Method for reducing undesirable furanones and phenol derivatives in wood pyrolysis condensates used for the production of smoke flavour mixtures

Abstract

The invention relates to a method for reducing undesirable furanones and phenol derivatives, such as 2(5H)-furanone and 1,2-dihydroxybenzene, in wood pyrolysis condensates used for the production of smoke flavour mixtures.

Description

[0001] proFagus Food Solutions GmbH PFF14298PC

[0002] Method for the reduction of undesirable furans and phenol derivatives in wood pyrolysis condensates used for the production of smoke flavor mixtures

[0003] The invention relates to a process for the reduction of undesirable furanones and phenol derivatives such as 2(5 / 7)-furanone and 1,2-dihydroxybenzene in wood pyrolysis condensates used for the production of smoke flavor mixtures.

[0004] Purified wood pyrolysis condensates are used as smoke flavorings in the food industry, primarily to impart the typical taste and aroma of a smoking process to foods without the need for actual smoking. This has several advantages:

[0005] 1. Time and cost savings: Traditional smoking can be very time-consuming and expensive. With smoke flavorings, the same taste can be achieved quickly and cost-effectively.

[0006] 2. Consistent and controlled aromas: With traditional smoking, the aroma can vary depending on the type of wood or smoke intensity. Smoke flavorings allow for a more precise and reproducible flavor.

[0007] 3. Versatility: Smoke flavorings can be used in various forms such as liquid smoke, powder or granules, and are therefore flexibly applicable in various products, from meat and cheese to sauces and snacks.

[0008] 4. Health Benefits: Traditional smoking can lead to the formation of potentially harmful substances such as polycyclic aromatic hydrocarbons (PAHs). Industrially produced smoke flavorings are therefore often manufactured in such a way that these substances are filtered out, making the final product safer.

[0009] Smoke flavorings are therefore a popular aid in food production to achieve the desired smoky taste quickly, cheaply and evenly.

[0010] Smoke flavorings are primarily produced in the food industry by controlled pyrolysis (heating under oxygen-deprived conditions) of wood—often beech, but also hickory, oak, or other woods. The resulting smoke is condensed (collected), filtered, and purified (to remove unwanted substances such as tar or carcinogenic substances like polycyclic aromatic hydrocarbons (PAHs)), resulting in a liquid form of smoke known as liquid smoke. This is mainly used by Fagus Food Solutions GmbH PFF14298PC.

[0011] It contains desired flavor compounds such as phenols, carbonyl compounds, and acids. Depending on requirements, the liquid smoke is concentrated and / or standardized to ensure a consistent flavor intensity. This process allows for the controlled and hygienic production of smoked food flavors and their application in a wide variety of products. The finished smoke flavorings are available in various forms—liquid, powdered, or paste—and can be directly incorporated into foods such as sauces, marinades, meat products, cheeses, or snacks. Liquid smoke is particularly popular because it is easy to dose and distribute evenly.

[0012] However, wood pyrolysis produces undesirable carbonyl compounds such as furanones (e.g. 2(5 / 7)-furanone) and also 1,2-dihydroxybenzene (common names: catechol, pyrocatechol), which are classified as potentially carcinogenic or genotoxic in higher concentrations and with long-term exposure.

[0013] The European Food Safety Authority (EFSA) and other regulatory authorities therefore set maximum limits for 2(5 / 7)-furanone and 1,2-dihydroxybenzene in smoke flavorings for food to minimize the risk, see https: / / www.efsa.europa.eu / de / topics / topic / smoke-flavourings

[0014] Manufacturers and the food industry therefore ensure that 2(5H)-furanones and 1,2-dihydroxybenzene are only present in controlled amounts in food or use alternative methods for producing smoke flavors that contain less risky components.

[0015] Methods are known to remove furanones and other potentially harmful compounds from smoke flavorings or to reduce their concentration:

[0016] 1. Certain furanones can be removed by vacuum distillation. However, this method is technically complex due to the required vacuum generation, and is often not selective enough or not economical.

[0017] 2. Activated carbon filtration: Activated carbon binds many organic substances, including furanones, and helps to filter them out of a solution such as liquid smoke, but not selectively.

[0018] 3. Enzymatic treatment can also be used to chemically degrade furanones or convert them into harmless byproducts. However, smoke flavorings are complex, which makes enzymatic degradation difficult. proFagus Food Solutions GmbH PFF14298PC

[0019] Against this background, the object of the invention is to at least partially alleviate the problems described with reference to the state of the art and, in particular, to provide a simple and cost-effective process for the reduction of undesired furanones (or lactones in general), such as 2-(5H)-furanone, as well as undesired phenol derivatives, such as 1,2-dihydroxybenzene (catechol, pyrocatechol), from wood pyrolysis condensates, such as those used in the food industry for the production of smoke flavorings (e.g., "liquid smoke"). The process is applicable to both the tar and the "spirit" fractions of wood pyrolysis. Spirit fractions are fractions that originate from the condensed gas phase of wood pyrolysis. Tar fractions can either be extracts / deposits formed from them or can also condense in the reactor. They therefore do not necessarily have to pass through a gas phase.

[0020] In particular, the invention is based on the understanding that certain undesirable carbonyl compounds, especially furanones as cyclic esters (lactones), cannot be reliably and permanently removed from wood pyrolysis condensates by purely physical separation steps such as steam distillation, water washing, or extraction. The invention therefore aims to chemically transform these compounds in a targeted manner through an alkaline-catalyzed, irreversible hydrolysis (saponification) of the lactone structure in order to sustainably reduce the toxicologically relevant furanones.

[0021] The problem according to the invention is solved by a method comprising the steps of claim 1. Advantageous and / or preferred embodiments of the method are the subject of the dependent claims. The description may serve to further specify the features of the claims.

[0022] The proposed method is for reducing undesirable furanones and phenol derivatives in wood pyrolysis condensates used to produce smoke flavor mixtures, in which

[0023] a wood pyrolysis condensate is subjected to steam distillation and

[0024] The resulting distillate is thermally treated with an aqueous alkali solution, then optionally neutralized with an acid and subsequently subjected to liquid-liquid extraction.

[0025] The invention is described in detail below, whereby the disclosed specific embodiments of the invention, examples, or results are intended solely for illustration and are in no way to be interpreted as limiting the scope of protection of the invention as defined in the accompanying claims. proFagus Food Solutions GmbH PFF14298PC

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by a person skilled in the technical field of the invention. The person skilled in the art may also refer in full to the introductory explanations.

[0027] The use of definite or indefinite articles (“der”, “die”, “das”, “ein”, “eine”) is to be understood (especially in connection with the claims) as including at least one element or component, unless otherwise stated here or the context clearly indicates otherwise.

[0028] The conjunction “or” is to be understood as an inclusive and not an exclusive “or”, i.e. as “and / or”, unless otherwise stated here or the context clearly indicates otherwise.

[0029] The use of terms such as "for example", "e.g", "like" or variations thereof is intended solely to better illustrate the invention and must in no way be interpreted as a limitation of the scope of protection of the invention as defined in the attached claims.

[0030] All numerical values, whether explicitly stated or not, are to be understood as approximate values ​​(at least within the usual margin of error). Furthermore, the specification of value ranges serves only as an abbreviation and, unless otherwise stated, refers to every single value that falls within the range, even if that value is not individually specified.

[0031] Glossary

[0032] "Steam distillation": This is a process for the gentle separation of thermally sensitive substances, such as essential oils from plant materials. Steam is used as a carrier gas to dissolve and transport the volatile components. The advantages of steam distillation are that it is a gentle method, as high temperatures are not required, thus preventing the thermal decomposition of sensitive substances.

[0033] "Liquid-liquid extraction" (also known as solvent extraction) is a physicochemical separation process in which one or more components are extracted from a liquid. Fagus Food Solutions GmbH PFF14298PC

[0034] A mixture (e.g., solution or emulsion) is selectively extracted using a second solvent that is immiscible or only partially miscible with it. The target substance distributes itself between the two phases according to its solubility. The partition coefficient describes the ratio of the substance concentration(s) in the two phases. After extraction, the two phases are separated by settling (e.g., in a separatory funnel).

[0035] 1,2-Dihydroxybenzene, also known as catechol or pyrocatechol, is an organic compound belonging to the phenol class. It has a benzene-like structure with two hydroxyl groups (-OH) bonded to adjacent carbon atoms (positions 1 and 2) of the benzene ring. Catechol is toxic at high concentrations. It can irritate the skin and mucous membranes, and chronic exposure can be harmful to health because catechol is potentially carcinogenic.

[0036] Furanones are unsaturated lactones (intramolecular, cyclic esters). They occur in various forms, which differ in the position of the keto group (e.g., 2-furanones) and additional substituents. Furanones are widespread in nature and often possess antimicrobial, antioxidant, or anti-inflammatory properties. Furanones can be mutagenic or toxic, with the specific effect depending on the substitution and the dosage.

[0037] Designs

[0038] A method for reducing undesirable furanones and phenol derivatives in wood pyrolysis condensates used for the production of smoke flavor mixtures is proposed, in which

[0039] a wood pyrolysis condensate is subjected to steam distillation and

[0040] The resulting distillate is thermally treated with an aqueous alkali solution, then optionally neutralized with an acid and subsequently subjected to liquid-liquid extraction.

[0041] The charcoal pyrolysate can optionally be neutralized with an acid to retain phenols.

[0042] Simply washing smoke or smoke condensates with water is merely a physical purification step in which certain water-soluble components can be partially removed. Such a washing step differs fundamentally from the treatment according to the invention of an already obtained wood pyrolysis condensate, as described in proFagus Food Solutions GmbH PFF14298PC

[0043] Targeted chemical reactions are induced on unwanted components. In particular, a targeted chemical conversion of furanones is sought, going beyond mere pH adjustment or physical separation.

[0044] The furanones to be removed from the distillate may be compounds that are sparingly or insoluble in water. The alkali treatment saponifies the furanones in question, which are intramolecular, cyclic esters; that is, the ester is hydrolytically cleaved. The treatment provided in the process according to the invention is not merely a neutralization of acidic components of the distillate, but a targeted chemical reaction. The furanones exist as intramolecular, cyclic esters (lactones) and are irreversibly hydrolytically cleaved by the thermal treatment with the aqueous alkaline solution. This alkaline ester hydrolysis permanently destroys the lactone structure of the furanones, so that regeneration of the original furanones is no longer possible.In principle, acidic hydrolysis of furanones would also be possible; however, this leads to a chemical equilibrium between hydrolyzed and non-hydrolyzed lactones, so that the majority of the furanones remain in their cyclic form. Such acidic hydrolysis is therefore unsuitable for the sustained reduction of furanones. In contrast, alkaline ester hydrolysis proceeds practically quantitatively and irreversibly, so that the unwanted furanones are permanently chemically transformed and thus reliably reduced.

[0045] The aqueous alkaline solution used for ester hydrolysis (or saponification) (e.g., sodium hydroxide (NaOH) or another agent that releases hydroxide ions) can typically be used at a concentration of approximately 1 M to 10 M. Often, a concentration in the range of approximately 2 M to 5 M (e.g., approximately 15 wt% NaOH) is sufficient, as this provides an adequate amount of hydroxide ions to effectively hydrolyze esters. Ester hydrolysis can typically be carried out at temperatures between 60°C and 90°C, e.g., at approximately 70°C. The duration of the thermal treatment is not subject to any particular limitations; approximately 30 minutes is typically sufficient. If necessary, shorter or longer thermal treatments can be performed, e.g., 15 min, 45 min, 60 min, or 120 min. Advantageously, the thermal treatment can be carried out under reflux.

[0046] The acid used for neutralization, if optional, is not subject to any special restrictions, provided it fulfills its purpose. For example, hydrochloric acid can be used in any suitable concentration. proFagus Food Solutions GmbH PFF14298PC

[0047] Liquid-liquid extraction is not subject to any particular restrictions regarding the solvents used. The expert selects the solvent based on what is feasible in the process and which washing steps are required. Suitable solvents include, for example, dichloromethane, chloroform, or ethyl acetate. If the extract is to be washed multiple times, ethyl acetate is a good choice, for instance, because the aqueous phase has a higher density in the separatory funnel and can be separated more easily.

[0048] The sequence according to the invention, consisting of alkaline hydrolysis, (optional) neutralization, and subsequent liquid-liquid extraction, does not merely serve to separate ionic or protonated compounds, but rather to remove the reaction products formed during hydrolysis from the distillate. The liquid-liquid extraction is thus functionally linked to a prior chemical conversion of the furanones and does not represent an isolated purification step.

[0049] It is clear to those skilled in the technical field of the invention that the representative embodiments and details of the invention described above are intended only to illustrate the present invention, and that various modifications and alterations can be made without thereby departing from the scope of protection of the invention as defined in the attached claims.

[0050] Surprisingly, it was found that the alkaline hydrolysis according to the invention not only leads to a significant reduction in the furanone content, but also simultaneously influences phenolic byproducts in a way that contributes to an improved sensory quality of the resulting smoke aromas. This combined effect was unforeseeable for those skilled in the art and goes beyond what can be achieved by purely physical purification or washing steps.

Claims

proFagus Food Solutions GmbH PFF14298PC Claims 1. A process for reducing undesirable furanones and phenol derivatives in wood pyrolysis condensates used for the production of smoke flavor mixtures, in which a wood pyrolysis condensate is subjected to steam distillation and The resulting distillate is thermally treated with an aqueous alkaline solution and then subjected to liquid-liquid extraction.

2. The method according to claim 1, wherein the distillate obtained is neutralized with an acid after thermal treatment with aqueous alkali solution and subsequently subjected to liquid-liquid extraction.

3. The method of claim 1 or 2, wherein the furanones comprise 2(5H)-furanone.

4. A method according to any of the preceding claims, wherein the phenol derivatives comprise 1,2-dihydroxybenzene.

5. Method according to any of the preceding claims, wherein the aqueous alkaline solution is about 1-10 molar.

6. Method according to one of the preceding claims, wherein the thermal treatment of the distillate with the aqueous alkali solution is carried out at about 60-90 °C for about 15-60 min and optionally under reflux.

7. A method according to any of the preceding claims, wherein the liquid-liquid extraction is carried out with dichloromethane, chloroform, or ethyl acetate.