胆固醇是一种高营养价值的脂质,很容易通过酶和非酶途径进行氧化,导致各种各样的胆固醇氧化产物(COP),更常见的命名氧固醇。在动物产品中发现的主要氧固醇是7α-羟基胆固醇,7β-羟基胆固醇,7-酮胆固醇,5α,6α-环氧胆固醇,5β,6β-环氧胆固醇,胆固醇-3β,5α,6β-三醇,和25-羟基胆固醇.它们都是由胆固醇自动氧化产生的,因此属于非酶氧化固醇亚家族,即使7α-羟基胆固醇和25-羟基胆固醇是,在某种程度上,也是酶促产生的。最近在人和牛来源的牛奶中首次检测到另一种完全酶促来源的氧固醇,即27-羟基胆固醇。如今,气相色谱或液相色谱与质谱联用,可以准确测量生食品和工业加工食品中的所有这些氧固醇。虽然非酶氧化固醇通常表现出体外相关的细胞毒性,最重要的是7β-羟基胆固醇和7-酮胆固醇,27-羟基胆固醇,以及25-羟基胆固醇,显示了广谱的体外抗病毒活性,抑制SARS-CoV-2包括,并可能有助于先天免疫。氧固醇的定量是多年来提供的,几乎总是集中在几个家庭的化合物。更全面的COP测量,还包括酶促起源的氧固醇,是,如今,可用,更好地展示了系统地采用这一系列化合物作为质量标记的许多优点,安全,在加工和储存中选择配料和营养价值。关于食品的保质期,COP监测已经为更合适的包装提供了有用的提示。建议鉴定在食品生产和储存中常规评估的非酶和酶氧固醇的子集。
Cholesterol is a lipid of high nutritional value that easily undergoes oxidation through enzymatic and non-enzymatic pathways, leading to a wide variety of cholesterol oxidation products (
COPs), more commonly named oxysterols. The major oxysterols found in animal products are 7α-hydroxycholesterol, 7β-hydroxycholesterol, 7-ketocholesterol, 5α,6α-epoxycholesterol, 5β,6β-epoxycholesterol, cholestan-3β,5α,6β-triol, and 25-hydroxycholesterol. They are all produced by cholesterol autoxidation, thus belonging to the non-enzymatic oxysterol subfamily, even if 7α-hydroxycholesterol and 25-hydroxycholesterol are, in part, generated enzymatically as well. A further oxysterol of the full enzymatic origin has recently been detected for the first time in milk of both human and bovine origin, namely 27-hydroxycholesterol. Nowadays, gas or liquid chromatography combined to mass spectrometry allows to measure all these oxysterols accurately in raw and in industrially processed food. While non-enzymatic oxysterols often exhibited in vitro relevant cytotoxicity, above all 7β-hydroxycholesterol and 7-ketocholesterol, 27-hydroxycholesterol, as well as 25-hydroxycholesterol, shows a broad spectrum in vitro antiviral activity, inhibition of SARS-CoV-2 included, and might contribute to innate immunity. Quantification of oxysterols was afforded over the years, almost always focused on a few family\'s compounds. More comprehensive
COPs measurements, also including oxysterols of enzymatic origin, are, nowadays, available, which better display the many advantages of systematically adopting this family of compounds as markers of quality, safety, and nutritional value in the selection of ingredients in processing and storage. Regarding foodstuff shelf life,
COPs monitoring already provided useful hints for more suitable packaging. The identification of a subset of non-enzymatic and enzymatic oxysterols to be routinely assessed in food production and storage is proposed.