Impact of Tragacanth and Xanthan Gums on the Physical and Textural Characteristics of Gluten-free Cake

The quality of cakes made of wheat flour depends on the quantity and quality of its gluten proteins; however, these proteins may have side effects for some people, including the patients with celiac, and the only way to cure this disease is to take a lifelong gluten-free diet. This research aims to produce gluten- free cake by using rice flour and xanthan and tragacanth gums, including two treatments of xanthan gum (0.5 &1 %), two treatments of tragacanth gum (0.5 & 1%), four combination treatments of xanthan gum and tragacanth, and one control treatment (without gum). The effects of tragacanth and xanthan gums on the texture characteristics, moisture content, water activity (aw), color, volume, apparent density, and porosity of the resulting cake were investigated. The data obtained were analyzed by the use of factorial experiments with three replications (3*3) and a Completely Randomized Design (CRD). The results showed that the treatments containing gum have less texture stiffness compared to the control. Among the treatments, those having the combination of 0.5% tragacanth and 1% xanthan gum hold the maximum content of moisture. The L component amount of gluten-free cake samples was increased compared to the control while the rate of a and b components was decreased. The maximum amount of aw is related to the 0.5% treatment tragacanth and 1% xanthan, and the lowest aw belongs to the control. Apparent and bulk density has a difference with the control, and the minimum amount and the maximum amount belong to the treatment containing 1% tragacanth and the control, respectively. Samples containing 1% xanthan and 0.5% tragacanth could be desirable due to less texture stiffness, maximum content of moisture and aw, high color score, minimum density, and better keeping quality during the storage period.