Publications by authors named "Hyunbeen Park"

Considering that textile-based sensors are suitable for monitoring/communicating human vital health information, organic electrochemical transistors (OECTs) are considered as an efficient device platform for augmenting the capabilities and effectiveness of smart textile applications in diverse areas. Herein, we investigated the fabrication process and properties of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)-TEMPO-oxidized cellulose nanofiber (CNF) composites as active channel materials for fiber-type OECTs. Utilizing highly crystalline, mechanically rigid, and chemically robust CNFs directly extracted from biomass-derived tunicate, we fabricated PEDOT:PSS-CNF composite fibers with varying CNF portions (0, 5, 10, 20, and 30 %) through a simple one-step wet-spinning process using sulfuric acid-based coagulation media.

View Article and Find Full Text PDF

This study investigated the effect of various roasting conditions on regular and decaffeinated green beans. Regular and decaffeinated green beans from Guatemala, Brazil, Ethiopia, and Colombia were prepared under light, medium, and dark roasting conditions. Analysis of the decaffeination-induced changes in nonvolatile compounds revealed that decaffeinated green coffee beans had significantly lower concentrations of trigonelline (25%) and total carbohydrates (16%) but a higher chlorogenic acid content (10-14%) than regular green coffee beans (bothp < 0.

View Article and Find Full Text PDF

Background: l-Leucine powder (LP) was added to green Robusta coffee beans in order to reduce the difference in flavour between Robusta and Arabica coffee. l-Leucine was selected as an additive based on the Maillard reaction. The pre-treatment method conducted in this study was a short soaking (M1) or spraying procedure (M2), then LP was added at varying levels up to 3% (w/w, 30 g kg ).

View Article and Find Full Text PDF

This study analyses the biogenic amines (BAs) formed in mackerel cooked by various methods and conditions. Five BAs, including tryptamine, β-phenylethylamine, putrescine, histamine, and spermidine, were analysed by high-performance liquid chromatography with UV detection. The level of total BAs was higher in the mackerel fillet (108.

View Article and Find Full Text PDF

Volatile compounds of coffee brewed under various roasting conditions and by different brewing methods were analyzed. Green coffee beans () were roasted at 235 °C for 13 min, 240 °C for 15 min, and 245 °C for 17 min. Roasted coffee beans were ground into particles of three different sizes (710, 500, and 355 μm) and brewed by an espresso coffee machine and the cold brew method.

View Article and Find Full Text PDF