Physical and mechanical properties of high-amylose rice and pea starch films as affected by relative humidity and plasticizer

• Published in: Journal of food science 2004-12, Vol.69 (9), p.E449-E454
• Main Authors: Mehyar, G.F, Han, J.H
• Format: Article
• Language: English
• Subjects: amylose; Biological and medical sciences; edible film; edible films; elongation at break; films (materials); Food industries; Food science; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; glycerol; Humidity; mechanical properties; Oxygen; oxygen permeability; packaging materials; Peas; Permeability; plasticizers; relative humidity; Rice; rice starch; starch; Starch and starchy product industries; starch film; tensile property; tensile strength; water; water solubility; water vapor permeability
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1365-2621.2004.tb09929.x

The tensile properties, water vapor permeability, oxygen permeability at different relative humidities (RH), and water solubility of edible films made of high-amylose rice starch (RS) or pea starch (PS) were measured and compared with the most commonly used edible films. Photomicrography of starch films shows amylopectin-rich gels and amylose-rich granules. The addition of glycerol into starch films made amylose-rich granules swollen and continuously dispersed between amylopectin-rich gels. Tensile strength of RS and PS films decreased when RH increased from 51% to 90%, whereas elongation-at-break (E) of both films increased when RH increased. Water vapor permeabilities of both films were similar, resulting in 130 to 150 g mm/m2/d / kPa. Oxygen permeability of RS and PS were very low (< 0.5 cm3 micrometer/m2/d/kPa) below 40% RH, and 1.2 to 1.4 at 45% RH. Water solubility of PS film was 32.0%, which is lower than that of RS film (44.4%). Overall high-amylose rice and pea starch films possess an excellent oxygen barrier property with extremely high stretchability.