Wechselwirkung zwischen Proteinen und oxydierten Lipiden

Abstract

Oxidized lipids react with proteins to form lipoproteid complexes in which the lipids are bound to the proteins in part by physical forces, in part by covalency. The free radicals resulting from the cleavage by hydroperoxides are the major precursors of the lipoproteid complexes. The interaction is associated with protein denaturation and oligomer formation. The lipids contained in the lipoproteid complexes are only in part extracted by chloroform-methanol; in part not until after acid or alkaline hydrolysis. The nutritive value of the protein moiety is diminished by the reaction of the hydroperoxides with methionine and cysteine and by the reaction of the peroxidic radicals and aldehydes with lysine and other basic amino acids. Secondary reactions of the lipoproteid complexes lead to brown coloured, only partly soluble compounds which often impair the organoleptic value. The rancidity products of the fats are neutralized by the reaction with proteins. The action of highly unsaturated oxidized lipids on proteins results in the development of a fishy aroma.

Protein Aggregation in Food Models: Effect of ?-Irradiation and Lipid Oxidation

“…Interactions of proteins with lipids are of great importance in food chemistry, especially the reactions with autoxidizing lipids, which may lead t o considerable deterioration of foodstuffs. Among the many possibilities of reactions may be mentioned the formation of protein-lipid complexes that are bound through physical forces, covalent crosslinking of proteins either by pure protein radical recombination or by bridging with degradation products from the oxidizing lipids such as malondialdehyde, protein scission, and blocking of essential amino acids (Kummerow 1966; Karel 1975; Pokorny and Janicek 1975;Matsushita 1975;Gardner 1979;Schaich 1980). Feeding trials of proteins reacted with oxidizing lipids revealed a decreased nutritive value of these proteins Horigorne and Miura 1974;Yanagita and Sugano 1975;Sugano and Yanagita 1978;Pokorny 1977).…”

“…The isoelectric pattern of the higher aggregates of myoglobin induced by oxidizing lipids with a displacement to even lower isoelectric points (Fig. 2) indicates the preferential damage to basic amino acids on lipid oxidation (Matsushita 1975;Pokorny and Janicek 1975;Pokorny 1977;Gardner 1979).…”

Effects of lipid oxidation on fish lipids — amylopectin interactions

“…The systems were subjected to selective extraction (20 cm 3 CHCl 3 + system), during a 30 s during mixing with a mechanical blender in a ground glass thimble as described by Pokorny [27]. The thimble content was subsequently transferred to a separator to remove the chloroform layer, which was filtered through a folded filter with anhydrous sodium sulphate.…”

Color Deterioration of Oil during Frying

“…The amino-carbonyl reaction, the major pathway for nonenzymatic browning of foods, is well known. Pokorny et al (9) reported that a 1:10 mixture of oxidized lipids/protein was discolored by storing at 60 as carbonyl group generated in the lipids reacted with amino group of protein. Koga et al observed that glycine, alanine, and leucine discolored frying oil in their model experiment (10).…”