Yu-Ri Kwon

Quality Characteristics and Antioxidant Properties in Spray-dried and Freeze-dried Powder Prepared with Powdered Seaweed Extracts

This study was designed to compare the quality characteristics of spray-dried (SD) and freeze-dried (FD) powders prepared with hot water extracts of sea mustard (Undraia pinnatifada) and sea tangle (Laminaria longissima). The moisture content of FD seawed was lower than that of SD, and sea mustard had a higher overall moisture content than sea tangle. The alginic acid content of SD seaweed was significantly higher than that of FD seaweed for both species. There were relatively higher contents of phenolic compounds in SD powders than in FD powders. DPPH radical scavenging ability was significantly greater in SD seaweed, and also, SOD-like activity in SD powders was higher than those of FD powders. However, the nitrite scavenging activity of FD powders of sea mustard (10 mg/mL) was higher than that of SD. In conclusion, spray-dried sea mustard and sea tangle extracts exhibited higher physiological functionalities than their freeze-dried counterparts.

Physicochemical properties of acorn (Quercus acutissima Carr.) tea depending on steaming and hot-air drying treatments

This study was performed to determine the effects of preconditioning process (Con, roasting; SR, steaming and roasting; HDR, hot air drying and roasting; SHDR, steaming hot air drying and roasting) and roasting on the antioxidant and physicochemical properties of acorn (Quercus species) tea. Each sample was extracted in 95°C hot water for 5 min. The color values of lightness and yellowness were the highest in HDR, and redness were the highest in the control. The total sugar content was the highest in SHDR. Total polyphenol and total flavonoid contents of HDR tea were higher than those of teas prepared by the different processes. DPPH and ABTS radical scavenging abilities of HDR were 75.66% and 98.16%, respectively, which were higher than those of other teas. In the sensory evaluation, HDR tea was ranked significantly higher than other teas in terms of flavor, taste and overall acceptability. Finally, acorn tea treated with drying was superior to other treatments in antioxidant and quality properties. The result suggests that HDR can be applied to acorn tea to achieve better quality and functionality.

Antioxidant and physiological activities of Hijikia fusiforme by extraction methods

The physiological properties of extracts from Hizikia fusiforme with different extraction methods (hot water extraction, autoclave extraction and high pressure extraction) were investigated. The amounts of substances related to polyphenol and flavonoids contents were the highest in autoclave extract (30.51 mg/g and 4.78 mg/g, respectively). The DPPH radical scavenging activity was the highest in the autoclave extract (81.80%) at the 5 mg/mL. Autoclave extract exhibited the strongest ABTS radical scavenging activity and reducing power among the three extraction methods. However, ferrous ion chelating, TBA reactive substances and xanthine oxidase inhibition activity of high pressure extract were higher than those of the other extracts. Additionally, the tyrosinase and elastase inhibition activities of high pressure extract with a concentration of 1 mg/mL were higher than those of the other extracts. These results suggest that extracts of Hizikia fusiforme have a potential to act as functional materials, and autoclave and high pressure extractions are superior to hot water extraction for enhancement of the biological activity.