Showing 1 results for Water Activity.
N. Meghdadian, M. Shahedi, G. H. Kabir,
Volume 8, Issue 1 (4-2004)
Abstract
Iranian flat breads generally have short shelf life. The result of this situation is usually enormous bread wastage. Among the most important factors involved are lack of proper packing and storage methods. In this study, the best temperature for bread packing was determined and the effects of three types of plastic wrapping on Taftoon bread baked of the typical flour were investigated after 72 hours of storage. These wrappings included a two-layer wrapping of oriented polypropylene and polyethylene (OPP/PE) with a thickness of 60 µ, a three-layer wrapping of PP/PE/PE with a thickness of 70 µ, and a two-layer polyethylene with a thickness of 70 µ together with cardboard and plastic. Bread packing was carried out at two different temperature ranges (20-25oC and 45-50oC). Results from moisture measurements and water activity test indicated that the characteristics of breads packed in different wrappings showed significant differences (p<0.01). Moisture percentage and water activity (aw) were lower in layers with higher permeability to moisture and water vapor and, consequently, algal growths reduced in these wrappings. Reduced moisture content, however, reduced the final bread quality score. It was also found that employing cardboard covered in polyethylene had no significant effect on bread shelf life during 72 hours of bread storage. Another finding from the present study was that packing a large number of 10×10 cm bread pieces within one single wrapping with cardboard and plastic was satisfactory and that the presence of the cardboard helped maintain bread shape during transportation and storage.
