• Journal of Environmental Science International
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• v.21 no.10
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• pp.1265-1274
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• 2012

This study was conducted to investigate the extraction characteristics including total polyphenol compound content (TPC) and the antioxidative effect of Rumex crispus root extract on commercial corn oil. Extraction yield was increased with extraction temperature but decreased with extraction ratio. No significant differences in aromatics content were found among the extracts prepared with various extraction conditions; extraction ratio, extraction temperature, extraction pH and composition of extractant. Total flavonoid content of the extract was increased with extraction temperature and extraction pH, and highest value of it was found when extractant composition of ethanol in water was 75%. Total polyphenol compound content (TPC) of the extract with 10 fold extraction ratio showed the highest value, but no significant difference in TPC was found with extraction temperature. Reducing power and DPPH (${\alpha}$,${\alpha}$-diphenyl-${\beta}$-picrylhydrazyl) radical scavenging ability (RSA) of the extract in spectrophotometric absorbance were decreased with extraction ratio but increased with extraction temperature and showed 63.1%~98.4% and 67.6%~86.7% of those of ascorbic acid in reducing power and DPPH RSA, respectively. The antioxidative effects of the extract on corn oil were 84.8~93.0% of that of commercial butylated hydroxytoluene, the antioxidant index value was highest when the ethanol composition to water in extractant was equal ratio.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1116-1123
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• 2020

Velvet antler (VA) is a historically traditional medicinal supplement and is well known in Asian countries for its pharmaceutical and health benefits. The objectives for this study were to optimize the hot water extraction (HWE) of VA for the Korean VA industry, and to determine the most effective pretreatment method among microwave (MW), ultrasonication (US), and enzymatic (EZ) techniques. Using response surface methodology, optimum extraction temperatures and times were determined by central composite design configuration based on extraction yield and sialic acid content. Various quality parameters of VA extract including yield, soluble solid, protein, and sialic acid contents were also compared with the conjunction of HWE and pretreatment. The yield and sialic acid content of VA extract were determined to be 40% and 0.73 mg/g, respectively, under an optimum temperature of 100℃ at 24 h of extraction time. The yields from VA extracts pretreated with MW, US, and EZ were 17.42%, 19.73%, and 29.15%, respectively. Among the tested commercial enzymes, pepsin was the most effective proteolytic enzyme and led to the highest yield (47.65%), soluble solids (4.03 °brix), protein (1.12 mg/ml), and sialic acid (3.04 mg/ml) contents from VA extract.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.936-941
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• 2005

Green tea was extracted with different solvents such as hot water, varying concentrations of ethanol and carbon dioxide fluid. The carbon dioxide fluid extraction of green tea was a very effective extraction method in terms of antioxidant yield and stability. At pressure of 125kgf, antioxidant extract of green tea produced a yield 1.87 and 2.8 times higher than hot water and $95\%$ ethanol extract, respectively. Antioxidant extract of carbon dioxide fluid was also very stable during 7-day storage at 35?.

• The Korean Journal of Food And Nutrition
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• v.24 no.3
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• pp.458-463
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• 2011

The effect of subcritical water for the extraction of total polyphenols and flavonoids from apple peel was investigated, and then the antioxidant activity of the extracts was estimated. Maximum yields of total polyphenolic compounds($36.4{\pm}1.9mg$ quercetin equivalent(QE)/g dried material) and flavonoids($9.9{\pm}0.8mg$ QE/g dried material) were obtained by subcritical water extraction(SWE) with operating conditions of $190^{\circ}C$, 1,300 psi, and 20 min. Furthermore, the highest antioxidant activity($76.1{\pm}1.1%$) was observed in the extract obtained from SWE using the same conditions. The flavonoids from the SWE of apple peel were compared to three conventional extraction methods in terms of their extraction efficiency and antioxidant activity. The SWE was significantly more effective than hot water ($90^{\circ}C$), methanol, and ethanol extraction for flavonoid yield by 4.7-, 2.2-, and 1.3-fold, respectively, and for antioxidant activity by 11.0-, 4.9, and 2.8-fold, respectively.

• Journal of Life Science
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• v.23 no.7
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• pp.913-918
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• 2013

The applicability of the ultrasonic wave method to the extraction of useful components from seaweeds was investigated. Extracts from freeze-dried Ecklonia cava powder were prepared with hot water ($65^{\circ}C$), water ($24^{\circ}C$), 50% ethanol, and 100% ethanol, and ultrasonic extraction was also performed. The content of phenolic compounds and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and tyrosinase inhibitory activity of the extracts were analyzed, and differences in the data obtained by the ultrasonic extraction and the traditional extraction methods were compared. The phenolic content in the E. cava extract by ultrasonic extraction (142.80 mg/g) was approximately 14 times higher than the phenolic content in the hot water extract (10.03 mg/g). The DPPH radical scavenging and the tyrosinase inhibitory activities of the ultrasonic extract were approximately 4 times and 14 times higher than the hot water extracts, respectively. The correlation between the phenolic content and the DPPH radical scavenging activity ($R^2$=99.47) and between the phenolic content and the tyrosinase inhibitory activity ($R^2$=99.99) was very high. These results indicate that ultrasonic extraction is more suitable than traditional extraction for the extraction of useful components from E. cava.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.828-832
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• 1990

Pileus and stipe extracts of shiitake mushroom were prepared with various ethanol concentration by different extraction time at $60^{\circ}C$. Yields, total reducing sugars, free amino acids and nucleotides in ultrafiltrated extracts were analyzed. Yields were higher in hot water extracts but there was no difference depending on changes of extraction time. Total reducing sugar contents got higher by hot water extraction than by solvent extraction. In hot water extracts of the pileus and stipe, reducing sugar content were in the range of $416.18{\sim}488.18\;mg%\;and\;435.37{\sim}452.12\;mg%$, respectively. Threonine+serine, glutamic acid, lysine and arginine were dominent in the free amino acids pool of raw material. The contents of free amino acids in hot water extracts of pileus and stipe were about 528.46mg% in 2 hr and 221.01 mg% in 3 hr. The proportion of bitter amino acids in extracts to total free amino acid contents was in the range of $16{\sim}29%,\;35{\sim}37%$ in pileus and stipe extracts, respectively. Nucleotides contents were higher in pileus than in the stipe. When the 25% ethanol solution was used for extraction solvent, nucleotides contents in pileus and stipe extracts was high.

• The Korean Journal of Food And Nutrition
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• v.34 no.2
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• pp.174-180
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• 2021

The purpose of this study was to determine the optimum extraction method suitable for the availability of biological activities in unripe apples known to be rich in functional components. Unripe apples 'Hongro' picked on May 28th, 2019 were extracted by various extraction methods (hot water, ethanol, enzymatic pre-treatment, ultrasonic wave, and subcritical water) and their extracts were investigated yield, effective component contents, and antioxidant activities. Overall, the yields by the extraction solvent were higher in water than in organic solvent(ethanol) because water-soluble compounds were eluted from a polar solvent. Total phenol contents of the ultrasonic wave (ethanol) extracts were significantly higher in 6 times than hot water extract. Contents of flavonoid were highest in the ethanol extract at 29.14 mg QE/g. Contents of tannin and ursolic acid were also significantly higher in the ultrasonic wave (ethanol) extract. The DPPH radical and ABTS radical scavenging activities were the strongest in the ultrasonic wave (ethanol) extract. Correlation between effective components and antioxidant activities was high in the total phenol content with ABTS and the ursolic acid content with DPPH (p<0.01). The above results suggested that ultrasonic wave (ethanol) extract of unripe apples has the potential to act as a functional material.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.779-783
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• 1999

The process of alginate preparation was shortened with microwave pretreatment and hot water extraction without any other treatment. The yield of extracted alginate was very different according to raw material and microwave treatment conditions. The yield of extracted alginate from sea mustard was higher than sea tangle and increased with the temperature rise and time of microwave treatment. Optimum extraction conditions by microwave treatment were 90 min at $100^{\circ}C$ for the sea mustard and 120 min at $100^{\circ}C$ for the sea tangle. On the other hand, the solubility of the alginate from sea mustard was $69\%\~80\%$ and the viscosity were 8.7$\~$1.5 cps, respectively. The solubility and the viscosity of the sea tangle alginate was higher than the sea mustard to $77\~84\%$ and in the range of 8.9$\~$1.8 cps, respectively. The extraction temperature by hot water greatly influenced on the yield of alginate, but the solubility and viscosity was not affected by the hot water extraction. The molecular weight of alginate obtained through the extraction by $Na_2CO_3$ solution and the microwave pretreatment was 800 kDa, and in the range of 12$\~$45 kDa, respectively.

• Food Science and Preservation
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• v.12 no.2
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• pp.146-150
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• 2005

A comparative study of pretreatment and extraction methods was conducted to investigate their effects on nutritional and bioactive components during hot-water extraction of Acanthopanax senticosus. The herb samples, ground and sifted $(8\~20\;mesh)$ were pretreated with ultrasound (20 kHz), microwave (2,450 MHz) or roasting $(180^{\circ}C)$ for 10 min, and then extracted by a boiling $(180^{\circ}C)$ under atmospheric pressure or a pressured boiling $(121^{\circ}C)$ for 2 hr. In general, the pretreatments improved the extraction efficiency and the DPPH radical scavenging activity of extract. Particularly, the extraction yields of soluble solids, total sugar and phenolic compounds were increased in microwaving methods, and the protein yield and the radical scavenging activity were higher in roosting pretreatment. Yields of soluble solids, total sugar, protein and phenolic compouds in pressured extraction were higher than those in nonpressured extraction. These results suggested that pretreatment including microwave radiation, sonication and roasting and pressured extraction can be utilized for improving the extraction efficiency of A. senticosus.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.5
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• pp.60-67
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• 2011

Hemicelluloses pre-extracted from Korean mixed wood chip were investigated as a wet-end additive. Hemicelluloses dissolved in hot water and alkali solution were isolated by ethyl alcohol precipitation from pre-extractives. They showed molecular weight of 9,000 ~ 27,000 g/mol as revealed by size exclusion chromatography. The reduction of molecular weight through hot water extraction was caused by autohydrolysis. Chemical composition of the hemicelluloses were analyzed with high-performance liquid chromatography and UV-Vis spectroscopy. As the surface charge of isolated hemicelluloses were negative, the adsorption of hemicelluloses onto softwood unbleached kraft pulp fiber was promoted by poly-DADMAC. The physical properties of handsheets increased as the molecular weight of hemicellulose increased. On the other hands, the optical property decreased with hemicellulose adsorption.