Hop plant

Hops. Hops are the blossoms of the female hop plant, wild in North and Middle Europe, North Asia, and North America. The composition of hops is shown Hi Table 5 (see also ref. 11). 

Table 16.2 lists more than 80 examples of new isoprenylated chalcones reported in the period 1992 to 2003 (see also Figure 16.7). Almost half of the compounds described here are from the Leguminosae, a trend that is also evident in earlier surveys. Other plant families that are well represented in Table 16.2 are the Moraceae and the Cannabinaceae. The literature on isoprenylated flavonoids in general has been reviewed by Barron and Ibrahim to the end of 1994 57 jjjg phenolic constituents of Glycyrrhiza species (licorice), among which are many isoprenylated chalcones, were the subject of an extensive review that includes literature published up to the end of 1996. Nomura and Hano have reviewed the literature on isoprenylated phenolic compounds of the Moraceae to the end of 1993. More recent descriptions of isoprenylated flavonoids are available for the hop plant, Humulus lupulus (Cannabinaceae),and the Moraceae genera Artocarpus and Dorstenia. ... 

The extraction of spice oleoresins is relatively new, and industrial plants have been in operation for about the last ten years. Because the CO2 extracts are different to the conventional processed oleoresins, the acceptance in the food industry is growing slowly. The spice plants are much smaller than the decaffeination and hop plants, and use extractors of between 200 and 8001. The same is true for medical herbs and high value fats and oils, which are more or less at the beginning of development. 

As an example, the hops plant described before (8.1.4.) is used again, and the 350 bar, double-stage separation process is chosen. From Fig. 8.1-15 it is obvious that interest and... 

Marijuana is derived from the Indian hemp plant, Cannabis sativa, a member of the Cannabaceae family and the Urticales (nettle) order. Some botanists claim that this genus contains as many as three other species C. indica, C. ruderalis, and even Humulus lupulus, the hops plant. Other botanists insist that the differences between plants reflect simple variations, not different species. 

As presently classified, cannabis is included along with the hops plant (Humulus) in a distinct family called Cannabaceae, although some botanists still prefer to assign it to the Moraceae family which also includes the mulberry plant to which cannabis was closely tied in ancient China. 

Dimefox is very toxic its lOj for rats being 3-5 mg/kg. It has a weak contact-insecticidal effect but at the same time excellent systemic properties. It is mainly used in hop cultures against plant lice and mites. The concentration of the insecticide in the hop plant attains its maximum one week after treatment of the soil and from this time on degradation causes a continuous decrease in concentration (Dejonckheere, 1974). 

Warmke was also the author of the famous hops-grafting experiments, in which marijuana and hops were grafted onto one another. His data showed transfer of cannabinoids into the hops plants, but he used water fleas as his test animals and the data never had any clear relationship to cannabinoid content Since then it s been shown that cannabinoids are produced locally and do not translocate. In any event, a recent repeat of this latter experiment using modern chemical techniques showed absolutely no transfer of cannabinoids into the hops portion of the grafts—either from the marijuana bottoms to the hops tops or from the marijuana tops to the hops bottoms. Hundreds, perhaps thousands of people, have attempted to produce more potent, or at least undetectable marijuana, on the basis of a few dead fish and water fleas. One is reminded of Mark Twain s comment like science because it gives one such a wholesale return of conjecture from such a trifling investment of fact. ... 

The various fecretions of vegetables, as of odour, fruit, gum, refin, wax, honey, feem brought about in the fame manner as in the glands of animals the taftelefs moifture of the earth is converted by the hop-plant into a bitter juice as by the caterpillar in the nutlhell the fvveet kernel is converted into a bitter powder. While the power of abforption in the roots and barks of vegetables is excited into a Iion by the fluids applied to their mouths like the lafteals and lymphatics of animals. 

Chalcones were originally discovered in plants as the yellow flower pigments of Coreopsis and other yellow-rayed Compositae. After that, they have subsequently been found in other plant families including Solanaceae, Anacardiaceae, Caesalpiniaceae, Piperaceae, and Apiaceae. 6 -Deoxychalcones were known to be chemical constituents of leguminous plants, but it is scarcely reported that they were found in other plant species. A lot of chalcones were isolated from either Compositae (Asteraceae) or Leguminosae (Fabaceae), two families well known to accumulate these. Besides, various prenylchalcones can be found in hop plants (Cannabaceae). 

This group of natural products comprises the prenylated acylphloroglucinols, e.g., bitter acids from the hop plant (Humulus lupulus) and hyperforin from St. John s wort Hypericum... 

Hop plants have a fair resistance to frost as the root system is very large and burrows deep into the ground. This is necessary during the period of very rapid growth. New shoots of the roots are sometimes harvested and eaten as a culinary delicacy resembling asparagus. 

To assure consistency and uniformity of brewing value, the multiplication of hop plants for large-scale growing is always carried out by shoot cultivation (2). The base of the vine is burled in the fall and new roots and shoots form, which can be planted in the spring. Shoot formation is also possible from other plant parts such as the lateral branches on the vines. 

The iabiie beta acids, present in hops, are sensitive to oxidation reactions, initiated by air (auto-oxidation). Thus, the beta acids are converted partiaiiy in the hop plant and to a greater extent during storage of the hops. The oxidation is almost quantitative in the brewing process. A very complex reaction mixture is formed. The experimental data show that auto-oxidation occurs via radical mechanisms, which transform the polyfunctional beta acids to a large number of oxidized compounds. In particular the three 3-methyl-2-butenyl side chains are very sensitive to oxidation, either at the double bonds or in the allylic positions. The native compounds are usually oxidized further or transformed by hydration and/or elimination. These reactions are responsible for the complexity. Reaction between two side chains leads to bicyclic and tricyclic derivatives. It is remarkable that in all known oxidized compounds derived from the beta acids, at least one 3-methyl-2-butenyl group remains unchanged. 

The dried flower cones of the female hop plants of various sorts and cultivars are materials for alpha acids determinations. In the last decades, several preparations such as hop extracts, hop pellets, enriched hop, have been introduced on the market, aiming to stabilize the brewing value of hops or to improve the beer quality. Nowadays, more than half of the total hops production is processed in this way. 

---