CONTRIBUTION OF WHEAT-FLOUR FRACTIONS TO BEAK HOT PASTE VISCOSITY

The quality of many baked products, noodles, gravies, and thickeners i s related to the pasting properties of wheat (Triticum aestivum L.) fl our, yet different flours vary markedly in their pasting performance. The objective of the present research was to assess the role of the wh eat flour fractions, gluten, water solubles, prime and tailing starche s, in the contribution to peak hot paste viscosity among three selecte d wheat cultivars. Straight-grade flours were fractionated and reconst ituted. Fractions were examined independently and were deleted in othe rwise fully reconstituted flours. Fractions were exchanged between cul tivars for reconstituting flours, and fractions were substituted indiv idually into a common starch base. The flours from the cultivars Klasi c, McKay, and Madsen differed markedly in their peak hot paste viscosi ties, and were fractionated and reconstituted with only a small effect on paste viscosity. Results clearly showed that prime starch was the primary determinate of flour paste viscosity, but the other fractions all exerted a significant effect. Tailing starch increased paste visco sity directly due to pasting capacity of starch or indirectly through competition for water. Gluten also increased paste viscosity through c ompetition for water. The water-soluble fraction from different cultiv ar flours was more variable in effect.