Effect of Water-Mediated Arylation Time on the Properties of Soy Protein Films

Abstract

In situ and dip coating methods were used to prepare arylated soy protein films designated as ISP and DSP, respectively. ISP and DSP protein films were arylated with 2,2-diphenyl-2-hydroxyethanoic acid, in the presence of water, at different time intervals to impart the hydrophobicity in the protein films. DSP and ISP series films suffered a dramatic loss of mechanical properties with the increase in arylation time. Morphological characterization of the soy protein films arylated at different time intervals was done by scanning electron microscopy. It was observed that the increase in arylation time leads to the clustering of the hydrophobic units, through hydrophobic interactions, resulting in the hydrophobic collapse. Hydrophobic collapse in the arylated protein films showed significant decrease in the mechanical properties of the protein films. However, the water uptake of these protein films was independent of the arylation time. The immediate implications of these experimental results are related to the promising use of water-mediated arylated soy proteins as films and composites.