• Korean Journal of Food Science and Technology
• /
• v.32 no.5
• /
• pp.1079-1086
• /
• 2000

Pectinesterase inhibitor(PEI) of ripened kiwi fruit(Actinidia chinensis) was separated with affinity chromatography using CNBr-activated Sepharose 4B being covalently bound by orange pectinesterse(PE). The affinity resin strongly and selectively bound PEI, which could be eluted in high yield as a single peak by pH 9.5 without loss of inhibitory activity. The separated PEI had maintained almost inhibitory activity at $-25^{\circ}C$ and $5^{\circ}C$ during 30 days but lost it at room temperature in 4 weeks. The PEI possessed a molecular weight of 16.6 KDa, as estimated by 12.5% SDS-PAGE. PEI had optimum pH of 7.5, optimum temperature of below $10^{\circ}C$ and stability up to $70^{\circ}C$. Also, optimum inhibitory activity for PEI was obtained in 0.2 M NaCl of substrate solutions. The kind of inhibition on tomato pectinesterase was found to be noncompetitive, using citrus pectin as substrate. Fresh orange juice added with crude PEI extracts maintained almost the same cloud stability as pasteurized juice. In case of apple juice, the addition of crude PEI extracts to apple juice had decrease of L-ascorbic acid with nearly no effect on cloud loss.

• Food Science and Preservation
• /
• v.31 no.3
• /
• pp.444-451
• /
• 2024

This study aimed to investigate the characteristics of protein hydrolysates derived from defatted egg yolk using various proteolytic enzymes and compare the antioxidant activity of the resulting hydrolysates. The defatted egg yolk powder was subjected to enzymatic hydrolysis using four different proteases (alcalase, bromelain, flavourzyme and neutrase), and the resulting hydrolysates were evaluated for their antioxidant properties. Through analysis of available amino group contents and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it was observed that the defatted egg yolk powder treated with alcalase, flavourzyme, and neutrase for 12 h exhibited a high degree of hydrolysis value. Based on the RC₅₀ values obtained from two different antioxidant analyses, all hydrolysates showed comparable antioxidant activity, except for the alcalase hydrolysate, which demonstrated notably higher scavenging activity against hydrogen peroxide than the other hydrolysates. These findings suggest the potential of protein hydrolysates from defatted egg yolk, a by-product of lecithin extraction, as natural antioxidants.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.12
• /
• pp.1746-1752
• /
• 2009

This study was carried out to compare the physicochemical characteristics of the tofu (soybean curd) with the additions of sorghum powder (SP). With increasing amounts of sorghum powder, the yields of tofu were increased. The tofu made of 5 and 7% (w/w) addition rates of SP gave the similar yields with that of control. Moisture contents of the tofu made of roasted sorghum powder after steeping for 15 hours (WR-SP) were higher than those of the control and the tofu made of roasted sorghum powder after washing (SR-SP) without steeping. The dietary fiber contents of tofu were higher in the SP-added tofu than control. The potassium contents increased with SP addition rates, while calcium and magnesium decreased. With increasing SP addition rates, hardness of the tofu decreased. With increasing amounts of SP, the L- and b-values of tofu decreased, whereas a-value increased. The total polyphenol, flavonoid and tannin contents, and ascorbic acid equivalent antioxidant capacity in the tofu extracts increased with increasing SP rates. Antioxidant components and activity were the highest in the tofu made of roasted sorghum powder after washing without steeping with the addition rates of 3-10%.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.4
• /
• pp.521-528
• /
• 2016

This study was conducted to investigate changes in the proximate composition, antioxidant activities, and ${\alpha}$-glucosidase inhibitory activity of Opuntia ficus-indica (OFI) cladodes cultivated in Jeju (JJ1, JJ2, JJ3) and Jeonnam (JN1, JN2). The difference in the proximate composition (crude protein, lipid and ash content) of OFI between the two regions was not significant. Ca, Mg and Na were the major mineral components of OFI. The ascorbic acid content of OFI ranged from 57.87 to 143.72 mg/100 g. A 70% ethanol extract was used to investigate the antioxidant content and activity as well as the ${\alpha}$-glucosidase inhibitory activity. The total polyphenol and flavonoid contents of OFI were 38.69~55.29 and 3.33~4.03 mg/g, respectively. The antioxidant activities based on the DPPH and ABTS free radical scavenging assays were 45.19~61.52% and 39.15~51.96%, respectively, at a concentration of 1 mg/mL. The inhibitory activity of OFI extracts against rat intestinal ${\alpha}$-glucosidase was 29.72~45.73% at 1 mg/mL concentration, and JN1 showed the highest ${\alpha}$-glucosidase inhibitory activity. This information could be very useful for authentication of Opuntia species with the highest potential as sources of nutritional and therapeutic elements.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.3
• /
• pp.320-326
• /
• 2012

This study was conducted to investigate the antibacterial and antioxidative activities of water and ethanol extracts from a mixture of roasted coffee and red ginseng. The antibacterial effects of each extract were determined by the classical paper disc method. A water extract of mixture samples inhibited growth of all strains, but antibacterial effects were mostly weakened. Ethanol extracts showed stronger antibacterial effects than water extracts in all strains except Gram negative Escherichia coli and the fungi strain Candida albicans. Also, the antibacterial effect of the Bacillus cereus strain appeared in all samples, and the ES2 sample formed a clear zone of 19 and 20 mm against Pseudomonas aeruginosa and S. Typhimurium respectively (MIC=0.25 and 0.125 mg/mL). Determinations of free radical elimination for the different mixture extracts using 1,1-diphenyl-2-picrylhydrazyl (DPPH) were compared with ascorbic acid and butylated hyderoxytoluene as positive controls. The water and ethanol extracts of mixture samples (100 ${\mu}g/mL$) showed 55.38~60.01% and 59.37~70.50% DPPH scavenging activities, respectively. DPPH scavenging activities of all mixture samples were slightly higher than roasted coffee and red ginseng samples. However, DPPH scavenging activity decreased when red ginseng extract composed more than 70% of the total extract. The total polyphenol in the mixture samples measured by the Folin-Denis method revealed the highest level of polyphenol content in ethanol extract of sample 3, whereas polyphenol content differed with different mixture ratios, ranging from 105.16~119.79 mg/g in ethanol extract. In the water extract, the polyphenol content was greatest with water extract of sample 1, whereas in other samples the content varied from 93.75~109.18 mg/g.

• Journal of Life Science
• /
• v.21 no.4
• /
• pp.561-567
• /
• 2011

This study was performed to evaluate the anti-inflammatory and antioxidant activities of methanol extract from natural products. Cell viability was determined by MTT assay. The production of NO and TNF-${\alpha}$ were measured by Griess assay and enzyme-linked immunosorbent assay (ELISA). In order to effectively screen for anti-inflammatory agents, we first examined the inhibitory effects of 24 natural products on the production of lipopolysaccharide (LPS)-induced nitric oxide (NO) in RAW 264.7 cells. Three extracts of Terminalia chebula Retz., Lavandula spica L., and Dalbergia odorifera T. significantly inhibited NO production. The three extracts significantly decreased production of NO in a dose-dependent manner. Terminalia chebula Retz. decreased TNF-${\alpha}$ production. Antioxidative effects of the three extracts were measured based on polyphenol and flavonoid contents and DPPH radical scavenging activity assay. The three extracts showed high polyphenol contents as well as strong DPPH scavenging activities. In particular, Terminalia chebula Retz. contained the highest polyphenol and flavonoid levels of 616 and $96\;{\mu}g/mg$, respectively, compared to Lavandula spica L. and Dalbergia odorifera T. As DPPH radical scavensing activities, RC50 values of Terminalia chebula Retz. were $2.09\;{\mu}g/ml$.

• Journal of Life Science
• /
• v.29 no.3
• /
• pp.337-344
• /
• 2019

The free radical scavenging, cytotoxic effects, and flavonoid content of fractions from Lycopus lucidus Turcz leaves were here investigated. The flavonoid contents of 85% methanol (MeOH) and n-butanol (BuOH) fractions of the leaves were 41.5 mg/g and 77.2 mg/g, respectively. In DPPH and ABTs+ assays, 85% MeOH and n-BuOH fractions from the L. lucidus Turcz leaves had a greater scavenging effect (p<0.05). The n-BuOH fraction (0.5 mg/ml concentration) had scavenging effects of 88% and 92% in the DPPH and ABTs+ assays, respectively (p<0.05). Cell viability tests showed that treatment with L. lucidus Turcz leaf fractions caused cytotoxicity in the growth of AGS, HT-29, and HT-1080 cancer cells. Of the different fractions, the 85% MeOH sample displayed the highest cytotoxic activity; the $IC_{50}$ values of this fraction against AGS, HT-1080, and HT-29 cancer cells were 0.03 mg/ml, 0.14 mg/ml, and 0.16 mg/ml, respectively. These biological results indicate that the n-BuOH fraction was more effective in anti-oxidant activity while the 85% MeOH fraction was stronger in cytotoxic effects, and they suggest that these two fractions from L. lucidus Turcz leaves may contain valuable bioactive compounds, such as flavonoids.

• Journal of the East Asian Society of Dietary Life
• /
• v.24 no.1
• /
• pp.101-108
• /
• 2014

This study was conducted in order to compare the biological activities of water extracts and sugar immersion extracts of green pepper (Capsicum annuum L.), purslane (Portulaca oleracea L.) and shiitake (Lentinula edodes (Berk.) Pegler) by measuring total polyphenol and flavonoid contents, antioxidant activities and inhibitory effects on ${\alpha}$-amylase and ${\alpha}$-glucosidase. The contents of total polyphenols and flavonoids were higher in water extracts than in sugar immersion extracts. The anti-oxidative activities of water and sugar immersion extracts were measured using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity assay and reducing power assay. All extracts scavenged radicals in a concentration-dependent manner, and water extracts showed stronger radical scavenging activity and reducing power than sugar immersion extract. However, they all exhibited lower activities than ascorbic acid. Compared to the anti-diabetic drug acarbose, which was used as a positive control, the two types of extracts exhibited low ${\alpha}$-glucosidase inhibitory activities, although the activity of sugar immersion extracts were 2-fold higher than that of water extracts. ${\alpha}$-Amylase inhibitory action was not observed for any of the extracts. Finally, by cytotoxicity test, we confirmed that sugar immersion extracts were safer than water extracts. These results indicate that water extracts and sugar immersion extracts of green pepper, purslane and shiitake have different advantages in terms of their antioxidant and anti-diabetic effects, respectively.

• Korean Journal of Plant Resources
• /
• v.32 no.5
• /
• pp.423-432
• /
• 2019

In order to select potential plant resources as functional materials and natural antioxidants, we evaluated antioxidant activity and serotonin derivatives of safflower germplasm collected from five countries. N-(p-Coumaroyl) serotonin (CS) and N-feruloylserotonin (FS) were analyzed by using Ultra Performance Liquid Chromatography (UPLC). Total polyphenol content (TPC) was determined by Folin-Ciocalteu method and antioxidant activities were estimated by 2,2-diphenyl-1-picryl-hydrazil (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), Ferric reducing antioxidant power (FRAP) and Reducing power (RP) assays. The TPC showed a range of 28.25 to $90.53{\mu}g$ gallic acid equivalent (GAE)/mg dried extract (DE). DPPH, ABTS, FRAP and RP assay were in the range of 18.76 to 93.98, 48.91 to 163.73, 3.80 to 132.29 and 26.32 to $80.08{\mu}g$ ascorbic acid equivalent (ASCE)/mg DE, respectively. Among the five countries, safflower seed collected from Iran had the highest levels of serotonin derivatives and antioxidant activities than other countries (p<0.05). CS showed high correlation with TPC, ABTS and DPPH (r=0.673,0.727,0.820), and FS showed high correlation with DPPH (r=0.740). Accessions IT321214 and IT321215 could be useful for development of new functional materials and could be used as a source of valuable natural antioxidant materials.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.3
• /
• pp.271-279
• /
• 2012

Total twenty cultivars of potato (Solanum tuberosum L.) were grown at Gangneung where is located in low land of Korea. Their tubers were harvested from 100 to 120 days after planting, and over 150 g of tubers were selected for quality evaluation. Dry matter, starch, amylose in starch, ascorbic acid, protein, individual sugars and mineral were analyzed and mealiness of cooked potatoes were also evaluated by panel test. Dry mater content was the highest in 'Haryeong', 'Jayoung' and 'Shepody', and the biggest starch granules were observed in 'Jayoung' and 'Sinnamjak'. In addition, the content of amylose was highest in 'Haryeong', 'Chudong' and 'Goun'. Mineral content showed the slight difference between cultivars, but it's tendency was not clear. Vitamin C content was highest in 'Jayoung' as 62.5 $mg{\cdot}100g^{-1}$ FW, and 'Chugang' exhibited the highest content of protein. Sugar content was lower in cultivars for single one than double cropping. The lowest sugar content was observed in 'Atlantic' and 'Namseo' among cultivars for single cropping, and in 'Goun' for double cropping. As a result of analysis for quality factors, we could select nine cultivars ('Atlantic', 'Gahwang', 'Gawon', 'Goun', 'Hareong', 'Irish Cobbler', 'Jasim', 'Jayoung' and 'Shepody') with high dry matter content and low reducing sugar as a cultivar group for processing. Additionally, seven cultivars ('Chugang', 'Gawon', 'Goun', 'Hareong', 'Irish Cobbler', 'Jasim' and 'Seohong') with high mealiness and amylose content and five cultivars ('Atlantic', 'Chudong', 'Gahwang', 'Jopung' and 'Jowon') with low mealiness and amylose content were classified as groups for boiled or steam cooking and for soup or pot dishes, respectively.