Bioactive Diterpenes and Serotonin Amides in Cold-Pressed Green Coffee Oil (Coffea arabica L.)

Abstract

Cold pressing is an environment-friendly mechanical extraction for oils from seeds. In this work, cold-pressed green Arabica coffee oil was investigated related to the influence of the pressing variables (preheating, exit diameter, screw speed, and particle size) on the chemical oil composition, mainly on the diterpenes and, for the first time in the scientific literature, on the content of serotonin amides (β N-alkanoyl-5-hydroxytryptamides (Cn-5HT)). The oil yield from screw pressing varied from 2.65 to 6.27%, with major yields obtained as the size of the particle and temperature increased. Soxhlet extraction produced 9.46 ± 0.04% of oil. The fatty acid content of the oils varied from 32.79 to 33.49% and showed no significant difference among the different pressing conditions. The amount of the diterpenes kahweol and cafestol ranged from 13.33 to 16.72 mg g-1 and 37.11 to 47.14 mg g-1 of oil, respectively, summing 50.44 to 63.86 mg g-1 of diterpenes. The total content of Cn-5HTs ranged from 307.92 to 1716.52 µg g-1, being 114.42 to 577.37 µg g-1 for arachidic acid-5-hydroxytryptamide, (C20-5HT) and 193.50 to 1068.08 µg g-1 for behenic acid-5-hydroxytryptamide (C22-5HT) in oil, the most abundant in coffee bean. From the 16 cold press treatments, six conditions showed significant amounts of these compounds. Aspects related to the biological activity and relevance of coffee lipid diterpenes and Cn-5HTs are discussed.