An investigation of influence of solvent on the degradation kinetics of carotenoids in oil extracts of Calendula officinalis

Abstract

The stability of carotenoids was studied in marigold oil extracts prepared with following solvents: Myritol 312®, paraffin oil, almond oil, olive oil, sunflower oil, grape seed oil, and soybean oil. The concentration of the carotenoids was determined by spectroscopic measurement at 450 nm. Degradation rate showed a first order dependence on the concentration of carotenoids with a faster first stage (which lasted 35-50 days, depending on the solvent) and a slower second stage. The highest degradation rates were observed in extracts prepared with linoleic acid rich solvents (sunflower oil, soybean oil and grape seed oil), while the lowest were found in oil with saturated fatty acids (Myritol 312®) and paraffin oil. These results confirm the connection between the degradation of carotenoids and lipid autoxidation, and suggest that the influence of the oil solvents on the stability of oil extracts of Calendula officinalis is a factor that must be considered when selecting a solvent for the production of marigold oil extracts.

U ovom radu ispitana je stabilnost karotenoida u ekstraktima nevena u: Myritol 312®, parafinskom ulju, bademovom ulju, maslinovom ulju, suncokretovom ulju, ulju koštica grožđa i sojinom ulju. Značajna razlika u masno-kiselinskom sastavu ispitivanih ulja omogućuje određivanje veze između brzine razgradnje karotenoida i masno-kiselinskog sastava. Ustanovljeno je da se razgradnja karotenoida odvija u skladu sa kinetikom prvog reda po karotenoidima sa dve faze: prvom, koja traje 35-50 dana, u toku koje je razgradnja brža, i drugom fazom za koju su karakteristične manje brzine razgradnje. Najveće brzine razgradnje su izmerene u ekstraktima proizvedenim sa ekstragensima bogatim linolnom kiselinom (suncokretovo ulje, sojino ulje i ulje koštica grožđa), a najmanje u onima koji su pripremljeni sa rastvaračima koji sadrže zasićena jedinjenja (parafinsko ulje i Myritol 312®). Ovi rezultati pokazuju da na brzinu razgradnje karotenoida u uljanim ekstraktima značajno utiče proces autooksidacije lipida i da uticaj vrste ulja na stabilnost karotenoida u uljanim ekstraktima Calendula officinalis mora biti uzet u obzir prilikom izbora ekstragensa.