Determination of physicochemical and sensory properties of gluten-free biscuits comprising different flour sources

Celiac disease is a chronic, inflammatory disease occurring in small intestine as an immune response to gluten. This malfunction can appear at any age, when foods containing gluten are introduced into the diet. Production of different and desirable gluten-free snack products is significant for consumers‟ quality of life. In this study, buckwheat flour and chestnut flour were used as main ingredients to produce gluten-free biscuit formulations while alternatives with chia seeds were also evaluated. Therefore, all formulations used might also be considered as "functional foods" in addition their gluten-free properties. First of all, ingredients used in the biscuit formulations were evaluated for their proximate properties such as total ash, moisture, protein, carbohydrates, lipids, dietary fiber and total energy. Biscuits were evaluated for their physical properties (weight, volume, expansion, thickness and bulk density, color) and texture. Shelf life evaluation and sensory analysis tests for consumer preferences were also performed in the final products. According to the results gathered on dry weight basis, buckwheat and chestnut flour contained 11.4% and 5.24 protein; 1.88 and 3.83 % ash; 1.70 and 1.57% lipids; and 72.38 and 68.39% carbohydrates, respectively. Chestnut dietary fiber content was about 18.04% while buckwheat flour had about 7.56 %. Hardness in buckwheat samples are highest (47.8 N) when compared with chestnut samples (40.8 N) and chia seeds included formulations. Spread ratio values were generally higher in chestnut samples and addition of chia seeds made no significant effects. Volume of biscuits were quite similar in all samples (25 cm3). Samples with chia seeds were significantly different bulk density properties in comparison to samples without seeds. This study was significant for using uncommon but functional ingredients in gluten-free biscuit formulations and investigating them in many perspectives.