Cereal Chem 72:172-176  |  VIEW ARTICLE

Relationship Between Endosperm Texture and the Occurrence of Friabilin and Bound Polar Lipids on Wheat Starch.

G. A. Greenblatt, A. D. Bettge, and C. F. Morris. Copyright 1995 by the American Association of Cereal Chemists, Inc. 

Endosperm texture affects the milling and end-use properties of wheat grain. A better understanding of the physical-chemical mechanism and the genetic control of endosperm texture in wheat would aid in breeding, marketing, and utilization of grain. Here, we report on the relationship between endosperm texture and the occurrence of friabil in, a family of 15-kDa proteins, and bound glyco- and phospho-lipids on water-washed wheat starch. These two classes of bound polar lipids follow the same pattern of occurrence as friabilin: approximately equal levels in soft and hard wheat flour, much reduced levels in water-washed soft wheat starch compared to flour, and much reduced levels in hard wheat starch compared to soft. The type and quantity of these bound polar lipids is highly conserved among both soft and hard wheat starches. Further, these lipids are implicated in the interaction of friabilin with soft wheat starch. Propan-2-ol and water (90:10), which is effective in removing bound polar lipids from starch, renders most friabilin components extractable with an aqueous salt solution. These results suggest that most friabilin components interact with starch through lipid-mediated hydrophobic interactions and ionic interactions. In addition, the results provide both an additional biochemical marker for grain softness and new insight into the possible physical- chemical mechanism and the genetic control of endosperm texture in wheat.