Effect of storage on the physicochemical functional and rheological properties of taro (Colocasia esculenta) flour and paste

Abstract

Recent studies have led to the development of a simple process for the production of precooked taro flour for the preparation of achu (taro paste). The objective of this study was to determine optimal conditions for the preservation of taro flour. For this purpose, flour was produced from boiled taro tubers. Cooked tubers were sun dried using a solar dryer, ground through a 500 μm sieve and further separated by using 250, 150 and 75 μm sieves. Flours were sealed in polyethylene bags and kept at ambient temperature (25°C) and at 4°C. One set of flour not sealed was exposed at 25°C.
Flours were stored for 5months. Physico-chemical and rheological properties of flours and paste were determined monthly. Increases in water content of flours were recorded, especially for exposed flours. Resistant starch increased with storage. Water absorption capacity and water solubility index increased during the first three months and decreased thereafter. Flour color also varied. Angle of repose increased while cohesion decreased. Paste produced from these flours decreased in hardness with storage. The highest value of gumminess was observed in the paste made from flours with particle size above 250 μm. In fact, the degree of variations of each parameter depended mainly on the storage level. This study revealed that flours kept in polyethylene bags at ambient temperature may be stored for three months without significantly (p<0.05) altering their physico-chemical properties whereas 4 to 5 months is the maximum storage in polyethylene bags at 4°C.