Effect of Ripening Stage and Temperature on Free Fatty Acid Content of Jatropha curcas Oil During Storage

Abstract

The lipid content of J. curcas L. black-fruit seed was not different from that of yellow-fruit seed for all accessions: Mukdahan, Satun and Surin. However, protein in the black-fruit seed from all accessions was significantly (P < 0.05) higher than that of the yellow-fruit seed. Samples of seed and pressed seed oil were stored at 4, 37 and 50 °C for free fatty acid (FFA) analysis. The moisture contents of Mukdahan accessions stored at 4, 37 and 50 °C were constant after 60 d at 12.0, 5.5 and 3.5%, respectively, for both the yellow- and black-fruit seed. The FFA contents of Surin black-fruit seed stored at 4, 37 and 50 °C increased from 0.49% to 0.77, 0.72 and 0.63% in 2 mth, respectively, while the yellow-fruit seed showed less of an increase at 37 and 50 °C and at 4 °C did not change. The FFA content of oil from the Mukdahan yellow-fruit seed did not change over 4 mth. The FFA content of black-fruit oil increased rapidly at all temperatures. However, when settling the oil before storage, the oil of the yellow fruit did not change at any temperature, while the oil of the black-fruit seed could be kept for 4 mth at 4 and 37 °C with the FFA content not exceeding 1%.