Drying the African Palm Tree (Borassus aethiopum, Mart) Fruits in View of Producing Edible Flour

摘要

In order to valorize the rapidly deteriorating fruits of the palm tree Borassus aethiopum Mart under hot and humid climate, drying assays for preservation were carried out. Fruits morphological parameters (weight, diameter and pulp thickness) from two most producing agro ecological zones of Cameroon were measured. Pulps obtained upon pulping the fruits were cut out and dried using an electric dryer under mild conditions (40°C and 20% drying air humidity). Physico-chemical and functional characterization of fresh and dried pulps allowed evaluating the influence of drying on some pulp components. Morphological characteristics of fruits were not significantly different (p<0.05) from one origin zone to another. Fruits average diameter and pulp thickness were 14 cm and 8 mm, respectively while average weights varied between 1270.04±16.69 and 1324.55±85.99 g. Average yield in flesh was 38%. Drying kinetic obtained was classical and revealed that the fifth hour was the necessary time of drying to obtain pulps with constant characteristics and acceptable maximum residual moisture content of 15%. In addition, at this time the pulps contained 60 and 55% of their initial total carotenoids and vitamin C contents, respectively. The flour obtained after milling and sieving comprised mostly particles of 250-500 μm sizes and showed appreciable physico-chemical and functional properties: Water Absorption Capacity (WAC) of 313-407%; Solubility Index (SI) of 39-51%; Fiber content (FB) of 14-30% DM. These results demonstrate the feasibility of flour production from pulps of this Cameroonian palm tree.