Kinetic study on photostability of retinyl palmitate entrapped in policosanol oleogels

Food Chem. 2018 Jul 30:255:252-259. doi: 10.1016/j.foodchem.2018.02.025. Epub 2018 Feb 7.

Abstract

Photostability of all-trans retinyl palmitate (RP) (100% bioactivity) was studied in policosanol oleogels (PCOs) (7-12% w/w policosanol in soybean oil) after UVA irradiation. RP was incorporated into PCOs at levels of 0.04%, 0.1% and 1% (w/w). PCOs efficiently protected RP from UVA-mediated degradation. Over 75% RP-activity remained in PCOs after 4 days of UVA irradiation, while 12% RP-activity remained in soybean oil. HPLC analysis showed that cis-RP was formed in liquid soybean oil after 2 days of UVA irradiation while it was absent in PCOs matrices. PCOs blocked the energy absorption from UVA and further dampened the UVA-mediated ionic photodissociation and free radical reaction due to matrix immobilization. For all samples, RP photodegradation followed a 2nd order reaction. From the reaction kinetics, it would be possible to predict the RP photodegradation rate in PCO matrices. PCOs were shown to be a promising matrix to protect RP from photodegradation.

Keywords: Oleogel; Photostability; Policosanol; Retinyl palmitate.

MeSH terms

  • Diterpenes
  • Fatty Alcohols / chemistry*
  • Fatty Alcohols / radiation effects
  • Kinetics
  • Organic Chemicals / chemistry
  • Organic Chemicals / radiation effects
  • Photolysis*
  • Retinyl Esters
  • Ultraviolet Rays
  • Vitamin A / analogs & derivatives*
  • Vitamin A / chemistry
  • Vitamin A / radiation effects

Substances

  • Diterpenes
  • Fatty Alcohols
  • Organic Chemicals
  • Retinyl Esters
  • oleogels
  • Vitamin A
  • policosanol
  • retinol palmitate