• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.248-257
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• 2019

This study aimed to determine the chemical components of different cultivars (Gabjubaekmok, Sangjudungsi, and Godongsi) of persimmon (Diospyros kaki Thunb.) and the effects of maturity. The detected free sugars were fructose and glucose, and glucose levels tended to increase with maturity. Palmitic acid, oleic acid, linoleic acid and stearic acid, and potassium were major components. In the amino acid component analysis, the following were usually present in the following month: glutamic acid in Gabjubaekmok in July, lysine in Sangjudungsi in August, and threonine in Godongsi in October. Vitamin C tended to increase with aging, and fruit harvested in July had the highest total phenolic and flavonoid contents. In the metabolite analysis, there were significant differences among cultivars and with maturity. The major physiological compounds were analyzed using ultra performance liquid chromatography quadrupole time-of-flight tandem mass ($UPLC/Q-TOF/MS^2$) and were citric acid and gallic aicd. As maturity progressed, citric acid increased but gallic acid decreased.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.906-914
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• 2020

To investigate the usefulness of natural plants, physicochemical characteristics, functional components and physiological activities of dodder(Cuscuta australis R.Brown) were experimented. The extraction of dodder was carried out at 60℃ in shaking bath with 10 times of distilled water for three hours. Harmful metals such as lead, cadmium and arsenic were not detected, but the content of mercury from dodder was 0.0004ppm in acceptable standards. The extraction yield was 23.45%, total content of phenolics equivalent to gallic acid was 699.8 mg/100g and total content of flavonoid equivalent to naringin was 373.8 mg/100g. 28 kinds of free amino acids were detected with the contents of 252mg/100g in the dodder extract, and the contents of anserine and sarcosine were analysed highest in all amino acids. From the comparison of physiological activities of dodder extract with those of ascorbic acid, total reducing power, electron donating ability based on DPPH radical scavenging and ferric reducing antioxidant power was equivalent to 88%, 56% and 40%, respectively, of ascorbic acid. The nitrite scavenging activity of dodder extract was 78% of ascorbic acid on pH 1.5, but the antioxidant index of dodder on perilla oil was about 4 times greater than that of ascorbic acid.

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.119-124
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• 2020

Populus Tomentiglandulosa (PT) is known for pharmacological effects against ischemia-injury and immune activity. This study aimed to investigate the nutritional components, total phenol and flavonoid contents, antioxidant activities of PT extract. Among the mineral contents, the K content (907.5 mg/100 g) was the highest in the PT extract. Vitamins C (6.1 mg/100 g) and nicotinic acid (3.1 mg/100 g) were also found in high amounts. Fructose (2.2%) and glucose (1.6%) were found as free sugars in the PT extract. The total phenolic and flavonoid contents of PT extract were 115.4±0.85 mg GAE/g and 20.9±1.14 mg QE/g, respectively. Results of HPLC analysis of PT extract identified catechin (9.1±0.27 mg/g), caffeic acid (4.1±0.57 mg/g), p-coumaric acid (2.1±0.49 mg/g), chlorogenic acid (1.6±1.86 mg/g), and gallic acid (1.4±0.35 mg/g), respectively. These results suggest that the PT extract possesses high nutritional component and antioxidant properties, which can be used as functional bioresources.

• Natural Product Sciences
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• v.22 no.4
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• pp.299-306
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• 2016

This study aimed to establish the quantitative method to analyze the content of peroxynitrite-scavengers belonging to polyphenols in six Korean Quercus species (Quercus mongolica, Q. dentata, Q. acutissima, Q. alienta, Q. serrata, and Q. variabilis) by HPLC. The twelve peroxynitrite-scavengers, flavanols (catechins: (+)-catechin, (-)-epicatechin, and (-)-epigallocatechin), flavonols (kaempferol and quercetin), flavonol glycosides (astragalin, quercitrin, and isoquercitrin), flavonol acylated glycosides (astragalin 6''-gallate and isoquercitrin 6''-gallate), gallic acid and its dimer (ellagic acid) were analyzed by HPLC. Further, anti-Alzheimer's activity was assayed in a passive avoidance testusing mice by measuring the retention latency (sec), the concentration of acetylcholine (ACh), and acetylcholinesterase (AChE) activity. Simultaneous analysis of the extracts of the six Quercus leaves was achieved on a Capcell C18 column ($5{\mu}m$, $250mm{\times}4.6mm\;i.d.$) with a gradient elution of 0.05% HAc and 0.05% HAc in $CH_3CN$. In the extract of Q. mongolica leaves, the content of gallic acid (32.53 mg/g), (+)-catechin (28.78 mg/g), (-)-epicatehin (22.03 mg/g), astragalin 6''-gallate (20.94 mg/g), and isoquercitrin 6''-gallate (44.11 mg/g) and peroxynitrite-scavenging activity ($IC_{50}$, $0.831{\mu}g/ml$) were high. This extract delayed the retention latency and inhibited acetylcholinesterase activity in scopolamine-induced memory impairment of mice, suggesting that it has anti-Alzheimer's activity.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1218-1223
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• 2009

Total phenolics and antioxidant activities of water and 80% methanol extract of chestnut inner skin were investigated. The antioxidant properties of both extracts of chestnut inner skin were evaluated using different antioxidant tests, including 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, reducing power, ferric reducing ability of plasma (FRAP), and inhibitory effects on ${\beta}$-carotene bleaching. The 80% methanol extract of inner skin exhibited the higher DPPH, ABTS radical scavenging activities, reducing power, and FRAP than water extract of inner skin and did also in a concentration-dependent manner. However, inhibitory effects on ${\beta}$-carotene bleaching of 80% methanol extract was similar to those of water extract, 35.09 and 39.07% at 1 mg/mL, respectively. The total phenolic contents of water and 80% methanol extract from chestnut inner skin were 5,801.42 and 9,735.56 mg/100 g, respectively. High performance liquid chromatography (HPLC) analysis showed that gallic acid was the predominant phenolic compound in water and 80% methanol extract from inner skin. These water and 80% methanol extracts of chestnut inner skin can be utilized as an effective and safe source of antioxidants.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1258-1262
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• 2009

Total phenolics and antioxidant properties of various Korean commercial vinegars (apple vinegar, AV; blueberry vinegar, BV; grape vinegar, GV; lemon vinegar, LV; Opuntia ficus vinegar, OFV; persimmon vinegar, PV; Prunus mume vinegar, PMV; rice vinegar, RV) were investigated. The total phenolic contents of 8 vinegars were within the range of 54.18-491.02${\mu}g/mL$. The vinegars were also capable of scavenging 1,1-dipehnyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radicals in a manner dependent on concentration. The greatest reducing power was observed in PV relative to the other vinegars. The ferric reducing ability of plasma (FRAP) of PV, PMV, GV, and BV were 1.012, 0.969, 0.931, and 0.856 at a dose of 1 mL, respectively. Therefore, our study verified that the GV, PV, and PMV have powerful antioxidant activities which are correlated with its high level of phenolics, particularly gallic acid, and epigallocatechin.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.498-506
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• 2016

A croquette added with heat-treated kimchi at 20% showing higher sensory preferences was analyzed for its physicochemical properties and antioxidant activity using a croquette without kimchi as a control. Compared with the control, kimchi-added croquette had 3.3-fold higher organic acids content (p<0.001), resulting in a significant reduction of pH (p<0.001) and higher metal chelating activity (p<0.001). Upon addition of kimchi, total reducing capacity increased from 109.4 to $139.4{\mu}g/g$ gallic acid equivalents (p<0.01), and DPPH radical scavenging activity also increased 2-fold, which corresponded to 54% of the electron-donating ability of 0.35 mM gallic acid. In addition, contents of free amino acids and ${\gamma}-aminobutyric$ acid (GABA) appreciably increased by 1.6-fold (p<0.01) and 10-fold (p<0.001), respectively. This could be attributed to the ingredients of kimchi and/or enzymatic transformation of precursors by microorganisms during kimchi fermentation. Kimchi-added croquette was determined to be a good source of dietary fiber relative to its calorie content. Texture profile analysis showed no significant differences in hardness, springiness, cohesiveness, gumminess, and chewiness between the two croquettes with or without kimchi. Taken together, this study shows that utilization of heat-treated kimchi as a filling for croquette could be a good strategy to improve both the nutritional quality and antioxidant activity of croquette.

• Journal of Microbiology and Biotechnology
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• v.22 no.2
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• pp.199-206
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• 2012

Naturally immobilized tannase (tannin acyl hydrolase, E.C. 3.1.1.20) has many advantages, as it avoids the expensive and laborious operation of isolation, purification, and immobilization, plus it is highly stable in adverse pH and temperature. However, in the case of cell-associated enzymes, since the enzyme is associated with the biomass, separation of the pure biomass is necessary. However, tannic acid, a known inducer of tannase, forms insoluble complexes with media proteins, making it difficult to separate pure biomass. Therefore, this study optimizes the production of cell-associated tannase using a "protein-tannin complex" free media. An exploratory study was first conducted in shake-flasks to select the inducer, carbon source, and nitrogen sources. As a result it was found that gallic acid induces tannase synthesis, a tryptose broth gives higher biomass, and lactose supplementation is beneficial. The medium was then optimized using response surface methodology based on the full factorial central composite design in a 3 l bioreactor. A $2^3$ factorial design augmented by 7 axial points (${\alpha}$ = 1.682) and 2 replicates at the center point was implemented in 17 experiments. A mathematical model was also developed to show the effect of each medium component and their interactions on the production of cell-associated tannase. The validity of the proposed model was verified, and the optimized medium was shown to produce maximum cell-associated tannase activity of 9.65 U/l, which is 93.8% higher than the activity in the basal medium, after 12 h at pH 5.0, $30^{\circ}C$. The optimum medium consists of 38 g/l lactose, 50 g/l tryptose, and 2.8 g/l gallic acid.

• Korean Journal of Food Science and Technology
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• v.50 no.1
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• pp.117-121
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• 2018

Puffing process modifies the chemical and physical properties of the grains. In this study, oats were puffed by subjecting them to pressure of 1.0 and 1.2 MPa, following which the bioactive constituents and antioxidant activities in the oat extracts were investigated. The polyphenol content in puffed oat extracts increased in a pressure-dependent manner (109 and 157 mg gallic acid equivalent/100 g at 1.0 and 1.2 MPa, respectively). In addition, gallic acid was synthesized after puffing ($518{\mu}g/g$ of extract at 1.0 MPa) and was the most abundant phenolic acid in puffed oats. The antioxidant activities, which were determined by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2, 2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activities, were improved in oat extracts after puffing (+245 and +184% at 1.2 MPa, respectively). In conclusion, puffing process of oats increased the extractability of polyphenols, including gallic acid, which positively affected its antioxidant activities. These results will provide useful information when using puffed oats for food production.

• The Korean Journal of Food And Nutrition
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• v.31 no.1
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• pp.135-142
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• 2018

We investigated the influence of germination and high hydrostatic pressure (HHP) treatment conditions on the conversion of functional compounds and antioxidant activity in adzuki bean. The adzuki bean germinated at $25^{\circ}C$ for three- or six-days, and was later subjected to HHP at 0.1, 50, 100, or 150 MPa for 24 h. The highest polyphenol content (5.36 mg gallic acid equivalents (GAE)/g) and flavonoid content (0.91 mg catechin equivalents (CE)/g) were observed after germination for six days and HHP treatment at 100 MPa for 24 h, respectively. The total phenolic acid contents increased with increasing applied pressure from 88.86 to $208.26{\mu}g/g$ (100MPa, 24h). Phenolic acids are divided into two categories; those that exhibit increased content upon HHP treatment, and those that exhibit decreased content. The increasing phenolic acids were gallic acid, chlorogenic acid, (+)-catechin, ${\rho}-coumaric$ acid, ferulic acid, heperidin, salicylic acid, protocatechuic acid, cinnamic acid, naringenin. The total anthocyanin content decreased with increasing applied pressure from 22.42 mg/100 g to 6.28 mg/100 g (150 MPa, 24 h). The highest ABTS radical scavenging activity (8.02 mg eq AA/g) and DPPH radical scavenging activity (1.22 eq Trolox/g) were observed after germination for six days and HHP treatment at 100MPa for 24h, respectively. These results suggested that the combination of HHP and germination can lead to improved functionality in adzuki bean.