Effects of pre-harvest soil management practices and post-harvest processing on phytochemical qualities of turmeric (Curcuma longa)

Phytochemicals from turmeric (Curcuma longa L.) have a plethora of beneficial, including medicinal uses. To increase their dietary intake, besides minimizing processing losses, exploring pre-harvest soil managements to increase their content naturally may be a suitable option. We made an attempt to assess the effect of pre-harvestsoil management by either organic manuring or inorganic fertilization with or without agricultural liming and postharvest processing through curing followed by drying at 60 ± 2° C on phytochemical properties of turmeric cultivar Meghaturmeric 1 grown in the acid soils of sub-tropical climate of northeast India. Pre-harvest management of soils significantly (P ≤0.001) influenced the phytochemical concentration of turmeric rhizomes. Curcumin concentration in fresh mother rhizome was 15-38% higher than the fresh finger rhizomes. Similarly, fresh mother rhizomes had 21-22% more β-carotene and 7-9% more anti-oxidants than the fingers. Post-harvest processing of fresh rhizomes (mother and fingers) to yield dry powder resulted in significant reduction of curcumin (by 2.0-8.0%), β carotene (by 8-28%) and anti-oxidant (by 43-64%) concentrations. Pre-harvest soil managements by poultry manuring with liming considerably increased the phytochemical concentrations in the turmeric rhizomes.