THE INFLUENCE OF AMYLOSE AND AMYLOPECTIN CHARACTERISTICS ON GELATINIZATION AND RETROGRADATION PROPERTIES OF DIFFERENT STARCHES

Physico-chemical properties of starch from wheat, rye, barley (waxy, h igh-amylose and normal-amylose), waxy maize, pea and potato (normal-am ylose and high amylopectin) were studied. Emphasis was given to the am ylose (total, apparent and lipid-complexed) and amylopectin characteri stics as well as to the gelatinization and retrogradation properties m easured using differential scanning calorimetry. The total amylose con tent varied from ca. 1% for waxy maize to 37% for high-amylose barley. The amylopectin characteristics were determined by high-performance s ize-exclusion chromatography after debranching with isoamylase. The we ight-average degree of polymerization (<(DP)over bar>(w)) was 26, 33 a nd 27 for the A-, B-, and C-type starches, respectively. In general, t he potato starches exhibited the highest retrogradation enthalpies and the cereal starches the lowest, while the pea starch showed an interm ediate retrogradation enthalpy. The data were analysed by principal co mponent analysis (PCA). The <(DP)over bar>(w) showed positive correlat ion to the melting interval, the peak minimum, the offset temperatures of the retrogradation-related endotherm as well as to the gelatinizat ion and retrogradation enthalpies. However, the high-amylose barley re trograded to a greater extent than the other cereal starches, despite low <(DP)over bar>(w) (24). The amylose content was negatively correla ted to the onset and the peak minimum temperatures of gelatinization. (C) 1998 Elsevier Science Ltd. All rights reserved.