• Proceedings of the Korean Society for Bioinformatics Conference
• /
• 2003.10a
• /
• pp.5-5
• /
• 2003

The purple acid phosphatases comprise a family of binuclear metal-containing enzymes. The metal centre contains one ferric ion and one divalent metal ion. Spectroscopic studies of the monomeric, ${\sim}$36 kDa mammalian purple acid phosphatases reveal the presence of an Fe(III)Fe(II) centre in which the metals are weakly antiferromagnetically coupled, whereas the dimeric, ${\sim}$110 000 kDa plant enzymes contain either Fe(III)Zn(II) or Fe(III)Mn(II). The three dimensional structures of the red kidney bean and pig enzymes show very similar arrangements of the metal ligands but some significant differences beyond the immediate vicinity of the metals. In addition to the catalytic domain, the plant enzyme contains a second domain of unknown function. A search of sequence databases was undertaken using a sequence pattern which includes the conserved metal-binding residues in the plant and animal enzymes. The search revealed the presence in plants of a 'mammalian-type' low molecular weight purple acid phosphatase, a high molecular weight form in some fungi, and a homologue in some bacteria. The catalytic mechanism of the enzyme has been investigated with a view to understanding the marked difference in specificity between the Fe-Mn sweet potato enzyme, which exhibits highly efficient catalysis towards both activated and unactivated phosphate esters, and other PAPs, which hydrolyse only activated esters. Comparison of the active site structures of the enzymes reveal some interesting differences between them which may account for the difference. The implications fur understanding the physiological functions of the enzymes will be discussed.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.2
• /
• pp.211-216
• /
• 2003

The objective of this study was to determine the degradability of cassava chip (CC), cassava waste (CW), yellow sweet potato (YP), white sweet potato (WP), purple sweet potato (PP), corn meal (CM), and rice bran (RB) using in situ technique. Two ruminally fistulated steers with an average weight of $303{\pm}10kg$ were used to determine in situ degradabilities of DM and OM. Seven feed sources were weighted in nylon bags ($38{\mu}m$ pore size) and incubated ruminally for 1, 2, 4, 6, 8, 12, 24, and 48 h. The results showed that asymptote (a+b) and effective degradability (ED) of DM of energy sources ranked from the highest to the lowest; CC, YP, WP, PP, RB, CW, and CM (99.3, 92.5; 97.6, 87.9; 97.5, 87.9; 97.2, 87.8; 87.5, 63.6; 78.6, 63.0 and 81.7; 59.3, respectively) and for OM asymptote (a+b) and effective degradability (ED) were similar to those of degradation of DM (99.4, 93.4; 98.8, 89.8; 98.5, 89.4; 98.4, 88.1; 92.4, 65.8; 85.1, 66.9 and 83.6, 63.3, respectively). It was concluded that disappearance characteristic of CC was the highest and it may potentially facilitate the achievement of optimal ruminal availability of energy: protein especially with NPN for microbial protein synthesis.

• Korean Journal of Food Science and Technology
• /
• v.29 no.5
• /
• pp.913-918
• /
• 1997

Taste components of traditional kochujang prepared with various raw materials, were investigated during 90 days of fermentation. The major free sugars, maltose and glucose, were higher in malt added kochujang than others. The major organic acids of kochujang were succinic and citric acids, followed by formic acid. The contents of succinic acid in the kochujang decreased during fermentation, whereas that of citric acid increased. Purple sweet potato kochujang was highest in total free amino acids. The major free amino acids were glutamic acid, serine and aspartic acid. They remarkably increased during fermentation. Among the nucleotides and their related components in kochujang, cytidine-5-monophosphate was the most abundant component at the beginning of aging period, while hypoxanthine increased remarkably during fermentation. Kochujang prepared with purple sweet potato Chinese matrimony vine contained higher amounts of organic acids and nucleotides than the others.

• Preventive Nutrition and Food Science
• /
• v.2 no.3
• /
• pp.191-196
• /
• 1997

The antioxidative activity of seven different acylated anthocyanin pigments isolated from grape, sweet potato, eggplant and red cabbage was evaluated bvy using linoleic acid autoxidation and rat liver microsomal systems. The acylated anthocyanins were isolated and purified by Amberlite SAD-7, ODS and Sephadex LH-20 column omatography, and preparative HPLC. Most of acylated anthocyanisns exhibited antioxidative activity as strong as $\alpha$-tocoperol, and especially peonidin3-O--(6-O-trans-caffeyl)-2-O-(6-O-trans-feuloylglucopyranosyl)-$\beta$-D-glucopyranosyl-5-O-$\beta$-D-glucopyranoside from purple sweet potato showed the strongest activity, comparable to BHA (not significant, p<0.05) in the linoleic acid system. Meanwhile, two acylated anthocyanins from the pericarps of grape and eggplant inhibited considerably the MDA formation from rat liver microsomal lipid peroxidation induced by FeSO$_4$/$H_2O$$_2$. In particular, malvidin 3-O-(6-O-p-coumaroyl)-$\beta$-D-glucopyranosde from grape pericarps showed the strongest antioxidant activity, comparable to $\alpha$-tocopherol (not significant, p<0.05). These results suggest that the acylated anthocyanins from fruits and vegetables can be used as potential dietary ntioxidants and natural colorants.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.40 no.4
• /
• pp.423-430
• /
• 2014

In this study, the antioxidative effects for the extracts of purple sweet potato (Ipomoea batatas L. Lam.) were investigated. The purple sweet potato was extracted with 70% ethanol and the ethyl acetate fraction was obtained from the extracts. The yields of extract and ethyl acetate fraction were 39.2% and 3.49% per dried powder, respectively. To confirm the antioxidative effects of the extracts, free radical scavenging activities (1,1-diphenyl-2-picrylhydrazyl), total antioxidant capacity by luminol-dependent chemiluminescence assay and the protective effects against reactive oxygen species (ROS) in erythrocytes were measured. Free radical scavenging activities ($FSC_{50}$) of the 70% ethanol extract and ethyl acetate fraction were $90.16{\mu}g/mL$ and $7.69{\mu}g/mL$, respectively. The free radical scavenging activity of ethyl acetate fraction was higher than that of (+)-${\alpha}$-tocopherol ($8.98{\mu}g/mL$). Total antioxidant capacities ($OSC_{50}$) of the 70% ethanol extract and ethyl acetate fraction were $5.75{\mu}g/mL$ and $1.92{\mu}g/mL$, respectively. The capacity of ethyl acetate fraction was similar to L-ascorbic acid, known as a prominent water soluble antioxidant ($1.50{\mu}g/mL$). The cellular protective effects of the ethyl acetate fractions on the $^1O_2$-induced cellular damage of human erythrocytes were increased in a concentration dependent manner ($5{\sim}50{\mu}g/mL$). The ${\tau}_{50}$ value in $5{\mu}g/mL$ was 45.6 min which was higher than that of (+)-${\alpha}$-tocopherol in all concentrations. These results indicate that the ethyl acetate fraction of purple sweet potato (I. batatas) has the excellent antioxidative capacity and could be applicable to anti-aging cosmeceutical ingredients for skin aging inhibition.

• The Korean Journal of Food And Nutrition
• /
• v.27 no.1
• /
• pp.22-30
• /
• 2014

In this study, purple sweet potato bread was prepared by the addition of 0.005%, 0.010%, 0.015% and 0.020% hemicellulase. It's effect on product quality and consumer evaluation were examined. The results showed that the dough pH and total titratable acidity were not significantly different between samples. In the fermentation power of dough expansion, a 0.015% addition sample was the highest between the samples. The bread pH decreased significantly as hemicellulase was increased, whereas. Bread total titratable acidity was significantly decreased. The addition of hemicellulase samples were significantly higher in specific volume and baking loss than the control sample. The moisture content was not significantly different between samples. In colors, the lightness of the control sample was the highest, the redness of the 0.020% addition sample was the lowest while the yellowness of the control was the lowest. The hardness and the fracturability decreased significantly as hemicellulase was increased. The resilience indicated reverse effects. In consumer evaluation, the color and softness were not significantly different between samples. And the hemicellulase addition of samples was higher in flavor than that of the control sample. The overall acceptability was the highest at 5.67 with a 0.010% addition sample. According to these results, the addition of 0.010% hemicellulase in purple sweet potato bread would be the optimum level.

• Korean Journal of Food Science and Technology
• /
• v.28 no.2
• /
• pp.345-351
• /
• 1996

Studies on extraction and color characteristics of purple sweet potato (PSP) pigment were performed to provide the basic information for the utilization of PSP as a new source of natural food colorant. PSP pigment was extracted well with the polar solvents such as distilled water, ethanol, and methanol. but hardly extracted with the non-polar solvents. Among the tested solvents, 20% ethanol solution containing 0.1% citric acid was found to be the most efficient for extraction of the pigment from PSP. PSP contained high amount of pigment not only in the epidermis but also in the flesh of the potato. The PSP pigment was heat stable even under pretreatments such as autoclaving and blanching of the potato before extraction. The optimum temperature of the extraction for the PSP Pigment was decided to be $30^{\circ}C$ by considering the stability and the rate of extraction. The pigment was markedly influenced by the change of pH. The color of the pigment solution was red at the pH range of $1.0{\sim}3.0$, became blue at $7.0{\sim}8.0$, then turned green at $9.0{\sim}10.0$. A characteristic batho-chromic shift of the pigment solution was observed as the pH of the solution increased.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.6
• /
• pp.955-961
• /
• 2014

This study was carried out to investigate the amounts of vitamin C in 22 sweet potato cultivars cultivated in Korea as well as evaluate the effects of cooking methods on vitamin C contents. Methods for determining vitamin C was validated by determining linearity, specificity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy using HPLC. Results showed high linearity in the calibration curve with a coefficient of correlation ($R^2$) of 0.9999. The LOD and LOQ values for ascorbic acid (AA) were 0.03 and $0.10{\mu}g/mL$, respectively. The relative standard deviations (RSDs) for intra- and inter-day precision of AA were less than 5%. The recovery rates of AA and dehydroascorbic acid (DHA) were in the range from 98.21~98.64 and 98.28~100.68%, respectively. Depending on cultivar, contents of AA, DHA, and total ascorbic acid (TA) in sweet potatoes varied in the range from 37.76 (Sinyulmi)~89.25 (Juhwangmin), 23.37 (Sinjami)~63.94 (Sinyulmi), and 68.52 (Sinjami)~115.95 (Juhwangmin) mg/100 g, respectively, and their average levels were $56.98{\pm}12.53$, $36.46{\pm}9.03$, and $93.44{\pm}12.00mg/100g$, respectively. The average TA levels were also dependent on flesh color, whish was significantly higher in general sweet potato and orange sweet potato than in purple sweet potato. Steaming, baking, and frying processes significantly reduced AA (10.61~58.41%), DHA (2.57~52.81%), and TA (14.54~49.92%) contents in sweet potatoes. The highest reduction of AA, DHA, and TA contents was observed after baking, followed by steaming and frying. We expect that the basic information provided by this study will be useful to plant breeders and food scientists.

• Journal of Plant Biotechnology
• /
• v.32 no.4
• /
• pp.307-311
• /
• 2005

The anthocyanin biosynthesis in callus culture of purple sweet potato (Ipomoea batatas L. cv. Borami) was investigated under growth in different light intensity and light emitting diodes (LED) treatment. Pigmented calli were induced from leaf explants cultured on MS agar medium supplemented with $0.5\;{\mu}M$ 2,4-D under light condition. The color value of these calli extracted after $2{\sim}4$ weeks of cultures was $0.4{\sim}0.5\;mg/mL$. Irradiation intensity is an important factor for anthocyanin biosynthesis. The optimal anthocyanin accumulation occurred on light intensity of 3000 lux. Light irradiation of 3000 lux and blue light treatment for 2 h resulted in a significant enhancement of anthocyanin accumulation. This value was 1.4 fold that the control.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.3
• /
• pp.369-377
• /
• 2013

In order to increase the utilization of sweet potato leaves and stalks as much as roots, it is necessary to study their beneficial potential. In this study, the antioxidant, antiallergic and anti-inflammatory effects of sweet potato leaves and stalks were evaluated by measuring total polyphenol and flavonoid contents, DPPH radical scavenging effects, the reducing power and inhibition effects on xanthine oxidase (XO), 5-lipoxygenase (LOX), and cyclo-oxygenase (COX)-2 activities. Blanched sweet potato leaves (SL), raw whole purple stalks (ST) and peeled stalks (PST) were freeze-dried and extracted with 95% ethanol. Total polyphenol content was highest in SL (11.03 mg/g), followed by ST (0.87 mg/g), and PST (0.37 mg/g). Total flavonoid content was highest for SL (9.01 mg/g), followed by ST (0.50 mg/g) and PST (0.25 mg/g). The $IC_{50}$ for DPPH radical scavenging effects was highest for SL ($43.6{\mu}g/mL$), followed by ST ($308.4{\mu}g/mL$) and PST ($1,631.3{\mu}g/mL$). The reducing power was highest for SL ($59.72{\mu}g$ ascorbic acid eq./mL), followed by ST ($12.56{\mu}g$ ascorbic acid eq./mL) and PST ($2.18{\mu}g$ ascorbic acid eq./mL) with $1,000{\mu}g/mL$ of ethanol extract. The inhibition rate on XO activity was highest for SL (13.06%), followed by ST (5.05%) and PST (0.0%) at $250{\mu}g/mL$ extract treatment. The inhibition rate on COX-2 activity was highest for SL (55.34%), followed by ST (2.18%) and PST (0.0%) at $250{\mu}g/mL$ extract treatment. The inhibition rate on 5-LOX activity was highest for SL (91.16%), followed by ST (33.38%) and PST (14.93%) at $50{\mu}g/mL$ treatment. Taken together, sweet potato leaves showed high antioxidative, anti-allergic and anti-inflammatory activities, especially with very strong inhibition effects on 5-LOX activity. These beneficial effects of sweet potato leaves might be mainly caused by the high content of polyphenols and flavonoids.