Geographical variations in seed oils from Rubus chamaemorus and Empetrum nigrum

Seeds of cloudberry (Rubus chamaemorus) and crowberry (Empetrum nigrum) growing wild in Finland between latitudes 60.5 and 69.5 degrees were studied. Seed size, seed oil content and the composition of seed oil triacylglycerols were determined for berries collected from 14 areas. The weight of 100 seeds varied between 0.6 and 0.9 g in cloudberries and between 0.09 and 0.13 in crowberries. Cloudberry seeds collected in southern Finland were heavier (P < 0.05) than those collected in more northern areas. The seed oil content of cloudberries varied from 9.1 to 12.4% and that of crowberries from 3.9 to 11.4%. Southern cloudberry seeds had lower (P < 0.05) oil contents, whereas those of crowberry had higher (P < 0.01) oil contents compared with their northern counterparts. The lower the seed weight, the higher the oil content was in cloudberries (r = -0.61). The M(r) distribution of triacylglycerols showed no differences between cloudberry samples from south and north Finland. The seed oil of crowberry from the north contained more triacylglycerols of 52 acyl carbons (8 mole%) and less of those of 54 acyl carbons (87 mole%) than the corresponding sample from the south (6 and 90 mole%, respectively). The most abundant fatty acids were linoleic, alpha-linolenic, oleic and palmitic, which constituted over 95% of all fatty acids in both berry species. Latitudinal differences existed in the fatty acid compositions; for example, the proportion of linoleic acid was highest (P < 0.05) and that of alpha-linolenic acid lowest (P < 0.01) in cloudberries from Lapland. Crowberries from southern Finland contained more alpha-linolenic acid (P < 0.001) and less linoleic acid (P < 0.001) than berries collected from other areas. Copyright (C) 1997 Elsevier Science Ltd.