Characterization of chia (Salvia hispanica L.) white and dark seeds and oils

Abstract

The increasing popularity of chia oil as a source of ω-3 fatty acids is evident. This fact led us to this study concerning the differences between white and dark Argentinean chia seed morphology and the oils obtained from them. Salvia hispanica fruit consists in a nutlet, commonly named as seed, whose morphology was examined using scanning electron microscopy. Both types of seeds are very similar, with some differences in pericarp surface and layer of bone cell arrangement. The analysis of the corresponding oils revealed slightly, but statistically significant differences in some parameters, mainly in fatty acid composition, iodine value, refractive index and acid value. In spite of the differences in fatty acid composition, both white and dark chia seed oils possess a high ω-3 and ω-6 content, showing their importance from a nutritional point of view. Chia seed oils contained about 280-300 mg/kg of tocopherols, natural antioxidants, mainly γ-tocopherol (≈ 85%) and δ-tocopherol. The high oil yieldand similar physico – chemical properties in comparison with other commercial edible oils, make it a potential alternative oil source. Furthermore, the fatty acid composition and tocopherol content play a significant role in the quality of the oil.