Oxidation and formation of oxidation products of β-carotene at boiling temperature

beta-Carotene is one of the most important lipid component extensively used in food industries as source of pro-vitamin A and colorant. During processing and storage beta-carotene is oxidized and degraded to various oxidation compounds. Some of these compounds are also the key aroma compounds in certain flowers, vegetables and fruits. The methods for analysis and determination of these oxidized products formed during food boiling or preparation are key to the understanding the chemistry of these compounds. This paper presents a novel analytical method incorporating high performance liquid chromatography with diode array and mass spectrometric detection for the characterization of oxidation, isomerization and oxidation products of beta-carotene in toluene at boiling temperature. HPLC and APCI-MS was optimized using oxidized sample and flow injection analysis of the standard beta-carotene respectively. beta-Carotene was oxidized in the Rancimat at 110 degrees C for 30, 60 and 90 min. The oxidized samples were than analyzed by HPLC system at 450 nm and 350 nm as well as scanning and single ion monitoring mass spectrometry. A total of ten oxidation products and three Z-isomers were reported. Extensive isomerization was observed during treatment at the control accelerated conditions. The oxidation products include five apo-carotenals, three diepoxides, one mono-epoxide and one short chain species. Results show that the method was reproducible, accurate and reliable for the separation and identification of oxidation products of beta-carotene. (C) 2012 Elsevier Ireland Ltd. All rights reserved.