title: Relationship between branching density and crystalline structure of A- and B-type maize mutant starches.
abstract: Amylopectin from two double maize mutant starches of A-crystalline (wxdu) and B-crystalline type (aewx) was subjected successively to hydrolysis involving alpha and beta amylases, which isolated clusters and all branching zones of clusters (BZC). Enzymatic analysis together with ionic and size-exclusion chromatography revealed the structural features of the clusters and BZC and their role in starch crystallization. A-type clusters were larger (dp(n) > 80) and contained more (but shorter) chains than B-type clusters. The BZC of A-type starch was also larger, but with a shorter distance between the branching points than in B-type BZC. A-type clusters had a densely packed structure and B-type a poorly branched structure. Models for the structure of A- and B-type clusters are presented, and a hypothesis for the influence of cluster geometry on crystallization is proposed.
authors.affiliation: INRA, BP 71627, Nantes, France.
authors.forename: C
authors.initials: C
authors.lastname: Gérard
authors.forename: V
authors.initials: V
authors.lastname: Planchot
authors.forename: P
authors.initials: P
authors.lastname: Colonna
authors.forename: E
authors.initials: E
authors.lastname: Bertoft
mesh_terms: D000687:Amylopectin / Q000737:chemistry* / Q000235:genetics; D002236:Carbohydrate Conformation; D002847:Chromatography, Agarose; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003912:Dextrins / Q000737:chemistry; D006868:Hydrolysis; D009154:Mutation; D013213:Starch / Q000737:chemistry* / Q000235:genetics; D003313:Zea mays / Q000737:chemistry* / Q000235:genetics*; D000516:alpha-Amylases / Q000378:metabolism; D001614:beta-Amylase / Q000378:metabolism
chemical_list: D003912:Dextrins; D013213:Starch; D000687:Amylopectin; D000516:alpha-Amylases; D001614:beta-Amylase