Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-07-06
2001-11-06
Stockton, Laura L. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06313306
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to N-(2-Mercaptoethyl)-1,3-thiazolidines, processes for their preparation and their use as aromatizing substance in foods and drinks and for spraying food aromas and for room air fragrancing.
BACKGROUND OF THE INVENTION
In the flavor industry, there is still a great demand for substances which impart an of-factory impression to foods and drinks such as results in the thermal treatment during boiling, baking, and roasting of foods. The resultant aromatizing compounds exhibit especially roasted notes. However, these compounds in particular have been scarcely alable. In addition to the flavor, which is larely actually perceived retronasally as an odor, the orthonasally perceived odor currently plays an important role. Therefore, flavor compounds are also of importance which impart a correspondingly strong and typical odor to a food or drink.
The most important reaction which proceeds in the thermal treatment of foods is the reaction between reducing, sugars and amino acids which is called the Maillard reaction. During this Maillard reaction, flavorings of the heterocycle class of chemical substances are formed. These compounds contain one or more heteroatoms, various side chains and are aromatic or partially hydrogenated (P. A. Finot, H. U. Aeschbacher, R. F. Hurrell, R. Liardon, The Maillard Reaction in Food Processing, Human Nutrition and Physiology, Birkhäuser Verlag, Basle, 1990).
SUMMARY OF THE INVENTION
As a novel class of odorant and flavoring substances, N-(2-Mercaptoethyl)-1,3-thiazolidines and their disulphides of the formula
have been found, wherein R
1
, R
2
and R
3
are identical or different and R
1
is hydrogen, methyl, ethyl, propyl or isopropyl, R
2
is hydrogen, acetyl, propionyl, isobutyryl, methyl, ethyl, propyl or isopropyl and R
3
is hydrogen or
Substituted N-Mercaptoethyl-1,3-thiazolidines and their disulphides are odorants and flavorings.
DETAILED DESCRIPTION OF THE INVENTION
The inventive substituted N-Mercaptoethyl-1,3-thiazolidines and their disulphides, in particular N-(2-Mercaptoethyl)-1,3-thiazolidine, surprisingly have very low threshold values. For example, the inventive N-(2-Mercaptoethyl)-1,3-thiazolidine has a surprisingly low threshold value at 0.005 ng/l in air. This makes it possible to use it as an aromatizing constituent at very low concentrations. In addition, N-(2-Mercaptoethyl)-1,3-thiazolidine imparts a particularly strong and typically roasted flavor to foods.
Compared with the thiazolines, among which, especially 2-acetyl-2-thiazoline is a known flavoring (J. Kerler, J. G. M. van der Veen, H. Weenan, Food Rev. Int., 1997, 13, 553-575), little is known to date on the thiazolidine class of substances as flavorings. Although in the scientific literature, thiazolidines are also described as reaction products of sugars and amino acids, these thiazolidines are not, however, distinguished by corresponding aromatizing properties and therefore do not appear either as industrially used flavorings.
Surprisingly, N-(2-Mercaptoethyl)-1,3-thiazolidine develops virtually no retronasal flavor activity in aqueous solutions, that is to say, on tasting, it is scarcely perceived to have flavor. However, it has a very strong orthonasal action and develops an intensive roasted odor note. Thus, although the flavoring N-(2-Mercaptoethyl)-1,3-thiazolidine of the present invention has similar sensory properties to furfurylthiol, it has a much more intense aroma and has a considerably lower odor threshold. This was determined at 0.005 ng/l in air. Thus, the compound belongs to the most aroma-intensive compounds, which are known in flavor chemistry.
N-(2-Mercaptoethyl)-1,3-thiazolidine was identified as a thermal reaction product of cysteamine with fructose (Example 1). Its structural origin, however, is not as simple to explain. Presumably, cysteamine and formaldehyde contribute to its thermal formation. It was identified by fractionating the extract from the reaction mixture by gas chromatography and subsequent mass spectromectric analysis. N-(2-Mercaptoethyl)-1,3-thiazolidine was unambiguously identified by comparison with the analytical data of an authentic sample.
In addition, systematic experiments have also been carried out by using a chromatograpic method which is termed gas chromatography-olfactometry (GC-O). In this method, the compounds which were separated during the chromatographic process are sniffed individually with the nose at the end of the capillary column. Using these methods, the olfactory and gustatory qualities of N-(2-Mercaptoethyl)-1,3-thiazolidine were pre-evaluated.
The structure was demonstrated by comparison with synthesized N-(2-Mercaptoethyl)-1,3-thiazolidine. N-(2-Mercaptoethyl)-1,3-thiazolidine can be prepared starting from thiazolidine. Thiazolidine is admixed with ethylene sulphide and heated under an inert gas atmosphere for 24 hours at 80° C. After purification N-(2-Mercaptoethyl)-1,3-thiazolidine is obtained (Example 2).
The compound of the present invention N-(2-Mercaptoethyl)-1,3-thiazolidine is, because of its outstanding organoleptic character, particularly suitable as a flavoring for use in flavor compositions. It is particularly surprising that N-(2-Mercaptoethyl)-1,3-thiazolidine imparts a very intensive roasted note to the relevant compositions at extremely low concentrations. In this case the flavor is perceived particularly by smell (orthonasally).
In ready-to-use flavors, the amount of the compound of the present invention used is preferably between 0.00005 and 1% by weight, in particular between 0.0001 and 0.5% by weight, based on the total composition. Flavor compositions of this type can be used in the entire food and drink sector. In particular, they are suitable for aromatizing snacks, soups, sauces, ready-to-eat meals, fat compositions, bakery products, yogurt, ice cream and confectionery products. The dosage of flavor compositions of this type is preferably 0.005 to 2% by weight, in particular between 0.01 and 1% by weight, based on the finished food or drink.
The ready-to-use flavors can be used in liquid form or in spray-dried form or in encapsulated formn. Whereas, in liquid form, they are used in a solvent which is customary in practice, such as ethanol, propylene glycol, vegetable oil triglycerides or triacetin, the dry flavors are produced by spray-drying or by encapsulation according to a process customary in the flavor industry. These are the extrusion and spray granulation processes.
Owing to the intense odor activity, the compound of the present invention N-(2-Mercaptoethyl)-1,3-thiazolidine is also suitable, in particular, for aromatizing packages of foods and drinks, and also for other applications (e.g. spraying of food aromas and for room air fragrancing).
REFERENCES:
patent: 3980089 (1976-09-01), Pittet et al.
patent: 1428902 (1966-12-01), None
Food. Rev. Int., 13(4), month unavailable, 1997, pp. 553-575, Josef Kerler et al, “&agr;-Acetyl-N-Heterocycles in the Maillard Reaction”.
Chemical Abstracts, vol. 104, No. 13, Mar. 31, 1986, Columbus, Ohio, US; abstract No. 109619a, Seite 726; XP002149361, Zusammenfassung, & JP 60 149592 A (Hasegawa, T., Co., Ltd.) Aug. 7, 1985.
Tank, CA 55:796i, Jan. 9, 1961.
Engel Wolfgang
Guntert Matthias
Lambrecht Stefan
Schieberle Peter
Cheung Noland J.
Gil Joseph C.
Haarmann & Reimer GmbH
Stockton Laura L.
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