The stabilization and release performances of curcumin-loaded liposomes coated by high and low molecular weight chitosan

A comprehensive stability evaluation for curcumin-loaded liposomes (Cur-LP) coated by low (LCS) or high (HCS) molecular weight chitosan with three gradient concentrations (L: low; M: medium; H: high) was the main objective of this study. Apart from leading to a higher encapsulation efficiency (>90%), all chitosan-coated Cur-LP displayed an improved stability with respect to resistant to salt, sunlight, heat, accelerated centrifugation and long-term storage at 4 °C. Increasing the molecular weight and concentration of chitosan could effectively improve the stability of Cur-LP, in which HCS-H coatings displayed the best performance. According to the fluorescence probe analysis, the mechanical reinforcement of liposomes and the concomitant reduction in membrane fluidity accounts for the major contribution to vesicle stability. Secondly, a simulated digestion model was used to prove the applicability of sustained curcumin release, achieved by adjusting the molecular weight and concentration of the chitosan stabilizer for Cur-LP. The results of this study show that high molecular weight chitosan used at relatively high concentrations, is a promising coating material for improving the stability and sustained release of Cur-LP in vitro

High-internal-phase emulsions (HIPEs) for co-encapsulation of probiotics and curcumin : enhanced survivability and controlled release

Synergistic biological activities of probiotics and curcumin can be achieved based on the gut-brain axis. However, it is still a challenge for utilizing both of them in actual food products due to their high sensitivity to environmental conditions. In the present study, high-internal-phase emulsions (HIPEs) were fabricated to co-encapsulate the probiotics and curcumin in response to the customer demand for convenience. beta-Lactoglobulin-propylene glycol alginate composite hydrogel particles (beta-lgPPs) with proper size and intermediate wettability were prepared at beta-lg to PGA mass ratio of 2 : 1 and employed as particulate emulsifiers. Stable HIPEs with a fixed oil fraction (phi = 0.8) could be formed within a wide range of beta-lgPPs concentrations, ranging from 0.1 to 2.0 wt%. Confocal laser scanning microscopy (CLSM) images indicated that the interfacial structure of the oil droplets was composed of both beta-lg nanoparticles and a PGA network, which jointly contributed to the gel-like structures in HIPEs. An increase in elasticity and gel strength, as well as centrifugal stability, could be achieved by elevating the particle concentration as determined by diffusing wave spectroscopy and Lumisizer analysis. HIPEs with high particle concentrations showed a high resistance against pasteurization since no obvious flocculation or coalescence could be observed in these emulsions. HIPEs also provoked a significant reduction in the death of LGG as well as the chemical degradation of curcumin: up to 7.91 log CFU cm(-3) of LGG and 93.0% of curcumin were retained after pasteurization treatment. Moreover, the HIPEs could also retard the release of curcumin and protect the LGG in simulated gastrointestinal tract conditions. The results from this work provide useful information for developing a promising delivery system for the co-encapsulation of curcumin and probiotics