El presente trabajo se ha centrado en el desarrollo de emulsiones alimentarias aceite-en-agua estabilizadas con proteínas de atún. Específicamente, se ha analizado la influencia del método de conservación de las proteínas aisladas (liofilización, congelación) y de las condiciones de procesado seleccionadas sobre el comportamiento reológico y la microestructura de dichas emulsiones. Se han preparado emulsiones aceite en agua (con un contenido del 70% en peso de aceite) estabilizadas con proteínas de atún. La concentración de emulsionante usada ha sido 0,50% en peso. El comportamiento reológico de estas emulsiones no depende significativamente del método de conservación de la proteína empleado. Por otra parte, un aumento de la velocidad de agitación durante el proceso de manufactura de la emulsión da lugar a una disminución continua del tamaño medio de gota y a un aumento de las funciones viscoelásticas dinámicas, menos significativo a medida que aumenta dicha velocidad de agitación. | This work is focused on the development of o/w salad dressing-type emulsions stabilized by tuna proteins. The influence of protein conservation methods after the extraction process (freezing or liofilization) on the rheological properties and microstructure of these emulsions was analyzed. Processing variables during emulsification were also evaluated. Stable emulsions with adequate rheological and microstructural characteristics were prepared using 70% oil and 0.50% tuna proteins. From the experimental results obtained, we may conclude that emulsion rheological properties are not significantly affected by the protein conservation method selected. On the contrary, an increase in homogenization speed favours an increase in the values of the linear viscoelastic functions. Less significant is the fact that as agitation speed increases further, mean droplet size steadily decreases.

Green cleaner and disinfectant can provide a better environment and they can reduce cleaning cost by eliminating the cost of harsh cleaning chemicals, minimizing cleaning chemicals storage space, reducing cost for wastewater treatment and reducing logistics cost for chemical supply. This study explored the personal view of Small and Medium Enterprises (SMEs) top to bottom workers towards the challenges during cleaning and disinfection process and their readiness in accepting a green cleaner and disinfectant. In this work, the advantages and disadvantages of electrolyzed water (EW) as green cleaner and disinfectant were discussed. A lab-scale batch ion-exchange membrane electrolysis unit was used to produce acidic electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). The stability of AcEW and AlEW was also studied based on its physical changes (pH, oxidative-reduction potential (ORP), chlorine content and hydrogen peroxide content) in 7 days of storage, whereby measurements were taken daily. The pH maintained for both AcEW and AlEW during the 7 days of storage. The ORP maintained at plateau for the first 5 days of AcEW storage. After 5 days, AcEW showed a decreasing trend. While ORP for AlEW increases drastically between day 1 and 2. Then, the ORP reaches a plateau after three days. The amount of free chlorine, total chlorine and hydrogen peroxide content was 10 mg/L, respectively, on the day of production. However, all the properties decreased gradually and there were no chlorine and hydrogen peroxide detected on the 7th day. The results from this study can be used as a guideline to store the EW and to understand the stability of the EW, which can benefit the SME food manufacturers.

Water-adsorption data and glass transition temperatures (Tg) of maltodextrins with dextrose equivalent (DE) values ranging from 4 to 38, horseradish roots, and strawberries were used to establish relationships between water activity (aw), water content (m), and Tg. Critical m values were considered as those depressing Tg to 25C. Corresponding values of critical aw were obtained from GAB isotherms that were used to model water adsorption. The use of BET isotherms was tested, but the model showed poor correlation with experimental data at high aw values, especially for low DE maltodextrins. Critical m and aw values were lowest for strawberries (1.5 g H2O/g solids; 0.07 aw). The values increased with decreasing DE, ranging from 72 (0.44 aw) to 11.2 g H2O/g solids (0.70 aw). Understanding of water-sorption properties and Tg is valuable in controlling processability and stability, and for determining of food-packaging requirements.

This work deals with the manufacture of oil-in-water food emulsions stabilised by tuna proteins. The influence of protein and oil concentrations on the linear viscoelastic properties and microstructure of these emulsions was analysed. Stable emulsions with suitable linear viscoelastic response and microstructural characteristics were formulated with 70 wt.% oil and, at least, 0.25 wt.% tuna protein. Similarly, emulsions with oil concentrations between 45 and 70 wt.% were prepared using 0.50 wt.% protein. All these emulsions showed a predominantly elastic response in the linear viscoelastic region and a well-developed plateau region in its mechanical spectrum. Rheological and droplet size distribution results pointed out an extensive droplet flocculation, due to interactions among emulsifier molecules located at the oil–water interface of adjacent droplets. As a result, the linear viscoelastic behaviour was controlled by protein–protein interactions, allowing the use of the plateau modulus to successfully normalise both the storage and loss moduli as a function of frequency onto a master curve, irrespective of the selected emulsion formulation.

The objective of this research was to study the effect of water activity and glass transition temperature on the fat hydrolysis in a food model system. The model system was prepared with tapioca starch, casein, palm oil and sugar as 58, 14, 16 and 12 g/100 g model matrix, respectively. Hydrolysis reaction was accelerated bycommercial lipase at six levels of water content and water activity. Moisture sorption isotherm was obtained using isopiestic method while monolayer value was determined by BET equations. Glass transition temperature was determined from amorphous ingredients of starch and casein. Hydrolysis reaction showed a significantincrease above the monolayer value at 3.55 g water/100 g solid and aw 0.19. Hydrolysis occurred even at the glassy state of the model system. The role of water in the hydrolysis reaction is more related to the water activity concept rather than glass transition concept.

Achieving the reuse of traditional egg by-products, salted duck egg whites (SEW), is an urgent problem to be solved. In this current work, we constructed a heat-induced gel-assisted desalination method for SEW. Subsequently, a top-down way was utilized to prepare desalted duck egg protein nanogels (DEPN) with uniformly distributed diameters and their application in the oil/water (O/W) interface system was explored. The results revealed that the increase of DEPN concentration could lower the droplet size, however, the size was negatively correlated with the oil phase fraction. Moreover, the effect of pH, ionic strength, and temperature on the emulsion stability demonstrated that the DEPN-stabilized emulsion displayed superior physical stability under different conditions. The addition of NaCl resulted in the significant decrease in droplet size of the emulsion, while further increasing the NaCl concentration, the droplet size did not decrease accordingly. Besides, heat-treatment and cold-treatment had little negative effect on the stability of the emulsion. Even if the droplet size of the emulsion increased at 80 °C for 3 h, the morphology of the emulsion remained unchanged. Our study demonstrated DEPN had great potential as a stabilizer for food-grade Pickering emulsions.

Microemulsions are thermodynamically stable systems that have attracted considerable attention in the food industry as delivery systems for many hydrophobic nutrients. These spontaneous systems are highly dependent on ingredients and composition. In this work phase diagrams were constructed using two surfactants (Kolliphor RH40 and ELP), water, sunflower oil, and ethanol as cosurfactant, evaluating their physicochemical properties. Stability of the systems was studied at 25 and 60 °C, monitoring turbidity at 550 nm for over a month to identify the microemulsion region. Conductivity was measured to classify between water-in-oil and oil-in-water microemulsions. The phase diagram constructed with Kolliphor RH40 exhibited a larger microemulsion area than that formulated with Kolliphor ELP. All formulations showed a monomodal droplet size distribution with low polydispersity index (<0.30) and a mean droplet size below 20 nm. Systems with higher water content presented a Newtonian behavior; increasing the dispersed phase content produced a weak gel-like structure with pseudoplastic behavior under flow conditions that was satisfactorily modeled to obtain structural parameters. | Fil: Mori Cortés, Noelia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina | Fil: Lorenzo, Gabriel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina | Fil: Califano, Alicia Noemi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina

Achieving the reuse of traditional egg by-products, salted duck egg whites (SEW), is an urgent problem to be solved. In this current work, we constructed a heat-induced gel-assisted desalination method for SEW. Subsequently, a top-down way was utilized to prepare desalted duck egg protein nanogels (DEPN) with uniformly distributed diameters and their application in the oil/water (O/W) interface system was explored. The results revealed that the increase of DEPN concentration could lower the droplet size, however, the size was negatively correlated with the oil phase fraction. Moreover, the effect of pH, ionic strength, and temperature on the emulsion stability demonstrated that the DEPN-stabilized emulsion displayed superior physical stability under different conditions. The addition of NaCl resulted in the significant decrease in droplet size of the emulsion, while further increasing the NaCl concentration, the droplet size did not decrease accordingly. Besides, heat-treatment and cold-treatment had little negative effect on the stability of the emulsion. Even if the droplet size of the emulsion increased at 80 °C for 3 h, the morphology of the emulsion remained unchanged. Our study demonstrated DEPN had great potential as a stabilizer for food-grade Pickering emulsions.

A new analytical isotherm equation that can be applicable to water vapor-food systems was developed. The model describes the multilayer adsorption on energetically heterogeneous surfaces by assuming that the local isotherm for a specific site is given by the GAB isotherm, and the distribution of energetically different sites is represented by a generalized exponential function. The new isotherm was tested, using published experimental data. Results showed that the model provides an accurate and simple description of the adsorption characteristics for heterogeneous adsorbents.

Gels are viscoelastic systems built up with a liquid phase entrapped in a three-dimensional network, which can behave as carriers for bioactive food ingredients. Many attempts have been made to design gel structures in the water phase (hydrogels, emulsion gels, bigels) or oil phase (organogels, bigels) in order to improve their delivery performances. Hydrogels are originated from proteins or polysaccharides, which are suitable for the delivery of hydrophilic ingredients. Organogels are mainly built up with the self-assembling of gelator molecules in the oil phase, and they offer good carriers for lipophilic ingredients. Emulsion gels and bigels, containing both aqueous and oil domains, can provide accommodations for lipophilic and hydrophilic ingredients simultaneously. Gel structures (e.g. rheology, texture, water holding capacity, swelling ratio) can be modulated by choosing different gelators, modifying gelation techniques, and the involvement of other ingredients (e.g. oils, emulsifiers, minerals, acids), which then alter the diffusion and release of the bioactive ingredients incorporated. Various studies have proved that gel-based delivery systems are able to improve the stability and bioavailability of many bioactive food ingredients. This review provides a state-to-art overview of different gel-based delivery systems, highlighting the significance of structure–functionality relationship, to provide advanced knowledge for the design of novel functional foods.