Synthesis of Linoleic Acid Hydroperoxides as Flavor Precursors, Using Selected Substrate Sources

Abstract

The objective of the research was the synthesis of linoleic acid hydroperoxides (HPOD) and their recovery, using selected sources of linoleic acid (LA) as substrate. This is part of on‐going work aimed at the development of an economically viable biotechnological process for the production of natural flavors. The investigated sources included pure (100 %) LA and commercial (67 %) LA as well as safflower oil (SO) and its hydrolyzed product. A model describing commercial LA oxidation by lipoxygenase, based on Michaelis–Menten kinetics, was developed. The conversion of pure LA and commercial LA resulted in insignificant differences in HPOD yield of 69.7 and 68.9 %, respectively. However, there was a significant difference in the HPOD yield, obtained from the SO (2.0 %) and that from the hydrolyzed SO (58.0 %) in comparison to that from pure LA (69.7 %). The ratios of the different 9‐ and 13‐HPOD isomers were insignificantly different for the sources containing free LA, with 13‐(9Z,11E)‐HPOD was the highest relative percentage. Using optimized conditions, HPOD yields were 85.9 and 74.0 % for the commercial LA and the hydrolyzed SO, respectively. Based on experimental findings, commercial (67 %) LA was selected as the most appropriate alternative to pure LA for the production of HPOD. An efficient extraction procedure for the recovery of HPOD was also developed.

Selected dehydrogenases in Yarrowia lipolytica JMY 861: their role in the synthesis of flavor compounds

“…Synthesis of HPODs. The production of HPODs, using commercial (67%) LA, was obtained, according to the procedure described previously by Aziz et al 11) The reaction mixture consisted of 4 mM of LA, 0.2% (v/v) of Tween-20, and sufficient glycine-NaOH buffer solution (0.2 M, pH 9.0) to adjust the final volume of the mixture to 300 mL. The LOX activity was 45,000 unit/mg solid enzyme, with 1 enzyme U being equal to 0.001 absorbance/min, at pH 9.0 and 25°C.…”