Citral encapsulation for an antimicrobial natural powdered-additive: Performance of wall material and drying process

Abstract

Citral encapsulation was analyzed by spray and freeze-drying to obtain an antimicrobialadditive in powder. Different formulations containing alginate andmodified starch (Capsul®) as encapsulating agents (1% and 3% w/w, respectively)and maltodextrin as a wall material at different concentrations (variedfrom 1:1–1:4 Citral:Maltodextrin) were prepared. The powders were evaluatedfor physical and antimicrobial properties against Escherichia coli to obtain anatural antimicrobial food additive. Citral:Capsul:Maltodextrin powders obtainedby spray-drying showed the best physical properties, considering encapsulationyield (EY) (75%–80%), encapsulation efficiency (EE) (78%), and particlesize (5–10 μm), and a higher microbial inhibition at a lower additive concentration(1.5%–2% w/w), independently of maltodextrin concentration used.Powders obtained by freeze-drying emulsions showed an EY 70%, EE70%, particle sizes between 80 and 1250 μm, and a higher percentage ofrehydration for antimicrobial activity (2.5%–4% w/w). An increase in maltodextrinconcentration led to a decrease in %EE, an increase in particle size, andthe powder concentration required to inhibit microbial growth. Therefore, theformulation 1:1:1 Citral:Capsul:Maltodextrin showed by spray-drying showedthe best characteristics to obtain a natural antimicrobial additive.