Determination of acrolein generation pathways from linoleic acid and linolenic acid: increment by photo irradiation

Abstract

Abstract2-Propenal (acrolein) is a toxic aldehyde generated from the thermal degradation of edible oils. While previous studies have suggested that linolenic acid (LnA) is the origin of acrolein formation in edible oils, these studies were performed under thermal conditions where only the fatty acid hydroperoxide (FAOOH) isomers derived from radical oxidation were formed. In this study, we reinvestigated the acrolein generation pathway through another oxidation mechanism involving singlet oxygen (1O2) oxidation (type II photo-oxidation). Standards of the main FAOOH isomers (oleic acid hydroperoxide, linoleic acid hydroperoxide (HpODE), and linolenic acid hydroperoxide (HpOTE)) found in edible oils were prepared, and their decomposition products, including those derived from1O2 oxidation (i.e., 10- and 12-HpODE) were analyzed by GC-EI-MS. We found that 1O2 oxidation products of linoleic acid (LA) and LnA but not OA, are significant sources of acrolein formation. The amount of acrolein formed from edible oils high in LA (e.g., rice bran oil) increased by photo irradiation. Further investigation into the mechanism of acrolein generation demonstrated that the amount of acrolein derived from 1O2 oxidation-specific HpOTE isomers (i.e., 10- and 15-HpOTE) was two times greater than that of other HpOTE isomers (i.e., 9-, 12-, 13-, and 16-HpOTE). The results of the present study provide a new pathway of acrolein formation from type II photo-oxidation. This information can be used to inform on oil storage and processing conditions to reduce exposure and dietary intake of acrolein.

RETRACTED: Integrated the embedding delivery system and targeted oxygen scavenger enhances free radical scavenging capacity

“…Most of the oil deterioration is caused by the automatic oxidation of lipids. For example, the linoleic acid [(9E,12E)-octadeca-9,12-dienoic acid] readily forms a peroxyl radical with oxygen, then hydroperoxides products can be formed by the further reaction ( Kato et al, 2022 ). The scheme for the free radical mechanism of linoleic acid is shown in Fig.…”

Dietary triacylglycerol hydroperoxide is not absorbed, yet it induces the formation of other triacylglycerol hydroperoxides in the gastrointestinal tract

“…First, we could only trace a small portion of the degradation products that may be formed from the administered TGOOH. Based on the reports by Kanazawa et al [ 8 , 48 ] and other investigators that proposed the degradation pathway of lipid hydroperoxides [ 37 , 49 , 50 ], it appears that TGOOH is degraded in the gastrointestinal tract to yield breakdown products such as aldehydes. Since such compounds appear to be transported into the systemic circulation [ 48 , 51 , 52 ], future studies should broaden the scope of analysis to include other biological samples ( e.g., blood and liver).…”

Origin and Fate of Acrolein in Foods

“…By following the idea of Esterbauer's review, Ewert elucidated a similar mechanism of acrolein formation from linoleic acid [18]. In a recent study, Kato et al [37] also confirmed that the singlet oxygen oxidation products of linoleic acid and linolenic acid, but not oleic acid, are significant sources of acrolein formation. Moreover, acrolein was confirmed to be the major volatile in the early stages of fish oil oxidation and may be responsible for flavour deterioration [38].…”