| Curcumin was a type of hydrophobic plant polyphenol having many functionalproperties, such as, antioxidant, anti-tumor and so on. Its application in the food is limitedby poor solubility and low bioavailability. Polysaccharides are the most commonly usedmaterial for the fabrication of a nanocarrier system to improve the bioavailability ofhydrophobic functional ingredients. In this research, curcumin nanoparticles was preparedby the complexation of polyelectrolytes, that is, chitosan and gum Arabic to enhance thesolubility and bioavailability of this pigment. The key factors involved, which influencethe complexation, were studied. On the basis, the formulation to prepare nanoparticles wasoptimized. Additionally, physicochemical properties of prepared nanoparticles were alsostudied for better understanding and its potential application in the food industry.pH, mass ratio and concentration of polymers all have direct effect on the interactionbetween these two polysaccharides. Turbility, size distribution, Zeta potential andfluorescence probe―pyrene‖studies were used to indicate the interaction process. At themass ratio of1:1and pH4.0, the size distribution of the complex was most concentratedwhile the Zeta potential was higher than30mV. The fluorescence intensity I1/I3variedfrom0.95to1.10. The value was much smaller than that in water, which suggested theformation of hydrophobic shell. The polymers concentration also had direct influence onthe particle size of nanocomplex. Higher the concentration, the larger was average particlesize and stronger was the complexion.Nanoparticless of varying droplet sizes were prepared by adjusting the polymerconcentration and their bioavailability was compared. Results showed that thebioavailability of encapsulated curcumin was improved. On the other hand, bioavailabilityhad a negative correlation with the particle size. After polysaccharides addition, particlesize increased. On the other hand, polymers have ability to prevent the particlesaggregation. Based on the storage stability results, the optimal conditions were determinedas follows: mass ratio of Tween80and phospholipid was1:1, added amount of curcuminwas4%of polysaccharide, total amount of small molecular weight emulsifier was10timesof curcumin weight. Under these process condition and formulation parameters, theaverage particle size of complex reached to260~280nm, polydispersity index0.270whilethe encapsulation efficiency of curcumin was about85%. The particle size distributionremained stable and the retention rate was about70%after storage of one month. TheFTIR analysis confirmed the formation of complex. The X-ray diffraction resultsdemonstrated that the exsisting state of curcumin transformed from crystal form toamorphous state.The physicochemical properties of nanoparticles were also studied. Results suggestedthat this type of nano-carrier could increase the solubility of curcumin to7000times. Therehydration property of the lyophilized nanoparticles was best when sugar was added as acryoprotectant. Particle size increased and dispersed well in water after being lyophilized.Meanwhile, the light stability and antioxidant property were also enhanced. After being digested in the simulated gastric fluid for3h, the release rate of curcumin was10%, Therelease mechanism matched the Ritger-Peppas model. The n value was0.7774, whichshowed collaboration of Fickian and dissolution diffusion. The release rate reached to75%in simulated intestinal fluid for6h, and the release mechanism matched first order kineticmodel, which showed this kind of wall material had good intestinal positioning releaseproperty. The influence of sterilization methods on particle stability were compared in thisstudy. They were pasteurization, UHT and autoclaving. Results showed that autoclavinghad the greatest influence on the particle size stability while pasteurization has the leasteffect on size distribution and the total amounts of curcumin. UHT has the least influenceon encapsulation efficiency. |
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