Fatty acid composition of edible pine seeds with emphasis on North American and Mexican pines of the Cembroides subsection

Abstract

The fatty acid compositions of the edible seeds from six Pinus species (P, monophylla, P. nelsonii, P. maximartinezii, P. flexilis, P. sabiniana, and P, gerardiana) have been established. The dehulled seeds are generally rich in oil, up to ca. 65 % by weight, and are characterized by high levels of both oleic and linoleic acids, generally with less than 12 % of saturated acids. Delta 5-olefinic acids are low as compared to most other conifer species: 5,9-18:2 acid, 0.03-0.43 % 5,9,12-18:3 acid, 0.13- 1.60 % 5, 11-20:2 acid, trace-0.13 %; and 5, 11,14-20:3 acid, 0.23-0.78 %. Their sum is less than 2.5 % of total fatty acids. Pinus monophylla, P. nelsonii, P. maximartinezii, and I? edulis, from the same subsection Cembroides, and which grow in semi-arid regions in the Southwest of the United States and in Mexico, are united by their low content of Delta 5-olefinic acids (1 % at most). When considering P. gerardiana, an Himalayan species, this observation can apparently be extended to the section Parrya. Owing to the recognized antiquity of this section, the reduction in the activities of the enzymes responsible for the biosynthesis of Delta 5-olefinic acids appears an early event in the history of pine evolution, more precisely in the Strobus subgenus. However, a similar reduction also occurred independently in species from other sections of the same subgenus leg: P. flexilis) or from the other genetically distinct pine subgenus Pinus leg, P. pinea and P. sabiniana), It is hypothesized that such reductions might be linked to some climatic adaptation.