Isolation of Wheat Puroindoline-b from Flour by Preparative Acid Electrophoresis.

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, lipidcomplexed 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 Atype granule content was positively correlated with starch pasting attributes, which might suggest that granule size itself could contribute to wheat starch pasting behavior.