17D-1 |
|
Y.-K. PARK, S.-T. Jung, and E.-H. Kim. Food Engineering & Food Industrial Technology Research Center(RRC), Mokpo National University, 61, chungkye-myon, muan-gun, Chonnam, 534729, South Korea Quercetin is known to reduce the carcinogenic activity of several cooked food mutagens, inhibit enzymatic activities associated with several types of tumor cells, enhance the antiproliferative activity of anticancer agents, and inhibit the growth of transformed-tumorigenic cells. With these beneficial effects, there has been increasing interest in foods that contain quercetin and its derivatives. Onions are reported to contain high levels of quercetin and its derivatives. Onion kimchi is usually used for food in the area where onions are produced in Korea. It is made in small amounts in most homes and there are a few commercial products. In addition, pickles, beverages, and snacks are made of onions and are on the markets. We analyzed the change and quantitate major flavonoids and their glycosides for onion kimchi fermentation by Sephadex LH-20 chromatography and HPLC. And in order to investigate the optimum condition for fermentation of onion kimchi, we made kimchi in which red pepper, sugars, and fish sauce were added according to the slice size of onion. During the process of fermentation, we analyzed changes such as pH, total titratable acidity, reducing sugar, Vit C, and microorganism, etc. We were able to separate onion flavonols into five fractions by Sephdex LH-20 chromatography. Five peaks obtained from HPLC were matched with those five peaks of Sephdex LH-20 chromatogram, and compounds with the HPLC retention times of 9.6, 12.1, 13.2, 14.2 and 15.8 min corresponded with five fractions, quercetin diglucoside, rutin, isorhamnetin glycoside, quercetin monoglucoside and quercetin, respectively. While the kimchi was fermenting, the amount of the quercetin glycosides decreased more and more through dissolving. On the other hand, the amount of the quercetin aglycone increased. In addition, pH, reducing sugar and Vit C decreased but the total titratable acidity and microorganisms increased.
Session 17D, Food Chemistry: Chemical effects of food processing and preservation
|