しょう油分析法に関する研究-5-バニリン-硫酸法によるレブリン酸の比色定量法
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概要
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The reaction of levulinic acid with vanillin in the presence of sulfuric acid was applied to the colorimetric microdetermination. Levulinic acid when heated with this reagent for 5min. at 100°C develops a highly stable blue color with absorption maximum at 610mμ, whose intensity is proportional to the amount of levulinic acid. There is a linear relation within 0.7mg of levulinic acid per ml. The slightly yellow reagent in a brown bottle maintains a constant chromogenic capacity at least for 30 days. The amounts of levulinic acid in the commercial shoyu sauces were examined by the colorimetric microdetermination. The shoyu sauces were extracted with ether at pH 3.0 more than 6 hours. Aldehydes, alcohols and other organic interfering substances in the extracts were removed by oxidation with chromic acid mixture. After repeated extraction with ether, the levulinic acid in the extracts was assayed. The method requires only simple, readily available chemicals and equipment, and is rapid and sensitive. Recovery of levulinic acid from shoyu sauce was good (97_??_103%).
- 公益社団法人 日本農芸化学会の論文