The data were analyzed using SPSS into one-way ANOVA, and means separation was carried out with the LSD method The result showed that high temperature resulted in the decrease of DP5-9 and DP15-22, and increase of DP10-13 and DP greater than 42 of amylopectin
in rice endosperm.
The main differences in starch composition that influence physicochemical and metabolic properties of rice are caused by the variation in the ratio of its two macromolecules, amylose and amylopectin
. Amylose is essentially a linear molecule in which D-glucose units are linked by a-1.4 glucosidic bonds, while amylopectin
, a branched polymer, contains both a-1.4 and a-1.6 bonds.
Regardless of the source, starch contains amylose and amylopectin
. Both are polymers of glucose molecules, with distinct properties and functionalities.
It is also hydrophilic through its inherent amylose and amylopectin
Wheat is mostly starch, which is a polymer--or chain--of glucose molecules containing amylose (the straight-chain form) and amylopectin
(the branched-chain form).
Total amylolytic activity was determined by measuring reducing power released following hydrolysis of amylopectin
(Sigma, product A-7780; Bernfeld, 1955) with DNS color reaction (Summer, 1925).
Its grainy structure consists of two polysaccharides called amylase and amylopectin
. The first one, being 20% of starch, is a linear polysaccharide soluble in water.
Similarly, D'Alphonso (2002) found that across 15 countries, total starch varied between 645.4 and 696.2 g/kg and the amylopectin
content of that starch varied between 732.5 and 828.6 g/kg.
Granulemorphology, composition and amylopectin
Starch is composed of two parts: amylose and amylopectin
whose percentages are different in various kinds.
The high retrogradation tendency observed for the control sample could be due to the crystallization involving amylose molecules and the long-branch chain of amylopectin
Baked products grow stale when gelatinized starch, particularly amylopectin