• Food Science and Preservation
• /
• v.8 no.2
• /
• pp.157-163
• /
• 2001

Optimal conditions for hot water extraction of Liriope spicata tuber were investigated with changes in solvent ratio(2∼6 fold) and heating time(1∼5 hr) by response surface methodology. The content of extractable solids increased with an increased in solvent ratio, and the highest content showed at heating time of 3 hr. The content of total steroid saponin increased with a decrease in solvent ratio, and increased with an increase in heating time at increasing the solvent ratio. The content of non-reducing sugar containing oligosaccharides at a lower solvent ratio didn’t show changes depending on heating time, while that at a higher ration decreased with an increase in heating time. Optimal extraction conditions using hot water as the limited conditions of 15∼18% extractable solids, 1.5∼2.0% total steroid saponin, 6∼8% reducing sugar, 6∼7% non-reducing sugar and 13∼15 brix were 3 hrs of heating time and 4 fold of solvent ratio.

• Polymer(Korea)
• /
• v.26 no.3
• /
• pp.307-315
• /
• 2002

Major factors affecting the impact resistance of high impact polystyrene (HIPS), the rubber-toughened grade of polystyrene, are rubber-phase particle size and size distribution, molecular weight, morphology, and degree of grafting. Accordingly, it is important to control or investigate these factors. In this study, the effect of solvent content was analyzed by the morphology and particle size distribution of rubber phase, and final properties in bulk-solution polymerization of HIPS. The prepolymerization time was, first, determined by measuring the evolution of particle size distribution of dispersed phase to explain the phase inversion with time. As the solvent content increased, the size of rubber particle increased and then gradually decreased. Rubber-phase morphology was likely to have higher degree of grafting as the solvent content increased. Rheological and mechanical properties decreased as the solvent content increased because of the decrease of matrix molecular weight due to the chain transfer reaction to solvent and the existence of residual solvent. Nevertheless, the impact resistance seemed to increase when the rubber particle size increased.

• Journal of the Korean Applied Science and Technology
• /
• v.41 no.2
• /
• pp.520-529
• /
• 2024

Lycium barbarum extract has a high potential to be developed as a health functional food due to the various health-promoting effects of Lycium barbarum. This study analyzed changes in nutritional and functional components depending on the extraction solvent (purified water and a mixture of purified water and alcohol) and the condition of the sample. The nutritional components (carbohydrates, protein, fat, ash), organic acids, amino acids, total phenolic compounds, and total flavonoids of the extract produced during the extraction process were analyzed. The nutritional composition and functional substances of the extracts showed some differences depending on the type of solvent and the condition of the sample. The amounts of crude protein (7.61%), crude fat (1.63%), carbohydrate (90.22%), and ash (0.54%) of dried Lycium barbarum extract using purified water as a solvent were similar to those of the powder sample extract. The highest content of citric acid was 4.31 mg/mL, similar to the case of acetic acid, when the powder sample used a mixture of purified water and alcohol as a solvent. The highest amino acid content was 357.39 mg/mL when the powder sample was mixed with purified water and alcohol as a solvent. The total amount of phenolic compounds was 686.16 g/L when the powder sample was extracted with a mixture of purified water and alcohol as a solvent. The highest total flavonoid content was 111.32 g/L when the powder sample was extracted with a mixture of purified water and alcohol as a solvent.

• Applied Chemistry for Engineering
• /
• v.20 no.6
• /
• pp.685-691
• /
• 2009

Dispersions of fumed silica are made in 6 kinds of mono-solvents and mixed solvents which have hydroxyl group, non hydroxyl group, different polarity, and different molecular size. The viscosity and rheology behaviors of the each dispersion are investigated according to the viewpoint of solvent characteristic. The silica dispersion in polar solvent with hydroxyl group is stable and low viscous sol. The silica dispersion in non-polar solvent with non-hydroxyl group is high viscous gel. When the solvent with hydroxyl group is added to the silica dispersions with non-polar solvents, they show the reduction of viscosity with solvent content. They have minimum critical content which shows no viscosity change. The minimum critical solvent content is decreased according to the polarity of solvents with no hydroxyl group. The solvation layer which is formed on the silica surface through hydrogen bonding between hydroxyl-containing solvent and the silanol group of silica surface is the reason of stable and low viscous sol. In case of non-polar solvent, silanol on adjacent silica particles interacted directly by hydrogen bonding show high viscous and flocculated gel.

• Journal of the Korean Chemical Society
• /
• v.28 no.4
• /
• pp.210-216
• /
• 1984

Solvatochromic comparison methods were applied to determine Taft's solvent parameters, ${\pi}^{\ast}$(solvent polarity-polarizability), ${\alpha}$(solvent hydrogen bond donor acidity) and ${\beta}$ (solvent hydrogen bond acceptor basicity) for MeOH-MeCN solvent mixtures. Swain's solvent parameters A(anion solvation scale) and B(cation solvation scale) were also determined by least square fitting of kinetic data in the same binary solvent mixtures. It was found that: (i)${\beta}$ depends on the basicity of the solvent and increases with the MeOH content owing to the increase in polymeric structure of methanol; (ii) ${\pi}^{\ast}$depends on the dipole moment of the solvent and increases with the MeCN content of the solvent; (iii) ${\alpha}$ increases rapidly with the MeOH content as the hydrogen bond donor acidity of the solvent mixtures increases. Taft's reaction constants a and s and Swain's reaction constants a and b were determined for the reactions reported from our laboratory previously using solvent parameters determined in this work. No meaningful inter-relationship was found between the two set of reaction parameters, but a good linear correlation was found between the ratios a/s and a/b. Solvent effect on the reaction mechanism, substituent effect and leaving group ability were examined in the light of these reaction constants ratios.

• Journal of the Korean Applied Science and Technology
• /
• v.16 no.1
• /
• pp.83-94
• /
• 1999

Glycoside fatty acid esters were synthesized by lipase-catalyzed glycosylation of fatty acids with methyl glycoside in solvent and solvent free process. Optimum condition of solvent process using 2-methyl-2-propanol were : moral ratio of methyl glycoside to fatty acid 1:3: initial concentration of methyl glycoside 50g/l:enzyme(immodilized lipase Novozym 435 from Candidia antarctica) content 1%(w/v) : desiccant content 9%(w/v); reaction temperature $60^{\circ}C$: reaction time 10hrs. The yield of 99% was obtained. Solvent-free process was carried out in total absence of solvent at $70^{\circ}C$ under reduced pressure, 5-20mmHg. To give meximum yield of 99% at the optimum condition of molar ratio of methyl glycoside to fatty acid 1:3, enzyme content 10%(w/w), and reaction time 10hrs. The glycosylation reactivity of different glycosylation agents were sequent to $Methyl-{\beta}-D-fructofuranoside$. $Methyl-{\beta}-D-glucopyranoside$. $Methyl-{\beta}-D-fructofuranosi$ de, and $Methyl-{\alpha}-D-glucopyranoside$.

• Korean Journal of Agricultural Science
• /
• v.46 no.1
• /
• pp.85-92
• /
• 2019

This study was intended to provide basic data for a health functional food study by exploring antioxidant activity of reflux extract according to the concentration of ethanol and the extract of ultrasonic waves extracted and reflux extracted under the same solvent conditions. In the same solvent condition, the reflux extract ($75.10{\pm}1.99mg$) showed a higher total phenol content than the ultrasonic wave extract ($51.74{\pm}2.28mg$). Flavonoids also had a higher reflux extract ($25.05{\pm}1.53mg$) than did ultrasonic extracts ($16.23{\pm}1.95mg$). Reflux extract according to ethanol concentration was found to have a higher phenol content than the 70% ethanol extract ($40.60{\pm}1.49mg$) in 60% ethanol extract. Flavonoid content was also similar to phenol content in reflux extract as determined by ethanol concentration from 60% ethanol ($25.05{\pm}1.53mg$) to 70% ethanol extract ($6.60{\pm}0.46mg$). In addition, the antioxidant activity (DPPH, TEAC, FRAP, ORAC) of the reflux extract in the same solvent conditions tended to be higher than that of ultrasonic extracts. Also, 60% ethanol extract had better antioxidant activity than 70% ethanol extract. However, an analysis of phenolic acid content through HPLC showed that the ultrasonic extract had a higher content in the same solvent condition than did the reflux extract. Not only the presence of phenolic acid, but also those of other compounds are believed to be attributed to the activity of antioxidants. Therefore, further studies are needed to clarify this phenomenon.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.3
• /
• pp.496-501
• /
• 1994

The synthesis of lauryl palmitate from palmitic acid and lauryl alcohol was investigated in organic solvents using lipase. Water-immiscible organic solvent such as hexane, toluenem cyclohexane, and isooctane were found to be suitable of ester synthesis . The effect of water content on the initial rate of conversion was examined . As the content increased, the reaction rate increased. But addition of water in organic solvent decreased therostability of enzyme . The best lauryl palmitate synthesis was achieved with water content of 0.2-0.4% reaction temperature of 4$0^{\circ}C$ and 45$^{\circ}C$ for Candida cylindracea lipase porcine, pancreatic lipase, respectively. when ester synthesis was carried out under the optimum conditions, the conversion yield of palmitate into lauryl palmitate after 70hrs reached 85% and 69 % for the Candida cylindracea lipase and porcine opancreatic lipase, respectivley.

• Journal of Life Science
• /
• v.5 no.4
• /
• pp.155-161
• /
• 1995

The effects of substrate concentration, enzyme concentration, reaction temperature, and water content were investigated in intramolecular esterification. This study used cyclohexane as organic solvent, power lipase as enzyme, and benzyl alcohol and octanoic acid as substrate. The initial reaction rate was found to be proportional to enzyme concentration; followed Michaelis-Menten equation for octanoic acid; and was inhibited by benzyl alcohol . The observed initial reaction rate first increased, then decreased with increasing reaction temperature, giving rise to the maximum rate at 20$\circ$. The drop in the reaction rate at higher temperature was to partition equilibrium change of substrate between organic solvent and hydration layer of enzyme molecule in addition to the deactivation by enzyme denaturation. Water layer surrounding enzyme molecule seemed to activate in organic solvent and the realistic reaction was done in the water layer. In the enzymatic reaction in organic solvent, the initial reaction rate was influenced by partition quilibrium of substrate, so the optimum condition of substrate concentration, enzyme concentration, reaction temperature, and water content would give a good design tool.

• New & Renewable Energy
• /
• v.19 no.4
• /
• pp.27-34
• /
• 2023

In this study, microalgal oil was extracted from Nannochloropsis oceanica cultured in an open raceway pond and converted into biodiesel using a solid acid catalyst. Microalgal oil was extracted from two types of microalgae with and without nitrogen starvation using the KOH-solvent extraction method and the fatty acid content and oil extraction yield from each microalgae were compared. The fatty acid content of N. oceanica was 184.8 mg/g cell under basic conditions, and the oil content increased to 340.1 mg/g under nitrogen starvation conditions. Oil extraction yields were 90.8 and 95.4% in the first extraction, and increased to 97.5 and 98.8% after the second extraction. Microalgal oil extracted by KOH-solvent extraction was yellow in color and had reduced viscosity due to chlorophyll removal. In biodiesel conversion using the catalyst SO₄^2-/HZSM-5, solvent-extracted oil showed a FAME content of 4.8%, while KOH-solvent-extracted oil showed a FAME content of 90.4%. Solid acid catalyst application has been made easier by removal of chlorophyll from microalgal oil. The FAME content increased to 96.6% upon distillation, and the oxidation stability increased to 11.07 h with addition of rapeseed biodiesel and 1,000 ppm butylated hydroxyanisole.