Grain quality and properties of starch and amylopectin of intermediate-and low-amylose Indica Rices

Issue Date

6-2011

Abstract

Selected intermediate-and low-apparent amylose content (AC) Philippine rices differing in alkali spreading value (index of starch gelatinization temperature, GT) and cooked rice hardness were characterized for differential scanning calorimetry (DSC) measurement of gelatinization of granular starch, content of long-chain amylopectin and true amylose by high-performance size exclusion chromatography of debranched starch and amylopectin, and amylopectin chain ratio (ACR) of Σ degree of polymerization (DP) 6-10/Σ DP 6-24 of debranched starch by capillary electrophoresis. The Waxy gene alleles were mainly 17G and 20G for intermediate-AC samples and 17T and 20T for low-AC samples, regardless of GT. Long-chain amylopectin content was as predicted from apparent amylose content, and ACR was as predicted from GT by DSC and alkali spreading value. AC of milled rice was higher than that of debranched starch by size exclusion chromatography. Differences in long-chain amylopectin content cannot explain differences in cooked hardness among both AC types, and ACR alone cannot explain differences among intermediate AC type. The lower AC of starch of intermediate-AC rice with intermediate GT compared with those of intermediate-AC rice with low GT probably contributed to its softer cooked rice. Increase in cooked hardness from staling was higher for high-and intermediate-GT samples, particularly in low-AC types.

Source or Periodical Title

Philippine Agricultural Scientist, The (Formerly: The Philippine Agriculturist)

ISSN

0031-7454

Volume

94

Issue

2

Page

140-148

Document Type

Article

College

College of Agriculture and Food Science (CAFS)

Frequency

quarterly

Physical Description

tables; references

Language

English

Subject

alkali spreading value, amylograph viscosity, amylopectin chain ratio, apparent amylose content, capillary electrophoresis, cooked rice hardness, differential scanning calorimetry, gel consistency, gelatinization temperature, high-performance size exclusion chromatography, long-chain amylopectin, RVA viscosity, soluble starch synthase IIa, true amylose content

En – AGROVOC descriptors

ORYZA SATIVA; GRAIN; AMYLOSE; AMYLOPECTIN; DIFFERENTIAL SCANNING CALORIMETRY; JELLIFICATION

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