Effect of esterification with fatty acid of β-cryptoxanthin on its thermal stability and antioxidant activity by chemiluminescence method

beta-Cryptoxanthin, a pro-vitamin A carotenoid of potential interest for health, was found in vegetables and fruits in both free and esterified forms. Stabilities of free beta-cryptoxanthin (FCX) and its esters including beta-cryptoxanthin laurate (CXL), beta-cryptoxanthin myristate (CXM), and beta-cryptoxanthin palmitate (CXP) against heat were studied by high performance liquid chromatography-mass spectrometry (IPLC-MS). All beta-cryptoxanthin fatty acid esters were more stable against heat than FCX. The antioxidant activities of FCX and its esters on superoxide anion, hydroxide radical and singlet oxygen were investigated by the pyrogallol-luminol system, the CuSO4-phenanthroline-Vc-H2O2 system, and OH-NaClO-H2O2 system, respectively, using chemiluminescence (CL) methods in vitro. The antioxidant activities of beta-cryptoxanthin fatty acid esters were not significantly different in all methods, furthermore, no synergetic effects amongst them were obtained. These results suggest that esterification of OH groups with fatty acids might not affect antioxidant activity of beta-cryptoxanthin but stabilize beta-cryptoxanthin against heat degradation. (C) 2010 Elsevier Ltd. All rights reserved.