Puffing as a Novel Process to Enhance the Antioxidant and Anti-Inflammatory Properties of Curcuma longa L. (Turmeric)

Abstract

Curcuma longa L. (turmeric) is used as a food spice; however, its strong taste restricts wider applications as a food ingredient despite its well-known health benefits. To develop an effective yet simple process for enhancing its antioxidant and anti-inflammatory activities, turmeric was gun-puffed at various pressures. Puffed turmeric exhibited an increase in its brown color and porous structures, indicating the occurrence of the Maillard reaction and vaporization during the process. Proximal analysis revealed that puffing did not alter the major constituents, although a very small decrease in crude fat extraction was observed under some circumstances. Total phenolic compounds in the extract were significantly increased after puffing, and subsequent assessment of antioxidant capacity, as determined using independent 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays, demonstrated enhanced antioxidant capacity in a puffing-pressure-dependent manner. Turmeric extract was further tested for the regulation of inflammatory responses in the murine macrophage RAW264.7 cell line. Suppression of pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α in lipopolysaccharides (LPS)-induced macrophages was amplified using puffed-turmeric extracts compared to the control extract. Furthermore, macrophage-activation assessment revealed downregulated expression of inflammation-relevant cluster of differentiation (CD)80 and CD86 using puffed-turmeric extract in a puffing-pressure-dependent manner. However, expression of major histocompatibility complex (MHC)-II, which controls adoptive immunity, was not affected by treatment with any of the turmeric extracts. Overall, the current study demonstrated that puffing is a promising and simple method for enhancing the antioxidant and anti-inflammatory properties of turmeric.