EFFECT OF STRONG GLUTEN FLOUR ON QUALITY OF WHEAT TORTILLAS FORTIFIED WITH CROSS-LINKED RESISTANT STARCH

Abstract

ABSTRACT Tortillas have become popular and thus are an attractive vehicle to improve dietary fiber consumption. This work investigated the effect of a high dietary fiber cross-linked resistant starch (RS4), and strong gluten bread flour on wheat tortilla textural and quality attributes. Commercial tortilla and bread flours (TF and BF, respectively) were substituted with RS4 containing 90% dietary fiber at 0, 15, 20 and 25%. RS4 substitution decreased mixing resistance of both BF and TF dough, but had minimal effect on water absorption. The RS4-substituted tortillas required significantly less force (4.5–8.8 N) to extend than control (8.7–10.6 N), implying they were more tender. RS4 substitution increased opacity and diameter of tortillas, both desirable attributes. The RS4-substituted BF tortillas were significantly more shelf stable, retaining good flexibility (average score = 4.0) after 18 days of storage, compared with RS4-substituted TF tortillas, which lost flexibility within 4 days of storage. PRACTICAL APPLICATIONS Tortillas are currently popular due to the convenience they provide consumers and have surpassed sandwich bread as the preferred wrap for quick meals in the U.S.A. This makes tortillas a logical target to improve dietary fiber consumption. However, attempts to increase the dietary fiber content of tortillas have been unsuccessful due to the negative impact on product texture and shelf stability. Complicating the problem further is the fact that wheat tortilla flour does not have clearly defined quality parameters, as is the case with bread flour. This leads to inconsistent and unpredictable product quality. Taking advantage of the strong gluten in bread flour and the well-defined raw material quality parameters can allow for incorporation of significant dietary fiber in tortillas without adverse impact on product texture and shelf stability. This would eliminate the need for expensive additives to obtain desirable product texture.