醬油中果糖酸之快速定量分析   全文下載

A Rapid Method for Direct Determination of Levulinic Acid in Soy Sauce

本研究建立了直接注入氣相層析分析醬油中果糖酸之快速、簡便測定方法。採用直接注入（splitless direct injection）方式，以極性之CP-wax管柱（30 m × 0.53 mm）分析定量醬油中之果糖酸，選擇水溶性之1,6- 己二醇（1,6-hexanediol）為內標準，最低檢出量為10μg／mL左右。添加果糖酸2.5、5.0 及10.0 mg／mL於1mL檢體中，直接注入GC分析，其回收率為98~103%，變異係數在6.3%以下，顯示直接注入法之精確性高，且檢體不需經前處理即可直接分析，簡單且快速。以本方法分析不同廠牌之動、植物蛋白質酸水解液11件、醬菜醬瓜類之調味液12件及醬油23件，共46件之果糖酸含量。醬菜醬瓜調味液之果糖酸含量2.1 ~ 4.7 mg／mL及醬油之果糖酸含量7.8 ~ 24.5 mg／mL。此結果顯示國內、外醬油及醬菜醬瓜均有使用植物蛋白質酸水解液之情形。且醬油中果糖酸之含量已遠超過CNS中國國家標準（1 mg／mL）。由市售純釀醬油中之果糖酸含量顯示，與標示『100% 純釀造』不符。"

A simple and rapid method was developed to determine the levulinic acid level in soy sauce using mega pore polar column (CP-Wax, 30 m × 0.53 mm) with splitless direct injection gas chromatography. Direct quantitative analysis of levulinic acid in soy sauce was carried out without any sample pretreatment procedure. A water-soluble compound, 1,6-hexanediol, was used as the internal standard. The detection limit for levulinic acid was 10µg/mL. Recoveries from soy sauce and pickled condiment liquid were performed by spiking 2.5, 5.0, or 10.0 mg to 1 mL of test samples and were found to be at the range of 98-103% with coefficients of variation less than 6.3%. Fourty-six food samples including animal and vegetable protein hydrolysate, pickle condiment liquid, and soy sauce were analyzed using the proposed method. Levulinic acid contents in pickled condiment liquid were found to be 2.1-4.7 mg/mL and in soy sauce were 7.8-24.5 mg/mL, which were higher than CNS regulated level (1.0 mg/mL), indicating commercial pickles and soy sauce might be adulterated with vegetable protein hydrolysate. These results were inconsistent with the labeling of '100% fermented soy sauce' on the packages. 本研究建立了直接注入氣相層析分析醬油中果糖酸之快速、簡便測定方法。採用直接注入（splitless direct injection）方式，以極性之CP-wax管柱（30 m × 0.53 mm）分析定量醬油中之果糖酸，選擇水溶性之1,6- 己二醇（1,6-hexanediol）為內標準，最低檢出量為10μg／mL左右。添加果糖酸2.5、5.0 及10.0 mg／mL於1mL檢體中，直接注入GC分析，其回收率為98～103%，變異係數在6.3%以下，顯示直接注入法之精確性高，且檢體不需經前處理即可直接分析，簡單且快速。以本方法分析不同廠牌之動、植物蛋白質酸水解液11件、醬菜醬瓜類之調味液12件及醬油23件，共46件之果糖酸含量。醬菜醬瓜調味液之果糖酸含量2.1～4.7 mg／mL及醬油之果糖酸含量7.8～24.5 mg／mL。此結果顯示國內、外醬油及醬菜醬瓜均有使用植物蛋白質酸水解液之情形。且醬油中果糖酸之含量已遠超過CNS中國國家標準（1 mg／mL）。由市售純釀醬油中之果糖酸含量顯示，與標示『100% 純釀造』不符。