Effect of Oxidized Potato Starch on the Physicochemical Properties of Soy Protein Isolate-Based Edible Films

Sabina Galus1*, Andrzej Lenart1, Andrée Voilley2 and Frédéric Debeaufort2,3

Department of Food Engineering and Process Management, Faculty of Food Sciences, Warsaw University of Life Sciences-SGGW
 (WULS-SGGW), 159c Nowoursynowska St., PL-02-776 Warsaw, Poland

2EA 581 EMMA, AgroSup Dijon, 1 esplanade Erasme, University of Burgundy, F-21000 Dijon, France
3IUT-Dijon Department of Biological Engineering, 7 Boulevard Dr. Petijean, B.P. 17867, F-21078 Dijon cedex, France

Article history:

Received August 20, 2012

Accepted March 19, 2013 

Key words:
soy protein, oxidized starch, edible films, mechanical properties, water vapour permeability


The influence of oxidized starch on the physicochemical properties of cast soy protein isolate films is determined in this study. Films were cast from heated (70 °C for 20 min) alkaline (pH=10) aqueous solutions of 7 % soy protein isolate containing 50 % (by mass) glycerol as a plasticizer and different levels of added oxidized starch (0, 5, 10, 15, and 20 %, by mass). For all types of films, opacity, contact angle, tensile strength, elongation at break, water vapour permeability, measured at 25 °C for four relative humidity differentials (30–53, 30–75, 30–84 and 30–100 %), differential scanning calorimetry and microstructure were determined after conditioning film specimens at 25 °C and 30 % relative humidity for 48 h. Oxidized starch content significantly affected (p<0.05) tensile strength, from 0.95 to 1.51 MPa, temperature at maximum degradation rate from 64.8 to 74.2 °C and water vapour permeability from 1.08·10–10 to 3.89·10–10 g/(m·Pa·s) at relative humidity differentials of 30–50 and 30–100 %, respectively. Various internal arrangements were observed as a function of film composition (percentage of oxidized starch). 

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