Blanching and drying period affect moisture loss and vitamin C content in Ziziphus mauritiana (Lamk.)

Abstract

Wider utilization of Ziziphus mauritania (Lamk) Ber fruits in sub-Saharan Africa is hindered by the rapid deterioration of the fresh fruits and darkening of sun-dried fruits. This study was undertaken to
determine the effect of pre-drying treatment, drying method and the subsequent duration of storage on the quality attributes of Z. mauritiana fruits harvested from the Zambezi Valley. The vitamin C content
was high at the beginning of the drying period and progressively decreased as the drying increased, and was lowest at three weeks for all drying methods. Effect of drying method was not significant (P >
0.05). The purity (chroma) and lightness (value) of fruit colour decreased (P < 0.001) with increasing drying duration irrespective of the drying method. Blanching fruits before drying significantly (P< 0.001) decreased the colour chroma of the fruits (6.4) in comparison with non-blanched fruits (6.6). Further work to determine the causes of darkening in drying Z. mauritiana fruits and sensory evaluations to
determine the level of darkening that is acceptable to consumers is warranted.