EFFECT OF GELLED INNER AQUEOUS PHASE RHEOLOGY ON THE COLOUR DEGRADATION OF MUITLE AQUEOUS EXTRACTS INCORPORATED INTO WATER-IN-OIL-IN-WATER DOUBLE EMULSIONS

The aim of this work was to study different W1/O/W2 double emulsions in preserving color muitle aqueous extract (MAE), for which the work was divided into two fold, formulation and analysis of primary emulsion W1/O and W1/O/W2 double emulsions. Sodium alginate (SA), xanthan gum, guar gum, locust bean gum were used as gelling agents of MAE, and it was found that SA produced inner aqueous phase with enhanced viscoelastic properties, resulting in a W1/O primary emulsion with more uniform mean droplet size and distribution than when using the other gelling agents or ungelled MAE. Subsequently W1/O/W2 double emulsions were produced containing MAE gelled with SA or ungelled in the inner aqueous phase stabilized using pure gum Arabic (GA) or a blend of GA-mesquite gum (MG) in a 70:30 ratio in the outer aqueous phase. The double emulsion formulated with gelled MAE and 70:30 GA-MG blend exhibited more uniform mean inner water and outer oil droplet sizes, and protected best the anthocyanins contained in MAE to preserve its color when exposed to 8 h sunlight, providing a half-time life (t1/2) of 55.23 h. The double emulsion formulated with ungelled MAE and stabilized with pure GA displayed a t1/2 of 7.40 h. Keywords: double emulsions, muitle aqueous extract, gelling agents, viscoelastic properties, droplet size, half-time life

Synthesis, Controlled Release, and Stability on Storage of Chitosan-Thyme Essential Oil Nanocapsules for Food Applications

The nanoencapsulation of thyme essential oil has been greatly important in food science, given its remarkable antioxidant and antimicrobial capacity. However, its analysis in storage has not been established in terms of physical stability, antioxidant capacity, and release studies. In this paper, chitosan-thyme oil nanocapsules were prepared by the ionic gelation method. These were characterized for differential calorimetry, release kinetic, and infrared spectroscopy. The chitosan-thyme oil nanocapsules were stored at 4 and 25 °C for 5 weeks, the changes in particle size, zeta potential, stability (diffuse reflectance), and antioxidant capacity were analyzed and associated with nanocapsules’ functionality. The results show that the storage time and temperature significantly modify the particle size (keeping the nano-size throughout the storage), the release of the bioactive was Fickian with t0.193 according to Korsmery & Peppas and best described by Higuchi model associated with changes in the zeta potential from 8 mV to −11 mV at 4 °C. The differential scanning calorimetry and infrared spectroscopy results confirm the good integration of the components. The antioxidant capacity revealed a direct relationship with residual oil concentration with a decrease in the ABTS test of 15% at 4 °C and 37% at 25 °C. The residual bioactive content was 77% at 4 °C and 62% at 25 °C, confirming nanoencapsulation effectiveness. The present investigation provides helpful information so that these systems can be applied in food conservation

pH-indicating properties and storage stability of a smart edible film based on nopal-mucilage/gellan gum and red cabbage anthocyanins

Nopal mucilage is a complex polysaccharide with great potential in the preparation of the films to food packaging. In this work, was develop a smart edible film with pH-indicating capabilities based on nopal mucilage, gellan gum, and red cabbage anthocyanins (70:20 w/w, and 10% respectively). Physical properties, appearance, and colorimetric functionality were characterized to pH range 2.5-5.9. Color stability, measured by CIELAB, was tested with different storage conditions and time and interpreted by differential tristimulus colorimetry. Results showed films whit uniform appearance, flexibility, easy-handling, and excellent color response within the pH range studied. The evolution of color difference (ΔE*ab) confirmed that the colorimetric functionality of films was stable at short storage periods (8 days) under natural conditions of sunlight and oxygen exposure, while a more extended storage period was affected. Results showed that the film is an excellent barrier and presents color changes triggered by pH changes

Diseño de una estructura intersticial para una emulsión de aceite de semilla de uva mediante diseño de experimentos y respuesta superficial

12 páginasAn interstitial structure was designed to prepare a mini (nano) - emulsion of grape seed oil; the interface was composed of surface active molecules (biopolymers and surfactants) to produce the mini (nano) - emulsion by interfacial deposition of oil by displacement of acetone from the dispersed phase. Design of Experiments of mixes and Respond Surface was used to determine the best formulations for the system: F1, Surfactants: Tween 20, T, (0.68%), Dimodan, D, (0.317%) and Panodan, P, (0.0013%) and F2, Polymers system: Gum Arabic, GA, (0.029%), Maltodextrin, MD, (0.115%) and whey protein concentrate,WPC, (0.187%). The proposed formulation was prepared considering the lowest value of surface tension for surfactants and the highest value for the polymers system. A leptokurtic size distribution was obtained for the interstitial structure, prepared with a stirring rate of 10000 rpm and resulting in an average diameter of 0.185 µm and a Z -potential of -18.23 mV. The emulsion was prepared using this structure and resulting average size and Z-potential values were 0.188 µm and -18.55 mV respectively. These results were not significantly different from those of the interstitial structure and therefore, it was concluded that the final composition of the emulsion and preparation procedure were adequate.Se diseñó una estructura intersticial para preparar una mini (nano) - emulsión de aceite de semilla de uva; la interfase estaba compuesta por moléculas tensioactivas (biopolímeros y surfactantes) para producir la mini (nano) - emulsión por deposición interfacial de aceite por desplazamiento de acetona de la fase dispersa.Se utilizó Diseño de Experimentos de mezclas y Respond Surface para determina

EFECTO DE BOQUILLAS NEUMATICAS DE DOS FLUIDOS EN LASCARACTERÍSTICAS DE ESTABILIDAD DE LAS EMULSIONES ELABORADASCON MÉTODO DE ALTA ENERGÍA (MICROFLUIDIZACIÓN)

16 páginasThe atomization of oil in water emulsions is used in the food industry such as in the preparation of capsules, films and coatings among others. However, the passage through the atomization devices could have an influence on the properties of the emulsion and, consequently of the final product. In the present work, it was evaluated the influence of two fluid nozzles of different dimensions on stability parameters of oil in water emulsion produced by microfluidization and using gum Arabic as wall material. Results indicated that the droplet size, the polydispersity index and the Turbiscan stability index of atomized emulsions were affected by and Oswald ripening mechanism as compared with those of the original emulsion. The confocal laser scanning microscopy images confirmed that the passage of the emulsion through the atomization devices decreased the thickness of wall material of the droplets with respect to the original emulsion. It was concluded that, in the proper design of the final products prepared by atomization it must be considered its effect on the stability of the atomized emulsions by including during the processing, a suitable sampling-characterization on-line schem