Development and Characterization of Refractance Window-Dried Curcuma longa Powder Fortified with NaFeEDTA and Folic Acid: A Study on Thermal, Morphological, and In Vitro Bio Accessibility Properties

<i>Curcuma longa</i> powder was prepared by refractance window drying (RWD) and was fortified. Fortification of dried turmeric powder with folic acid and NaFeEDTA, along with its characterization, was achieved. Characterization techniques, such as FTIR, XRD, TGA, DSC, FESEM, and particle size analysis, have been considered to study the morphological, thermal, and crystalline properties of the resulting fortified turmeric. In vitro digestion studies were carried out to determine the retention of nutrients after fortification. The RW-dried and fortified turmeric powder exhibited a stable average particle size and PDI values in the range of 1500-1600 nm, for 0.25-0.29, respectively. The fortified turmeric powder exhibited enhanced crystalline properties with sharp and high intensity peaks for NaFeEDTA-fortified turmeric powder. In vitro digestion studies affirmed the bio-accessibility of the novel fortified turmeric powder at 9.77 mg/100 g and 12.74 mg/100 g for folic acid and NaFeEDTA fortification cases, respectively. Thus, the findings confirmed that there was no significant influence of fortification on the characteristics of folic acid and the NaFeEDTA-fortified RW-dried turmeric powder product.