Preparation and optimization of submicron chitosan capsules by water-based electrospraying for food and bioactive packaging applications

ABSTRACT

In the present study, a well-defined set of chitosans, with different degrees of acetylation (DA) and degrees of polymerization (DP), were processed by solution electrospraying from a water-based solvent. The solution properties, in terms of surface tension, conductivity, viscosity, and pH, were characterized and related to the physico-chemical properties of the chitosans. It was observed that both DA and DP values of a given chitosan, in combination with biopolymer concentration, mainly determined solution viscosity. This was, in turn, the major driving factor that defined the electrosprayability of chitosan. In addition, the physico-chemical properties of chitosans highly influenced solution conductivity and results indicated that the chitosan solutions with low or low-to-medium values of conductivity were the most optimal for electrospraying. The results obtained here also demonstrate that a good process control can be achieved by adjusting the working conditions, i.e. applied voltage, flow-rate, and tip-to-collector distance. Finally, it was also shown that electrosprayability of chitosan with inadequate physico-chemical properties can be improved by solution mixing of very different kinds of this polysaccharide. The resultant electrosprayed submicron chitosan capsules can be applied for encapsulation of food additives and to develop bioactive coatings of interest in food packaging, where these particles alone or containing functional ingredients can be released from the package into the food to promote a health benefit.

KEYWORDS:

• Chitosan
• degree of acetylation
• degree of polymerization
• electrospraying
• bioactive packaging

Acknowledgements

This research was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) project AGL2015-63855-C2-1-R. Sruthi Sreekumar wants to thank the German Academic Research Council for her doctoral scholarship. Sruthi Sreekumar and Philipp Lemke also acknowledge the Short Term Scientific Mission (STSM) program of European Cooperation in Science and Technology (COST) Action MP1206 for financial support during their stay at IATA-CSIC, Valencia.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the European Commission [COST Action MP1206];Spanish Ministry of Economy and Competitiveness (MINECO) [Project AGL2015-63855-C2-1-R].