Complex Coacervation Of Gelatin Research Articles

Rapeseed oil as the extraction solvent motivates fucoxanthin-loaded high internal phase emulsion preparation for food 3D printing

Fucoxanthin (FX), a non-provitamin A carotenoid pigment, is a well-known natural antioxidant contained in brown algae. The present study deals with an ultrasonic-assisted FX extraction process from Undaria pinnatifida with rapeseed oil as the solvent. Then, high internal phase emulsions (HIPEs) with the FX-rich rapeseed oil as the oil phase was constructed using a simple one-step method for food 3D printing. The FX-loaded HIPEs were stabilized by the gelatin (GE)-based microgel, which were prepared by GE complex coacervation with sodium alginate and transglutaminase cross-linking, for the improved delivery and stability of FX. FX-loaded HIPEs stabilized by 2 wt (wt)% GE-based microgel showed a small and uniform particle size and a stable microstructure. The HIPEs stabilized by 2 wt% GE-based microgel had the best FX stability (residual FX 84.81 ± 0.82%) and bioaccessibility (38.26 ± 1.21%). The excellent viscoelasticity, recovery rate and thixotropy of the HIPEs stabilized by 2 wt% GE-based microgel further confirmed the best 3D printing performance. Therefore, rapeseed oil as the extraction solvent motivates FX-loaded HIPEs preparation, and GE-based microgel concentration is crucial for 3D printing.

Preparation of β-ionone microcapsules by gelatin/pectin complex coacervation

β-ionone has a unique violet odor and good biological activity, which is an essential fragrance component and potential anticancer drug. In this paper, β-ionone was encapsulated using complex coacervation of gelatin and pectin, followed by cross-linking with glutaraldehyde. The pH value, wall material concentration, core-wall ratio, homogenization conditions, and curing agent content were investigated in the single-factor experiments. For example, the encapsulation efficiency increased with the homogenization speed, which reached a relatively high value at 13000 r/min for 5 min. The gelatin/pectin ratio (3:1, w/w) and pH value (4.23) significantly affected the size, shape, and encapsulation efficiency of the microcapsule. The fluorescence microscope and SEM were used to characterize the morphology of the microcapsules, in which the microcapsule has a stable morphology, uniform size, and spherical multinuclear structure. FTIR measurements confirmed the electrostatic interactions between gelatin and pectin during complex coacervation. Thermogravimetric analysis (TGA) revealed that the microcapsules could maintain good thermal stability over 260 °C. The release rate of β-ionone microcapsule was only 20.6 % after 30 days at the low temperature of 4 °C. These findings provide an effective carrier to deliver flavors like β-ionone and could be useful in the fields of daily chemicals and textiles.

Microencapsulation of vitamin D3 by complex coacervation using carboxymethyl tara gum (Caesalpinia spinosa) and gelatin A

Vitamin D3 plays a fundamental role in human health; however, it is highly susceptible to environmental conditions and the gastrointestinal tract. In this study, complex coacervates obtained from gelatin A and carboxymethyl tara gum (CMTG) were used as wall materials for the encapsulation of vitamin D3 (VD3). Zeta potential and turbidity measurements were employed to optimize the pH and ratio (gelatin A:CMTG), and the results showed that the ideal conditions for the complex coacervation were pH 4.0 and a 6:1 ratio. The encapsulation efficiency (EE) was determined as a function of the total concentration of biopolymers (TC%) and the core-to-wall ratio, and the greatest EE (80%) was achieved at a TC of 1% and a ratio of 1:2; spherical particles with an average size of 0.25 µm were obtained. The microencapsulation increased the thermal stability of VD3, and FTIR confirmed the presence of the biopolymers and VD3 in the capsules. An in vitro simulation showed a more pronounced release in the small intestine with a vitamin bioaccessibility of 56%. The encapsulation of bioactive lipophilic compounds by complex coacervates of gelatin A and CMTG resulted in improved stability and prolonged release during digestion.

Production of probiotic kefir fortified with encapsulated structured lipids and investigation of matrix effects by means of oxidation and in vitro digestion studies

The aim of the present study is to encapsulate structured lipids (SLs) by complex coacervation of gelatin and gum arabic with or without using transglutaminase enzymes and to develop a functional kefir product via the addition of encapsulated SLs in the form of suspension and freeze-dried coacervates. Encapsulated SLs were evaluated for their oxidative stability during 30 days of cold storage. The data showed that coacervate solutions were more sensitive to lipid oxidation compared to freeze-dried capsules. Traditionally produced kefir samples that were fortified with complex coacervation products were stored for 10 days at 4 °C. The pH values of the samples decreased, whereas titratable acidity consistently increased during the storage period. Moreover, an in vitro controlled release study was conducted with a fortified kefir sample containing freeze-dried capsules. According to the results, kefir had no significant matrix effect on oil release from the freeze-dried capsules (p > 0.05).

Encapsulation of structured lipids containing medium‐ and long chain fatty acids by complex coacervation of gelatin and gum arabic

AbstractIn this research, structured lipids (SLs) containing 78% of long‐chain fatty acids (FAs) at sn‐2 position and medium chain FAs at sn‐1,3 positions were encapsulated by complex coacervation method using gelatin and gum Arabic as wall materials in order to obtain protein–carbohydrate complexes. The objective of this study was to investigate the effects of experimental parameters such as wall material concentration (1–2%), core : wall ratio (1:1 and 2:1) and homogenization rate (7,400, 10,000, and 15,000 rpm) on encapsulation process of the SL. The highest microencapsulation efficiency (84.11 ± 0.77%) was obtained in gelatin 2% (w/v), gum arabic 2% (w/v), 1:1 core : wall ratio (w/w), and at 15,000 rpm homogenization rate. In addition, particle size for the coacervates ranged from 19 to 263 nm. Moreover, the samples had smaller polydispersity index (PDI) values, which mean that they showed homogeneous size distribution pattern. Besides, morphological characteristics and thermal behavior of the capsules were determined via scanning electron microscope (SEM) and differential scanning calorimetry (DSC), respectively.Practical applicationsStructured lipids (SLs) with medium chain fatty acids (MCFAs, C6‐C10) at sn‐1 and sn‐3 positions, and long chain fatty acids (LCFAs, C12‐C24) at sn‐2 position has gained attention for food, nutritional and clinical purposes. These SLs are generally designed for special health requirements and meet the daily requirements of fatty acids, especially the long‐chain polyunsaturated fatty acids (LCPUFAs) for their health‐enhancing and disease‐preventing properties. The addition of LCPUFAs into the product formulation may lead an increase in the stability problems of these fatty acids, thus appropriate technologies such as encapsulation of lipids should be implemented. Encapsulation technology enables SLs to be protected from possible detrimental effects of food processing and storage conditions. The use of encapsulation technology in conjunction with SL production are evolving and ongoing issues, hence there is only few studies in the literature that considered encapsulation of SLs.

Particle size characteristics of buriti oil microcapsules produced by gelatin-sodium alginate complex coacervation: Effect of stirring speed

ABSTRACTThe influence of hydrodynamic conditions in the coacervation medium of the carotenoid-rich buriti oil using gelatin-alginate as wall materials was investigated. The stirring speed had strong influence on the size of the microcapsules, and Reynolds number higher than 70000 resulted in particle size D[4,3] lower than 200 μm. The carotenoid encapsulation efficiency was around 80%, with freeze-dried particles presenting intense yellow color. Although the size of the microparticles was highly dependent on the hydrodynamic conditions during coacervate formation, complex coacervation of gelatin and sodium alginate showed to be a feasible process to producing buriti oil microcapsules.

Microencapsulation of tuna oil fortified with the multiple lipophilic ingredients vitamins A, D3, E, K2, curcumin and coenzyme Q10

Complex coacervates of gelatin and sodium hexametaphosphate (SHMP) was used to microencapsulate tuna oil fortified with the multiple functional lipophilic ingredients, vitamin A, D3, E, K2, curcumin and coenzyme Q10. An emulsion homogenization speed of 15,000 rpm for 15 min resulted in low surface oil content (0.08%), high encapsulation efficacy (99.84%) and encapsulation yield (96.59%), with a significantly enhanced oxidative stability index (6.23 h). The Fourier transform infrared spectra showed that there was no observable oxidation of the oil during microencapsulation. This study shows that microencapsulation using complex coacervation is suitable for stabilizing multiple bioactive lipophilic ingredients.

Study of Complex Coacervation of Gelatin A and Sodium Alginate for Microencapsulation of Olive Oil

Complex coacervation of gelatin A and sodium alginate was carried out to obtain the maximum coacervate yield. Turbidity and coacervate yield (%) measurements were carried out to support the ratio of the two polymers and pH that produced maximum coacervation. The optimum ratio between gelatin A-sodium alginate and pH to form the maximum coacervate complex was found to be 3.5:1 and 3.5–3.8, respectively. Olive oil microencapsulation was carried out at the optimized ratio and pH. Microcapsules were crosslinked by using glutaraldehyde. Scanning electron microscopy studies confirmed the formation of free flowing spherical microcapsules of different sizes. The size of microcapsules increased with the increase in the concentration of the polymer. The encapsulation efficiency and the release rates of olive oil were dependent on the amount of crosslinker, oil loading and polymer concentration. Thermogravimetric study revealed improvement of thermal stability with crosslinking. Fourier Transform Infrared Spectroscopy study showed that there was no significant interaction between olive oil and gelatin-alginate complex.

Comparisons of simple and complex coacervations for preparation of sprayable insect sex pheromone microcapsules and release control of the encapsulated pheromone molecule

With dodecanol (C12OH) as a model molecule of insect sex pheromone as core material, natural polymers gelatin (GE) and acacia gum (AG) as wall materials, microcapsules aiming to be a sprayable environment-friendly pesticide were prepared via GE simple coacervation and complex coacervation of GE and AG. C12OH encapsulation in complex coacervation was higher than those in simple coacervation. Its encapsulation was enhanced with increase in wall material cross-linking. C12OH release revealed that samples from simple coacervation reached their end in 7 days, whereas those from complex coacervation manifested a quick release followed by a constant release. With increase in wall material cross-linking, the release was slowed down. SEM observation confirmed that core-shell morphology existed in the capsules.

Microcapsules by Complex Coacervation for Electronic Ink

Electrophoretic TiO2 nanoparticles in a low dielectric medium can be utilized in non-emissive flexible display such as an electronic paper. To prevent the aggregation and to reduce the density of neat TiO2 nanoparticles, the surface of TiO2 particles was modified by acrylic copolymer. The surface modified TiO2 nanoparticles, which were dispersed in low dielectric oils, were encapsulated by the complex coacervation of gelatin and gum Arabic. Then, core-shell type microcapsules were eventually fabricated. The capsules were crosslinked by the reaction between glutaraldehydes and amino groups in gelatinto improve the durability of the microcapsules. These microcapsules were stable during vacuum drying and were easily layered on the surface of the ITO substrates because of their flexibility. A simple electrophoretic display cell was constructed and both the color change and the response time were monitored.

Study on the antimicrobial activities of the capsaicin microcapsules

AbstractIn this study, capsaicin microcapsules were prepared by the complex coacervation of gelatin, acacia, and tannins. The antimicrobial activities of these microcapsules on the common microorganisms of food preservation, Botrytis cinerea and Aspergillus niger, were investigated. The factors affecting their antimicrobial effects, including the microcapsule concentrations, pH values, and release behavior were also examined. The results showed that the optimum pH for the antimicrobial effect was about 5.0, which might be related to the strongest protein‐precipitating ability of tannins at this pH value. The inhibitory activity of the system originated from the synergistic actions of both capsaicin and tannins. The release behavior of the microcapsules had an important influence on the antimicrobial effect for the long shelf‐life storage of foods. The present study indicated that the capsaicin microcapsules displayed potential antimicrobial applications in the food storage. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1318–1321, 2006

Local Delivery of Interleukin-2 and Adriamycin is Synergistic in the Treatment of Experimental Malignant Glioma

Local delivery of adriamycin (ADR) via biodegradable polymers has been shown to improve survival in rats challenged intracranially with 9L gliosarcoma. Likewise, local delivery of interleukin-2 (IL-2) has been shown to extend survival in experimental brain tumor models. In the current study, we hypothesized that local delivery of ADR and IL-2 might act synergistically against experimental intracranial glioma. Polyanhydride polymers (PCPP-SA) containing 5% ADR by weight were prepared using the mix-melt method. IL-2 polymer microspheres (IL-2 MS) were produced via the complex coacervation of gelatin and chondroitin sulfate in the presence of IL-2. Sixty male Fisher 344 rats received an intracranial challenge with a lethal dose of 9L gliosarcoma cells. In addition, a group of rats were injected with either IL-2 MS or empty microspheres. Five days later they received ADR or blank polymer. There were a total of four treatment groups: (1) empty microspheres, blank polymer; (2) empty microspheres, ADR polymer; (3) IL-2 MS, blank polymer; and (4) IL-2 MS, ADR polymer. Compared to control animals treated with empty microspheres and blank polymer, animals receiving empty microspheres and ADR polymer (P < 0.0004), IL-2 MS and blank polymer (P < 0.0005), and IL-2 MS combined with ADR polymer (P < 0.0000002) all showed statistically significant improvement in survival. In addition, animals receiving the IL-2/ADR combination had significantly extended survival compared to either ADR or IL-2 alone (P < 0.000003 and P < 0.0004, respectively). Both ADR and IL-2, when delivered locally, are effective monotherapeutic agents against experimental intracranial gliosarcoma. The combination ADR and IL-2 therapy is more effective than either agent alone.

Nanoencapsulation of capsaicin by complex coacervation of gelatin, acacia, and tannins

AbstractUsing gelatin and acacia as wall and capsaicin as core substance, nanocapsules were prepared by mixing two solutions of oppositely charged polymers, and then treated by hydrolysable tannins. The morphology and size distribution of the nanocapsules were analyzed by transmission electron microscope and laser particle size analyzer, respectively. The nanocapsules had a mean diameter of 300–600 nm, with mean drug loading content (20.81%) and encapsulation efficiency (81.17%) with good dispersion and spherical morphology. The interaction between gelatin and tannins is discussed in the article. Moreover, the addition of hydrolysable tannins in the system had an important influence on the morphology and particle distribution of the nanocapsules because of the synergistic actions of hydrogen bonding and hydrophobic effects. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2225–2229, 2005

Microencapsulation of capsaicin by the complex coacervation of gelatin, acacia and tannins

AbstractWith gelatin and acacia as walls and capsaicin as the core substance, microcapsules were prepared through the mixing of two solutions of oppositely charged polymers and were then treated with tannins. The processing factors included the stirring rate and the types and dosages of the surfactants used in the preparation of the microcapsules. The morphology and size distribution of the microcapsules were analyzed with optical microscopy, environmental scanning electron microscopy, and laser particle size analysis. The microcapsules had a mean diameter of 20–30 μm, a maximal drug loading content of 19.84%, and an encapsulation efficiency of 88.21% with a good dispersion, even distribution, and round shape. The influence of the tannins on the morphology and structures of the microcapsules was also investigated, and their interaction mechanism was examined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2669–2675, 2004

Micro‐encapsulation by complex coacervation: influence of surfactant

AbstractParaffin oil has been encapsulated using complex coacervation of gelatin and Arabic gum in the presence of a surfactant. Addition of an oppositely charged surfactant to a polyelectrolyte markedly increases the yield of the process. We report a two‐layer encapsulation of paraffin oil, based on a primary layer of interface active polyelectrolyte–surfactant complex, followed by a second layer of the conjugate polyelectrolyte–polyelectrolyte complex. Surfactant concentration has been found to be a crucial parameter to obtain good quality microcapsules and optimal yield. This confirms the importance of formulation aspects when looking for optimization of these techniques of micro‐encapsulation.© 2003 Society of Chemical Industry

Influence of pH adjustment on microcapsules obtained from complex coacervation of gelatin and acacia.

The coacervation behaviour of commercial grade gelatin and acacia mixtures was studied with five different acids to adjust the coacervation pH, i.e. HCl, HNO3, H2SO4, acetic acid, and citric acid. The electrical equivalence pH value (EEP) of the polymer mixture was determined by means of a streaming current detector (SCD). With all acids--except H2SO4--maximum coacervate yield was observed at the EEP. Using H2SO4 the EEP was found at a lower pH value than compared with the point of maximum coacervate yield. The quantity of coacervate at the EEP was significantly reduced in the presence of H2SO4 whereas with all other acids, almost no differences were found. The dependence of the coacervate volume on the added amount of acid did not change in parallel to the dry coacervate yield and there was no coincidence of the maximum coacervate volume and the EEP. The barrier properties of the capsule shells of corresponding microcapsules using indomethacin as a model drug were examined by dissolution studies. Indomethacin microcapsules showed the slowest release rate when the coacervation pH was adjusted to the EEP and not to the pH of maximum coacervate yield. As expected from the coacervation behaviour, dissolution profiles of the microcapsules were quite similar even when different acids were used for pH adjustment.