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Calorimetric Determination of the Amylose Content of Starches Based on Formation and Melting of the Amylose‐Lysolecithin Complex
Author(s) -
KUGIMIYA MASAYUKI,
DONOVAN JOHN W.
Publication year - 1981
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1981.tb15344.x
Subject(s) - amylose , chemistry , starch , differential scanning calorimetry , enthalpy , melting temperature , complex formation , chromatography , food science , thermodynamics , materials science , inorganic chemistry , physics , composite material
Amylose‐lysolecithin complexes, formed in an exothermic reaction when amylose or starches are heated with water and lysolecithin, melt at temperatures near 107°C. With excess lysolecithin present, formation of the maximum amount of amylose complex requires cooling after the first heating (during which gelatinization of starch takes place), and then reheating. An amylose with chain length of 300 glucose units took up 14% lysolecithin; the enthalpy of melting of this complex, observed by differential scanning calorimetry, was 5.9 cal/g amylose. Amylose content of a starch was calculated from the enthalpy of melting of its lysolecithin complex. Amylose contents for potato, tapioca, lima bean, wrinkled pea, amylomaize and waxy maize starches agreed with values obtained by iodine binding. Amylose contents of maize and wheat starches were larger than obtained by iodine binding, and in better agreement with amylose contents obtained by fractionation.