González J, Remaud G, Jamin E, Naulet N, Martin G G
Eurofins Scientific, Rue Pierre Adolphe Bobierre, Nantes, France.
J Agric Food Chem. 1999 Jun;47(6):2316-21. doi: 10.1021/jf981093v.
The delta(13)C values of fructose, glucose, and sucrose have been determined in authentic pineapple juices. The sugar fraction is separated from the organic acids by an anionic exchange process. Then the individual components (fructose, glucose, and sucrose) are isolated on a preparative HPLC device using a NH(2)-type column. It is demonstrated that no significant isotope fractionation occurs when close to 100% of material is recovered and when the hydrolysis of sucrose is avoided. The control of the recovery rates and of the sucrose hydrolysis rate after purification is recommended for a reliable interpretation of the results. Correlations between the delta(13)C values of fructose (delta(13)Cf), glucose (delta(13)Cg), and sucrose (delta(13)Csu) can be characterized by systematic differences between these values. For the set of measurements on authentic pineapple juices and concentrates, the mean and the standard deviation of the differences are delta(13)Cf - delta(13)Cg = -0.6 +/- 0.6 per thousand, delta(13)Cf - delta(13)Csu = -1.3 +/- 0. 6 per thousand, and delta(13)Cf - delta(13)Csu = -0.7 +/- 0.5 per thousand. The determinations of the (13)C content of fructose, glucose, and sucrose enable a refinement of the detection of added sugars in fruit juices, re-enforcing the SNIP-IRMS method.
已测定了纯正菠萝汁中果糖、葡萄糖和蔗糖的δ(13)C值。通过阴离子交换过程将糖组分与有机酸分离。然后使用NH(2)型柱在制备型高效液相色谱仪上分离出各个组分（果糖、葡萄糖和蔗糖）。结果表明，当回收率接近100%且避免蔗糖水解时，不会发生明显的同位素分馏。为了可靠地解释结果，建议控制纯化后回收率和蔗糖水解率。果糖（δ(13)Cf）、葡萄糖（δ(13)Cg）和蔗糖（δ(13)Csu）的δ(13)C值之间的相关性可用这些值之间的系统差异来表征。对于纯正菠萝汁和浓缩汁的一系列测量，差异的平均值和标准偏差为：δ(13)Cf - δ(13)Cg = -0.6 ± 0.6‰，δ(13)Cf - δ(13)Csu = -1.3 ± 0.6‰，以及δ(13)Cg - δ(13)Csu = -0.7 ± 0.5‰。果糖、葡萄糖和蔗糖(13)C含量的测定能够改进果汁中添加糖的检测，加强了稳定同位素比值质谱法。
