Study of the release of limonene present in chitosan films enriched with bergamot oil in food simulants

[EN] Chitosan films containing different concentrations of bergamot oil (BO) were obtained and the migration of limonene, the major oil component, to five liquid food simulants (aqueous solutions with 0%, 10%, 50% and 95% of ethanol and isooctane) was studied at 20 degrees C. The losses of BO and limonene during the film drying were also quantified. The release kinetics of limonene from chitosan matrix was described using an empirical model which relates the reduced concentration loss of limonene and the square root of time. The results show that kinetic constants for all films increased exponentially when the ethanol concentration increased in the aqueous system and were slightly greater when the film thickness was lower. Composite films remain intact in isooctane CH-BO and no release of limonene was observed. Hydration of the film to promote molecular mobility was essential to ensure the compound release. (C) 2011 Elsevier Ltd. All rights reserved.The author L. Sanchez-Gonzalez thanks the Ministerio de Educacion y Ciencia (Spain) for a FPU Grant (AP2006-026).Sánchez González, L.; Cháfer Nácher, MT.; González Martínez, MC.; Chiralt, A.; Desobry, S. (2011). Study of the release of limonene present in chitosan films enriched with bergamot oil in food simulants. Journal of Food Engineering. 105(1):138-143. https://doi.org/10.1016/j.jfoodeng.2011.02.016S138143105

Tracking System with Re-identification Using a RGB String Kernel

International audiencePeople re-identification consists to identify a person which comes back in a scene where it has been previously detected. This key problem in visual surveillance applications may concern single or multi camera systems. Features encoding each person should be rich enough to provide an efficient re-identification while being sufficiently robust to remain significant through the different phenomena which may alter the appearance of a person in a video. We propose in this paper a method which encodes people's appearance through a string of salient points. The similarity between two such strings is encoded by a kernel. This last kernel is combined with a tracking algorithm in order to associate a set of strings to each person and to measure similarities between persons entering into the scene and persons who left it

Effect of Pulsed or Continuous Delivery of Salt on Sensory Perception Over Short Time Intervals

Salt in the human diet is a major risk factor for hypertension and many countries have set targets to reduce salt consumption. Technological solutions are being sought to lower the salt content of processed foods without altering their taste. In this study, the approach was to deliver salt solutions in pulses of different concentrations to determine whether a pulsed delivery profile affected sensory perception of salt. Nine different salt profiles were delivered by a Dynataste device and a trained panel assessed their saltiness using time–intensity and single-score sensory techniques. The profile duration (15 s) was designed to match eating conditions and the effects of intensity and duration of the pulses on sensory perception were investigated. Sensory results from the profiles delivered in either water or in a bouillon base were not statistically different. Maximum perceived salt intensities and the area under the time– intensity curves correlated well with the overall perceived saltiness intensity despite the stimulus being delivered as several pulses. The overall saltiness scores for profiles delivering the same overall amount of sodium were statistically not different from one another suggesting that, in this system, pulsed delivery did not enhance salt perception but the overall amount of salt delivered in each profile did affect sensory perception

Characteristic Physicochemical of Oil Extract from Moringa oleifera and the Kinetics of Degradation of the Oil during Heating

Abstract: The aim of the study was to investigate the physicochemical properties and the kinetics of degradation of Moringa oleifera seed oil during heating. The seed is a good source of oil (40%). The physical properties of the oil extracts showed the state to be liquid at room temperature and indicated that the oil had refractive index, 1.4680; the peroxide value, 1.67 (meq O 2 /kg oil); free fatty acid, 2.10%; iodine value, 66.2%; saponification value, 167; unsaponifiable matter content, 0.87% and viscosity, 47.24 (mPa.s at 25°C). Gas liquid chromatography technique has been developed for identification and quantitative determination of total unsaturated and saturated fatty acids shows that the crude oil had 79.57 and 20.42% respectively. Differential Scanning Calorimetry (DSC) indicates the presence of three components in oil extracted. The first peak at low melting point appears at -31.10°C (∆H f = -5.36 J/g), the second peak appears to -7.03°C (∆H f = +49.56 J/g) and the last peak appears to +6.30°C (∆H f = +0.55 J/g). The degradation kinetic of the oil was also investigated. The thermal oxidation of the double bonds of the oil showed a first-order thermal oxidation kinetic and the Arrhenius plot yielded a straight line with a slope equivalent to activation energy of 1.593 KJ/mol. There is the possibility of considering the seed as feed supplement and its oil for industrial application

Online change detection in exponential families with unknown parameters

International audienceThis paper studies online change detection in exponential families when both the parameters before and after change are unknown. We follow a standard statistical approach to sequential change detection with generalized likelihood ratio test statistics. We interpret these statistics within the framework of information geometry, hence providing a unified view of change detection for many common statistical models and corresponding distance functions. Using results from convex duality, we also derive an efficient scheme to compute the exact statistics sequentially, which allows their use in online settings where they are usually approximated for the sake of tractability. This is applied to real-world datasets of various natures, including onset detection in audio signals

α-Synuclein in central nervous system and from erythrocytes, mammalian cells, and Escherichia coli exists predominantly as disordered monomer

Since the discovery and isolation of α-synuclein (α-syn) from human brains, it has been widely accepted that it exists as an intrinsically disordered monomeric protein. Two recent studies suggested that α-syn produced in Escherichia coli or isolated from mammalian cells and red blood cells exists predominantly as a tetramer that is rich in α-helical structure (Bartels, T., Choi, J. G., and Selkoe, D. J. (2011) Nature 477, 107-110; Wang, W., Perovic, I., Chittuluru, J., Kaganovich, A., Nguyen, L. T. T., Liao, J., Auclair, J. R., Johnson, D., Landeru, A., Simorellis, A. K., Ju, S., Cookson, M. R., Asturias, F. J., Agar, J. N., Webb, B. N., Kang, C., Ringe, D., Petsko, G. A., Pochapsky, T. C., and Hoang, Q. Q. (2011) Proc. Natl. Acad. Sci. 108, 17797-17802). However, it remains unknown whether or not this putative tetramer is the main physiological form of α-syn in the brain. In this study, we investigated the oligomeric state of α-syn in mouse, rat, and human brains. To assess the conformational and oligomeric state of native α-syn in complex mixtures, we generated α-syn standards of known quaternary structure and conformational properties and compared the behavior of endogenously expressed α-syn to these standards using native and denaturing gel electrophoresis techniques, size-exclusion chromatography, and an oligomer-specific ELISA. Our findings demonstrate that both human and rodent α-syn expressed in the central nervous system exist predominantly as an unfolded monomer. Similar results were observed when human α-syn was expressed in mouse and rat brains as well as mammalian cell lines (HEK293, HeLa, and SH-SY5Y). Furthermore, we show that α-syn expressed in E. coli and purified under denaturing or nondenaturing conditions, whether as a free protein or as a fusion construct with GST, is monomeric and adopts a disordered conformation after GST removal. These results do not rule out the possibility that α-syn becomes structured upon interaction with other proteins and/or biological membranes