Wilkes J G, Conte E D, Kim Y, Holcomb M, Sutherland J B, Miller D W
Department of Health and Human Services, Food and Drug Administration, National Center for Toxicological Research, Jefferson, AR 72079, USA.
J Chromatogr A. 2000 Jun 2;880(1-2):3-33. doi: 10.1016/s0021-9673(00)00318-6.
Off-flavors in foods may originate from environmental pollutants, the growth of microorganisms, oxidation of lipids, or endogenous enzymatic decomposition in the foods. The chromatographic analysis of flavors and off-flavors in foods usually requires that the samples first be processed to remove as many interfering compounds as possible. For analysis of foods by gas chromatography (GC), sample preparation may include mincing, homogenation, centrifugation, distillation, simple solvent extraction, supercritical fluid extraction, pressurized-fluid extraction, microwave-assisted extraction, Soxhlet extraction, or methylation. For high-performance liquid chromatography of amines in fish, cheese, sausage and olive oil or aldehydes in fruit juice, sample preparation may include solvent extraction and derivatization. Headspace GC analysis of orange juice, fish, dehydrated potatoes, and milk requires almost no sample preparation. Purge-and-trap GC analysis of dairy products, seafoods, and garlic may require heating, microwave-mediated distillation, purging the sample with inert gases and trapping the analytes with Tenax or C18, thermal desorption, cryofocusing, or elution with ethyl acetate. Solid-phase microextraction GC analysis of spices, milk and fish can involve microwave-mediated distillation, and usually requires adsorption on poly(dimethyl)siloxane or electrodeposition on fibers followed by thermal desorption. For short-path thermal desorption GC analysis of spices, herbs, coffee, peanuts, candy, mushrooms, beverages, olive oil, honey, and milk, samples are placed in a glass-lined stainless steel thermal desorption tube, which is purged with helium and then heated gradually to desorb the volatiles for analysis. Few of the methods that are available for analysis of food flavors and off-flavors can be described simultaneously as cheap, easy and good.
食品中的异味可能源于环境污染物、微生物生长、脂质氧化或食品中的内源性酶分解。食品中风味物质和异味物质的色谱分析通常要求首先对样品进行处理，以尽可能去除干扰化合物。对于气相色谱（GC）分析食品，样品制备可能包括切碎、匀浆、离心、蒸馏、简单溶剂萃取、超临界流体萃取、加压流体萃取、微波辅助萃取、索氏萃取或甲基化。对于鱼类、奶酪、香肠和橄榄油中的胺或果汁中的醛进行高效液相色谱分析，样品制备可能包括溶剂萃取和衍生化。橙汁、鱼类、脱水土豆和牛奶的顶空气相色谱分析几乎不需要样品制备。乳制品、海鲜和大蒜的吹扫捕集气相色谱分析可能需要加热、微波介导蒸馏、用惰性气体吹扫样品并用Tenax或C18捕集分析物、热解吸、冷聚焦或用乙酸乙酯洗脱。香料、牛奶和鱼类的固相微萃取气相色谱分析可能涉及微波介导蒸馏，通常需要吸附在聚二甲基硅氧烷上或在纤维上电沉积，然后进行热解吸。对于香料、草药、咖啡、花生、糖果、蘑菇、饮料、橄榄油、蜂蜜和牛奶的短路径热解吸气相色谱分析，将样品置于内衬玻璃的不锈钢热解吸管中，用氦气吹扫，然后逐渐加热以解吸出挥发性物质进行分析。很少有可用于分析食品风味和异味的方法能同时被描述为廉价、简便且良好。
