Structures of large, medium and small starch granules of barley grain
1999
Takeda, Y. | Takeda, C. | Mizukami, H. | Hanashiro, I.
The structure of amylose and amylopectin in large (L), medium (M) and small (S) starch granules fractionated from barley grain was examined. The L, M and S granules were 20, 7.5 and 2.3 micrometers in average diameter, and accounted for 79, 11 and 10% (w/w) in yield, respectively. The amylose content in L and M granules was 25.4 and 24.7%, respectively, higher than that (20.3%) in S granules. L and M granules had a smaller amylose (number average DP, DP(n) = 1640 and 1610) with a smaller number of chains (NC = 5.6 and 4.9) than S granules (DP(n) = 1900, NC = 7.2). The amylopectins from all the granules resembled each other in structure; they showed similar iodine affinity (0.60-0.75 g/100 g), average chain length (19-20), beta-amylolysis limit (55-56%), and chain length distribution although the distribution of short side-chains (DP = 6-37) and the phosphorus content slightly differed. These findings suggest that the regulation or genetic control for the synthesis of S granules differs from that for L and M granules.
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