Rheology of emulsion-filled alginate microgel suspensions

Abstract

Emulsion filled polysaccharide gels can be used as carrier systems of lipophilic bioactives in the food, pharmaceutical and cosmetics industry. This carrier system can exist either as bulk or discrete gel systems. In this study the rheological properties of discrete emulsion filled alginate microgel suspension was examined as a function of volume fraction () and oil content. Fine emulsion (220 nm) was encapsulated within alginate microgels (mean size 36.2-57.8 m) by using the impinging aerosol technique. The microgels (containing 0-77% w/w oil total solids basis) produced were estimated to have particle modulus in the range of 150-212Pa. An increase in oil content in the microgels led to more deformable microgels due to the reduction in gel density. The deformability of microgels influenced the bulk modulus and apparent viscosity of the concentrated suspension. At the same suspension volume fraction (), suspensions with more deformable microgels exhibited a lower bulk modulus. We also showed that the Carreau and Cross models were adequate in predicting the flow behaviour of the concentrated emulsion filled microgel suspension.

Stability and rheological behavior of coconut oil-in-water emulsions formed by biopolymers

“…The Carreau and Cross models, which describe the pseudoplastic behavior of suspensions, were used to model the flow curves of the emulsions evaluated. These models are useful for predicting apparent viscosity over a wide shear rate range [27] , in contrast to the power law model that was also used in this work. The parameters obtained by these models are shown in Table 1.…”

Air Extrusion System for Ionotropic Alginate Microgel Particle Formation: A Review

“…Despite alginate microgels of irregular shape are produced by the spray evaporation method, the impinging aerosols method, and the rehydration of spray‐dried alginate particles method, they can generate microgels at high throughput rates, up to 10 kg h −1 82 and at low cost. The production rate of these methods is mainly limited by the capacity of the spraying chamber.…”

“…Therefore, they are suitable for industrial applications in the manufacturing of agricultural, food, and household products where the size distribution and sphericity of the microgels are less emphasized 74. Among the three gelation methods, the impinging aerosols system appears to be the most promising system that features a simple setup with devices having few moving parts, which is safe and has a low maintenance cost 72, 82. The system can be operated as a continuous production process, with user‐friendly operating procedures, i.e., less complexity, and variable operating parameters to suit various production requirements 72, 82.…”

“…Among the three gelation methods, the impinging aerosols system appears to be the most promising system that features a simple setup with devices having few moving parts, which is safe and has a low maintenance cost 72, 82. The system can be operated as a continuous production process, with user‐friendly operating procedures, i.e., less complexity, and variable operating parameters to suit various production requirements 72, 82. Moreover, the system capability to encapsulate a wide range of bioactive materials with different characteristics has been proved 72, 82.…”

“…The system can be operated as a continuous production process, with user‐friendly operating procedures, i.e., less complexity, and variable operating parameters to suit various production requirements 72, 82. Moreover, the system capability to encapsulate a wide range of bioactive materials with different characteristics has been proved 72, 82. Materials produced to date include hydrophobic and hydrophilic drugs 20, 23, 72, viable probiotics bacteria 4, 28, 72, low‐molecular‐weight and pH‐sensitive proteins 24, 29, 72, and oil emulsions 18, 72.…”