Abstract:

In this present work, chitosan-whey protein isolate composite film (CWF) was prepared by casting technique
through mixing chitosan (CTS) dissolved in 2% (by volume) aqueous acetic acid with 1 g/100 mL whey protein isolate
(WPI) dissolved in deionized water under continuous stirring. The tensile strength (TS), breaking elongation rate (E), water
vapor permeability (WVP), and transparency of CWF were determined. The preparation conditions of CWF were optimized
to be CTS with a deacetylation degree (DD) of 90% and a molecular weight (MW) of 300 kD in a film-forming solution at
pH 3 with the addition of 1.5% glycerol and 0.5% WPI aqueous solution. The mechanical properties and stripping
property of CWF were significantly improved over those of CTS, and CWF also showed a slight improvement in WPI and
transparency. Scanning electron microscopy (SEM) analysis indicated that the cross-sectional microstructure of CWF was
uniform and compact, and the appearance was semi-translucent. Fourier transform infrared spectrometer (FTIR) results
showed a strong interaction and good compatibility between the molecules of CTS and WPI in the preparation of CWF.

Key words: chitosan-whey protein isolate composite film, physico-chemical properties, scanning electron microscopy (SEM);fourier transform-infrared spectrometer (FT-IR)