Evaluation of Various Properties of Amaranthus (Genus Amaranthus L.) Based Composite Flour Blends for Preparation of Gluten-Free Biscuits

Abstract

This research was conducted to investigate the pasting, rheological and functional properties, and gluten-free biscuit making potential of a composite flour prepared from grains of amaranthus, sorghum and finger millet. The formulation for the composite flour was obtained from D-optimal mixture design ratio using Design-Expert. The rheological and pasting properties of the composite flours were determined, while the proximate composition, physical dimensions, mineral concentration and sensory quality attributes of the biscuits were assessed. The results showed that there were significant (p<0.05) differences in the pasting profile of the control and amaranthus based composites flour except for pasting temperature. Water absorption capacity and water soliblity index increased as the blending ratio of amaranthus flour increased, while oil absorption capacity decreased. The proximate composition evaluation 13.75, 2.04, 1.77 and 31.75% were found to be the highest values of the biscuit samples in terms of protein, crude fiber, ash and crude fat, respectively. Mineral analaysis was carried out and there was a significant (p<0.05) difference in Fe, Ca, Zn and P content among the biscuit samples made from the composite flour blends. Similarly, the sensory evaluation indicated that there was a significant (p<0.05) differences in apperance, colour, texture, flavour and overall acceptability among the composite biscuit samples. However, the difference was insignificant (p<0.05) in crispiness of biscuit samples. In a nut shell this research revealed that a nutritionally dense gluten-free biscuits can be formulated without affecting the quality attributes of the biscuit. Thus, the composite flours can be used for the preparation of gluten free food products in africa, where the crops have not been effectively utilized in food processing industries.

Keywords

• composite flours
• gluten-free
• amaranthus
• sorghum
• finger millet