Plasticization of Zein: A Thermomechanical, FTIR, and Dielectric Study

Abstract

Zein, the main seed storage protein of maize, has been widely studied as a possible source of material for the production of biodegradable plastic films. Plasticization of zein is critical to make functional films. While there have been a number of publications which report the behavior of systems with a wide variety of plasticizers, there have been few which attempt to examine the interactions of protein and plasticizer at the molecular level. In this paper, we report on the plasticizing effects of water, glycerol, and 2-mercaptoethanol, which were examined by a combination of spectroscopy (FTIR and dielectric) and thermomechanical methods. The results suggest that both water and glycerol are adsorbed onto the protein and form hydrogen bonds with the amide groups. The plasticizer then builds up in patches on the protein surface. 2-Mercaptoethanol only exhibited a weak plasticizing effect due probably to disulfide bond breaking.

Formulation and characterization of silk sericin–PVA scaffold crosslinked with genipin

“…The amide II band in Fig. 2 (B-G) in samples containing glycerin has a reduced intensity compared with that of the sericin/PVA scaffold, similar to the results reported by Gillgren et al [29]. Generally, the amide II band responds to differences in the hydrogen bonding environment [30].…”

The Development of Direct Extrusion-Injection Moulded Zein Matrices as Novel Oral Controlled Drug Delivery Systems

“…Nevertheless it is reasonably to predict that small quantity of paracetamol may be dissolved during the pre-mixing stage and molecularly dispersed in the partially hydrated zein. Further loss of paracetamol crystallinity could be due to dissolution into the plasticised (by water) zein matrix during extrusion at the processing temperature above the T g of the zein/water matrix (24). Under this circumstance, the drug-polymer solubility may play an important role in inhibiting the recrystallization of molecularly dispersed drug in the polymer matrix.…”

Improved incorporation and stabilisation of β-carotene in hydrocolloids using glycerol

“…This is not completely surprising as glycerol is not the ideal plasticiser for zein. Recently, using a combination of spectroscopic and thermomechanical methods, the interactions between zein and glycerol in cast films were studied and it was found that glycerol is absorbed on the surface of the proteins at the highest absorption sites forming clusters and giving no evidence of proper dispersion (Gillgren, Barker, Belton, Georget, & Stading, 2009).…”