Whey protein-okra polysaccharide fraction blend edible films: tensile properties, water vapor permeability and oxygen permeability.
BACKGROUND
A hot-buffer-soluble-solid fraction (HBSS) and an alkaline-soluble-solid fraction (ASS) of okra polysaccharides (OKP) were obtained using sequential extraction. These fractions were combined with whey protein isolate (WPI) and glycerol (Gly) plasticizer to form blend edible films. Effects of OKP fraction and content on tensile properties, water vapor permeability (WVP) and oxygen permeability (OP) were determined.


RESULTS
HBSS film had significantly higher percent elongation (%E) and lower elastic modulus (EM), WVP and OP than ASS film. Increasing HBSS or ASS content in blend films with WPI significantly reduced film tensile strength and EM and increased film %E and WVP. OP values for WPI-HBSS blend films were significantly lower than OP for WPI or HBSS film. WPI-HBSS and WPI-ASS blend films had lower WVP and OP than WPI films with equivalent tensile properties.


CONCLUSIONS
WPI-HBSS blend films have higher WVP and lower OP than WPI film or HBSS film, indicating unique interactions between WPI and HBSS. Compared to WPI film, WPI-HBSS blend films have improved flexibility, stretchability and oxygen barrier. Different HBSS and ASS compositions and structures are responsible for property differences between HBSS and ASS films and between WPI-HBSS and WPI-ASS blend films.
Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Jatujak, Bangkok 10900, Thailand.
Arunya
A
Prommakool
Tanaboon
T
Sajjaanantakul
Theeranun
T
Janjarasskul
John M
JM
Krochta
D028483:Abelmoschus / Q000737:chemistry*; D018857:Food Packaging / Q000379:methods*; D008894:Milk Proteins / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D010539:Permeability; D011134:Polysaccharides / Q000737:chemistry*; D013227:Steam; D013718:Tensile Strength; D000067816:Whey Proteins
D008894:Milk Proteins; D011134:Polysaccharides; D013227:Steam; D000067816:Whey Proteins; D010100:Oxygen