• Food Science and Biotechnology
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• v.18 no.6
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• pp.1487-1494
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• 2009

The effects of drying temperature (55, 60, and $65^{\circ}C$) and addition levels of maltodextrin (MD) (10, 20, and 30%) on the physicochemical properties and nutritional quality of purple sweet potato flour were investigated. MD-added flours had higher $L^*$ values, water soluble index, total phenolic, and anthocyanin contents than untreated flour. However, $a^*$, $b^*$ values, water absorption index, and swelling capacity were dependent on the drying temperature and MD concentration. On the other hand, untreated flour had a higher ascorbic acid content compared to the MD-treated flour. Ascorbic acid contents decreased, whereas anthocyanin content was not significantly different, with increasing drying temperatures. MD was positively correlated with phenolic content, anthocyanin, hue angle, and water soluble index. However, there was no correlation between quality parameters and glass transition temperature. The best quality product was obtained when samples were pretreated with MD before drying, regardless of drying temperature.

• Journal of the Korean Ceramic Society
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• v.36 no.5
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• pp.513-520
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• 1999

Alumina-coated SiC whiskers wee prepared by the calcination (1150$^{\circ}C$, 1h, Ar) of the alumina hydrate layer which was precipitated homogeneously on whisker surface from a solution of Al2(SO4)3 and urea as a precipitant. In addition carbon coated SiC whiskers were prepared by the pyrolysis (1000$^{\circ}C$, 4h Ar) of phenolic resin coated whisker. The effects of coating conditions on the thickness and morphology of the coated layers were examined by SEM and TEM. It was found that Al2O3-coating layers become thinner and more uniform with decreasing the Al2(SO4)3 concentration. Thin (0.075-0.1$\mu\textrm{m}$) and uniformly alumina-coating layers were obtained at the Al2(SO4)3 concentration 0.010mol/l. On the other han carbon-coating layers were uniform but very thin (5-16 nm) in thickness. For thicker carbon-coating layers ethanol as a disperse medium was found to be more efficient compared tousing acetone.

• Journal of the Korean Society of Food Culture
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• v.30 no.6
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• pp.766-772
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• 2015

This research was conducted to investigate the effect of essential oil (EO) from Artemisia Princeps Pampanini on quality of tomato during storage. EO was extracted by steam distillation and diluted by 1 and 2%. Total phenolic contents and antioxidative activities of EO were analyzed. Tomato was packaged corrugated box covered with polypropylene (PP) film containing EO (1 and 2%) and then stored at room temperature for 10 days. During storage, appearance, weight loss rate, soluble solid contents, pH and a (redness) value were measured for tomato. Total phenolic contents of EO increased in a dose-dependence. The DPPH and ABTS radical scavenging activities also showed a concentration-dependent increase. The weight loss rate was lowest using the film packaged in 1% EO. During the storage period, soluble solid contents and pH increased in all treatments. The a value increased regardless of EO concentration in films. Especially, tomato packaged with EO film showed a lower a value than non EO-packaged ones. This result suggests that application of EO to film is effective for tomato quality preservation.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1299-1304
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• 2008

The potential antioxidant activities of different fractions from a 70% methanolic (MeOH) extract of Sonchus oleraceus were assayed in vitro. All of the fractions exception of n-hexane showed a strong antioxidant activity, especially the ethyl acetate (EtOAc) fraction, which showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity ($IC_{50}=19.25{\mu}g/mL$). The results of hydroxyl radical scavenging activity and a reducing power assay showed concentration dependence, the EtOAc fraction demonstrating a better result than the other fractions at the same concentration in the studies. Additionally, the fractions' total phenolic (TP) contents was measured, phenolic compounds such as tannic acid, p-coumatric acid, quercetin, epicathchin, and kaempferol being detected by high performance liquid chromatography (HPLC). Meanwhile, a regression analysis revealed a moderate-to-high correlation coefficient between the antiradical activity and the TP contents, suggesting that fractions obtained from the 70% MeOH extract of S. oleraceus are of potential use as sources of antioxidant material.

• Korean Journal of Food Science and Technology
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• v.54 no.4
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• pp.386-390
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• 2022

This study aimed to investigate the biological and antibacterial activities of phenolics from Sambucus sieboldiana var. pendula leaf extract. The phenolic contents of the S. sieboldiana var. pendula extracted with water and ethanol was 11.60 and 12.39 mg/g, respectively. The inhibitory effects of the water and ethanol extracts on the angiotensin converting enzyme (ACE) were 71.94-92.08 and 48.42-78.33%, respectively, and on xanthine oxidase (XOase) were 42.11-100 and 35.61-100%, respectively, at a phenolic concentration of 50-200 ㎍/mL. All these effects were found to be concentration-dependent. Additionally, the leaf extracts exhibited excellent antibacterial activities against Streptococcus mutans, Staphylococcus aureus, and Propionibacterium acnes. Hence, S. sieboldiana var. pendula was confirmed to have excellent antihypertensive, antigout, and antimicrobial properties.

• Culinary science and hospitality research
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• v.20 no.5
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• pp.29-33
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• 2014

In this study, we examined the antioxidant activity of the naturaceutical extract in vitro using total phenolic contents, total flavonoids contents, DPPH radical scavenging activity, reducing power assay, and phenolic acid contents. The total phenolic and total flavonoids contents of naturaceutical extract were 5.46 mg/g, 2.21 mg/g, respectively. The DPPH radical scavenging activity of natraceutical extract varied from 18.77 ($200{\mu}g/mL$) to 3.44 ($1,000{\mu}g/mL$). The reducing power of the natraceutical extract absorbance varied from 1.07 (0.78 mg/mL) to 3.44 (12.5 mg/mL), and reducing power of extract presented a concentration-dependent activity increase. The highest amounts of trans-ferulic acid, p-hydroxybenzoic acid, p-coumaric acid, vanillin, vanillic acid, p-hydroxybenzaldehyde, and trans-cinnamic acid were observed in the naturaceutical extract at the levels of 750.79, 619.75, 531.34, 222.04, 219.28, 107.40, and $89.56{\mu}g/g$, respectively. The results imply that this antioxidant effect of the naturaceuticals extract could be harnessed in the management and prevention of degenerative diseases associated with oxidative stress.

• Korean Journal of Pharmacognosy
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• v.50 no.4
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• pp.239-244
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• 2019

Boehmeria pannosa (Urticaceae) is a perennial herb widely distributed in Korea. In this study, investigation on the constituents of B. pannosa was conducted by chromatographic techniques and spectroscopic analysis. As a result, nine compounds including eight phenolic compounds, 3-hydroxy-1-(4-hydroxyphenyl)propan-1-one (1), β-hydroxypropiovanillone (2), C-veratroylglycol (3), 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-propan-1-one (4) 2,3-dihydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl) -1-propanone (5), p-coumaric acid (6), 4-hydroxybenzoic acid (7), vanillic acid (8) and one lignan, (-)-(7R,8S)-dihydrodehydrodiconiferyl alcohol (9) were isolated from the EtOAc-soluble fraction of B. pannosa. Among them, compounds 5, 6 and 9 inhibited α-glucosidase inhibitory activity more than 50% at the concentration of 100 μM.

• The Plant Pathology Journal
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• v.26 no.1
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• pp.57-62
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• 2010

Low-molecular-weight secondary metabolites from plants play an important role in reproductive processes and in the defense against environmental stresses or pathogens. In the present study, we isolated various volatiles and phenolic compounds from white Rosa rugosa flowers, and evaluated the pharmaceutical activities of these natural products in addition to their ability to increase survival in response to environmental stress and pathogen invasion. The DPPH and hydroxyl radical-mediated oxidation assay revealed that the white rose flower extract (WRFE) strongly scavenged free radicals in a dose dependent manner. Moreover, WRFE inhibited the growth of E. coli and fatally attacked those cells at higher concentration (>0.5 mg/mL). FITC-conjugated Annexin V stain provided further evidence that WRFE had strong antimicrobial activity, which may have resulted from a cooperative synergism between volatiles (e.g. 1-butanol, dodecyl acrylate and cyclododecane) and phenolic compounds (e.g. gallic acid) retained in WRFE. In conclusion, secondary metabolites from white rose flower hold promise as a potential natural source for antimicrobial and non-chemical based antioxidant agents.

• Natural Product Sciences
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• v.15 no.4
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• pp.208-212
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• 2009

The heartwood of Rhus verniciflua Stokes (Anacardiaceae) is widely used for a medicinal plant to treat diabetes mellitus and lingering intoxication in the folkloric society of Korea, while the stem bark has been traditionally used to treat menstrual disorder and helminthiasis. We previously reported that a flavonoid, fustin, isolated from the heartwood of R. verniciflua is effective in Alzheimer‘s disease and rheumatoid arthritis. To explore the possibility to produce more flavonoid-rich fraction from this plant, the MeOH extracts from the plant parts of stem bark, outer heartwood, and inner heartwood were quantitatively analyzed by HPLC. Phenolic or flavonoid compounds (chlorogenic acid, caffeic acid, p-coumaric acid, sulfuretin, fustin, fisetin, luteolin and astragalin) were detectable in the HPLC chromatogram. The orange-colored inner heartwood was found to contain the highest levels of fustin (16.96 mg/g) and sulfuretin (2.22 mg/g). Moreover, the inner heartwood accumulated fustin and sulfuretin at least 4-fold higher level as compared to the stem bark and outer heartwood. The levels of total phenolic compounds positively correlated with the extents of antioxidant properties. Therefore, the inner heartwood of R. verniciflua could be used to increase fustin concentration of the extract which is capable of treating Alzheimer‘s disease and rheumatoid arthritis.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.204-212
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• 2014

The bioactive compounds and antioxidant activity of aronia leaves at different stages of maturity were identified and evaluated. Young and old leaves were approximately 2 months of age and 4 months of age, respectively. The young leaves contained more polyphenols and flavonoids than the old leaves. Three phenolic compounds (i.e., chlorogenic acid, p-coumaric acid, and rutin) were detected by HPLC. Antioxidant activity was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical, and superoxide anion radical scavenging assays. The reducing power of aronia leaf extracts increased in a concentration-dependent manner ($0{\sim}100{\mu}g/mL$). The antioxidant activity of the 80% ethanol extract was greater than that of distilled water extract. The high phenolic compound content indicated that these compounds contribute to antioxidant activity. The overall results indicate that aronia leaves contain bioactive compounds, and that younger aronia leaves may be more favorable for extracting antioxidative ingredients because they contain more polyphenols.