Publication no. C-2002-1204-06R |  VIEW ARTICLE

Soft Wheat Starch Pasting Behavior in Relation to A- and B-type Granule Content and Composition (1).

S. V. Shinde (2), J. E. Nelson (3), and K. C. Huber (3,4). (1) University of Idaho Agric. Exp. Stn. Paper 02B01. (2) J.R. Simplot Co., Food Group, Caldwell, ID 83601-1059. (3) Department of Food Science and Toxicology, University of Idaho, P.O. Box 441053, Moscow, ID 83844. (4) Corresponding author. Phone: 208-885-4661. Fax: 208-885-2567. E-mail: <huberk@uidaho.edu> Cereal Chem. 80(1):91-98. Accepted September 16, 2002. Copyright 2003 American Association of Cereal Chemists, Inc.

Flours of two soft wheat cultivars were fractionated into native, prime, tailing, A-, and B-type starch fractions. Starch fractions of each cultivar were characterized with respect to A/B-type granule ratio, amylose content, phosphorus level (lysophospholipid), and pasting properties to investigate factors related to wheat starch pasting behavior. While both cultivars exhibited similar starch characteristics, a range of A-type (5.7-97.9%, db) and B-type granule (2.1-94.3%, db) contents were observed across the five starch fractions. Though starch fractions displayed only subtle mean differences (<1%) in total amylose, they exhibited a range of mean phosphorus (446-540 µg/g), apparent amylose (18.7-23%), and lipid-complexed amylose (2.8-7.5%) values, which were significantly correlated with their respective A- and B-type granule contents. A-type (compared with B-type) granules exhibited lower levels of phosphorus, lipid-complexed amylose, and apparent amylose, though variability for the latter was primarily attributed to starch lipid content. While starch phosphorus and lipid-complexed amylose contents exhibited negative correlation with fraction pasting attributes, they did not adequately account for starch fraction pasting behavior, which was best explained by the A/B-type granule ratio. Fraction A-type granule content was positively correlated with starch pasting attributes, which might suggest that granule size itself could contribute to wheat starch pasting behavior.