EFFECTS OF SIZE REDUCTION AND DRYING METHODS ON DRIED GINGER QUALITY AND OIL/OLEORESIN YIELD

ABSTRACT

A survey was carried out to appraise the existing handling and primary processing of ginger in Southern Kaduna Area of Kaduna. Alongside a set of experiments were carried out to examine the effects of these traditional size-reduction treatments and different drying methods on dried ginger quality and oil/oleoresin yield. Different samples of freshly harvested ginger in whole-unpeeled (WU), split-unpeeled (SU), whole-peeled (WP) and split-peeled (SP) forms were dried under sun drying (D1), solar drying (D2), natural air drying (D3) and fire-heated drying (D4) methods. The result  show that splitting ginger rhizomes into halves and spreading them on hard compact platform under the sun to dry is the popular primary processing technology in the study area. Split-dried ginger form was found to be the most accepted form in both the local and international ginger trade. The result in Table2a represents the summary of the data obtained on dried ginger oil/oleoresin content. The analysisindicates that the combined effect of size-reduction treatment (P) and drying methods (D)  on essential oil/oleoresin content of dried ginger was highly significant (0.05). Comparing the interaction means of the physical processing treatment (P) and the drying methods (D), the Whole-unpeeled samples dried under fire-heated drying method (WUD4), split-unpeeled samples dried under fire-heated drying method (SUD4), split-unpeeled samples dried under solar drying method (SUD2) and split-unpeeled samples dried under open-sun drying method (SUD1) recorded significant yields of ginger oil/oleoresin, while samples of whole-peeled (WP) and split-peeled (SP) dried under the different drying methods recorded very insignificant yields of oil/oleoresin. The study suggests that for industrial production of ginger oil/oleoresin, farmers should adopt drying ginger whole-unpeeled under fire-heated drying method.

Keywords: Primary Processing; Size-reduction Treatments; Drying Methods; Dried ginger; oil/oleoresin