Luo Shuangyan, Duan Hanying, Zou Yuchen, Qiu Ruixia, Wang Chao
Department of Food Science and Technology, Jinan University.
J Nutr Sci Vitaminol (Tokyo). 2017;63(1):69-80. doi: 10.3177/jnsv.63.69.
Winged beans are an important natural source of some micronutrients. This paper presents the first complete characterization of folate derivatives including polyglutamyl 5-methyltetrahydrofolate (5-CH-HPteGlu), folate species and total folate accumulating in pods and immature seeds of winged beans from 9 cultivars and 7 growth stages. 5-CH-HPteGlu and folate species were determined with a UHPLC-MS/MS method. Accurate determination of 5-CH-HPteGlu and folate species was optimized and validated according to EMA guidelines including method selectivity, sensitivity, linearity, accuracy, precision, matrix effect and carry-over. The level of total folate is in the range of 73-200 μg/100 g in the pods and 33-61 μg/100 g in the immature seeds. The predominant folate species in winged beans is 5-CH-HPteGlu. 5-CH-HPteGlu is the major polyglutamyl folate derivative. The level of total folate is increased about 4 fold with advancing maturity. For pods, the chain length is increased with growth which shifts from 5-CH-HPteGlu in the early stage to 5-CH-HPteGlu and 5-CH-HPteGlu in the 7th stage. Our findings demonstrate that winged beans are good source of folate. The validated UHPLC-MS/MS method allows for the determination of 5-CH-HPteGlu and folate species from other vegetable matrices.
四棱豆是一些微量营养素的重要天然来源。本文首次全面表征了四棱豆9个品种、7个生长阶段的豆荚和未成熟种子中积累的叶酸衍生物，包括聚谷氨酰基5-甲基四氢叶酸（5-CH-HPteGlu）、叶酸种类和总叶酸。采用超高效液相色谱-串联质谱法测定5-CH-HPteGlu和叶酸种类。根据欧洲药品管理局（EMA）的指导方针，包括方法选择性、灵敏度、线性、准确性、精密度、基质效应和残留，对5-CH-HPteGlu和叶酸种类的准确测定进行了优化和验证。豆荚中总叶酸水平在73-200μg/100g范围内，未成熟种子中为33-61μg/100g。四棱豆中主要的叶酸种类是5-CH-HPteGlu。5-CH-HPteGlu是主要的聚谷氨酰基叶酸衍生物。随着成熟度的提高，总叶酸水平增加约4倍。对于豆荚，随着生长，链长度增加，从早期的5-CH-HPteGlu转变为第7阶段的5-CH-HPteGlu和5-CH-HPteGlu。我们的研究结果表明，四棱豆是叶酸的良好来源。经过验证的超高效液相色谱-串联质谱法可用于测定其他蔬菜基质中的5-CH-HPteGlu和叶酸种类。
