Alginate and gellan-based edible coatings as carriers of antibrowning agents applied on fresh-cut Fuji apples

Alginate (2% w/v) and gellan (0.5% w/v)-based edible coatings were formulated to study the effect of glycerol (G) and antibrowning agents (N-acetylcysteine and glutathione) on water vapor resistance (WVR). The ability of the coatings to carry antibrowning agents was investigated following color changes of coated fresh-cut Fuji apples. Selected formulations obtained by a response surface analysis were 1.5% G, 1% N-acetylcysteine and 0.63% G, 1% N-acetylcysteine for alginate and gellan, respectively. The addition of sunflower oil with essential fatty acids (omega 3 and omega 6) at 0.025%, 0.05%, and 0.125% w/v concentrations was also investigated in an attempt to improve the barrier properties of the alginate and gellan coatings for fresh-cut apples. The WVR increased significantly from 15.70 and 14.60 s/cm to 19.2 and 27.6 s/cm for alginate and gellan coatings with sunflower oil, respectively, in comparison with oil free coatings. The addition of sunflower oil in gellan was more effective than in alginate to increase the WVR of coated apples. Alginate and gellan-based coatings proved to be good carriers for antibrowning agents. (c) 2006 Elsevier Ltd. All rights reserved.