芽菜中螢光物質理化性質之探討   全文下載

Studies on Physicochemical Properties of Fluorescent Substances in Bean Sprouts

探討五種常見的食用芽菜──綠豆芽、黃豆芽、豌豆芽、苜蓿芽及蘿蔔嬰中之螢光物質，使用六種溶媒萃取，發現甲醇的萃取效果最高，乙醇次之。五種芽菜中綠豆芽甲醇萃取物（ methanolic extracts of mungbean sprouts, MEMS）的螢光強度最高，其激發波長及發射波長分別為339及395nm。黃豆芽甲醇萃取物（methanolic extracts of soybean sprouts, MESS）的螢光強度次高，其激發波長及發射波長分別為350及410nm。螢光增白劑FB351的激發波長及發射波長分別為238及435nm。光照對MEMS、MESS及螢光增白劑FB351穩定性之影響，以日光的破壞效果最強，日光光照8小時，可使MEMS、MESS及FB351之螢光強度分別降為原來的27、28及0.8%。紫外燈長波長的影響次之，紫外燈短波長及日光燈又次之，但皆遠不及日光光照的影響。MEMS、MESS及FB351在30°C水浴中放置144小時，螢光強度分別降為原來的90、91及99%；在50°C水浴中放置144小時，螢光強度分別降為原來的89、87及75%。三者在空氣中皆相當安定。MEMS及MESS在鹼性條件下螢光強度較低，在pH 13時其螢光強度分別為pH 7時的28及11%。而螢光增白劑在鹼性條件下螢光強度較不受影響，部分螢光增白劑在pH 1的酸性條件下則螢光強度較低。 Using six kinds of extraction solvents to study the fluorescent substances in five common bean sprouts of mungbean, soybean, pea, clover and radish, we found that methanolic extraction had the highest efficiency, followed by ethanol. Among the five bean sprouts, the methanolic extract of mungbean sprouts (MEMS) had the highest fluorescence intensity, with excitation wavelength and emission wavelength of 339 and 395nm, respectively. The methanolic extract of soybean sprouts (MESS) had the second highest fluorescence intensity, with excitation wavelength and emission wavelength of 350 and 410nm. Those of fluorescent whitening agent FB351 were 238 and 435nm, respectively. The effect of light on the stability of MEMS, MESS and FB351 showed that sunlight was the most destructive followed by near ultraviolet, far ultraviolet and PL lamp, in a decreasing order. After an exposure to sunlight for 8hr, the fluorescence in tensity of the MEMS, MESS and FB351 were decreased to 27, 28 and 0.8%, respectively. Incubation of MEMS, MESS and FB351 at 30°C for 144 hr decreased their fluorescence intensity to 90, 91 and 99%, respectively, while after incubation at 50°C for 144 hr the corresponding percentages were 89, 87 and 75, respectively. They were, however, quite stable when exposed in air. Under alkaline condition at pH 13, the fluorescence intensity of MEMS and MESS only 28 and 11% of their values at pH 7, whereas the fluorescent whitening agents were not affected under such a condition. Part of the fluorescent whitening agents at pH 1, however, showed lower fluorescence intensity."

Using six kinds of extraction solvents to study the fluorescent substances in five common bean sprouts of mungbean, soybean, pea, clover and radish, we found that methanolic extraction had the highest efficiency, followed by ethanol. Among the five bean sprouts, the methanolic extract of mungbean sprouts (MEMS) had the highest fluorescence intensity, with excitation wavelength and emission wavelength of 339 and 395nm, respectively. The methanolic extract of soybean sprouts (MESS) had the second highest fluorescence intensity, with excitation wavelength and emission wavelength of 350 and 410nm. Those of fluorescent whitening agent FB351 were 238 and 435nm, respectively. The effect of light on the stability of MEMS, MESS and FB351 showed that sunlight was the most destructive followed by near ultraviolet, far ultraviolet and PL lamp, in a decreasing order. After an exposure to sunlight for 8hr, the fluorescence in tensity of the MEMS, MESS and FB351 were decreased to 27, 28 and 0.8%, respectively. Incubation of MEMS, MESS and FB351 at 30°C for 144 hr decreased their fluorescence intensity to 90, 91 and 99%, respectively, while after incubation at 50°C for 144 hr the corresponding percentages were 89, 87 and 75, respectively. They were, however, quite stable when exposed in air. Under alkaline condition at pH 13, the fluorescence intensity of MEMS and MESS only 28 and 11% of their values at pH 7, whereas the fluorescent whitening agents were not affected under such a condition. Part of the fluorescent whitening agents at pH 1, however, showed lower fluorescence intensity.