Chemical reactions involved in the deep‐fat frying of foods: VIII. Characterization of nonvolatile decomposition products of triolein

Abstract

A laboratory apparatus that could be used to treat pure triglycerides under simulated deep fat frying conditions was designed and built. By the use of this apparatus, the volatile decomposition products produced during frying could be quantitatively collected at the same time. Pure trilinolein was treated in this apparatus at 185 C for 74 hr. The volatile decomposition products were collected quantitatively'. Their fractionation and identification will be reported in a subsequent paper. The nonvolatile decomposition products were isolated from the treated trilinolein as the non-urea-adduct-forming methyl esters. They constituted 26.3% of the treated trilinolein and were separated into seven fractions by repeated liquid column chromatography. Chemical and physical analyses of these fractions indicated that the chemical reactions taking place under simulated deep fat frying conditions were not entirely the same as those during simple heating under air. One of the seven fractions was further purified by thin layer chromatography and then identified as a cyclic carbon to carbon linked dimer which amounted to 4.9% of the treated trilinolein. Another fraction was further purified by thin layer chromatography, followed by gas chromatography, and then identified as noncyclic hydroxy Ipaper of the Journal Series, New Jersey Agricultural Experiment Station, Rutgers, The State University. 2present address: Regional Research Lab., Hyderabad 9, India. dimers formed through carbon to carbon linkages. The noncyclic dimers constituted 2.8% of the treated trilinolein. The other four fractions were depolymerized by hydroiodic acid. The depolymerization products were fractionated by thin layer chromatography and then analyzed. It was estimated that the treated trilinolein contained 8.4% of trimers formed through carbon to carbon linkages, and 4.9% of dimers and trimers joined through carbon to carbon or carbon to oxygen linkages in the same molecule and also trimers, in which all the three monomeric units were joined through carbon to oxygen linkages.

Aging of oily soils on textile materials: A literature review

“…They may also be involved in promoting carbon-carbon radical reactions via H-abstraction: Early researchers studied polymeric products of monoand polyunsaturated compound oxidation; their findings were summarized by Swern et al (85) and Gardner (86). By thermally oxidizing triolein under simulated deep-fat frying conditions, Paulose and Chang (87) showed that polymers were formed by both carbon-to-carbon and carbonto-oxygen linkages. Although they did not identify the precise form of the oxygen linkages, they found indications of the presence of ether linkages.…”

Changes in Edible Fats and Oils During Processing

“…According to Doi and Urakami (1 976), soybean oil used continuously for frying contained dioxoacids, epoxides, oxolans and pyrans. Polymers produced under frying conditions are bound mainly by carbon-carbon or ether bonds (Paulose and Chang 1978), but rarely by peroxide linkages (Pokorny 1989).…”

Odor significance of undesirable degradation compounds in heated triolein and trilinolein

“…Owing to the complexity of the vegetable oil mixture of oxidation products, model frying or heating oil systems of a single triglyceride such as triolein and trilinolein have been studied to obtain a simpler mixture of oxidation products or potential volatile precursors (9)(10)(11)(12)(13)(14)(15)(16). One objective of this work with triolein and trilinolein was to better understand the production of negative odors in modified composition oils such as high-oleic-containing oils.…”