Food or edible material: processes – compositions – and products – Products per se – or processes of preparing or treating... – Hop derived ingredient – including hopping of wort
Patent
1979-10-31
1982-07-06
Naff, David M.
Food or edible material: processes, compositions, and products
Products per se, or processes of preparing or treating...
Hop derived ingredient, including hopping of wort
426 16, 426651, 426429, 426430, C12C 300, C12C 902, A23L 1221
Patent
active
043383483
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for the treatment of hops or hop products by the use of CO.sub.2 as extraction agent and subsequent separation of the resulting extract by evaporation of the CO.sub.2. Oestrogen-active substances can be isolated from the extract thus obtained or the alpha acids contained in this extract can be isomerised.
By hops is meant here the hop cone both in the freshly harvested state and in the redried commercial state and by hop products are meant products such as, for example hop powder, lupulin-enriched hop powder in the form of pellets, hop extracts and hop extract powder.
Processes for obtaining hop extracts are carried out in the conventional way by means of organic solvents and water. However, these solvents dissolve not only the desired extract from the starting material, but also undesirable substances. It is also not possible to prevent residues of the solvent from passing into the extract, which is undesirable for foodstuff purposes.
Furthermore, it is known to effect extractions by means of liquid gases, especially by means of CO.sub.2, due to which the above-described attendant phenomena are forestalled or at least occur only to a small extent, but it is not possible to prevent chlorophyll-like substances and higher molecular polyphenols from passing into the extract.
The problem of the invention is to prepare an extract of hops or hop products which contains virtually all bitter substances and of the polyphenols the desired proportion of low-molecular polyphenols and which also contains virtually all components of the hop oil. According to an advantageous form of realisation of the invention, oestrogen-active substances can be isolated from the extract by isolation methods known per se. Moreover, according to an especially advantageous form of realisation of the process, the extracts enriched in alpha acids can be subjected to an isomerisation process.
This is achieved according to the invention due to the fact that to obtain resins, hop oils and low-molecular polyphenols the CO.sub.2 is used in a temperature range up to its critical temperature and a pressure range over its critical pressure and sub-critical temperature conditions and supercritical pressure conditions are maintained during extraction.
The hop resins and hop oils are valuable constituents of the hop or hop products, as are also up to a certain proportion the low-molecular polyphenols. Furthermore, also oestrogen-active substances are present in the hop resins.
The critical temperatures and pressures mentioned here refer, for the pure CO.sub.2 introduced to this CO.sub.2 itself, whereas these concepts relate in the pressurised container to the enriched gas whose critical temperature and critical pressure are different from those of pure CO.sub.2, since they depend, for example on the ratio of concentrate to CO.sub.2.
In principle, any other liquefiable gas can be used instead of CO.sub.2, such as, for example N.sub.2 O, but CO.sub.2 is the most readily available and is relatively harmless and its critical temperature and critical pressure lie in a range which can easily be controlled industrially.
According to a preferred form of realisation of the invention, the proportion of extracted low-molecular polyphenols can be increased due to the fact that the extraction is effected with water as entrainer. In certain beer preparation processes a larger proportion of low-molecular polyphenols is desired, since a certain stability in relation to taste and storability is thereby achieved.
An indication of the proportion of low-molecular polyphenols is given by the P.I. index by which is meant the quotient of polyphenols and anthocyanogens. In other words, the level of the polyphenol index is an indicator of the degree of polymerisation or condensation of the polyphenols. Whereas with cone hops and hop powders the P.I. lies conventionally between 1.2 and 1.5 and with the hop extracts prepared by organic solvents and water it lies between about 2.5 and 4.5, it was found surprisingly that by the process according
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patent: 3939281 (1976-02-01), Schmengers
patent: 4154865 (1979-05-01), Grant
patent: 4212895 (1980-07-01), Lams et al.
patent: 4218491 (1980-08-01), Lams et al.
Lams et al., Preparation of Hop Extracts Without Using Organic Solvents, J. Inst. Brem., 1977, vol. 83, (pp. 39-40).
Aleksandrov et al., Induence of Temperature and Pressure During Liquid Carbonic Acid Extraction, Chemical Abstracts, vol. 73: 80397e, 1970, (p. 221).
Lams et al., Production of Solvent-Free Isomerized Extracts, J. American Soc. Brew. Chemist., vol. 35, No. 6, 1977, (pp. 187-191).
Knorr et al., Chemie und Technologie des Hopfens, Verlag Hans Carl Nurnberg, 1972, (p. 86).
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