title: Visualization of internal structure of banana starch granule through AFM.
abstract: Atomic force microscopy (AFM) is a high resolution technique for studying the external and internal structures of starch granules. For this purpose granules were isolated from bananas and embedded in a non-penetrating resin. To achieve image contrast of the ultrastructure, the face of the cut blocks were wetted in steam and force modulation mode imaging was used. Images of starch from green bananas showed large variation of height across the granule due to a locational specific absorption of water and swelling of amorphous regions; the data reveal that the center of the granules are structurally different and have different viscoelastic properties. Images of starches from ripe bananas showed an even greater different level of organization: absence of growth rings around the hilum; the central region of the granule is richer in amylose; very porous surface with round shaped dark structures; the size of blocklets are larger than the green fruits.
authors.affiliation: University of São Paulo, Department of Food Science and Experimental Nutrition, FCF, Cidade Universitária, CEP 05508-000 São Paulo, SP, Brazil.
authors.forename: Fernanda H G
authors.initials: FH
authors.lastname: Peroni-Okita
authors.affiliation: Institute of Food Research, Norwich Research Park, Colney Lane, Norwich NR4 7UA, Norfolk, UK, Reino Unido.
authors.forename: A Patrick
authors.initials: AP
authors.lastname: Gunning
authors.affiliation: Institute of Food Research, Norwich Research Park, Colney Lane, Norwich NR4 7UA, Norfolk, UK, Reino Unido.
authors.forename: Andrew
authors.initials: A
authors.lastname: Kirby
authors.affiliation: Federal University of Rio de Janeiro, Department of Metallurgic and Materials Engineering, Cidade Universitária, Ilha do Fundão, CEP 21941-972 Rio de Janeiro, RJ, Brazil.
authors.forename: Renata A
authors.initials: RA
authors.lastname: Simão
authors.affiliation: University of São Paulo, Department of Food Science and Experimental Nutrition, FCF, Cidade Universitária, CEP 05508-000 São Paulo, SP, Brazil.
authors.forename: Claudinéia A
authors.initials: CA
authors.lastname: Soares
authors.affiliation: University of São Paulo, Department of Food Science and Experimental Nutrition, FCF, Cidade Universitária, CEP 05508-000 São Paulo, SP, Brazil; University of São Paulo-NAPAN-Food and Nutrition Research Center, Cidade Universitária, São Paulo, SP, Brazil. Electronic address: hojak@usp.br.
authors.forename: Beatriz R
authors.initials: BR
authors.lastname: Cordenunsi
mesh_terms: D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D028521:Musa; D013213:Starch / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D013213:Starch
keywords: Banana; Microscopy; Starch; Structure