LIPOXYGENASES AND THE QUALITY OF FOODS

The significance of plant lipoxygenases for food quality is reviewed, with particular reference to the enzymes from pea and soybean. Various aspects of the sources of the enzymes, their activities, substrate an d product specificities, and co-oxidation potential are discussed in t he context of food quality and shelf life. The sequences of lipoxygena ses, predicted from DNA sequences, from different plants, are compared and the significance of sequence differences assessed in relation to enzyme specificity and the three-dimensional structure of soybean lipo xygenase-1. A novel scheme is proposed for the mechanism of the lipoxy genase-catalysed dioxygenation of polyunsaturated fatty acids in which two different pathways are suggested for the anaerobic and aerobic ox idations.