EFFECTS OF HYDROCOLLOIDS ON PROCESSING AND QUALITIES OF WHEAT TORTILLAS

Effects of hydrocolloids were evaluated in hot-press wheat tortillas. Natural (arabic, guar, and xanthan), modified cellulose (carboxymethyl -cellulose [CMC], hydroxypropyl methylcellulose, and methylcellulose), and commercial blends (mixtures of natural and modified cellulose gum s) were utilized. Farinograph values, mixing characteristics, dough ma chinability, tortilla characteristics (diameter, weight, moisture cont ent, and appearance), rollability over time, and freeze-thaw stability were determined. Increased levels of gums resulted in doughs that wer e more sticky and less cohesive throughout mixing. Doughs prepared wit h commercial blends containing cellulose gum exhibited characteristics similar to CMC, such as lower initial dough viscosity and longer doug h development times compared with those of the control. Hot-press whea t tortillas containing natural gums, modified cellulose gums, or comme rcial blends were consistently round, puffed, slightly browned, and of good quality. Tortilla diameters (159 mm), weights (41.4 g), and mois ture content (30.8%) were similar for all tortillas. Water absorption of dough increased when more gums were added. The rollability of torti llas was retained longer with CMC and cellulose-based commercial blend s. Rollability of all tortillas decreased during freezing and thawing, and tortillas containing CMC were significantly more rollable than co ntrol tortillas after five freeze-thaw cycles. Proper gluten developme nt appears to be essential for good dough machinability, tortilla qual ities, and tortilla shelf stability.