Effect of different processing methods on functional and physiochemical properties of turmeric (Curcuma longa Linn.) rhizome Var. Kapurkot Haledo-1

Abstract

This study was conducted to evaluate the impact of different processing methods on the functional and phytochemical properties of turmeric rhizomes. The experiment consisted of four treatments: Treatment 1 involved oven-drying the turmeric powder, Treatment 2 involved blanching followed by oven-drying, Treatment 3 involved cooking followed by oven-drying, and Treatment 4 involved sun-drying. Each treatment was replicated four times. The major findings of the study revealed that sun-drying (68.50%) and blanching/oven-drying (66.50%) positively influenced the dispersibility of turmeric powder. Blanching/oven-drying (0.32 g/ml) and cooking/oven-drying (0.30 g/ml) significantly improved the bulk density of turmeric powder (p<0.001), with no significant difference observed between these two treatments. The water absorption capacity of the turmeric powders ranged from 3.35 to 5.35 g/ml, with the sun-dried sample displaying the lowest capacity and the cooked/oven-dried sample demonstrating the highest capacity. Similarly, sun-dried powder exhibited the lowest swelling power and solubility, while heat treatment resulted in a substantial increase in both of these parameters. Additionally, the curcumin content was found to be highest in the cooked/oven-dried (3.11%) and sun-dried (2.99%) turmeric powder. In conclusion, this study suggests that blanching and cooking methods have wide applicability in the food industry to enhance the bulkiness of turmeric powder for appropriate packaging and handling. Moreover, these methods contribute to the characteristic flavor and aroma of turmeric. The findings emphasize the importance of considering different processing techniques for optimizing the functional and phytochemical properties of turmeric, thus enabling its effective utilization in various food applications.