Hirata Keiko, Shimamura Yasuhiro, Suzuki Keiko, Sadamasu Yuki, Ito Koichi
Tokyo Metropolitan Institute of Public Health, 3-24-1, Hyakunin-cho, Shinjuku-ku, Tokyo 169-0073, Japan.
Shokuhin Eiseigaku Zasshi. 2005 Dec;46(6):263-9. doi: 10.3358/shokueishi.46.263.
We have developed an analytical method for components of alpha-glucosyltransferase-treated stevia, a food additive product. Suitable conditions to separate additional sugar from alpha-glucosyltransferase-treated stevia by using glucoamylase were found (55 degrees C for 3 hr with 250 U of glucoamylase in 10 mL of reaction solution). By solid-phase extraction using a C18 cartridge column, polysaccharides were excluded from the sample, and the glycosides and sugar obtained after hydrolysis with glucoamylase were separated on another C18 cartridge column. The glycosides and sugar contents were determined by HPLC. By this method, additional sugar was detected in all of three product samples tested and the sugar was glucose. The contents of glucose and total glycosides (minus unreacted glycoside) were 25-42% and 35.7-52.5%, respectively. In alpha-glucosyltransferase-treated stevia, the sum of total glycosides and glucose amounted to 77.5-80.4% of the total and their recoveries from samples from which polysaccharide had been excluded by C18 cartridge column processing were over 85%. The contents of alpha-glucosyltransferase-treated stevia obtained by multiplying the sugar content by the coefficient (0.9) for hydrolysis and converting on dry weight basis were all over 80.0% and met the standard set by the Japan Food Additives Association.
我们开发了一种用于分析食品添加剂产品α-葡萄糖基转移酶处理甜菊糖苷成分的分析方法。发现了使用糖化酶从α-葡萄糖基转移酶处理甜菊糖苷中分离额外糖分的合适条件（在10 mL反应溶液中加入250 U糖化酶，55℃反应3小时）。通过使用C18柱进行固相萃取，多糖被排除在样品之外，用糖化酶水解后得到的糖苷和糖在另一根C18柱上分离。糖苷和糖的含量通过高效液相色谱法测定。通过这种方法，在所有测试的三个产品样品中均检测到额外的糖，且该糖为葡萄糖。葡萄糖和总糖苷（减去未反应的糖苷）的含量分别为25% - 42%和35.7% - 52.5%。在α-葡萄糖基转移酶处理甜菊糖苷中，总糖苷和葡萄糖的总和占总量的77.5% - 80.4%，并且通过C18柱处理排除多糖的样品中它们的回收率超过85%。通过将糖含量乘以水解系数（0.9）并以干重为基础换算得到的α-葡萄糖基转移酶处理甜菊糖苷的含量均超过80.0%，符合日本食品添加剂协会设定的标准。
