Rheological Studies Utilizing Various Lots of Zein in N,N-Dimethylformamide Solutions

• Published in: Journal of agricultural and food chemistry 2005-11, Vol.53 (23), p.9050-9055
• Main Authors: Selling, Gordon W, Lawton, John, Bean, Scott, Dunlap, Christopher, Sessa, David J, Willett, Julious L, Byars, Jeff
• Format: Article
• Language: English
• Subjects: amides; Animal, plant, fungal and microbial proteins, edible seaweeds and food yeasts; Biological and medical sciences; chemical concentration; Dimethylformamide; Food industries; Formamides; Fundamental and applied biological sciences. Psychology; N,N-dimethylformamide; Polymers - chemistry; rheological properties; Rheology; Solutions; Solvents; temperature; Thermodynamics; Viscosity; zein; Zein - chemistry
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf050893k

Rheological studies were carried out on solutions of zein in N,N-dimethylformamide (DMF), where the specific lot of zein, concentration, time, and temperature were varied. DMF is a good solvent for zein, giving clear, relatively low viscosity solutions. It was found that all of the zein solutions behaved in a non-Newtonian fashion. At high concentration and elevated temperature, zein solutions will increase in viscosity with time. A temperature study on the rate of viscosity rise illustrated that at temperatures above 40 °C, the rate of viscosity rise increased in a non-Arrhenius fashion. There can be significant lot to lot variations in commercially obtained zein that gives rise to differences in viscosity and rate of viscosity rises. With the samples studied, viscosity was found to double from one lot of zein to another. Size exclusion chromatography suggests that compositional differences between the lots drive the observed differences in viscosity. Keywords: Zein; rheology; lot variation