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FILM FORMING MECHANISM AND MECHANICAL AND THERMAL PROPERTIES OF WHEY PROTEIN ISOLATE‐BASED EDIBLE FILMS AS AFFECTED BY PROTEIN CONCENTRATION, GLYCEROL RATIO AND PULLULAN CONTENT
Author(s) -
GOUNGA MAHAMADOU ELHADJI,
XU SHIYING,
WANG ZHANG
Publication year - 2010
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.2009.00294.x
Subject(s) - whey protein isolate , pullulan , glycerol , whey protein , plasticizer , ultimate tensile strength , chemistry , food science , fourier transform infrared spectroscopy , chemical engineering , chromatography , materials science , polysaccharide , organic chemistry , composite material , engineering
Tensile strength (TS), elongation at break (EAB) and elastic modulus (EM) of edible films prepared from 5, 7 and 9% whey protein isolate (WPI) plasticized with different levels of glycerol (Gly) (WPI : Gly = 3.6:1, 3:1 and 2:1) were investigated in order to completely characterize WPI‐Gly films. On increasing protein concentration an increase in TS and EAB was observed. On the other hand, increasing Gly led to a decrease in TS and EM, while EAB increased. The addition of pullulan (Pul) into the film forming solution (FFS) increased EAB while TS, EM and thermal properties were reduced. This suggested that Pul had a similar effect as plasticizers. Films with higher Pul content showed lighter protein bands on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. Fourier transform infrared spectroscopy showed that hydrogen bonding was high in WPI : Pul films as compared with the control. This is attributed to the protein‐polysaccharide interactions brought about by the dominance of Pul in the FFS.PRACTICAL APPLICATIONS This work describes some physical properties of films based on blends of whey protein isolate (WPI) and pullulan (Pul), made after a previous study on some characteristics of films based on pure WPI plasticized by glycerol. The most studied proteins in the edible films technology being gluten and WPI, the use of Pul in mixture with WPI is considered as a new investigation to explore the utilization of WPI‐Pul in edible film and coating materials applied to food products. Furthermore, the use of WPI‐Pul films and coatings could potentially extend the shelf life and improve the stability of the coated products as shown by the resultant properties in this investigation and previous works.