Analysis of factors influencing lipid oxidation of almond seeds during accelerated ageing

Almond seeds age rapidly during storage at high relative humidity (80%) and moderate temperature (20 degrees C). The content of lipid decreased during accelerated ageing lip to 40 d. The levels of linoleic (C18:2) and linolenic (C18:3) acids in almond lipid fraction also decreased during ageing up to 20 d. The aged seeds contain high levels of malondialdehyde, a product of the peroxidation of unsaturated fatty acids. Lipoxygenase activity, which oxidizes unsaturated fatty acids was detected in almond seeds. Increased activity of this enzyme was observed during accelerated ageing. It is suggested that accelerated ageing leads to peroxidative changes to lipids. No changes in peroxide-scavenging enzymes such as superoxide dismutase and peroxidase were detected in accelerated-aged seeds. The accelerated ageing treatment could be a useful tool to investigate the mechanism of natural seed ageing. (C) 1998 Academic Press Limited.