Gas Chromatographic Determination of Glucono-δ-lactone in Soybean Curd

Analytical conditions for the determination of glucono-δ-lactone in soybean curd by gas chromatography were examined, and a standard method is proposed. The method is shown in Scheme 2.Glucono-δ-lactone is hydrolyzed gradually in aqueous solution, and partially decomposed to gluconic acid, so that glucono-δ-lactone and gluconic acid co-exist in solution. Since glucono-δ-lactone in basic solution is wholly transformed to gluconic acid, it was converted to, and determined as, gluconic acid. The coefficient of variation was 2.36% and the average recovery was 98%.