تاثیر تخمیر کنترل شده خمیرترش حاوی لاکتوباسیلوس پلانتاروم و لاکتوباسیلوس برویس بر میزان اسید فیتیک خمیر و نان تولیدی

Background and purpose: Phytic acid plays a major role in reducing the bioavailability of minerals in food. The aim of this study was to evaluate the effect of controlled sourdough fermentation on reduction of phytate content in dough and bread produced by whole wheat flour containing Lactobacillus plantarum and Lactobacillus brevis. Materials and methods: This experimental study was carried out as a joint project in Golestan University of Medical Sciences and Gorgan University of Agricultural Sciences and Natural Resources. After isolation of two dominant lactobacillus isolates from whole wheat sourdough and their molecular identification, the effect of controlled sourdough fermentation (dominant isolates were used as starter culture, under treatments (as separate or mixed with equal proportions) of 28, 32, 36 °C fermentation temperatures and 16, 24, 32 h fermentation times) was examined on phytate content of produced dough and bread, using a spectrophotometric assay based on the measurement of iron. Results: Sequencing of PCR products led to identification of Lactobacillus plantarum and Lactobacillus brevis as the dominant lactobacillus isolates from whole wheat sourdough. According to statistical analysis, by increasing fermentation time and temperature, the amount of phytate significantly decreased in dough and bread produced by each of dominant isolates (P≤ 0.05). Furthermore, mixture of lactobacillus as starter culture was more effective on phytate reduction compared with using them separately. Conclusion: Our results showed that controlled fermentation of whole wheat sourdough have significant effect on reduction of phytate and increasing the bioavailability of bread minerals.