Tocochromanol content and composition in Jatropha curcas seeds

Abstract

Physic nut (Jatropha curcas L.) is a promising seed oil source for biodiesel production. Natural antioxidants play a major role in maintaining oxidative stability of oils and they also have important food and industrial applications. Among them, tocochromanols are the most abundant in seeds. The objective of this research was to evaluate the variation for tocochromanol content and profile in a germplasm collection of 52 accessions of J. curcas. Seeds collected in two different periods, August and November of 2009, were analysed for tocochromanol content. Additionally, the dynamics of tocochromanol accumulation in developing seeds was studied. Total seed tocochromanol content averaged 307.2mgkg−1 in August and 303.7mgkg−1 in November, whereas total oil tocochromanol content averaged 507.4mgkg−1 in August and 500.8mgkg−1 in November. The tocochromanol fraction was made up of 15.4% gamma-tocopherol, 83.8% gamma-tocotrienol, and 0.8% delta-tocotrienol in August and 18.0% gamma-tocopherol, 80.4% gamma-tocotrienol, and 1.6% delta-tocotrienol in November. Genotype×environment effects were identified for tocochromanol content but not for the proportion of major tocochromanol homologues, which showed a high positive correlation between both environments. Developing seeds contained primarily alpha-tocopherol and gamma-tocopherol at early stages of development, with gamma-tocotrienol and delta-tocotrienol being practically undetectable. Gamma-tocotrienol content remained practically undetectable till 66 DAP and then increased pronouncedly to final levels of 177.1mgkg−1 (74.8% of the total tocochromanol content). The powerful antioxidant and health-promoting properties of gamma-tocotrienol encourages further studies on selection for the tocopherol/tocotrienol ratio in Jatropha and on the potential of tocochromanols as high added-value products derived from Jatropha seed oil production.