Determination of limonoate and nomilinoate A-ring lactones in citrus juices by liquid chromatography-electrospray ionization mass spectrometry.

The development of delayed bitterness in citrus products is a major problem to citrus producers and juice processors worldwide. A rapid and sensitive liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed to quantify the recognized precursors of limonoid derived delayed bitterness, limonoate and nomilinoate A-ring lactones, in a wide variety of citrus juices. The limonoid A-ring lactones were isolated by solid-phase extraction from juice samples, analyzed by negative ion LC-ESI-MS and quantified utilizing the standard addition method.