title: Starch determination, amylose content and susceptibility to in vitro amylolysis in flours from the roots of 25 cassava varieties.
abstract: BACKGROUND
  Cassava cultivars are classified following different criteria, such as cyanogenic glucoside content or starch content. Here, flours from the roots of 25 cassava varieties cultivated simultaneously in a single plantation, were characterized in terms of starch content (SC), amylose content (AC), α-amylolysis index (AI) and gel formation ability. Resistant starch content (RS) was measured in 10 of the samples.
  
  
  RESULTS
  Cassava flours exhibited high SC, low AC and low AI values, with differences among varieties. Cluster analysis based on these parameters divided the cultivars in four groups differing mainly in SC and AC. AI and AC were inversely correlated (r = -0.59, P < 0.05) in 18 of the cultivars, suggesting AC as an important factor governing the susceptibility to enzymatic hydrolysis of starch in raw cassava. Differences in susceptibility to amylolysis, assessed by RS, were also recorded in the sample subset analyzed. Most flours yielded pastes or gels upon heating and cooling. Gels differed in their subjective grade of firmness, but none exhibited syneresis, confirming the low retrogradation proclivity of cassava starch.
  
  
  CONCLUSIONS
  Some differences were found among cassava samples, which may be ascribed to inter-cultivar variation. This information may have application in further agronomic studies or for developing industrial uses for this crop.
authors.affiliation: Fundación Instituto IDEA, Carretera Nacional Hoyo de la Puerta-Baruta, Valle de Sartenejas, Caracas 1015A, Venezuela; Institute of Experimental Biology, Faculty of Sciences, Universidad Central de Venezuela, P.O. Box 47114, Caracas 1041A, Venezuela.
authors.forename: Luisa Elena
authors.initials: LE
authors.lastname: Mejía-Agüero
authors.forename: Florangel
authors.initials: F
authors.lastname: Galeno
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Hernández-Hernández
authors.forename: Juan
authors.initials: J
authors.lastname: Matehus
authors.forename: Juscelino
authors.initials: J
authors.lastname: Tovar
mesh_terms: D000688:Amylose / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D016000:Cluster Analysis; D018556:Crops, Agricultural / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism; D004044:Dietary Proteins / Q000737:chemistry / Q000378:metabolism; D005511:Food Handling; D005782:Gels; D006244:Hardness; D006868:Hydrolysis; D007700:Kinetics; D002365:Manihot / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism; D055292:Pancreatic alpha-Amylases / Q000378:metabolism*; D044367:Phase Transition; D010802:Phylogeny; D010940:Plant Proteins / Q000096:biosynthesis / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism; D013045:Species Specificity; D013213:Starch / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D034421:Sus scrofa; D014687:Venezuela
chemical_list: D004044:Dietary Proteins; D005782:Gels; D010940:Plant Proteins; D013213:Starch; D000688:Amylose; D055292:Pancreatic alpha-Amylases