Apparent water diffusivity has been studied on an emulsified food model made of gelatin and hydrogenized vegetable fat. Lipid content was varied from 0 to 50% w/w and three particle mean diameters were generated (40, 110, and 400 mu m) in gelatin samples containing 75g of water per 100g of fat-free sample. In joined compartment experiments, fatty hydrated gels were dehydrated in contact with either a dry pure gelatin compartment or an industrial sponge cake. Water content profiles were used to determine the apparent water diffusivity value using Ruiz Cabrera et al.'s method,([1]) which takes gel shrinkage into account.

The particular effect of 4 kinds of amino acid and peptide-rich food material (APRM) containing different charged amino acid contents on the gelatinization and retrogradation behavior of potato starch granules and on the water-vaporization behavior was analyzed by differential scanning calorimetry, rapid viscoanalysis, x-ray diffractometry, thermal gravimetry-differential thermal analysis, and pulsed NMR. APRM with a high-charged amino acid content produced unique gelatinization and retrogradation behavior in terms of an elevated gelatinization temperature, reduced viscosity, higher setback, and lower retrograded starch melting enthalpy. The recovered x-ray diffraction intensity decreased with increasing charged amino acid content. APRM with high-charged amino acid content could provide an improved paste having easy vaporization of external water in the swollen starch granules due to the reduced swelling.

Melanin nanoparticles (MNP) were isolated from squid ink and used for the preparation of gelatin-based nanocomposite films containing various concentration of MNP (0, 0.25, 0.5, and 1.0 wt%). The MNP was a spherical form with an average diameter of about 100 nm. The MNP was compatible with the gelatin matrix to form uniform nanocomposite films. The surface color of gelatin/MNP nanocomposite films was brown with decreased transparency, but other film properties such as mechanical, water vapor barrier, and thermal stability properties increased significantly compared with the neat gelatin film. All the film properties of the gelatin/MNP nanocomposite films were dependent on the MNP concentration. Also, the gelatin/MNP nanocomposite films exhibited a high antioxidant activity which has great potential for food packaging and biomedical applications.

Three experimental devices (joined cylinders, dry salting and a drying cell) were used to generate moisture and sodium chloride (NaCl) profiles in gels (gelatin, different starch/gelatin ratios) maintained at constant temperature (10 and 20°C). The moisture and chloride concentrations profiles were measured by a destructive method (slicing: 1 and 5 mm of thickness / analysis of moisture (oven) and chloride (potentiometric titration)). A drying cell was set up in order to generate salt and moisture gradients in salt added gelatin gels maintained at constant temperature and to obtain a large range of moisture fluxes (from 0,00003 to 0,0003 kg water per square meter and per second). For those investigated moisture fluxes, binary diffusion of moisture and chlorides seems to be the predominant phenomenon. Apparent diffusivities were either estimated by applying a direct data treatment method to measured profiles or identified by using a mathematical model taking the retraction of the gel into account. The direct data treatment method does not require any assumption on the D=f(X) relation. It can be applied to profiles with relatively few measurements - approximately 10 - when smoothing the experimental points by using a neural network. The two methods provided similar estimations of apparent moisture and chlorides diffusivities. The values depend neither on the strengh of gelatin gels (Bloom) nor on the anhydrous composition of the gel (ratio starch/gelatin). Apparent chloride diffusitivity is relatively constant and lower than mutual salt-water diffusivity. Apparent moisture diffusitivity decreases with moisture content when measured on gels during dehydration but, increases with decreasing moisture content in the gels during re-hydration. The addition of sodium chloride causes an increase of the apparent moisture diffusivity by a factor 10. | Trois dispositifs expérimentaux (cylindres accolés, salage à sec, cellule de séchage) ont été utilisés pour générer des profils de teneurs en eau et en chlorure de sodium (NaCl) dans des gels (gélatine, mélanges amidon/gélatine) à 10 et 20 °C. Ces profils ont été mesurés par analyses chimiques après découpe de tranches de gel d'épaisseurs 1 et 5 mm. Dans le cas du séchage, un dispositif original a permis de maintenir la température du gel constante et de faire varier la densité de flux d'eau évaporée de 0,00003 à 0,0003 kg d'eau par mètre carré et par seconde. Dans cette gamme, aucun effet d'entraînement du sel par l'eau n'a pu être mise en évidence. Les diffusivités apparentes ont été estimées soit en appliquant un traitement direct aux profils mesurés soit par identification avec un modèle de transfert couplé eau-sel qui tient compte de la rétraction du gel. Le traitement direct ne nécessite aucune hypothèse sur la forme de la relation D=f(X) ; il peut être appliqué à des profils constitués d'un nombre limité de mesures - environ 10 - grâce à un lissage par un réseau de neurones. Les deux méthodes ont fourni des estimations concordantes des diffusivités apparentes de l'eau et des chlorures. Elles ne dépendent ni de la force du gel (Bloom) ni de la composition du gel anhydre (ratio amidon/gélatine). Celle des chlorures est relativement constante et inférieure à la diffusivité mutuelle sel-eau. Celle de l'eau dépend de la teneur en eau initiale du gel, diminue avec la diminution de la teneur en eau en déshydratation mais augmente en réhydratation. L'ajout du chlorure de sodium provoque une augmentation de la diffusivité apparente de l'eau d'un facteur 10.

Three experimental devices (joined cylinders, dry salting and a drying cell) were used to generate moisture and sodium chloride (NaCl) profiles in gels (gelatin, different starch/gelatin ratios) maintained at constant temperature (10 and 20°C). The moisture and chloride concentrations profiles were measured by a destructive method (slicing: 1 and 5 mm of thickness / analysis of moisture (oven) and chloride (potentiometric titration)). A drying cell was set up in order to generate salt and moisture gradients in salt added gelatin gels maintained at constant temperature and to obtain a large range of moisture fluxes (from 0,00003 to 0,0003 kg water per square meter and per second). For those investigated moisture fluxes, binary diffusion of moisture and chlorides seems to be the predominant phenomenon. Apparent diffusivities were either estimated by applying a direct data treatment method to measured profiles or identified by using a mathematical model taking the retraction of the gel into account. The direct data treatment method does not require any assumption on the D=f(X) relation. It can be applied to profiles with relatively few measurements - approximately 10 - when smoothing the experimental points by using a neural network. The two methods provided similar estimations of apparent moisture and chlorides diffusivities. The values depend neither on the strengh of gelatin gels (Bloom) nor on the anhydrous composition of the gel (ratio starch/gelatin). Apparent chloride diffusitivity is relatively constant and lower than mutual salt-water diffusivity. Apparent moisture diffusitivity decreases with moisture content when measured on gels during dehydration but, increases with decreasing moisture content in the gels during re-hydration. The addition of sodium chloride causes an increase of the apparent moisture diffusivity by a factor 10. | Trois dispositifs expérimentaux (cylindres accolés, salage à sec, cellule de séchage) ont été utilisés pour générer des profils de teneurs en eau et en chlorure de sodium (NaCl) dans des gels (gélatine, mélanges amidon/gélatine) à 10 et 20 °C. Ces profils ont été mesurés par analyses chimiques après découpe de tranches de gel d'épaisseurs 1 et 5 mm. Dans le cas du séchage, un dispositif original a permis de maintenir la température du gel constante et de faire varier la densité de flux d'eau évaporée de 0,00003 à 0,0003 kg d'eau par mètre carré et par seconde. Dans cette gamme, aucun effet d'entraînement du sel par l'eau n'a pu être mise en évidence. Les diffusivités apparentes ont été estimées soit en appliquant un traitement direct aux profils mesurés soit par identification avec un modèle de transfert couplé eau-sel qui tient compte de la rétraction du gel. Le traitement direct ne nécessite aucune hypothèse sur la forme de la relation D=f(X) ; il peut être appliqué à des profils constitués d'un nombre limité de mesures - environ 10 - grâce à un lissage par un réseau de neurones. Les deux méthodes ont fourni des estimations concordantes des diffusivités apparentes de l'eau et des chlorures. Elles ne dépendent ni de la force du gel (Bloom) ni de la composition du gel anhydre (ratio amidon/gélatine). Celle des chlorures est relativement constante et inférieure à la diffusivité mutuelle sel-eau. Celle de l'eau dépend de la teneur en eau initiale du gel, diminue avec la diminution de la teneur en eau en déshydratation mais augmente en réhydratation. L'ajout du chlorure de sodium provoque une augmentation de la diffusivité apparente de l'eau d'un facteur 10.

Green chemistry or in other words “green world” is referred to a sustainable environment using biocompatible, biodegradable, renewable, economical, and simple materials, and methods. Without any exaggeration, the exceptional chemical and physical properties of ZnO bionanocomposites beside various utilizations, make it vital materials in research and green chemistry field. Biocompatible ZnO nanoparticles with fascinating antimicrobial, physicochemical, as well as photocatalytic performance could be applied as a prominent candidate to reinforce diverse biopolymer matrixes, for instance, chitosan, starch, cellulose, gelatin, alginate, poly(hydroxyalkanoates), carrageenan, and so on. With a combination of advantageous properties of these materials, they could be illustrated specific utilizations in different areas. In this regard, the following context focuses on highlighting the recent achievements of this category of material on three important and widely used scopes: eco-friendly food packaging, biomedical specially wound dressings, and water remediation technologies.

The present study aimed: (i) to develop models for the combined effect of water activity (0.99, 0.94 and 0.90), microstructure expressed as 0, 5, 10 and 20% w/v gelatin, and temperature (15, 20 and 25 °C), on growth and OTA production rates by Aspergillus carbonarius; and (ii) to evaluate the performance of the developed models on food matrices (jelly, custard and marmalade) of different viscosity at pH 5.5. The square root of biomass increase rate (fungal growth rate) and OTA production rate were determined by the Baranyi model and were further modeled as a function of temperature, gelatin concentration and aw by applying polynomial models. Time for visible growth and the upper asymptote of the OTA production curve were also determined by the Baranyi model. Increase in gelatin concentration resulted in a significant delay in all parameters describing fungal growth and OTA production rates, at all temperatures and aw. The effect of microstructure on fungal growth and OTA production rates was less evident at stress conditions of aw and temperature. Detection time for visible fungal growth was markedly influenced by aw and temperature. Coefficients of determination were 0.899 and 0.887 for the models predicting the square root (μₘₐₓ) of growth and OTA production rate, respectively. Predictions of growth rate agreed well with the recorded data of custard and marmalade, while observations of OTA production rate indicated low agreement with model predictions, in all food matrices except for marmalade. The present findings may provide a basis for reliable assessment of the risk of fungal growth and OTA production in foods of different structural and rheological properties.