Effect of polyols on shelf-life and quality of flat bread fortified with soy flour

Abstract

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