaluating if the gentian geographic origin influenced bitter and elemental and volatile composition and sensory profiles in the final products. For that, the chemical fingerprint of gentian powders and wines were carried by headspace solid phase microextraction gas chromatography coupled to mass spectrometry (HS&ndash

Substitution of carcinogenic solvent dichloromethane for the extraction of volatile compounds in a fat-free model food system

International audience; Dichloromethane is known as a very efficient solvent, but, as other halogenated solvents, is recognized as a hazardous product (CMR substance). The objective of the present work is to propose substitution solvent for the extraction of volatile compounds. The most important physico-chemical parameters in the choice of an appropriate extraction solvent of volatile compounds are reviewed. Various solvents are selected on this basis and on their hazard characteristics. The selected solvents, safer than dichloromethane, are compared using the extraction efficiency of volatile compounds from a model food product able to interact with volatile compounds. Volatile compounds …

Retention of Carvacrol and Ethyl Acetate in Aqueous Gels of Potato Starch and Konjac Glucomannan

The partition coefficients of two volatile compounds in dispersions containing potato starch (PS) and/or konjac glucomannan (KGM) have been determined by the phase ratio variation method using equilibrium headspace analysis by gas chromatography. The influence of the moment when volatile compounds were added and the effect of the polysaccharide dispersions were investigated. For ethyl acetate, retention by KGM was based on viscosity effect. Retention of carvacrol was important when amylose was accessible. The addition of KGM to PS suspensions decreased the retention governed by interactions with starch.

In situ Pesticide Detection in Food Processing by Microwave Transduction Combined with Molecularly Imprinted Polymers

International audience; Since 2005, the microwave transduction coupled with a sensitive material is devoted to gas detection. In this work, we demonstrate the possibility to detect liquid pollutant (pesticide, fungicide) for food-processing industry. The principle is based on the interaction of the pollutant with a sensitive material within a microwave structure. The sensor is submitted to an electromagnetic excitation in wideband frequencies (GHz) and presents a quantitative response to liquid pollutant expositions at low concentration. The retained sensitive material is a molecularly imprinted polymer (MIP) specific to the pesticide targeted in a model wine. The coupling with this materia…

Chapter 7. Physico-chemical properties of konjac glucomannan

International audience; The konjac flour is obtained from the tuber of the Amorphophallus konjac, a plant of the Araceae family. This plant is found in the wild and cultivated as a vegetable in Thailand, China, Vietnam, Korea, and Japan since the nineteenth century AD (Chua et al. 2012; Li et al. 2005). The major compound of konjac flours is glucomannan, the reserve polysaccharide of konjac. The glucomannans are also present under the same structural type in various plant species: orchid bulbs, lily, and Aloe vera seeds (Dorthe 2005). The konjac flour is obtained by crunching the tubers more or less finely. These are harvested after 2 or 3 years of plant development. The tubers are cut, dri…

Impact of konjac glucomannan on interactions aroma compound - potato starch in a hydrated gel

The objective of this study is to demonstrate that the presence of konjac glucomannan (KGM) in a potato starch matrix enhances its physical stability without inhibiting the molecular encapsulation of aroma compounds by amylose. For that purpose, the two selected polysaccharides are from plant tubers, abundant in nature.Starch is known to interact with volatile compounds either by trapping in amorphous phase or by forming inclusion complexes. This phenomenon is called molecular encapsulation. However, at high water content, these starchy matrices exhibit syneresis that can be harmful to the stability of the aroma compounds trapping over time. KGM has the ability to form highly viscous soluti…