I. Grondin et al., THE TRYACYLGLYCEROLS OF 2 SAPINDACEAE SEE D OILS - STUDY OF LITCHI-SINENSIS SONN. AND EUPHORIA-LONGANA LAM. LIPIDS, OCL. Oleagineux corps gras lipides, 4(4), 1997, pp. 295-300
Litchi and Longan seed oils are known for their high cyclopropanic fat
ty acid contents with respectively 41.5 % and 18.7 %. For these two oi
ls, the predominant cyclic fatty acids are the cis-7,8-methylenehexade
canoic (Mh) and cis-9,10-methyleneoctadecanoic (Mo) acids. The partiti
on of these two particular fatty acids in the triacylglycerols is stud
ied for the first lime in this paper. After isolation on open silica c
olumn, the triacylglycerols are analysed by high performance liquid ch
romatography and silver thin layer chromatography. Then, the triacylgl
ycerols are submitted to a chemical hydrolysis by ethylmagnesium bromi
de, reageant without structure specificity and regioselectivity. Resul
t combination allowed to determine the triacylglycerol composition of
the two seed oils with more interest for the position isomers having 2
(1, 3) type. The sn-2 position of the majority of the triacylglycerol
molecular species is esterified by oleic acid (O) which represent 50
% of fatty acids in internal position. The litchi seed oil is characte
rised by one majoritary triacylglycerol (OMoMo) with 26.1 % content. T
he longan seed oil present two major triacylglycerols O(PS) and O(MoMo
) with respectively 14.0 % and 11.2 % contents (P : palmitic acid, S :
stearic acid).