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Correlation of fine structure of amylopectin and starch granule protein with the rheological properties of
rice starch pastes. X. Z. HAN and B. R. Hamaker. Whistler Center for Carbohydrate Research and
Dept. of Food Science, Purdue University.
Ten rice starches with a fairly narrow range of amylose contents, but
wide variation in RVA pasting curves, were selected to study the relationship of amylopectin fine structure
and starch granule protein with RVA paste viscosity measurements. Amylopectin fine structure was found
to significantly correlate with some RVA parameters. Proportion of long chains of amylopectin (FrI) was
negatively correlated (r(^2) = 0.66, P<0.01) and proportion of short chains of amylopectin (FrIII) was
positive correlated (r(^2) = 0.80, P<0.001) with paste breakdown. A relationship was revealed using
multiple regression in the equation: RVA breakdown = -95 FrI + 299 FrIII - 185 (r(^2) = 0.82, P<0.01).
Peak viscosity was also found to correlate by multiple regression with amounts of amylopectin long chain,
amylopectin short chain, and 60 kDa starch granule bound starch synthase (GBSS). Amylopectin long chain
and GBSS were negatively related to peak viscosity, while amylopectin short chain was positively related.
Multiple regression analysis revealed the relationship by the equation: RVA peak viscosity = -225 - 1191FrI
+ 468 FrIII - 0.0202 x band density of GBSS (r(^2) = 0.71, P < 0.05). The study indicates relationships
involving amylopectin fine structure and starch granule protein with RVA pasting parameters, implying that
fine structure, in particular, relates to susceptibility or resistance of swollen granules to paste breakdown.
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