title: Impact of variety type and particle size distribution on starch enzymatic hydrolysis and functional properties of tef flours.
abstract: Tef grain is becoming very attractive in the Western countries since it is a gluten-free grain with appreciated nutritional advantages. However there is little information of its functional properties and starch digestibility and how they are affected by variety type and particle size distribution. This work evaluates the effect of the grain variety and the mill used on tef flour physico-chemical and functional properties, mainly derived from starch behavior. In vitro starch digestibility of the flours by Englyst method was assessed. Two types of mills were used to obtain whole flours of different granulation. Rice and wheat flours were analyzed as references. Protein molecular weight distribution and flour structure by SEM were also analyzed to justify some of the differences found among the cereals studied. Tef cultivar and mill type exhibited important effect on granulation, bulking density and starch damage, affecting the processing performance of the flours and determining the hydration and pasting properties. The color was darker although one of the white varieties had a lightness near the reference flours. Different granulation of tef flour induced different in vitro starch digestibility. The disc attrition mill led to higher starch digestibility rate index and rapidly available glucose, probably as consequence of a higher damaged starch content. The results confirm the adequacy of tef flour as ingredient in the formulation of new cereal based foods and the importance of the variety and the mill on its functional properties.
authors.affiliation: College of Agricultural and Forestry Engineering, University of Valladolid, Av. Madrid 57, 34004 Palencia, Spain; Ethiopian Institute of Agricultural Research, P.O. Box 2003, Addis Ababa, Ethiopia.
authors.forename: Workineh
authors.initials: W
authors.lastname: Abebe
authors.affiliation: Food Science Department, Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Avenida Catedrático Agustín Escardino 7, Paterna 46980, Valencia, Spain.
authors.forename: Concha
authors.initials: C
authors.lastname: Collar
authors.affiliation: College of Agricultural and Forestry Engineering, University of Valladolid, Av. Madrid 57, 34004 Palencia, Spain. Electronic address: fronda@iaf.uva.es.
authors.forename: Felicidad
authors.initials: F
authors.lastname: Ronda
mesh_terms: D004063:Digestion; D002523:Edible Grain / Q000737:chemistry*; D004798:Enzymes / Q000378:metabolism*; D005433:Flour; D005511:Food Handling; D006868:Hydrolysis; D055595:Mechanical Phenomena; D010316:Particle Size; D010858:Pigmentation; D010940:Plant Proteins / Q000032:analysis; D013213:Starch / Q000737:chemistry*
chemical_list: D004798:Enzymes; D010940:Plant Proteins; D013213:Starch
keywords: Functional properties; In vitro starch digestibility; Milling; Tef