Relationship between chlorophyll a and β-carotene in a lipid-containing model system during heating

The relationship between chlorophyll a (Chl a) and β-carotene during heating in the presence of fatty acid esters, methyl stearate, methyl oleate and methyl linoleate, was studied. Mixtures of Chl a, β-carotene and fatty acid esters were heated at 60°C and 120°C for varied lengths of time. Isomerization and degradation reactions of Chl a and β-carotene were monitored using HPLC with diode array detection. Three isomers of Chl a and four cis isomers of β-carotene were detected. Both the degradations of total amounts of Chl a and β-carotene during heating fit the first-order model. The degradation rates of total amounts of Chl a and β-carotene were highest in methyl stearate, followed by in methyl oleate and methyl linoleate. In the presence of fatty acid esters Chl a is more susceptible to isomerization and degradation than β-carotene during heating.