Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 8/13/2009
Publication Date: 9/13/2009
Citation: Schober, T.J., Bean, S. 2009. Potential of Prolamins from Maize and Sorghum to Form Gluten-like Structures in Wheat-free Bread [abstract]. Cereal Foods World. 54:A12. Interpretive Summary:
Technical Abstract: Prolamins from maize (zeins) are known to form viscoelastic, extensible, cohesive dough when mixed together with starch and water above their glass transition temperature (Tg, approximately 28 °C). By adding hydroxypropyl methylcellulose (HPMC, a surface-active hydrocolloid) to this formulation, leavened bread can be produced that closely resembles wheat bread. Zein-starch dough can be shaped like wheat dough and made into hearth-type breads, rolls or pretzels without the use of bread pans, a major advantage over traditional batter-like gluten-free doughs. However, the ability of zein-starch dough to hold its shape upon proofing depends on the zein quality. Several quality factors were identified in commercial zein, including protein content, molecular weight distribution of the proteins and lipid content. With commercial zein of the appropriate quality, it was possible to make rolls that closely resembled wheat rolls, whereas inadequate zein quality led to flat rolls. However, commercial zein is a by-product from starch isolation and therefore not easily available in a standardized quality. Isolation of zein directly from maize flour requires sufficiently hydrophobic solvents (e.g. 92% i-propanol) to be functional for breadmaking. Although regarded as highly analogous to zein, sorghum prolamins (kafirin) could not be used for breadmaking. However, some progresses in kafirin isolation led to an improved ability to aggregate above kafirin’s Tg into a gluten-like substance.