تأثیر عوامل تخمیر و درصد استخراج آرد بر میزان اسید فیتیک نا‌ن‌های سنگک و لواش ماشینی شهرستان مشهد

Bread, the main staple food of Iran, imparts a major portion of energy and protein to urban and rural diets. Due to the use of flour with high extraction rate and improper fermentation of the corresponding dough, traditional breads have a rather high level of phytic acid. This has a detrimental effect on absorption and availability of minerals (Ca, Fe, Zn, Mg, Cr, Cu, etc.), carbohydrates, proteins and lipids, thus leading, for e.g., to iron-deficiency anemia in the present study, flours with different extraction rates (with known phytic acid content) were used for baking “Sangak” and “Lavash” breads and analyzed for phytic acid. Different levels of yeast, times of fermentation and extraction rates of flour were applied in the preparation of breads and their phytic acid levels were then estimated. Based on technological merits and residual phytic acid contents, breads prepared from two types of treatments were selected, their chemical composition, availabilities of iron and lysine as well as organoleptic characteristics were evaluated. Results indicated that under the employed conditions total destruction of phytic acid in “Sangak” and “Lavash” is rather impractical. A considerable reduction in phytic acid was noted: in “Lavash” bread using 2.5% yeast, 4 h of fermentation and a 50-50 blend of flours with 81.0 and 86.5% extraction rates and in “Sangak” bread with similar conditions (except for the flour which was a 50-50 blend of 86.5 & 97.5% extraction rates). Available lysine was similar in both of the selected breads compared to their respective references. Their available iron contents, however, were higher than their corresponding references (P ≤ 0.05 ). No significant differences were observed with regard to organoleptic evaluations of selected breads as compared to their references (P ≤ 0.05 ). Overall, the above-mentioned treatments are recommended for the baking of “Sangak” and “Lavash” breads.