Improving the texture and delaying staling in rice flour chapati with hydrocolloids and α-amylase

Chapaties were prepared from rice flour so as to make this product available to patients suffering from gluten intolerance (celiac disease). The textural properties of the fresh and 24 h stored rice flour chapati were determined using a tensile deformation test. The extensibility and energy to rupture decreased whereas the peak force to rupture and tensile deformation modulus increased during storage. Different hydrocolloids like guar gum, xanthan, locust bean gum and hydroxypropylmethylcellulose were added to the rice flour at levels of 0.25% and 0.5% flour basis and it was observed that they improved the texture of chapati by keeping it more extensible during storage. Fungal alpha-amylase was also incorporated into the rice flour alone and in combination with the hydrocolloid and this resulted in further improvement in the texture. The retrogradation in the chapati after 24 h of storage was also studied using differential scanning calorimetry. Chapaties containing hydrocolloid and/or alpha-amylase showed lower retrogradation after storage. Rice flour chapaties can be made available to celiac disease patients and the undesirable textural changes, which take place in chapati as a result of starch retrogradation, can be delayed by the incorporation of hydrocolloids and alpha-amylase. (C) 2004 Elsevier Ltd. All rights reserved.