Tissue culture of cocoa beans (Theobroma cacao L.): Incorporation of acetate and laurate into lipids of cultured cells.

Suspension cultures of cocoa bean tissue readily incorporated exogenous acetate into lipids. The distribution of radioactivity from acetate in individual lipid classes after 48 hr was 20, 5, 1, 15, 25, and 35% in triglycerides, diglycerides, free fatty acids, sterol esters, sterols and polar lipids, respectively. The labeled acetate was rapidly incorporated into various fatty acids within 2 hr. The [1-(14)C] saturated fatty acids declined slightly after 4 hr, whereas [1-(14)C] oleate declined significantly after 2 hr. There was a concomitant increase in [1-(14)C] linoleate. The radioactivity associated with linolenate was relatively high up to 4 hr, declined by 24 hr, and then increased again. The kinetics of fatty acid labeling suggested that biosynthesis of linolenic acid in cocoa bean suspension culture may occur via the desaturation of linoleic acid and the chain elongation of dodecatrienoic acid. The patterns of fatty acid radiolabeling following incubation of cells with [1-(14)C] laurate was consistent with this mechanism.