The influence of glycerol, sorbitol, maltitol and propylene glycol on shelf life and quality of Barbari, Iranian flat bread, fortified with soy flour, was examined. Effects of different levels of polyols (0, 1 and 5 g/100 g) were analyzed during 2 weeks of storage at room temperature. Specific volume and width/height ratio of fresh breads were not affected by polyol addition, while it significantly decreased the moisture content of the bread. Propylene glycol significantly decreased water activity to 0.871 (1 g/100 g propylene glycol) and 0.867 (5 g/100 g propylene glycol) in comparison with the control (0.883). Evaluation of crumb hardness and moisture indicated that sorbitol and pro-pylene glycol were able to diminish bread staling. The rise in hardness in polyol-supplemented bread samples was not significantly more than the control between the first and second days of storage. Increase in hardness of bread samples was observed lower than the control after the second day in both levels of the sorbitol and 5 g/100 g propylene glycol. Acceptability of the breads, as indicated by panelists, was found to be higher than control bread for 5 g/100 g propylene glycol with 3.8 and 4.8 values, respectively. Results showed that propylene glycol can present the greatest effect on quality and shelf life of Barbari flat bread fortified with soy flour.

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