Reactivity of Malonaldehyde with Food Constituents

Abstract

SUMMARY Malonaldehyde and/or substances closely resembling it occur in foods as decomposition products of oxidizing polyunsaturated fatty acids. The reaction of malonaldehyde with various food constituents was studied. In the presence of water, malonaldehyde exists mainly as its nonvolatile enolate anion. As such, it can react with amino acids, proteins, glycogen, and other food constituents to form products in which the malonaldehyde exists in bound form. Aqueous malonaldehyde can be converted to its volatile isomer by acidification only but acid and heat are necessary to release malonaldehyde from its bound state in proteins. These combined observations throw light on problems connected with the quantitative recovery of 2‐thiobarbituric‐acid‐reactive substances (TBRS) in moist foods. Proteins prepared from frozen tuna fish contained appreciable amount of bound TBRS.