Staling of fresh and frozen gluten-free bread

The difficulty in finding gluten-free bread and its high price make it necessary to prolong its shelf life to facilitate its availability. Freezing is an interesting alternative. The storage of bread at over zero temperatures, 20 degrees C and 4 degrees C, showed faster staling at refrigerator temperatures. A good relationship between crumb firmness and the extent of starch recrystallization was obtained, although the effect of water loss was also detected. The study of freezing and frozen storage at -14 degrees C and -28 degrees C for 7 days showed a substantial effect of the storage temperature on gluten-free bread quality and shelf life. Breads stored at -28 degrees C retained a quality similar to that of fresh breads while a marked deterioration of the breads stored at -14 degrees C was observed. This effect, the strongest on bread texture, was a result of starch recrystallization. The glass transition, T-g' and onset of ice melting, T-m' of the maximally freeze-concentrated bread crumb were -37.1 +/- 0.6 degrees C and -19.3 +/- 0.2 degrees C respectively. The higher amount of unfrozen water at -14 degrees C could explain the acceleration of reactions responsible for bread staling during frozen storage. The use of storage temperatures below T-m' is recommended to retain high quality of the gluten-free bread during frozen storage. (C) 2011 Elsevier Ltd. All rights reserved.