Milling and particle size of cowpea flour and snack chip quality

Abstract

Texture and color attributes were determined for snack chips made from cowpea flour. Chips were prepared from flour milled through 0.5, 1.0, and 2.0 mm screens; in addition, the ratio of cowpea flour to cornstarch was varied. Snapping force was slightly higher for chips made from fine flour. In general, the ratio of total energy to peak force ( E/PkF) determined by the Kramer shear test increased with more finely milled flour, or addition of starch. Color values ( L*, a*, and b*) indicated that chips with greater cowpea protein/cornstarch ratios were darker and browner. Discriminant function analysis was used to relate instrumental measurements to consumer hedonic scores. Of particular importance was the ( E/PkF) ratio from the Kramer shear test. Chips with lower E/PkF values had higher acceptability scores. In turn, the E/PkF values were related to the extractable starch content. The apparent starch content was dependent on either the amount of starch added, or by the milling conditions. In general, chips produced from finely milled flours had greater apparent starch content than those produced from coarsely milled flours.