• Preventive Nutrition and Food Science
• /
• v.1 no.2
• /
• pp.179-185
• /
• 1996

Extraction yields of thiosulfinates from garlic were studied by using gas-in-liquis-dispersion(GLD) system to maxmize the thiosulfinate extraction. Extracted thiosulfinates were spectrophotometically quantified using synthesized dially1 thiosulfinate. The conditions for maximum extraction were optimized by response surface methodology. The volatile components extracted by various methods, such as hexane extraction, simultaneous steam distillation and GLD system, were compared by using gas chromatography. The results indicated that the thiosulfinate yield was increased by incresaing temperature and nitrogen gas flow rate, while the effects of bubble sizes on thiosulfinate extraction were not significant at the ranges tested. Application of GLD system resulted in extraction of more volatile components than other extraction methods, Therfore, it was suggested that GLD system was one of the efficient extraction methods among the ever introduced ones, for thiosulfinate extraciton.

• Korean Journal of Food Science and Technology
• /
• v.36 no.3
• /
• pp.403-409
• /
• 2004

Onion, licorice, abgelia root, Chinese date, pine needle, and mulberry leaf were used to extract functional components far onion complex drink. No differences were observed between water extraction at room temperature and methanol extraction in electron-donating ability (EDA), thiosulfinate content (TSC), and ascorbic acid content (AAC), whereas water extraction resulted in higher nitrite-scavenging ability at pH 1.2 and 3.0, and lower superoxide dismutase-like ability than methanol extraction. Level of water extracts prepared by hard-boiling for 3 hr at above $100^{\circ}C$ was higher in all functional abilities except TSC than those prepared at room temperature. Optimal conditions for water extraction and storage were $100-120^{\circ}C$ for 6 hr and low-temperature storage, respectively.

• The Korean Journal of Food And Nutrition
• /
• v.19 no.2
• /
• pp.219-226
• /
• 2006

This study was carried out to optimize the extraction conditions of oleoresin from garlic and to investigate its physicochemical changes during storage at $4^{\circ}C\;and\;25^{\circ}C$. Ethanol was used as solvent for extraction of oleoresin from garlic. On the basis of yield and thiosulfinate contents, the optimum mixing ratio of garlic to ethanol, extraction temperature, time, and number of extraction repeats were found to be 1 to 2(w/v), $30^{\circ}C$, 3 hours, and three extraction repeats, respectively. The yield and thiosulfinate contents of garlic oleoresin under the above condition were 14.52% and $209.93{\mu}mol/g$, respectively. Five volatile sulfide compounds were identified by GC/MS of garlic oleoresin, i.e., diallyl disulfide, methyl allyl trisulfide, 3,4-dihydro-3-vinyl-1,2-dithiin, 2-vinyl-4H-1,3-dithiin and diallyl trisulfide. After 30 days of storage at $4^{\circ}C$, the thiosulfinate content of garlic oleoresin was $32.37{\mu}mol/g$, while there was no detectable amount of thiosulfinate in the oleoresin stored at $25^{\circ}C$. Brown color and turbidity increased significantly during the storage of garlic oleoresin at $25^{\circ}C$ as compared to storage at $4^{\circ}C$, while relatively little change in acidity was observed in the oleoresin regardless of storage temperature.

• Korean Journal of Food Science and Technology
• /
• v.31 no.6
• /
• pp.1477-1483
• /
• 1999

In order to retain or remove the flavor components of onions, this study was performed to investigate the effect of seaweeds and adsorbents on volatile flavor components of onion juice by testing a sensory evaluation, measuring the amount of pyruvate and thiosulfinate, and investigating the changes of volatile components by SPME/GC. The main flavor compounds in raw onion juice were dipropyl tetrasulfide, 1-propenyl propyl trisulfide, methyl propyl trisulfide, dipropyl trisulfide. Volatile flavor compounds in onion juice treated with tangleweed, brown-seaweed, laver and celite showed a relatively decreasing tendency compared to untreated onion juice, but most of volatile flavor compounds in onion juice treated with activated charcoal and ${\beta}-cyclodextrin$ were removed. The result of the sensory evaluation with various materials for masking onion flavor showed a significant difference at the p<0.05 level. The amount of pyruvate and thiosulfinate treated with tangleweed, brown-seaweed, laver and celite showed little difference compared to untreated onion juice, but the amount of pyruvate and thiosulfinate treated with activated charcoal and ${\beta}-cyclodextrin$ decreased largely compared to untreated onion juice. As a result of the study, onion juice treated with tangleweed, brown-seaweed, laver and celite showed the effect of preserving the pungent taste and masking the onion flavor. Activated charcoal and ${\beta}-cyclodextrin$added to onion juice might have a role in removing the onion flavor by adsorbing volatile flavor compounds in onion.

• Food Engineering Progress
• /
• v.13 no.2
• /
• pp.92-98
• /
• 2009

An investigation was carried out to study the effects of extraction, heat treatment, and storage temperature on functional ingredients of onion. Extracts of onion paste and freeze dried onion were prepared by treatments with several solvents including hot water, methanol, and ethanol, and then contents of functional ingredients such as total phenol, flavonoid, quercetin, and thiosulfinate were determined. The highest levels of functional ingredients were observed in samples extracted using water at 100$^{\circ}C$ or ethanol. The skin extract contained 60-fold more quercetin than onion paste extract, whereas no thiosulfinate was detected in onion skin extract. Heat treatment of onion extracts at 60, 80, 105, and 121$^{\circ}C$ did not effect on the levels of all functional ingredients tested. During four-week storage, the levels of total phenol, flavonoid, and quercetin were not significantly changed regardless of storage temperature. However, the total thiosulfinate was rapidly reduced as the storage temperature increased.

• Korean Journal of Food Science and Technology
• /
• v.30 no.6
• /
• pp.1321-1326
• /
• 1998

Extraction and storage conditions of oleoresin were studied from root portion of peeled garlic, an waste of garlic industry. Extraction with ethanol and methanol showed an high solid yields of $27{\sim}37%$ at the temperature range of $30{\sim}50^{\circ}C$. Two hours of extraction were found to be economic because of no significant increase in furthur extraction. Storage of the oleoresin under anaerobic condition such as vaccum or nitrogen resulted in a less changes in pH, total acidity, color and thiosulfinate content, than those changes under aerobic condition. Most of the thiosulfinate was decreased for all conditions after 14 days of storage at $25^{\circ}C$. Glucose and sucrose were increased and most of organic acids were decreased during storage under nitrogen condition. Addition of ascorbic acid and cysteine into oleoresin retained the garlic flavor, effectively.

• Applied Biological Chemistry
• /
• v.51 no.3
• /
• pp.183-187
• /
• 2008

Alkyl thiosulfi(o)nates, analogs of allyl-2-propene-1-thiosulfinate isolated from Allium sativum and having antibacterial activity, were chemically synthesized and their biological activities were investigated. Alkyl thiosulfinates were prepared by oxidation of corresponding disulfides with organic peroxy acid, while alkyl thiosulfonates could be obtained by oxidation of the alkyl thiosulfinates using sodium periodate. All synthetic thiosulfi(o)nates showed antibacterial activity against Staphylococcus aureus B33 and antifungal activity against Candida utilis ATCC42416. Further more synthetic alkyl thiosulfonates displayed antioxidant activity and have also prevention effect of platelet aggregation induced by collagen in rat.

• Food Science and Biotechnology
• /
• v.14 no.1
• /
• pp.123-130
• /
• 2005

Hydrogen-donating capacity, scavenging activity of reactive oxygen including superoxide anion radical and hydrogen peroxide, metal-chelating activity, and reducing power of garlic extracts were investigated. All tested garlic extracts exhibited in vitro antioxidant activities, with Uiseong extract showing highest hydrogen-donating and hydrogen peroxide-scavenging activities, and reducing power, followed by Seosan and Samchek extracts, in proportion to total thiosulfinate contents. Higher scavenging activity of superoxide anion radical was observed in Uiseong than Seosan and Samchek extracts. Metal-chelating activity increased in order of Uiseong < Seosan < Samchek, showing inverse relations to total thiosulfinate content. Garlic extracts of Uiseong and Seosan showed weak prooxidant activities and that of Samchek showed strong antioxidant activity against $Cu^{+2}$-induced human LDL oxidation. Protective effects on peroxyl and hydroxyl radical-induced DNA strand damages were observed in all tested garlic cloves. These results indicate growing conditions of garlic cloves affect total thiosulfinate content and antioxidant activities.

• Korean Journal of Food Science and Technology
• /
• v.39 no.6
• /
• pp.600-607
• /
• 2007

In this study, attempts were made to develop a method for controlling the volatile sulfur compounds in garlic. Crude alliinase extracted from fresh garlic was applied to garlic pulp blanched far 5 min at $100^{\circ}C$, and the changes in the thiosulfinates and volatile compounds of the blanched garlic pulp reacted with the enzyme were investigated. Eight kinds of thiosulfinates from garlic were separated by HPLC, and identified by LC/MS/MS. When the alliinase was added to the blanched garlic pulp at 100, 200, 300, or 400 units, and reacted for 15 min, respectively, thiosulfinates were generated in the amounts of 37, 68, 77, and 80% of the fresh garlic content (control). Under the same conditions, we analyzed the volatile compounds, where 28 peaks were identified by GC/MSD. Of the 28 peaks, 23 were volatile sulfur compounds. The results of the analysis showed that all the volatile compounds were generated at amounts of 25, 36, 66, and 76% of the content of the control, respectively. These results indicate that the sulfur compound content of garlic can be regulated, depending upon the reaction conditions of allinase.

• Korean Journal of Food Science and Technology
• /
• v.46 no.2
• /
• pp.189-197
• /
• 2014

Onion juices were prepared by various heat treatments (at $105-120^{\circ}C$ for 4.5-5.5 h), from the onions cultivated with increasing numbers of sulfur applications (once for Sulfur-1, four times for Sulfur-4). As heat treatment intensity increased, the onion juices darkened (p<0.001), which adversely affected the sensory preference. In addition, increasing the heating temperature significantly increased the organic acid content of onion juices (p<0.001), and therefore, decreased pH (p<0.001). Heat intensity did not affect the thiosulfinate content of onion juices, suggesting that the rate of decomposition of thiosulfinate into low-molecular weight sulfur derivatives is similar over the temperature range of $105-120^{\circ}C$. Total flavonoids were higher in onion juices derived from Sulfur-4 than in Sulfur-1 onions, and increased with heat treatment intensity (p<0.001). These results indicated that heat-facilitated conversion of bound forms of flavonoids to their free forms increases the extractability of flavonoids from onions.