ABSTRACT
Background: Stevia leaves a residual flavor at moment of being consumed, and its sweet taste remains little time, whereby, encapsulation is an option to mitigate these problems. Objective: Evaluate the double emulsion system followed by complex coacervation in stevia encapsulation. Methods: The effect of the concentration of the sweetener was determined (3.5; 5; 7.5 and 10% p/p) as well as the concentration of the wall material (2.5 and 5% p/p), on the morphology, capsules size, and encapsulation capacity. The double emulsion was prepared, the coacervate was formed, and then capsules were lyophilized. The morphology and capsule size were measured before and after lyophilization by optical microscopy. From Fourier´s infrared transformed spectrometry, encapsulation capacity was analyzed. Water activity and solubility were measured in lyophilized capsules. Results: Micro and nanocapsules (minimum size of 19.39 ± 0.74µm and 62.33 ± 6.65µm maximum) were obtained. Micrographs showed that the encapsulation technique used, allows obtaining dispersed stevia capsules and those of round and homogeneous morphology. The encapsulation capacity was 84.37 ± 4.04%. The minimum value of water activity was 0.49 ± 0.01 and 17.65 ± 0.91% of solubility. Conclusions: An increased in encapsulation capacity was obtained when the highest concentration of the wall material was used. The capsule diameter increased as the sweetener concentrations increased. The formulation to 5% (p/p) of stevia and 5% (p/p) in wall material was associated with better controlled release of the sweetener, which allows establishing subsequent applications in which the sweet taste is prolonged and the stevia bitter taste concealed.
Antecedentes: La estevia deja sabor residual al ser consumida, y su sabor dulce permanece poco tiempo, por lo cual, la encapsulación es una opción para mitigar estos problemas. Objetivo: Se evaluó el sistema doble emulsión seguido por coacervación compleja en la encapsulación de estevia. Métodos: Se determinó el efecto de la concentración del edulcorante (3.5; 5; 7.5 y 10% p/p) y de la concentración del material de pared (2.5 y 5% p/p), en la morfología, tamaño de cápsulas, y capacidad de encapsulación. Se elaboró la doble emulsión, se formó el coacervado, y posteriormente, las cápsulas se liofilizaron. La morfología y el tamaño de las cápsulas, se midieron antes y después de la liofilización mediante microscopia óptica. A partir de espectrometría infrarroja de transformada de Fourier se analizó capacidad de encapsulación. En las cápsulas liofilizadas se midió actividad de agua y solubilidad. Resultados: Se obtuvieron micro y nanocápsulas (tamaño mínimo de 19.39±0.74µm y máximo 62.33±6.65µm). Las micrografías indicaron que la técnica de encapsulación usada, permite obtener cápsulas de estevia dispersas y de morfología redonda y homogénea. La capacidad de encapsulación fue 84.37±4.04%. El valor mínimo de actividad de agua fue 0.49±0.01, y solubilidad de 17.65±0.91%. Conclusiones: Se obtuvo incremento en la capacidad de encapsulación cuando se utilizó la mayor concentración del material de pared. El diámetro de las cápsulas aumentó a medida que se incrementaron las concentraciones del edulcorante. Se concluyó que la formulación a 5% (p/p) de edulcorante y de 5% (p/p) en material de pared fue el tratamiento que mejor se asocia a una liberación controlada de estevia, lo cual permite establecer posteriores aplicaciones en las que se prolongue el sabor dulce y enmascare el sabor amargo de la estevia.
Subject(s)
Humans , Stevia , Sweetening Agents , Capsules , EmulsionsABSTRACT
Objective: In order to improve the stability of grape polyphenols and strengthen slow-release effect, the study on micro- capisulazed grape polyphenols was carried out through the complex coacervation method using porous cornstarch as core material carrier. Methods: With the embedding rate as main index, the effect of all factors on the microencapsulation of grape polyphenols was investigated through the single factor test and orthogonal test, and its preparation technology was also optimized. Results: The best preparation technology was as follows: The experiment materials were 10 mL grape polyphenols solution of 25 mg/mL, 1.5 g porous cornstarch, 30 mL sodium alginate solution of 0.03 g/mL, 50 mL chitosan solution of 0.01 g/mL, and 50 mL calcium chloride solution of 0.05 g/mL, at pH value of 3.5. The microcapsules' appearance was superior with size distribution of the main in 600-850 μm, the embedding rate was 83.2%, and they had very good releasing property in simulated gastric and simulated intestinal environment. Conclusion: The product appearance and embedding rate of grape polyphenols microcapsules which used porous cornstarch as core material carrier and sodium alginate-chitosan as wall materials are better than those only used sodium alginate and chitosan as wall materials. Furthermore, the inclusion complex is proved to be successfully prepared by its structural characterization which is gotten from FTIR and scanning electron microscope (SEM).
ABSTRACT
BACKGROUND:Compared with conventional medications, drug micro-capsule system can control the release of drugs and have wel target properties and biocompatibility. The drugs can be concentrated at the focus and play an important role in clinic. OBJECTIVE:To prepare dacarbazine magnetic micro-capsules with different capsule materials and gelatin complex by coacervation, and to optimize capsule materials and preparation process. METHODS:Fe 3 O 4 RESULTS AND CONCLUSION:The solution complex coacervation method was better than the emulsion coacervation method. As for the solution complex coacervation method, the optimal capsule material was gelatin-sodium alginate, with drug embedding rate 37.90%, the yield rate 72.31%, and the average magnetization intensity 8.53 emu/g. The second material was gelatin-chitosan. As a capsule material, the gelatin was better than chitosan with single coagulation method. Drug embedding rate was 51.58%, the yield rate was 64.50%, and the average magnetization was 6.93 emu/g. Single coagulation method was better than coacervation method. complex coacervation, we prepared the gelatin-Arabic gum magnetic micro-capsule, gelatin-sodium alginate magnetic micro-capsules, gelatin-sodium carboxymethyl cel ulose magnetic micro-capsules, and gelatin-chitosan magnetic micro-capsules. With the emulsion complex coacervation method, we further prepared the gelatin-Arabic gum magnetic micro-capsule, gelatin-sodium alginate magnetic micro-capsules, gelatin-sodium carboxymethyl cel ulose magnetic micro-capsules, and gelatin-chitosan magnetic micro-capsules. The magnetic gelatin micro-capsules and magnetic chitosan micro-capsules were prepared with single coagulation method. The micro-capsules were determined for the embedding rate, the magnetic susceptibility, the micro-capsule size and the release performance, to define the optimal preparation technology of dacarbazine magnetic micro-capsules.
ABSTRACT
Complex coacervation is defined as associative interactions between oppositely charged functional groups of proteins and polysaccharides, which on separation, form a phase rich in polymeric compounds in equilibrium with another aqueous phase. So coacervates are macro-ionic hydrated complexes of two charged neutralized bioploymers. Voorn and Overbeek developed the first model on complex coacervation by applying Flory-Huggins theory for random mixing of polyions. Alternatively, Veis and Aryani proposed that initially charged pair of symmetrical aggregates forms, followed by phase separation, for modeling diverse range of aggregates. Physicochemical properties such as pH, ionic strength, ratio of protein to polysaccharide, polysaccharide and protein charge, and molecular weight, mechanical properties (shear force) and temperature affect the formation and stability of coacervates. Improved structural, rheological, interfacial and delivery properties of these complexes than individual biopolymer can be exploited in numerous domains. This article intends to elucidate the salient features of coacervates which may contribute to better understanding of protein-polysaccharide systems, for their application in foods, cosmetics, pharmaceutical, and medicine.