Utilization of sweet potato starches and flours as composites with wheat flours in the preparation of confectioneries

Freshly harvested roots of sweet potato variety TIS 87/0087 were processed into flour and starch using standard methods. Blends of Wheat and sweet potato composite flour was developed in the ratios 80:20, 70:30, 60:40 and 50:50. Also, blends of wheat and sweet potato starch were developed in the ratios 80:20, 70:30, 60:40 and 50:50. Whole sweet potato flour and starch were also included where 100% wheat flour was used as control or standard. Functional properties of wheat: sweet potato composite flour showed that water absorption capacity ranged from 2.0-2.5 g/ml, oil absorption capacity: 1.5-2.5 g/ml and bulk density: 0.68-0.82 g/ml. Gelatinization temperature ranged from 49.00-70.25°C. Wheat: sweet potato composite starch showed that water absorption capacity ranged from 1.5-2.0 g/ml, oil absorption capacity: 1.0-2.0 g/ml and bulk density: 0.74-0.78 g/ml. Gelatinization temperature ranged from 48.0-65.5°C. Sensory evaluation scores showed that up to 40% inclusion of sweet potato starch gave acceptable bread. Up to 40 and 50% inclusion of starch or flour to wheat gave acceptable cakes with desired colours. Also, 50% inclusion of starch or flour to wheat gave acceptable chinchin for colour and general acceptability.    Key words: Sweet potato, flour, starch, confectionery, functional properties, sensory evaluation.