Effects of surfactants on the functional and structural properties of kudzu (Pueraria lobata) starch/ascorbic acid films

The aim of this research was to evaluate the effects of surfactants (span 80, tween 20 or the blend of above surfactants at the ratio of 1:1) on the properties of kudzu starch/ascorbic acid films. Each surfactant decreased surface tension of the film-forming solution and delayed the release of ascorbic acid from film to water. Tween 20 improved the wettability of film-forming solutions on both glass and paraffin wax substrates, and promoted the formation of V-type crystal in the films. The film's surface morphology was different depending on the surfactant types. The film containing only tween 20 showed higher flexibility. water content and solubility, lower mechanical strength, and comparable water vapor permeability when compared with the film containing only span 80. The film adding blended-surfactant was not only without better morphology, wettability and mechanical properties but had the worst water barrier ability as regarding the film containing single surfactant. (C) 2011 Elsevier Ltd. All rights reserved.