• Food Science and Biotechnology
• /
• v.15 no.1
• /
• pp.33-38
• /
• 2006

This study was performed to provide basic rheological data of dandelion root concentrates in order to predict their processing aptitude and usefulness as functional foods material. The hot water and 70% ethanol extracts of dandelion root were concentrated at 5, 20, and 50 Brix, and their static viscosity, dynamic viscosity, and Arrhenius plots were investigated. Almost all hot water concentrates showed the typical flow properties of a pseudoplastic fluid, but evaluation using the power law model indicated that the 70% ethanol concentrates showed a flow behavior close to a Newtonian fluid. The apparent viscosity of hot water and 70% ethanol concentrates decreased with increasing temperature. Yield stresses of hot water and 70% ethanol concentrates by Herschel-Bulkley model application were in the range of 0.026 - 1.368 Pa and 0.022 - 0.238 Pa, respectively. The effect of temperature and concentration on the apparent viscosity was examined by Arrhenius equation. The activation energies of hot water and 70% ethanol concentrates were in the range of $8.762-23.778{\times}10^3\;J/mol{\cdot}kg$ and $3.217-20.384{\times}10^3\;J/mol{\cdot}kg$ with increasing concentration, respectively. Storage (G') and loss (G") moduli were generally increased with increasing frequency. For the 70% ethanol concentrates, G" predominated over G' at all applied frequencies and so they showed the typical flow behavior of a low molecular solution. However, for the hot water concentrates, G' predominated over G" at more than 1.9 rad/sec (cross-over point) and so they showed the typical flow behavior of a macromolecular solution.

• Korean Journal of Food Science and Technology
• /
• v.24 no.6
• /
• pp.597-602
• /
• 1992

To improve utilization of boxthorn (Lycii Fructus), the boxthron and mixed boxthron (Lycii Fructus, Schizandrae Fructus, Corni Fructus, Zizyphi Fructus, Zingiberis Rhizoma, Cinnamami Cortex) hot-water extractable concentrates were prepared by vaccum evaporation and its rheological properties were investigated. The rheological properties of concentrates $(20{\sim}50^{\circ}Bx)$ followed power low model and showed a pseudoplastic behavior at the temperature range of $20{\sim}60^{\circ}C$. The apparent viscosity of $20^{\circ}Bx$, $30^{\circ}Bx$, $40^{\circ}Bx$ and $50^{\circ}Bx$ boxthron hot-water extractable concentrate was 0.0074 Pa s, 0.0175 Pa s, 0.0431 Pa s and 0.0988 Pa s, that of mixed boxthorn hot-water extractable concentrate was 0.0099 Pa s, 0.0328 Pa s, 0.0720 Pa s and 0.1940 Pa s at $20^{\circ}C$ and 1500 l/s, respectively. The yield stress of boxthron and mixed boxthron hot-water extractable concentrates ranged from 0.045 to 6.253 Pa and from 0.022 to 8.891 Pa, respectively. The activation energy for the flow of boxthron and mixed boxthorn hot-water extractable concentrates increased from 1.6182 to $2.0543{\times}10^7\;J/kg{\cdot}mol$ and from 1.7057 to $2.1462{\times}10^7\;J/kg{\cdot}mol$ with the concentrations of concentrates, respectively.

• Food Science and Biotechnology
• /
• v.15 no.2
• /
• pp.264-269
• /
• 2006

Basic rheological data of dandelion leaf concentrates were determined to predict processing aptitude and usefulness of dandelion leaf concentrates as functional food materials. Hot water and 70% ethanol extracts of dandelion leaves were concentrated at 5, 20, and 50 Brix, and their static and dynamic viscosities, and Arrhenius plots were investigated. Most concentrated dandelion leaves extracted with hot water and 70% ethanol showed flow behaviors close to Newtonian fluid based on power law model evaluation. Apparent viscosity of concentrated dandelion leaves extracted with hot water and 70% ethanol decreased with increasing temperature. Yield stresses of concentrated dandelion leaves extracted with hot water and 70% ethanol by Herschel-Bulkley model application were 0.020-0.641 and 0.017-0.079 Pa, respectively. Activation energies of concentrated dandelion leaves extracted with hot water and 70% ethanol were $2.102-32.669{\times}10^3$ and $1.657-5.382{\times}10^3\;J/mol{\cdot}kg$ with increasing concentration, respectively. Loss modulus (G") predominated over storage modulus (G') at all applied frequencies, showing typical flow behavior of low molecular solution. G' and G" of concentrated dandelion leaves extracted with hot water slowly increased with increasing frequency compared to those of concentrated dandelion leaves extracted with 70% ethanol.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.9
• /
• pp.1415-1422
• /
• 2014

Hot water extraction concentrate was prepared from Alliun hookeri root (AHR) to evaluate its applicability to yogurt. The highest antioxidant activity of hot water concentrates was obtained under extraction conditions of 4 hr at $95^{\circ}C$. Antioxidant activities measured by DPPH radical assay, ABTS radical cation assay, reducing power, and cheating activity were highly correlated with total phenolic (89.51 mg/g) and total flavonoid (52.71 mg/g) contents, with R values of 0.94 and 0.96, respectively. Yogurt was fermented with a commercial lactic acid bacteria mixed strain (Yo-mix$^{TM}$ 305) for 10 hr at $42^{\circ}C$ after addition of 0~10% (w/w) hot water concentrates from AHR to yogurt base. As fermentation proceeded, pH and $^{\circ}Brix$ of yogurt decreased from 6.57~6.60 to 4.34~4.51 and from 8.10~8.90% to 4.60~5.25%, respectively, whereas titrate acidity, viscosity, and viable cell numbers increased from 0.22~0.23% to 1.01~1.10%, from $0mPa{\cdot}s$ to $202.55{\sim}290.50mPa{\cdot}s$, and from 6.40~6.80 log CFU/mL to 8.60~9.20 log CFU/mL, respectively. There was no significant difference in any sensory attribute between the control and 2.5% addition group, suggesting that 2.5% hot water concentrate from AHR could be used to manufacture yogurt.

• The Korean Journal of Food And Nutrition
• /
• v.24 no.4
• /
• pp.797-802
• /
• 2011

I assessed the B($a$)P content from the Ginseng extract, Red ginseng extract, and Ssangwha extract which have high viscosities. It wasn't easy to extract oil from these samples, consequently measuring of B($a$)P was difficult. In order to know the exact detecting contents, I injected standard material of B($a$)P to the above extractions and pre-treated for measurement but it was also difficult to measure of contents exactly. To improve of detecting method, I removed mucinous materials using a 85% phosphoric acid solution or 10% citric acid solution and then processed continuously with $60^{\circ}C$ hot water. The analysis revealed that extracting the samples contained B($a$)P determined the rate of each 70%, 55%, 67% could increase. As a result the detecting method of B($a$)P contents could be improved.

• Journal of Applied Biological Chemistry
• /
• v.52 no.3
• /
• pp.126-132
• /
• 2009

In order to elucidate the relationship between the rainfastness of fungicides and their water solubilities, the fungicide residues on the leaf surface of hot pepper was assessed and compared after the drop-wise applications of fungicide solutions on leaf surface followed by artificial raining. As the raining was progressed after application of aqueous acetone solution of fungicides, the residue levels of fungicides were drop rapid at the early stage of raining, but the decreasing rates of residue level were slowed down thereafter. The initial rainfastness was reversely proportional to the water solubilities of the fungicides. Whole amount of dimethomorph residue, which water solubility is 18 mg/L, was washed off by 2.5 mm of raining. Although WP formulations of fungicides showed remarkable decreases of rainfastness compared to the aqueous acetone formulations, the fungicides having low water solubility showed better rainfastness. Chlorothalonil and mepanipyrim suspension concentrates was better in rainfastness than their WP formulation, and the rainfastness of mepanipyrim suspension was reversely proportional to the median diameter of suspension particles in the range of 1 to 4 ${\mu}m$. In brief, the rainfastness of 5 fungicides tested on the pepper leaf was, in the early stage of raining, closely related to water solubility. But, as the raining is progressed, the effect of the unknown factor, which is related with the particle size of fungicides, becomes serious.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.11
• /
• pp.1518-1524
• /
• 2011

This study was investigated the quality characteristics and antioxidant activities of the Rehmanniae radix (Rehmannia glutinosa Libosch. var. purpurea Makino) paste (RRP) and Rehmanniae radix preparata extract (RRPP). RRP and RRPP were made from vacuum concentrates of hot water extracts. The sugar contents of RRP and RRPP were 65.3 and 72.0$^{\circ}Brix$, respectively, whereas the reducing sugar contents were 2.4% and 44.9%. The pH level was lowest in the RRPP. The DPPH and hydroxyl radical scavenging activity of RRPP were much higher than those of RRP. Total phenol contents of RRP and RRPP were 2.15 mg/mL and 12.36 mg/mL, respectively. FRAP values of RRP and RRPP were 0.55 mg/mL and 2.02 mg/mL, respectively. Based on these results, it can be concluded that RRPP was the most appropriate in terms of both physicochemical and antioxidative activities.