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

Abstract

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 degrees 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.

Effect of acid and base treatments on structural, rheological, and antioxidant properties of α-zein

“…6 at a shear rate between 0.7 and 100 s À1 for all pH-treated zein samples at 25°C. It can be seen that m values were between 0.9 and 1, confirming that all pH-treated zein in this study had weak shearing thinning behaviour, which was consistent with what Selling et al (2005) had reported on apparent viscosity of native zein solutions. Samples Z12.5 and Z2.7 ranked 1 and 2 in m value suggesting that their rheological behaviours were close to a Newtonian solution.…”

Improved Isolation of Zein from Corn Gluten Meal Using Acetic Acid and Isolate Characterization as Solvent

“…There is little difference in zein yield at 25-40°C and 55-70°C, however there is a difference at 40-55°C. Previously performed solution rheology studies showed that significant structural differences take place at >45°C (Selling et al 2005). In addition, with increasing temperature, both the secondary structure (Cabra et al 2006;Selling et al 2007a) and tertiary structure (Selling et al 2007a) change.…”

“…Higher molecular weight zein fractions that have multiple cysteines have been implicated in zein solution viscosity instability (Selling et al 2005). With this reduction in the HMW fraction of δ-zein present in the zein obtained from CGM using AcOH extraction, the resulting zein may provide solutions with improved solution stability.…”

Fabrication and Characterization of Zein‐Based Nanofibrous Scaffolds by an Electrospinning Method

“…These proteins can be classified into four distinct types according to their solubilities: α , β , γ and δ . Among them, α ‐zein is the most abundant and can be soluble in aqueous alcohol and N , N ‐dimethylformamide (DMF) 8. It has been examined as a raw material for applications from the beginning of the last century and was used for manufacturing buttons, fibers, coating, adhesives and binders etc 7.…”