Spatial variation of starch retrogradation in Arabic flat bread during storage
journal contributionposted on 2016-06-14, 11:26 authored by Latifah Abdullah Ali Al-Hajji, Vahid Nassehi, Andy StapleyAndy Stapley
Samples from different radial positions of flat Arabic bread were analysed by differential scanning calorimetry (DSC) immediately after baking and after up to 3 days storage. This showed that whilst almost complete gelatinisation initially occurs, higher levels of subsequent retrogradation (typically 1.5 to 3 times) occurred in an area intermediate between the centre and outside of the pita bread (viewed from above). This coincided with the region with the highest moisture content (30% w.b.) immediately after processing, and which is likely to have heated at the slowest rate. A parallel study using DSC which subjected dough samples to a temperature profile similar to that found in baking also found that relatively low heating rates of 20 °C min−1 produced slightly higher amounts of retrogradation (typically 5–25%) than higher heating rates of 200 °C min−1. In each case moisture contents during storage were comparable between samples, thus suggesting that the local heating rate experienced during baking is a key parameter that can explain differences in subsequent retrogradation in different regions of the pita bread.
Latifah Al-Hajji wishes to thank the Kuwait Institute for Scientific Research (KISR) for funding her PhD studies.
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