Abstract
The highly hydrophobic β-carotene is often distributed or dissolved in triglycerides to enhance either nutritional or coloring effects. This study aims at elucidating the physical state of β-carotene that at high concentrations are mixed into a solid high-melting tri-glyceride matrix by dissolution at high temperatures (165 °C) in the melted triglyceride. Extensive isomerization of β-carotene is observed by HPLC after melting crystalline all-trans β-carotene and in the solid mixtures of β-carotene and fully hydrogenated sunflower oil. Crystalline triglyceride is found in the mixed samples by XRPD analysis whereas no signs of crystalline lattice structures of β-carotene are detected. DSC thermograms show only the melting and recrystallization events of triglycerides, which are affected by the presence of β-carotene. Severe line broadening is observed in the 13C CP/MAS NMR spectra of the β-carotene-triglyceride mixtures when compared to crystalline β-carotene, demonstrating the lack of long-range order of the carotene. Altogether, the results demonstrate that β-carotene is present as an amorphous mixture of trans- and cis-isomers dispersed into a structure of crystalline triglyceride in the solid carotene-triglyceride mixtures. Practical applications: The amorphous structure of trans- and cis-isomers in solid formulations of β-carotene-triglyceride mixtures will strongly affect their functional properties related to nutrition and color as food ingredients.
| Originalsprog | Engelsk |
|---|---|
| Artikelnummer | 1900250 |
| Tidsskrift | European Journal of Lipid Science and Technology |
| ISSN | 1438-7697 |
| DOI | |
| Status | Udgivet - 1 feb. 2020 |