Hop constituents

Two minor products formed during the oxidation of colupolone (193) with molecular oxygen have been shown to have structures (195) and (196). The main product of oxidation is cohulopone (194), and (195) and (196) are considered to be derived from (194) by epoxidation and subsequent opening of the oxiran ring and intramolecular acetalization.  

Naya and Kotake have described the application of G.C.-M.S. to the rapid analysis of the volatile components in hops, and alternative syntheses of deoxyhumulones, the biogenetic congeners of the humulones and lupul-ones in hops, have been outlined.  

7 Naturally Occurring Polyolefinic Degraded and/or Modified Isoprenoid Compounds 

---

FL Rigby, JL Bethune. Counter current distribution of hop constituents The isolation and properties of cohumulone. Proc Am Soc Brew Chem, 1952, pp 119-129. 

Total resins. The part of the hop constituents which is characterized by solubility both in cold methanol and diethyl ether (mainly hard resins, uncharacterized soft resins, a-acids, and -acids). 

The bitter substances from hops, which are important in brewing, are also phloroglucinol derivatives. The humulones, lupulones and corresponding iso-compounds can be separated on silica gel G layers, using weakly polar solvents [4, 132, 211, 214]. The method proposed by Grant [67] for detection of hop constituents in beer or in extracts, appears most serviceable ... 

Processing of natural products with supercritical fluids-based technologies has been an extensive area of research during the past two decades. In fact, since many valuable products occurring in natural compounds, such as vitamins, aromas, natural pigments or essential oils, are soluble in supercritical fluids, their extraction from natural materials is one of the most widely studied applications of supercritical fluids. To date, SFE technology is used at industrial levels in economically relevant processes such as decaffeination of both colTee and tea and extraction of hop constituents and spices [19]. 

The fraction of the hop constituents which is precipitated by adding iead(ll) acetate is commoniy referred to as the hop aipha acids (1). The exact structure of the yeiiow-coloured lead salts is not known with certainty. However, the tertiary aicohoi function of the aipha acids (3, Fig. 2) must be invoived in the complex binding, as the hop beta acids do not form such iead saits. It has been established that a 1 1 compiex is formed (2). 

---