Lipids of potato tubers. II. Lipid‐degrading enzymes in different varieties of potato tuber

The levels of two lipid‐degrading enzymes, namely a hydrolytic enzyme (lipolytic acyl hydrolase) and an oxidising enzyme (lipoxygenase) were measured in tubers from 23 varieties of potato at harvest. Twenty‐two varieties had very high levels of the hydrolytic enzyme, ranging from 5 to 50 jumol of substrate hydrolysed/ min/g of fresh weight of tuber. One variety, Desiree, contained a much lower level of this enzyme (0.06 to 0.2 units/g fresh weight). All varieties contained high levels of lipoxygenase activity in the range of 1 to 25 μmol of 0 2 consumed/min/g fresh weight of tuber, with linoleic acid as substrate. The combined action of these enzymes in the degradation of potato tuber lipids is discussed.