Mechanical and Barrier Properties of Avenin, Kafirin, and Zein Films

Abstract

Biodegradable and renewable materials can be manufactured from prolamins, which are the major storage protein fraction of cereals. This paper investigates the material properties of oat prolamin (avenin), corn prolamin (zein), and sorghum prolamin (kafirin). Glass transition temperature, dry solid content, stress at break, strain at break, oxygen permeability, and water vapor permeability were analyzed at different plasticizer contents. Avenin was plasticized with glycerol, and kafirin and zein were plasticized with a mixture of polyethylene glycol, glycerol, and lactic acid. Avenin displayed potential, although it did not exhibit the mechanical qualities of gluten, which resembles avenin at the molecular level. Compared to kafirin and zein, avenin was more extensible at low plasticizer contents, while kafirin and especially zein were more extensible at the highest plasticizer content. Avenin was far weaker than the other two at all plasticizer contents. Kafirin and zein displayed similar barrier properties, whereas avenin was notably more permeable.

State of the Art in the Development and Properties of Protein-Based Films and Coatings and Their Applicability to Cellulose Based Products: An Extensive Review

“…At low plasticizer concentration, sorbitol led to a higher ultimate tensile strength than glycerol and mannitol. Gillgren et al [238] added polyethylene glycol, glycerol and lactic acid in different concentrations to kafirin, zein and avenin. In particular, zein was more stretchable at higher plasticizer contents [232] compared to zein films prepared in aqueous ethanol or acetone containing no plasticizer, glycerol or glycerol/poly(propylene glycol) (1:3 ratio).…”

Application Potential of Food Protein Modification

“…Even though collagen and gelatin coatings were reported to both effectively retain water in meat products (Antoniewski et al, 2007;Farouk et al, 1990), extensive moisture loss of kafirin coated pears compared to the uncoated product left them unacceptable toward consumers . The authors ) therefore suggested to prepare wax or triglycerides/kafirin mixtures instead of pure kafirin coatings to prevent moisture loss as kafirin films themselves do not function effectively as water barriers (Emmambux et al, 2004;Gillgren & Stading, 2008). Because lipids form a very suitable moisture barrier as a result of their hydrophobic character, lipophilized proteins possibly form more effective coatings for fruit.…”

Mechanical and Barrier Properties of Films from Millet Protein Pennisetin

“…Kafirin showed equal WVP at all plasticizer contents, as did zein at 20% and 30%, but higher at 40% (3.6 vs 2.5 gmm/m²h kPa). 4 A conclusion to be made about barrier properties is that, while the polarity of the plasticizer (hydrophilic or hydrophobic) and the plasticizer content are important, the microstructure also has an impact on the permeability. Error bars indicate the scatter as the 95% confidence interval Cavities, holes, or irregular and heterogeneous structure increase the gas permeability.…”

“…3 Until now studies have focused principally on prolamins such as avenin, kafirin, zein, and gliadin. [4][5][6][7] This study, however, focuses on pennisetin, the prolamin from pearl millet (Pennisetum glaucum). Pearl millet is cultivated for T. Gillgren : M.-V. Faye : M. Stading its edible seeds, consumed by humans and animals.…”