Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland.
School of Microbiology, University College Cork, Cork, Ireland.
Methods Mol Biol. 2021;2278:87-100. doi: 10.1007/978-1-0716-1274-3_8.
The biological significance of conjugated fatty acids (CFAs) has been linked to positive health effects based on biomedical, in vitro, and clinical studies. Of note, conjugated linoleic acids (CLAs) are the most widely characterized fatty acids as geometric isomers cis-9,trans-11 and trans-10,cis-12 CLA occur naturally in ruminant fats, dairy products, and hydrogenated oils. Concerning CLAs, it is known that bacterial biohydrogenation, a process whereby ruminal bacteria or starter cultures of lactic acid bacteria have the ability to synthesize CLA by altering the chemical structure of essential fatty acids via enzymatic mechanisms, produces a multitude of isomers with desirable properties. Bifidobacterium species are classed as food grade microorganisms and some of these strains harness molecular determinants that are responsible for the bioconversion of free fatty acids to CLAs. However, molecular mechanisms have yet to be fully elucidated. Reports pertaining to CLAs have been attributed to suppressing tumor growth, delaying the onset of diabetes mellitus and reducing body fat in obese individuals. Given the increased attention for their bioactive properties, we describe in this chapter the qualitative and quantitative methods used to identify and quantify CLA isomers produced by bifidobacterial strains in supplemented broth media. These approaches enable rapid detection of potential CLA producing strains and accurate measurement of fatty acids in biological matrices.
共轭脂肪酸（CFAs）的生物学意义已被证明与生物医学、体外和临床研究中的积极健康效果有关。值得注意的是，共轭亚油酸（CLA）是最广泛特征化的脂肪酸，其几何异构体 cis-9,trans-11 和 trans-10,cis-12 CLA 天然存在于反刍动物脂肪、乳制品和氢化油中。关于 CLA，已知细菌生物氢化是一种过程，其中瘤胃细菌或乳酸菌的起始培养物通过酶促机制改变必需脂肪酸的化学结构来合成 CLA，产生具有理想特性的多种异构体。双歧杆菌被归类为食品级微生物，其中一些菌株利用负责将游离脂肪酸生物转化为 CLA 的分子决定因素。然而，分子机制尚未完全阐明。与 CLA 相关的报告归因于抑制肿瘤生长、延缓糖尿病发作和减少肥胖个体的体脂肪。鉴于人们对其生物活性特性的关注度不断提高，我们在本章中描述了用于鉴定和定量双歧杆菌菌株在补充肉汤培养基中产生的 CLA 异构体的定性和定量方法。这些方法能够快速检测潜在的 CLA 产生菌株，并准确测量生物基质中的脂肪酸。
