Cold-pressing of oil from nine varieties of technical hemp at various conditions

Bc. Aleš Bartoníček

Master's thesis

Abstract:

This study analysed oil-related qualities of seeds of nine technical hemp varieties and examined the effect of different conditions during pressing on the oil yield and amount of residual oil in hemp cake. Cold-pressing was used because of the high polyunsaturated fatty acids content in the Cannabis sativa L. seeds.Seeds of varieties Białobrzeskie, Fedora, Santhica, Fibrol, Finola, Futura, Tiborszállási, Kompolti hibrid and KC Virtus were pressed at different conditions (100, 200, 300 kN and 20 °, 40 °, 50 °C) to determine oil yield. Hemp cakes were tested for residual oil by solvent extraction by petroleum ether. Oil-free hemp cakes were analysed for protein content by Kjeldahl method. Fatty acid profile of extracted hemp cake residual oil was examined by means of GC-MS and GC-FID.Higher force and higher temperature during pressing resulted in higher oil yield and simultaneously in lower residual oil in hemp cake. There were noticeable differences in oil content among varieties. Total oil content was highest in Fibrol variety (36.17 ± 0.53 %) and lowest in Santhica variety (32.29 ± 0.30 %). Varieties responded to pressing differently. Białobrzeskie and Fedora were established as the most suitable for pressing in terms of oil recovery. The protein content of dry oil-free seeds was highest in Santhica, Fibrol, Finola, Futura (39.08 ± 0.82 %; 38.91 ± 0.50 %; 38.84 ± 0.95 %; 38.65 ± 1.34 %, respectively) and lowest in Kompolti hibrid (34.88 ± 1.07 %). The highest amount of PUFAs was found in variety Finola (76.72 %). Kompolti hibrid had the highest content of essential FAs (73.99 %) and the lowest ω6/ω3 EFAs ratio (3.06) and can be considered as the best hemp variety for human nutrition.

Keywords

Cannabis sativa, technical hemp, hemp seed, hemp cake, fatty acid

Language used: English

Date on which the thesis was submitted / produced: 26. 4. 2019

Thesis defence

• Supervisor: doc. Ing. Jan Banout, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme / field:
Tropical Agriculture / Sustainable Rural Development in the Tropics and Subtropics