Optimization of physical properties of xanthan gum/tapioca starch edible matrices containing potassium sorbate and evaluation of its antimicrobial effectiveness

Response surface methodology was applied to study the effect of different levels of tapioca starch (TS) and xanthan gum (XG) on physical properties of edible films supporting potassium sorbate (KS) with the goal of contributing to the development of edible matrices with controlled release of the antimicrobial. Mechanical properties, water vapor permeability (WVP), solubility in water (SW) and color attributes were evaluated on TS-XG based films. XG addition produced an increase of Young modulus (YM), stress at break (sigma(b)) and SW. It also raised the yellow index (YI) values and decreased the strain at break (epsilon(b)). Edible film formulation was optimized with the goal of maximizing YM and epsilon(b) and minimizing SW and YI. The film with the selected formulation resulted an effective antimicrobial barrier against Zygo-saccharomyces bailii external contamination and its sorptional behavior was highly influenced by XG presence. It can be concluded that developed matrices could act as an effective active film with potential applications for food preservation. (C) 2013 Elsevier Ltd. All rights reserved.