The solvent is then cautiously evaporated, it scarcely being possible 5o to avoid loss of small quantities of aroma substances as a result of the evaporation. The extract of aroma substances is added again to the tea freed from theine. According to the invention quite low boiling solvents ,re first of all used for preparing the extract of aroma substances, more particularly halogen compounds, since only such dissolve sufficiently small quantities of theine.Īcetylene dichloride has proved to be particularly suitable for on account of its low boiling point it practically does not dissolve-theine at all under the prevailing conditiorln This agent, moreover, is in contradistinction to those hitherto employed, non-inflammable. The present invention removes the aforesaid disadvantages. Furthermore, the pleasant taste of the tea suffers when. Thus, for example, the contact of tea with ammonia gas in the hot leads to an impairment in the colour, so that the tea leaves after such treatment exhibit a repulsive brown-yellow appearance. A further disadvantage of the known processes consists in the fact that the tea undergoes a swelling under heat treatment and more particularly by the action of steam, with the consequence that the end product acquires an unattractive appearance. The known processes, in which the aroma substances are first dissolved out of the tea before the liberation and extraction of the theine, have various disadvantages, since substances are used as solvents which are unsuitable and in part also are liable to catch fire. Further it has to be borne in mind that theine, which possesses basic properties, is present in the leaf partly bound to plant acids so that for the purpose of extraction a liberation frOm this combination is first of all necessary. A special difficulty arises in effecting the removal of theine namely that the particularly sensitive aroma must in the case of tea be maintained, in contradistinction to the process in the case of coffee where the aroma is first produced in a process (roasting) which is carried out after the extraction. Attempts have been made, therefore, to free the tea leaves from the theine. It is known that tea, like coffee, contains a certain amount of caffeine or theine which, when tea is frequently partaken,/may have an injurious action on the heart and nerves.
0 Comments
Leave a Reply. |