|Relationship Between Endosperm Texture and the Occurrence of Friabilin and Bound Polar Lipids on Wheat Starch. Cereal Chemistry 72:172-176
|Greenblatt,G.A., Bettge,A.D., and Morris,C.F.
|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 friabilin, a family of 15-kDa
proteins, and bound glyco- and phospho-lipids on water washed wheat starch.
These tow 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 water (90:10), which is effective in removing
bound polar lipids form 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.
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