title: Molecular and morphological aspects of annealing-induced stabilization of starch crystallites.
abstract: A unique series of potato (mutant) starches with highly different amylopectin/amylose (AP/AM) ratios was annealed in excess water at stepwise increasing temperatures to increase the starch melting (or gelatinization) temperatures in aqueous suspensions. Small-angle X-ray scattering (SAXS) experiments revealed that the lamellar starch crystals gain stability upon annealing via thickening for high-AM starch, whereas the crystal surface energy decreases for AM-free starch. In starches with intermediate AP/AM ratio, both mechanisms occur, but the surface energy reduction mechanism prevails. Crystal thickening seems to be associated with the cocrystallization of AM with AP, leading to very disordered nanomorphologies for which a new SAXS data interpretation scheme needed to be developed. Annealing affects neither the crystal internal structure nor the spherulitic morphology on a micrometer length scale.
authors.affiliation: Laboratory of Food Chemistry and Biochemistry, and Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium. sara.gomand@biw.kuleuven.be
authors.forename: Sara V
authors.initials: SV
authors.lastname: Gomand
authors.forename: Lieve
authors.initials: L
authors.lastname: Lamberts
authors.forename: Cedric J
authors.initials: CJ
authors.lastname: Gommes
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.forename: Jan A
authors.initials: JA
authors.lastname: Delcour
authors.forename: Bart
authors.initials: B
authors.lastname: Goderis
mesh_terms: D000687:Amylopectin / Q000737:chemistry; D000688:Amylose / Q000737:chemistry; D003460:Crystallization; D011198:Solanum tuberosum / Q000737:chemistry; D013213:Starch / Q000737:chemistry*; D013696:Temperature
chemical_list: D013213:Starch; D000688:Amylose; D000687:Amylopectin