Plasticization of a Protein-Based Film by Glycerol: A Spectroscopic, Mechanical, and Thermal Study

Chunli Gao, Mats Stading, Nikolaus Wellner, Mary L. Parker, Timothy R. Noel, E. N. Clare Mills, Peter Belton

Research output: Contribution to journalArticlepeer-review

85 Citations (Scopus)

Abstract

Kafirin, the seed storage protein of the cereal sorghum, is highly homologous with the maize storage protein zein. The effects of plasticisation of a kafirin film by glycerol in the absence of water were examined by a combination of spectroscopic (NMR and infrared), rheological, and calorimetric methods. The results suggest that at low glycerol levels the glycerol is absorbed onto and possibly into the protein. Increasing the level of glycerol increases the motion of the protein and changes the protein conformation. There are corresponding changes of the mechanical properties of protein films. At 40% (w/w) of glycerol, two glass transition temperatures were observed, one of which corresponded to the glass transition temperature of pure glycerol. This result indicates that at this level of plasticizer there are sufficient glycerol/glycerol interactions occurring to allow a separate glass formation process for glycerol.
Original languageEnglish
Pages (from-to)4611-4616
Number of pages6
JournalJournal of Agricultural and Food Chemistry
Volume54
Issue number13
DOIs
Publication statusPublished - 2006

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