title: Microstructure, nutrient composition and antioxidant capacity of king palm flour: a new potential source of dietary fibre.
abstract: The objective of this research was to evaluate the chemical composition, microstructure, and antioxidant capacity of king palm flour obtained from residues from organic king palm (Archontophoenix alexandrae) processing. King palm flour exhibited high levels of dietary fibre (70.85%) and total ash (3.27%); low contents of protein (3.51%) and lipid (0.91%). Iron, magnesium, calcium and potassium contents were 7.31, 517.03, 801.33 and 1041.95 mg/100g, respectively. The high concentration of glucose, xylose and arabinose suggests the presence of some polysaccharides, such as cellulose and hemicelluloses (xyloglucans and arabinoxylans). Methanol and aqueous extracts of king palm flour showed 1.27 and 0.95 mg/g (Gallic Acid Equivalents) of total polyphenols, respectively. Methanol extract yielded the best antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH()) and 2,2'-azino-di(3-ethylbenzthiazoline sulphonate) (ABTS()(+)) methods. The micrographs of leaf sheath showed the presence of druses, which are characterized as calcium oxalate deposition, contributing to the calcium content in king palm flour. The presence of primary and secondary cell walls lignified in leaf sheath contributed to high levels of dietary fibre detected in king palm flour.
authors.affiliation: Department of Food Science and Technology, Federal University of Santa Catarina, Rodovia Admar Gonzaga 1346, 88034-001 Florianópolis, SC, Brazil.
authors.forename: Karina N
authors.initials: KN
authors.lastname: de Simas
authors.forename: Leila do N
authors.initials: Ldo N
authors.lastname: Vieira
authors.forename: Rossana
authors.initials: R
authors.lastname: Podestá
authors.forename: Manoela A
authors.initials: MA
authors.lastname: Vieira
authors.forename: Ismael I
authors.initials: II
authors.lastname: Rockenbach
authors.forename: Carmen L O
authors.initials: CL
authors.lastname: Petkowicz
authors.forename: João
authors.initials: J
authors.lastname: de Deus Medeiros
authors.forename: Alícia
authors.initials: A
authors.lastname: de Francisco
authors.forename: Edna R
authors.initials: ER
authors.lastname: Amante
authors.forename: Renata D M C
authors.initials: RD
authors.lastname: Amboni
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D052160:Benzothiazoles / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D002473:Cell Wall / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry; D004043:Dietary Fiber; D005419:Flavonoids / Q000737:chemistry; D005433:Flour; D005502:Food; D005936:Glucans / Q000737:chemistry; D000432:Methanol / Q000737:chemistry; D008856:Microscopy, Fluorescence / Q000379:methods; D052756:Nutritional Sciences; D010636:Phenols / Q000737:chemistry; D010851:Picrates / Q000737:chemistry; D018515:Plant Leaves / Q000378:metabolism; D059808:Polyphenols; D013451:Sulfonic Acids / Q000737:chemistry; D014990:Xylans / Q000737:chemistry
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D004043:Dietary Fiber; D005419:Flavonoids; D005936:Glucans; D010636:Phenols; D010851:Picrates; D059808:Polyphenols; D013451:Sulfonic Acids; D014990:Xylans; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D002482:Cellulose; C085118:arabinoxylan; C004931:1,1-diphenyl-2-picrylhydrazyl; D002118:Calcium; D000432:Methanol