Compositional and structural studies of the oils from two edible seeds: Tiger nut, Cyperus esculentum, and asiato, Pachira insignis, from Ghana

A comprehensive lipid profiling has been carried out on the seed oils of tiger nut, Cyperus esculentum, and asiato, Pachira insignis, from Ghana in order to evaluate their potential uses for the region. Composition of FAs and phytosterols were determined using GC-MS, while tocol composition was determined with HPLC. TAG composition and regiochemistry were determined using ES-FTICR-MS and C-13 NMR, respectively. The major FA components in asiato seed oil were palmitic acid (56.58%) and sterculic and dihydrosterculic acids (20.06% combined). The major FA components in tiger nut oil were oleic (65.55%), palmitic (16. 32%), and linoleic (12.13%) acids. Asiato seed oil had 18 major TAG classes, dominated by, C51:1 (38.45%) and C50:1 (13.941%). Tiger nut oil had 7 major TAG classes, with C54:3 (29.00%) and C52:2 (27.82%) dominating. The sn-1/3 and sn-2 positions in the TAGS for asiato oil were predominantly occupied by saturated acyl chains (87.25%) and cyclic acyl chains (71.44%), respectively. Oleoyl chain primarily occupied both sn-1/3 (52.68%) and sn-2 (77.62%) positions in the tiger nut oil. Total tocol content in asiato oil was 200.31 mu g/g. with gamma-tocopherol (182.99 mu g/g) dominating. Tiger nut oil had a total tocol content of 120.10 mu g/g, dominated by alpha-tocopherol (86.73) and beta-tocopherol (33.37 mu g/g).Tiger nut oil had total 4-desmethylsterol content of 986 mu g/g, dominated by beta-sitosterol (517.25 mu g/g) and stigmasterol (225.25 mu g/g), while asiato oil had total desmethylsterol content of 590.24 mu g/g, dominated by beta-sitosterol (518.91 mu g/g). The presence of cyclopropenoid FAs in asiato oil makes it unsuitable for food uses. Tiger nut oil can replace imported olive oil in food products in the West African region. (c) 2011 Elsevier Ltd. All rights reserved.