Water resistance, weight loss and enzymatic degradation of blends starch/polyvinyl alcohol containing SiO _2 nanoparticle

摘要

The aims of the study were to investigate the effect of polyvinyl alcohol (PVA) and nano-SiO _2 within the thermoplastic starch (TPS) blends on the rate and extent of starch enzymatic hydrolysis using enzymes α-amylase and amyloglucosidase. The results of this study have revealed that blends with a nano-SiO _2 content at 5wt.% exhibited a significantly reduced rate and extent of starch hydrolysis. The results suggest that this may have been attributed to interactions between starch and nano-SiO _2 that further prevented enzymatic attack on the remaining starch phases within the blend. The total solids that remained after 6000min were 54wt.% (TPS:PVA); 61wt.% (TPS:PVA:1% nano-SiO _2); 64wt.% (TPS:PVA:3% nano-SiO _2); 68wt.% (TPS:PVA:5% nano-SiO _2). The rate of glucose production from each nanocomposite substrates was most rapid for the substrate without nano-SiO _2 and decreased with the addition of nano-SiO _2, for TPS:PVA blend (226μg/mlh), 166μg/mlh (TPS:PVA:1% nano-SiO _2), 122μg/mlh (TPS:PVA:3% nano-SiO _2) and 94μg/mlh for (TPS:PVA:5% nano-SiO _2). Enzymatic degradation behaviour of TPS:PVA:nano-SiO _2 was based on the determinations of water resistance, weight loss and the reducing sugars. It has been established that the nanoparticles hinder degradation, while the susceptibility to enzymatic degradation varies in the order: TPS:PVA>TPS:PVA:nano-SiO _2.