Characterization of some heated fat components

Abstract

Substances produced at low levels in fat by heating were isolated and characterized. Partially hydrogenated soybean oil (Iodine Value 78) was heated at 182 C for 10, 8.5‐hr, days with exposure to air. The oil was converted to ethyl esters, which were distilled and adducted with urea. The nonadductable fraction was subjected to chromatographic separations, and some of the components were purified sufficiently for chemical and spectroscopic characterization. Substances recognized include aromatic esters, saturated and unsaturated cyclic esters, ethoxyoctadecenoate, ethoxyhydroxyoctadecanoate, oxo‐octadecanoate, oxo‐octadecenoate, and cyclic hydroxy esters, all having 18 carbons in the acid chain.

Nutritional and metabolic studies of distillable fractions from fresh and thermally oxidized corn oil and olive oil

“…The heating of fats in air is known to cause the formation of volatile scission products, nonvolatile oxidized derivatives such as cyclic monomers and dimers, as well as polymers (1,(23)(24)(25)(26)o However, the nature and extent of these degradation products depend on the kind of fat and the way it is heated. The thermal oxidative treatment, to which the fats used in this study were subjected, was designed to approximate the conditions used by food processors and restaurants for deep frying.…”

“…Numerous studies have been conducted on the amount and types of toxic substances formed in fats used for cooking or deep drying and also on which of the commercial edible fats are most susceptible to degradation at high temperatures (1)(2)(3)(4). It is known that nutritive properties of a fat can be impaired readily by thermal oxidation as indicated by subsequent nutritional evaluation of the oxidized fat using test animals.…”

Exacerbating effect of dietary 12-keto oleic acid on vitamin E deficiency in the rat.

“…Heat denatura tion of unsaturated fatty acids is known to give rise to long-chain, keto-unsaturated acids (3,4). KOKATNUR and his collaborators (5) found that the presence of small amounts of these long-chain keto fatty acids accelerated the development of encephalomalacia in chicks, kept on a vitamin E deficient diet.…”

The effects of cyclic fatty acid monomers on cultured porcine endothelial cells

“…In the case of vegetable oils used in deep-fat frying processes, the formation of lipid oxidation products can be substantial even though a majority of vegetable oils are modified for increased stability by reducing the degree of unsaturation using catalytic hydrogenation. The formation of these partially degraded lipid products can be attributed to the exposure of the frying medium to water (from food), oxygen, metals (from food or equipment), and the high temperature of the frying process (10,11). Various lipid breakdown products have been identified in frying fats and oils derived from both animal and vegetable sources (12,13) and are absorbed by the fried food (14)(15)(16).…”