Preparation of turmeric powder with various extraction and drying methods

Background: In this study, turmeric (Curcuma longa L.) powder was prepared with various extraction and drying methods. Extractions were performed using three solvents (water, 50% ethanol, and 70% ethanol) and three drying methods, namely, spray drying (SD), freeze drying (FD), and spray-freeze drying (SFD). Results: Levels of the curcuminoids, curcumin, demethoxycurcumin, and bisdemethoxycurcumin, in turmeric powder preparations were analysed using HPLC, and scanning electron microscopy and laser particle size analysis were used to observe and estimate the surface and size distribution of particles. The total amount of curcuminoids ranged from 0.59–14.35 mg/g turmeric powder, and as the concentration of ethanol increased, the level of curcuminoids, antioxidant activity, and average particle size significantly increased (all p < 0.05). In addition, the abundance of curcuminoids significantly increased in the order of SFD, FD, and SD (p < 0.05), whereas the average particle size significantly increased in the order of FD, SFD, and SD (p < 0.05). Conclusions: The highest TPC and TFC were detected in SFD turmeric powder preparations, whereas the average particle size significantly increased in the order of FD, SFD, and SD. Based on this study, we also showed that the level of curcuminoids, antioxidant activity, TPC, TFC, and average particle size were most affected by the extraction solvent. Graphical Abstract: [Figure not available: see fulltext.].