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Abstract Organic solvents of diethyl ether and pentane were tested against ethanol for the extraction of terpenoids and cannabinoids from hemp inflorescence. It is not well known how pretreatment of grinding and extraction conditions, that is, number of extractions, temperature, and solvent residence time affect extraction yield and product compositional profiles, so these were examined in this study. As a general trend, diethyl ether and pentane had better selectivity towards the terpenoids and cannabinoids compared to ethanol. It was found that even though grinding to reduce the particle size of the inflorescence did not dramatically increase the total extraction yield, it increased the yield of the first extraction as well as the content of terpenoids and cannabinoids in the extract. Extraction residence time trial revealed the benefit of shorter time and the different behavior of the two classes of compounds. Increasing the extraction temperature from 4 to 21°C improved the total extraction yield by all three solvents, however, no additional improvement was seen at 30°C. To achieve high concentration of the bioactive compounds in the extract, multiple extraction at 21°C with short residence time, such as 15 min, are preferred for the solvents tested, and an extract having about 6% terpenoids and 59% main cannabinoids was obtained using pentane. This systematic study provides a guide to commercial processing optimization and directions for further investigation.
Tao et al. (Fri,) studied this question.