O'Neil C A, Schwartz S J
Department of Food Science, North Carolina State University, Raleigh 27695-7624.
J Chromatogr. 1992 Oct 30;624(1-2):235-52. doi: 10.1016/0021-9673(92)85682-j.
Cis/trans configurations of carotenoids are known to effect the biochemistry of carotenoids in certain situations. Methodology for separating carotenoid cis/trans isomers is of importance to nutritionists and food scientists because cis isomers of provitamin A carotenoids have lower provitamin A activities than the all-trans form. Traditional food processing and preservation methods, especially thermal treatments, induce the formation of cis isomeric forms. However, many challenges, are apparent for identifying and analyzing cis/trans isomers present in foods and other biological tissues. The development of current chromatographic methods for the separation of carotenoid cis/trans isomers is reviewed. For the separation of beta-carotene isomers, most procedures employ either Ca(OH)2 or Vydac C18 columns. In general, polymeric C18 columns allow for the detection of cis carotenes, while monomeric C18 columns provide for some separation of certain xanthophylls. The main cis isomers detected in foods are the 13-cis and 9-cis forms, although other forms have also been found (mainly 15-cis and various di-cis isomers). More studies involving the metabolism and physiological consequences of cis/trans isomers in the diet are needed. However, due to limitations in current techniques, further method development in the area of separation, detection and quantitation of cis/trans carotenoid isomers will be required.
已知类胡萝卜素的顺式/反式构型在某些情况下会影响类胡萝卜素的生物化学性质。分离类胡萝卜素顺式/反式异构体的方法对营养学家和食品科学家而言至关重要，因为维生素A原类胡萝卜素的顺式异构体的维生素A原活性低于全反式形式。传统的食品加工和保存方法，尤其是热处理，会促使顺式异构体形式的形成。然而，在识别和分析食品及其他生物组织中存在的顺式/反式异构体方面存在许多明显的挑战。本文综述了当前用于分离类胡萝卜素顺式/反式异构体的色谱方法的发展情况。对于β-胡萝卜素异构体的分离，大多数方法采用Ca(OH)₂或Vydac C18柱。一般来说，聚合物C18柱可用于检测顺式类胡萝卜素，而单体C18柱可对某些叶黄素进行一定程度的分离。在食品中检测到的主要顺式异构体是13-顺式和9-顺式形式，不过也发现了其他形式（主要是15-顺式和各种二顺式异构体）。需要开展更多涉及饮食中顺式/反式异构体的代谢及其生理影响的研究。然而，由于当前技术的局限性，在类胡萝卜素顺式/反式异构体的分离、检测和定量领域还需要进一步开发方法。
