Drying-dependent changes in phytochemicals and bioactivities of Curcuma stahlianthoides Škorničk. & Soonthornk., a vulnerable endemic Thai species

Juthamas  Kongphapa; Sutthinut  Soonthornkalump; Suphatta  Phothiset; Sukontip  Vianmana; Arissara  Phosanam; Bongkochmas  sopa; Amporn Srikram

doi:10.34044/j.anres.2026.60.5.14

Authors

Juthamas Kongphapa Department of Food Technology and Nutrition, Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon 47000, Thailand
Sutthinut Soonthornkalump Department of Agriculture, Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon 47000, Thailand
Suphatta Phothiset Department of Food Technology and Nutrition, Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon 47000, Thailand
Sukontip Vianmana Biodiversity-based Innovation Research Unit, Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon 47000, Thailand
Arissara Phosanam Department of Food Technology and Nutrition, Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon 47000, Thailand
Bongkochmas sopa National Corn and Sorghum Research Center, Faculty of Agriculture, Kasetsart University, Nakhon Ratchasima 30320, Thailand
Amporn Srikram Department of Food Technology and Nutrition, Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon 47000, Thailand

DOI:

https://doi.org/10.34044/j.anres.2026.60.5.14

Keywords:

Antimicrobial activity, Antioxidant activity, Curcuma stahlianthoides, Phytochemicals

Abstract

Importance of the work: There is a lack of documentation regarding the nutritional and phytochemical composition and bioactivities of Curcuma stahlianthoides Škorničk. & Soonthornk., an endemic species in Thailand, as well as the effects of drying methods on these properties.

Objectives: To evaluate the effects of sun drying and freeze drying on the phytochemicals and bioactivities of C. stahlianthoides rhizomes.

Materials and Methods: Rhizomes were sun-dried or freeze-dried, ground into powder and analyzed for proximate composition, total curcuminoid content (using highperformance liquid chromatography), total phenolic and flavonoid contents, antioxidant activities (2,2-diphenyl-1-picrylhydrazyl, 2,2-azino-bis-3-ethylbenzothiazoline-6- sulfonic acid and ferric ion reducing antioxidant power assays) and antibacterial activity based on minimum inhibitory concentration determination.

Results: The freeze-dried samples contained higher fat (4.16%) and protein (3.44%) contents than the sun-dried samples (3.28% and 2.93%, respectively), while the carbohydrate content was comparable at approximately 78%. The freeze-dried samples had a higher mean ± SD total phenolic content (1.67 ± 0.08 mg gallic acid equivalents/g) and total flavonoid content (4.82 ± 0.17 mg quercetin equivalents/g) than the sun-dried extracts (p < 0.05). Antioxidant activities and antibacterial effects were also enhanced, particularly against Gram-positive bacteria, with minimum inhibitory concentrations of 12.5–25 mg/mL. Extraction yields were 2.75% for the sun-dried and 2.18% for the freezedried samples, while the total curcuminoid content was 12.95 µg/g dry weight and 14.11 µg/g dry weight, respectively. The total phenolic content had a strong positive correlation with antioxidant activities (Pearson’s correlation coefficient > 0.90, p < 0.05).

Main finding: Drying methods influenced phytochemical retention and related antioxidant and antibacterial activities of C. stahlianthoides, offering new insight into post-harvest processing and utilization of this rare Thai species.