General properties and the fatty acid composition of the oil from the mophane caterpillar, Imbrasia belina

A preliminary investigation of the bulk properties of the oil from the edible mophane caterpillar (phane), Imbrasia belina, showed a significant difference in the iodine values of the oils from mature and young phane. Detailed analysis of the fatty acid composition of the two oil samples was thus carried out by capillary gas chromatography (GC) and complemented with ¹H and ¹³C nuclear magnetic resonance (NMR) studies to investigate the degree of unstauration in the two oil samples. While these studies showed that the oil samples from the mature and young mophane caterpillar were much the same in fatty acid composition, the data revealed a significant divergence from a literature report on phane oil. This earlier report puts the ratio of total saturated to total unsaturated fatty acids at approximately 1:1 (48.2:48.8, in percentages) and estimates the fatty acid composition for the major fatty acids as 16:0 (31.9%), 18:0 (15.2%), 18:1 (20.4%), 18:2 (9.9%), and 18:3 (19%). The data collected from the present work, however, showed the fatty acid composition for total saturated and total unsaturated fatty acids to be 40.5 and 57.0%, respectively. This work estimated the fatty acid composition for the major fatty acids as 16:0 (27.2%), 18:0 (12.3%), 18:1 (16.1%), 18.2 (10.7%), and 18:3 (29.0%). Thus, linolenic acid was the most abundant fatty acid in the phane oil. The GC results of the present analysis were largely corroborated by studies of the composition of fatty acid classes in the phane oil estimated from integrals of ¹H and ¹³C NMR signals. Oils from other edible Lepidoptera larvae are also known to be much richer in unsaturated than saturated fatty acids.