Elsevier

Food Hydrocolloids

Volume 27, Issue 2, June 2012, Pages 487-493
Food Hydrocolloids

N,N,N-trimethyl chitosan nanoparticles as a vitamin carrier system

https://doi.org/10.1016/j.foodhyd.2011.09.002Get rights and content

Abstract

There is considerable interest in incorporating stabilized vitamins into biopolymeric nanoparticles, especially in the development of carriers and active systems for pharmaceutical and food applications. Amongst biopolymer, chitosan is highly desirable owing to its good biocompatibility, biodegradability and ability to be chemically modified. In this paper, nanoparticles from three kinds of water-soluble derivative chitosan (N,N,N-trimethyl chitosan, TMC) have successfully been synthesized by ionic gelation with tripolyphosphate (TPP) anions. Combinations of concentrations of TMC and TPP have resulted in nanoparticles with varying sizes for which the capability for loading with vitamins was investigated. Zeta potential measurement and particle size analysis demonstrated that the size of the nanoparticles was optimized (196 ± 8 nm) when the lowest TMC and TPP amounts were used, i.e., 0.86 mg mL−1 and 0.114 mg mL−1 respectively. As the TMC and/or the TPP concentrations increase, the resulting size of the nanoparticles increases considerably. Three different vitamins (B9, B12 and C) were tested as additives and the final system characterized in relation to size, morphology, spectroscopic and zeta potential properties. In general, the incorporation of vitamins increased all the TMC–TPP original nanoparticle sizes, reaching a maximum diameter of 534 ± 20 nm when loaded with vitamin C. The presence of vitamins also decreases the zeta potential, with one exception observed when using vitamin C. The preliminary results of this study suggested that all TMC/TPP nanoparticles can be successfully used as a stable medium to incorporate and transport vitamins, with potential applications in foodstuffs.

Graphical abstract

Highlights

► Trimethyl chitosan/TPP nanoparticles have spherical shape and size near 196 nm. ► Entrapment of vitamins C, B9 and B12 increases the nanoparticles size. ► Solid-state spectroscopy attests the crosslinking in nanoparticle/vitamin system. ► Trimethyl chitosan/TPP/vitamin is a stable system. ► Cast nanoparticles film displays regular distribution over polar glass surface.

Introduction

N,N,N-trimethyl chitosan (TMC) is a cationic polyelectrolyte obtained by extensive methylation of chitosan parent polymer (de Britto & Assis, 2007a). The resulting derivative is a water-soluble polysaccharide useful for a variety of applications and particularly suitable for nanoparticle processing (Xu, Du, Huang, & Gao, 2003). TMC is a non-toxic and biocompatible polymer from which particles with sizes in the range of 100–200 nm can be easily obtained via an ionic gelation process, using sodium tripolyphosphate (TPP) as a counterion. For these, efficiencies of up to 90% can be attained to drug entrapment, according to the analysis of bovine serum albumin as a model drug, as performed by Xu et al. (2003). Several others applications have emerged for TMC nanoparticles including a nasal and oral vaccine delivery system (Slütter & Jiskoot, 2010), protein carrier (Luo, Zhang, Cheng, & Wang, 2010), insulin controlled release (Sadeghi et al., 2008) and applications as a food additive (Chen & Subirade, 2005).

Particularly in foodstuffs, the use of edible nanoparticles as a carrier or release system has many potential applications (Matalanis, Jones, & McClements, 2011). Flavors, antioxidants, enzymes, antimicrobials and vitamins are able to be encapsulated or immobilized on nanoparticles, thus retaining activity. Vitamins, for example, are sensitive and unstable compounds that lose their functionality when exposed to inappropriate temperatures, oxygen, light or humidity (Ottaway, 1993). The encapsulation of vitamins may partially help to reduce some of these limitations, thus providing a prolonged shelf life and stability in a foreign medium. Encapsulated vitamins have particularly interesting applications as nutritional supplements for the enrichment of processed products in certain foods. In beverages for example, the encapsulation can act positively in masking the flavor of the vitamins and minerals, providing a tastier product for consumers (Chen & Wagner, 2004). Nanoparticles can also be associated with a polymeric matrix, providing an alternative way to fortify coatings or edible films thus envisaging the development of active packaging (Coma, 2008, Garcia et al., 2010, Imran et al., 2010, Kerry et al., 2006, Sekhon, 2010). The incorporation of nutrients in food employing nanoparticles is undoubtedly emerging as one of the fastest growing technologies in the alimentary field with potentially many applications. However the control of nanoparticle processing parameters and ensuring reproducibility still require further development.

The purpose of the present study was to produce TMC chitosan-based nanoparticles with controllable sizes by TPP crosslinking and then evaluate the loading efficiency of these nanoparticles with vitamins. The resulting structure of these nanoparticles was analyzed by solid-state 13C NMR spectroscopy and by Fourier Transform Infrared techniques. The morphological characterization was carried out by Atomic Force Microscopy and Scanning Electron Microscopy. In addition the stability of the nanoparticles was evaluated through zeta potential analysis.

Section snippets

Materials

Sodium tripolyphosphate (TPP) and medium molecular weight chitosan (80% deacetylated) were purchased from Aldrich Chemical Company Inc. (USA), and used as delivered. Dimethylsulfate was obtained from Vetec (Brazil) and the other chemicals from Synth (Brazil). Vitamins of pharmaceutical grade were acquired in a local drugstore with following specifications, according to the manufacturer: vitamin C, white powder, assay = 99%, heavy metal < 10 ppm, ash = 0.03%, oxalic acid < 0.3%; vitamin B9

Results and discussion

According to Agnihotri, Mallikarjuna, and Aminabhavi (2004), drug loading in micro/nanoparticulate systems can be attained by two basic methods: i) by incorporation, in which charge is carried during the preparation of the particles and ii) by incubation, in which the charge is carried after the formation of the particles. In the first methodology, the drug is dissolved or dispersed into the polymer solution, being physically entrapped into the matrix during the particle formation. In the

Conclusions

In the preparation of TMC–TPP nanoparticles, the smallest particle size distribution (196 nm) was obtained when the combination of the lowest TMC and TPP ratio was used. The concomitant decrease in zeta potential for the addition of high concentration of TPP is understood in terms of the neutralizing effect of two opposite charged species (TMC and TPP). The incorporation of vitamins C, B9 and B12 into nanoparticles was confirmed either by particle size, zeta potential and spectroscopic

Acknowledgments

The authors are grateful to FINEP/MCT, Embrapa (Rede AgroNano), and Brazilian research financing institutions FAPESP, CNPq and CAPES for their financial support.

References (28)

Cited by (95)

  • Nanocellulose hybrid systems: Carriers of active compounds and aerogel/cryogel applications

    2022, Nanocellulose Materials: Fabrication and Industrial Applications
View all citing articles on Scopus
View full text