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 antimicrobial additive in powder. Different formulations containing alginate and modified starch (Capsul®) as encapsulating agents (1% and 3% w/w, respectively) and maltodextrin as a wall material at different concentrations (varied from 1:1–1:4 Citral:Maltodextrin) were prepared. The powders were evaluated for physical and antimicrobial properties against Escherichia coli to obtain a natural antimicrobial food additive. Citral:Capsul:Maltodextrin powders obtained by spray‐drying showed the best physical properties, considering encapsulation yield (EY) (75%–80%), encapsulation efficiency (EE) (~78%), and particle size (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%, EE ~70%, particle sizes between 80 and 1250 μm, and a higher percentage of rehydration for antimicrobial activity (2.5%–4% w/w). An increase in maltodextrin concentration led to a decrease in %EE, an increase in particle size, and the powder concentration required to inhibit microbial growth. Therefore, the formulation 1:1:1 Citral:Capsul:Maltodextrin showed by spray‐drying showed the best characteristics to obtain a natural antimicrobial additive.