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beta-Conglycinin (7 S globulin) and glycinin (11 S globulin) are the major reserve proteins of soybean. They were localized by the protein A immunogold method in thin sections of Glycine max (soybean) cv. Maple Arrow. In cotyledons, both globulins were simultaneously present in all protein bodies. Statistical analysis of marking intensities indicated no correlation between globulin concentration and size of protein bodies. The immunogold method failed to detect either globulin in the embryonic axis and in cotyledons of four-day-old seedlings. Similar observations were made with cotyledons of two soy varieties lacking either the lectin or the Kunitz trypsin inhibitor. In another variety (T-102) lacking the lectin, the 7 S globulin could not be detected.

-The heat treatment of milk powders during food manufacturing induces physical and chemical modifications that are governed by material phase transitions. The main aim of this work was to describe the heat-induced physical changes occurring in whole milk powder (WMP). The study was based on increasing the water activity (a w ) of the powder in order to relate the glass transition temperature (Tg) to the parameters resulting in changes in physical properties. Colour changes in milk powder due to non-enzymatic browning (NEB) were monitored by spectrophotometry based on the CIE L*a*b* function. Changes in particle structure were investigated by scanning electron microscopy (SEM). WMPs at low and high water activities (0.28 and 0.35) were heated in closed tubes and their physical properties (a w , lactose crystallisation and free fat release) monitored. The results showed that the kinetics of lactose crystallisation and the resulting increase in a w were clearly influenced by the Tg, modulated here by the water content of WMP at the time of heat treatment. The kinetics of free fat release was related to the trend of lactose crystallisation. SEM showed that the free fat was released onto the particle surfaces and formed a fat layer covering the lactose crystals. Porosity then resulted inside the powder matrix due to empty cavities formerly occupied by fat globules. In addition, the chemical reactivity of WMP expressed by colour changes showed a delay in triggering the NEB reaction in milk powder at low water content only. The results of this study showed that the heat treatment of WMP under specific process parameters (a w , temperature and time) enables not only modulation of free fat release and browning but also changes in the microstructure of the powder particles.whole milk powder / heat treatment / free fat / crystallisation / browning Résumé -Changements physiques de la poudre de lait entier traitée thermiquement. Le traitement thermique des poudres de lait inhérent à certains procédés de fabrication alimentaire induit des modifications physiques et chimiques, gouvernées par les transitions de phase du matériau. L'objectif principal de ce travail a été de décrire les changements physiques dans la poudre de lait entier (WMP) induits par le traitement thermique. L'approche de cette étude était basée sur l'augmentation de l'activité d'eau (a w ) de la poudre afin de relier la température de transition vitreuse (Tg) aux variations de paramètres permettant le changement des propriétés physiques. Le changement de couleur de la poudre de lait dû au brunissement non-enzymatique (NEB) a été mesuré en utilisant la méthode spectrophotométrique basée sur la lecture CIE des fonctions L*a*b*. La modification de la structure des particules a été examinée par microscopie à balayage électronique (SEM). Deux WMP à basse et haute a w (0.28 et 0.35) ont été chauffés dans des tubes hermétiques et les propriétés physiques telles que a w , cristallisation du lactose, matière grasse libre, ont été suivies. Les résultats ont ...

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A new cationic colloidal gold complex has been developed for ultrastructural localization of cell surface anionic sites by transmission and scanning electron microscopy. The marker is prepared by labelling gold particles of suitable sizes (6 to 70 nm in diameter) with chitosan, a polymer of beta (1----4)-linked D-glucosamine. Using human red blood cells as a model, chitosan-gold complexes were shown to be specific for anionic sites and at pH 2 for sialic acid residues. The binding capacity of complexes of different sizes with carboxymethyl and phosphorylated celluloses was examined as a function of pH and ionic strength. The results indicated that these complexes can be used under acidic conditions as well as in physiological buffers. The complexes were further tested by transmission and scanning electron microscopy in detecting anionic sites on cells of various origins such as Escherichia coli, Lactobacillus maltaromicus, Lactobacillus reuteri, Saccharomyces cerevisiae, Saccharomyces rouxii, Schizosaccharomyces pombe, Fusarium oxysporum, Catharantus roseus.