• Food Science and Preservation
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• v.11 no.1
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• pp.88-93
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• 2004

This study was conducted in order to compare reflux extraction(RE) and microwave-assisted extraction(MAE) in extraction efficiency and establish optimum microwave extraction conditions in obtaining Aster scaber Thunb extracts. Extraction time was reduced considerably in MAE. When 70％ methanol, 50％ methanol, 70％ ethanol, or 50％ ethanol was used, no difference was found in the amount of soluble solid and total phenol between MAE and RE. The optimum microwave-assisted extraction conditions for Aster scaber Thunb were achieved by 120-150 watts of microwave energy and 4∼8 minutes of extraction time. No significant changes were found in antioxidant activity using DPPH scavenging method over the variation of microwave power or extraction time. The use of diluted methanol or ethanol improved soluble solid content(30.8％), total polyphenol content(2.9％) and antioxidant activity(69％ ).

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.68-68
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• 2023

베리류 과수 가운데 블루베리, 아로니아, 복분자, 오디, 산딸기, 라즈베리 등 6종의 에탄올 추출물을 이용하여 총 폴리페놀 함량을 측정하고, DPPH법을 이용하여 항산화 활성을 측정하여 상호간 상관 관계를 분석하였다. 총 폴리페놀 함량은 아로니아> 복분자> 오디> 블루베리> 라즈베리> 산딸기 순으로 나타났으며, 항산화 활성은 아로니아> 라즈베리 >복분자> 블루베리> 오디> 산딸기 순으로 나타났다. 이러한 결과로 총폴리페놀 함량과 항산화 활성과의 상관관계가 있다는 것을 확인하였으며, 그 중에서도 아로니아와 복분자가 강력한 항산화 활성이 있는 것으로 나타났다. 그러나 라즈베리의 경우는 총폴리페놀 함량이 낮은데도 불구하고 항산화 활성이 높았다. 따라서 앞으로 라즈베리에 대한 선행연구가 필요하리라 생각된다. 이와 같은 결과들로 미루어 볼 때, 6종 베리류(블루베리, 아로니아, 복분자, 오디, 산딸기, 라즈베리) 에탄올 추출물은 농도 의존적으로 항산화 활성에 대한 효과가 양호하였으며, 이러한 연구결과들을 활용하여 트러블, 염증 억제제 및 항균활성으로 기능성 화장품의 신소재 개발이 가능하다고 판단된다.

• Food Science and Preservation
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• v.21 no.6
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• pp.784-789
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• 2014

This work aimed to investigate the changes in the nutrient contents and antioxidant activity of Peucedanum japonicum Thunb. by ripening stage, growing condition, and blanching. The crude protein content of the young leaves (3.6~4.3%) was higher than that of the mature leaves (3.1~3.9%). Higher calcium contents were observed in the greenhouse-cultivated samples (225.9~259.2 mg/100 g) compared to the field-cultivated samples (178.5~199.5 mg/100 g). The vitamin C and folate contents (18.1~83.8 and 175.8~220.2 mg/100 g, respectively) of the field-cultivated samples were significantly (p<0.05) higher than those of the greenhouse-cultivated samples (13.1~57.7 and 133.0~148.8 mg/100 g, respectively). The growing condition and blanching were significant factors affecting the changes in the vitamin and polyphenol contents. The ${\beta}$ carotene contents of the blanched samples increased 2.6-fold compared to those of the raw samples. The total polyphenol contents (10.2~17.1 mg/g extract) and DPPH radical scavenging activity ($IC_{50}=2.0{\sim}3.0mg/ml$) of the blanched samples were significantly (p<0.05) higher than those of the raw samples (1.8~4.3 and $IC_{50}=16.2{\sim}21.1mg/ml$, respectively).

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1349-1356
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• 2014

This study investigated the biological activities of 70% methanol extracts from black chokeberry and blueberry by measuring DPPH, superoxide anion and ABTS radical scavenging activities, metal chelating effect, reducing power, and nitrite scavenging activity. Extraction yields of black chokeberry and blueberry were 62.90% and 67.09%, respectively. Total polyphenol and total flavonoid contents were 117.20 mg/g and 32.50 mg/g for black chokeberry and 42.26 mg/g and 26.39 mg/g for blueberry, respectively. Black chokeberry had higher antioxidant activity than blueberry. DPPH and ABTS radical scavenging activities, nitrite scavenging activity, and metal chelating effect of black chokeberry were 98.29%, 96.68%, 97.64%, and 91.33%, respectively, at a concentration of 5 mg/mL, which were equal to those of ascorbic acid (positive control). These results suggest that black chokeberry has potent biological activities, and in the future, the availability of black chokeberry will increase in the field of value added food products.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.358-362
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• 2017

In this study, the optimization of extraction parameters (solvent, temperature, time, solvent concentration) for the maximization of polyphenol extraction was performed to produce value-added food and cosmetic additives using a byproduct of coffee extraction process (coffee residue). All of the extraction parameters evaluated in this experiment had significant effects on polyphenol extraction and the results showed the effect of NaOH concentration on the polyphenol production was most significant among tested parameters. Especially, hot water extraction using acid or base was effective rather than hot-water extraction and the addition of 0.1 mol of NaOH increased 1.5 times extraction concentration compared with hot-water extraction using distilled water. It was found that hot-water extraction with NaOH was more effective than hot-water extraction, and 36.5 mg GAE/g DM was obtained under optimum condition of $100^{\circ}C$, 2 mol of NaOH and 30 min. This result was 2.9 times higher than that of 12.5 mg GAE/g DM obtained from the hot-water extraction before optimization. Thus, coffee residue could be used for food and cosmetic industry as a high-value additive such as antioxidant.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.857-864
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• 2013

This study was investigated the effects of heat treatment on polyphenolic compounds and antioxidant activities of yacon. Raw yacon was heated at $100^{\circ}C$ and $121^{\circ}C$ for 15, 30, or 60 min by using an autoclave. The browning intensity, levels of free and bound phenolic and flavonoid compounds, and 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) radical-scavenging activity of yacon extracts following heat treatment were measured. The browning index, free polyphenolic content, and antioxidant activities in the extracts were significantly increased (p<0.05) with both increased heating temperature and time, while bound polyphenolic levels were decreased. The levels of free phenolic and flavonoid compounds in the yacon extract heated to $121^{\circ}C$ for 60 min were increased by 1.2 and 1.1 folds compared to raw yacon respectively. Moreover, DPPH and ABTS radical-scavenging activities of the yacon heated to $121^{\circ}C$ for 60 min were 1.7 fold and 2.0 fold higher, respectively, than those of raw yacon. A significant (p<0.01) correlation was observed among browning intensity, free and bound phenolic and flavonoid levels, and DPPH and ABTS radical-scavenging activities in heated yacon extract. Thus, heat treatment can be used as a method to enhance the antioxidant compound content in and the antioxidant activity of yacon.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.198-202
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• 2018

The present study aimed to investigate the effect of germination and temperature on the antioxidant activity of coffee. Green beans were germinated at 20 and $40^{\circ}C$. Germinated green beans were dried and roasted. Ground coffee was brewed at $90^{\circ}C$ for 5 min. Coffee samples were analyzed for antioxidant compounds and for its antioxidant activity. The total polyphenol content (TPC) and total flavonoid content (TFC) in coffee brewed with coffee beans germinated at $20^{\circ}C$ (CG20) were significantly higher than those in coffee brewed with non-germinated coffee beans (CNG). The same tendency was observed on 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging assays. TPC and TFC of coffee brewed with germinated coffee beans decreased with an increase in germination temperature from 20 to $40^{\circ}C$. In conclusion, germination of coffee beans contributes to an increase in its antioxidant activity. However, setting the appropriate temperature for germination is an important factor in determining the antioxidant activity of coffee.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.813-818
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• 2007

For this study, extracts of Vitex rotundifolia stems were prepared using reflux water extraction (WE), reflux ethanol extraction (EE) and hot water extract under high pressure (HWE). The extracts were investigated for the total content of phenolic compounds, antioxidant activities, and inhibitory potencies for xanthine oxidase and tyrosinase. The EE extraction method yielded the highest content of polyphenol compounds (176.34 mg/g). The electron donating abilities (EDA) were 93.46${\sim}$96.92%, when extracts were assayed at 1.0 mg/mL. The superoxide dismutase (SOD)-like activity was the highest in the WE extract (47.32% at 1.0 mg/mL). The nitrite scavenging abilities (pH 1.2) were 84.61${\sim}$88.36% and the inhibition of xanthine oxidase were over 90% at 0.5 mg/mL. Tyrosinase inhibition of HWE and WE were 57.84% and 53.47% respectively. It implies that V. rotundifolia stems have potent physiological activities and their activities were differently exhibited depending on solvent fractions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1309-1314
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• 2006

This study analyzed the contents of vitamin C, polyphenol compounds, and evaluated the inhibitory activities against xanthine oxidase and tyrosinase of Lepista nuda extract prepared by the reflux and microwave-assisted methods. The vitamin C content of the fresh L. nude was $9.92{\pm}0.02$ mg/100 g. The content of phenolic compounds in the fresh L. nuda was $1.87{\pm}0.02\;mg/g$. The ethanol extracts prepared by reflux method and microwave-assisted method showed the highest phenol contents of $12.06{\pm}0.12\;mg/g\;and\;11.84{\pm}0.17\;mg/g$, respectively. The inhibitory rates on xanthine oxidase and tyrosinase of ethanol extracts prepared by the microwave assisted method showed the highest value of 99.78% and 30.30% at the concentration of $3,000{\mu}g/mL$. The inhibitory activities on xanthine oxidase and tyrosinase were increased depending on the extract concentration.

• Food Science and Preservation
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• v.13 no.5
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• pp.616-622
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• 2006

This study was intended to analyze the contents of polyphenol compounds and vitamin C, and the inhibitory activities of xanthine oxidase and tyrosinase to measure physiological efface of various extract of Lespedeza bicolor. The vitamin C content was $26.42{\pm}0.08mg/100g$. The content of phenolic compounds included in the flesh L bicolor was $1.14{\pm}0.02mg/g$. The ethanol extract by reflux method and water extracts by the microwave-assisted method showed the highest content as 154.95 mg/g and 145.17 mg/g, respectively. The xanthine oxidase inhibitory tate of water extracts was the highest value of 87.85% at the concentration of 1,000 ug/mL. All kinds of extracts showed the highest inhibitory activity for the xanthine oxidase at the concentration of 1,000 ug/mL and a decreasing pattern of the inhibitory race over the concentration of 1,000 ug/mL. The tyrosinase inhibitory rate was increased with an increment of the extract concentrations, and the activity of ethanol extracts was the highest as 55.22% at the concentration of 3,000 ug/mL.