Effect of different drying treatments on concentration of curcumin in raw Curcuma longa L.

Abstract

Curcuma longa L., commonly known as turmeric, is a member of the ginger family (Zingiberaceae), native to Southwest India. Curcumin is the active ingredient of the turmeric. In traditional Indian medicine, turmeric has been used to treat stomach and liver ailments, as well as topically to heal sores, for its supposed antimicrobial property. The curcumin is believed to have a wide range of biological effects including antiinflammatory, antioxidant, antitumor, antibacterial, and antiviral activities, which indicate potential in clinical medicine. In conventional processing of turmeric, raw turmeric rhizomes boiled and dried under direct sunlight for 1-4 hrs and 25-30 days, respectively although which is highly sensitive to the heat and sunlight. This work described the effect of different drying treatments including shade, direct sunlight, solar dryer, convection oven and hot-air drying on the concentration of curcumin. The Reflux method was used to analyse the concentration of curcumin in turmeric powder prepared under different drying treatments. The results had shown that without boiling turmeric rhizomes took too much time to reach the final moisture contents below 10% in all drying treatments which was not feasible economical and hygienically. The optimum conditions for drying of turmeric rhizomes were 1 hr boiling and drying at 70 o C in hot-air dryer.

Effects of Variety and Curing and Drying Methods on Quality Attributes of Turmeric (Curcuma domestica) Powder

“…A negative impact of shade drying (GSD) than STD on curcumin concentration was also reported previously [33]. The GSD took 16 days, followed by OSD, and the color of GSD dried samples appeared dull due to a lower rate of moisture loss with a natural convection.…”

Design, development, and drying kinetics of infrared‐assisted hot air dryer for turmeric slices

“…Solar drying was also widely used for drying turmeric, but it has several disadvantages, such as more drying time during insufficient sunlight, laborious process, and the chances of contamination, and infestation is more (Borah et al, 2017). Several researchers (Fudholi, Ariffin, Ruslan, Othman, & Sopian, 2012; Lokhande, Kale, Sahoo, & Ranveer, 2013; Gan, Charters, Driscoll, & Srzednicki, 2017; Raza, Ali, Yusof, Nasir, & Muneer, 2018) had been conducted studies in hot air dryers, but the major drawbacks are more consumption of energy and drying time in falling rate period, which makes the product harder (Raza et al, 2018).…”

Drying Behavior and Curcuminoids Changes in Turmeric Slices during Drying under Simulated Solar Radiation as Influenced by Different Transparent Cover Materials

“…Curcumin in turmeric rhizomes is reduced by direct and indirect solar radiation. Raza et al [ 27 ] reported lower curcumin contents of dried rhizomes from sun drying and solar tunnel drying than that from shade drying. Mahayothee et al [ 28 ] also reported that drying in a solar greenhouse dryer covered with a polycarbonate sheet reduced curcumin contents in cassumunar ginger.…”