Quality evaluation of cold-pressed hemp seed oil of industrial hemp varieties (Cannabis sativa L.)

Bc. Rebeka Hadlová

Master's thesis

Abstract:

Hemp oil is becoming more and more valuable thanks to its content of polyunsaturated fatty acids, -linolenic acid and linoleic acid. And also, the fact of relatively low content of saturated fatty acids. Thanks to its high amount of unsaturated fatty acid and chlorophyll, the hemp oil prone to rancidity. The process of devaluation of oil is fasten up by heat and light, therefore it should be stored in dark cold place.The diploma thesis focused on determination of changes occurring in hemp oil obtained from 9 different varieties of Cannabis sativa L., namely: Sathica, Futura, Fedora, Fibrol, Kompolti hybrid, KC Virtus, Bialobrzeskie, Tiborsallasi and Finola. Oil samples were stored under different storage conditions: under the room temperature and in the fridge. Chemical properties of the samples were investigated several times over 24 weeks by peroxide value, iodine value, saponification value, acidity value, ester value, when degustation panel assessed organoleptic properties of freshly prepared oil samples.The experiments pointed out that the refrigerated samples were more stable, and their shelf life was prolong. The overall most stable variety was proven to be Bialobrzeskie. It has the lowest values or was at the top of the lowest value. That goes for both type of storage. The highest values occur in case of iodine value, but still was not that far from general mean. On the other side of the scale, with the most repetition of high values was variety Fibrol for room conditions and Finola for cool conditions. But still was not that far on the scale from other varieties. In case of sensory evaluation as the most tasteful variety was also evaluated Bialobrzeskie. After all, the experiments showed that longer shelf life, overall oil quality and decreasing inside processes (oxidation, changing colour, rancidity) is provided by correct storage at lower temperatures.

Keywords

hemp seed oil, sensory analyses, peroxide value, acidity value, iodine value, ester value, saponification value, cannabis sativa, technical hemp

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 / Tropical Crop Management and Ecology