The Alcohol’s Influence Studies on the Hop Granules Organic Compound Group’s Extraction

The article is devoted to the question of studying methods for hop organic compounds groups isolating. The purpose of the work was to study the influence of physicochemical methods for extracting hop organic compounds groups (bitter resins, polyphenols and nitrogen ones), using the example of the Cascade variety, with alcohols with different numbers of hydroxyl groups. The research was carried out using generally accepted photoelectrocolorimetric methods of analysis, as well as methods of statistical data processing. The authors showed that ethanol, propylene glycol and glycerin under different conditions of physicochemical treatment contributed to the extraction of bitter resins in an amount of about 30.8%, and alkaline reagents influenced the increase in the yield of total resins. The yield of polyphenolic compounds in the presence of ethanol without ultrasound increased after 20 min of treatment by 2.2 times in the control and by 2.7 times when using ethanol and KOH. The use of alkaline reagents (catalyte and KOH) and ethanol made it possible to increase the yield of phenolic compounds by 1.4 and 2 times, respectively, compared to the extracts obtained without ultrasound after 10 min of treatment. Increasing the duration of treatment in the presence of ultrasound and alkaline reagents led to a decrease in the yield of polyphenolic compounds. The use of propylene glycol also showed a decrease in the content of polyphenols without ultrasound in 20 minutes, and the most effective way to isolate polyphenols was a combination of ultrasound, propylene glycol and KOH, which in 20 minutes increased the yield of compounds by 2 times compared to treatment without ultrasound. Extraction with glycerol makes it possible to increase the yield of phenolic compounds by 1.5 times, in combination with KOH — by 2.8 times compared to 10 min of treatment without ultrasound. Ultrasound in combination with KOH and 10 min of treatment increases the yield of polyphenols by 6.6 times compared to treatment without ultrasound. The results regarding the extraction of nitrogenous compounds are presented. The effectiveness of using ultrasound and ethanol, catalyte and 10 min of treatment has been shown. At the same time, the yield of nitrogenous substances increased 3 times compared to treatment without ultrasound. It is noted that the release of nitrogenous compounds depends on the structure of the alcohol and extraction conditions. It has been shown that there is a moderate relationship (0.5≤r≤0.7) between the content of total polyphenols and bitter resins in the structure of hops, which depends on the structure of the extractant. Statistical analysis showed that there is a relationship in the structure of hops between bitter resins, phenolic and nitrogen compounds.