HK1192121A - Process to produce a yeast-derived product comprising reducing sugar - Google Patents

Abstract

This invention relates to a process to produce a yeast-derived product as well as a yeast autolysate or yeast extract comprising at least 1% w/w reducing sugar based on the total dry matter weight of the yeast extract or yeast autolysate. The invention also relates to a process to produce a reaction flavour. The yeast extract or yeast autolysate is very suitable for the production of a reaction flavour.

Description

Method for producing yeast derivatives comprising reducing sugars

Technical Field

The present invention relates to a process for the production of a yeast derivative and a yeast autolysate or yeast extract comprising at least 1% w/w reducing sugar based on the total dry matter weight of the yeast extract or yeast autolysate. The invention also relates to a method for producing a reaction flavour.

Background

Reaction flavours are produced as a result of the Maillard (Maillard) reaction between amino acids and reducing sugars. This reaction, its products and their effect on the taste of foods have been the subject of some research. (Motram D.S., (1998) Food Chemistry,62pp.415-424, "flavour in media and media products: a review" and references therein;,R.,Schliemann,R.,Woelm,G.,(1988)Tech.Charact.Prod.Appl.Food Flavours,pp.107-114,“Study on the effect of fat in meat flavourformation”）

the preparation of reaction flavours by yeast derivatives, such as yeast extract or autolysate, is one method well known in the art. However, to produce the maillard reaction, it is often necessary to add a reducing sugar, such as glucose. However, the addition of glucose to yeast derivatives prior to the Maillard reaction poses a disadvantage, since it constitutes an additional process step, which is considered inconvenient. Furthermore, the addition of non-yeast derivatives to the process to produce a reaction process is often considered by the consumer to be non-natural and therefore undesirable. It is an object of the present invention to provide a yeast derivative, such as a yeast extract or an autolysate, comprising reducing sugars derived from oligosaccharides and polysaccharides normally present in yeast cells used for the preparation of yeast derivatives. These are, for example, trehalose which is mainly present in the cytoplasm of yeast cell walls, glycogen and various glucans. It is a further object of the present invention to provide a process for the production of reaction flavours from yeast derivatives whereby no or only little additional components are added.

Description of the invention

In a first aspect the invention provides a process for the production of a yeast derivative comprising (a) hydrolyzing yeast protein by contacting a suspension comprising yeast cells with an endoprotease and (b) contacting the preparation obtained in step (a) with one or more enzymes selected from the group consisting of alpha-trehalase (EC 3.2.1.28), glucoamylase (EC 3.2.1.3), endoglucanase and exoglucanase.

The endoglucanase may be selected from the group consisting of endo-1, 3-beta-glucanase (EC 3.2.1.39), lichenase (EC 3.2.1.73), endo-1, 6-beta-glucanase (EC 3.2.1.75) and endo-1, 3(4) -beta-glucanase (EC 3.2.1.6). The exoglucanase may be selected from the group consisting of 1, 3-beta-glucosidase (EC 3.2.1.58), glucan 1, 6-beta-glucosidase and beta-glucosidase (EC 3.2.1.21).

The following enzymes and combinations are highly preferred embodiments of the enzymes used in step (b) of the process of the invention:

(1) alpha-trehalase (EC 3.2.1.28)

(2) Alpha-trehalase (EC 3.2.1.28) and glucoamylase (EC 3.2.1.3)

(3) Alpha-trehalase (EC 3.2.1.28) and one or more enzymes selected from the group consisting of endoglucanases and exoglucanases.

(4) Alpha-trehalase (EC 3.2.1.28) and one or more enzymes selected from the group consisting of endoglucanases

(5) Alpha-trehalase (EC 3.2.1.28) and one or more enzymes selected from the group consisting of exoglucanases

(6) Alpha-trehalase (EC 3.2.1.28) and glucoamylase (EC 3.2.1.3) and one or more enzymes selected from the group consisting of endoglucanases and exoglucanases

(7) Alpha-trehalase (EC 3.2.1.28) and glucoamylase (EC 3.2.1.3) and one or more enzymes selected from the group consisting of endoglucanases

(8) Alpha-trehalase (EC 3.2.1.28) and glucoamylase (EC 3.2.1.3) and one or more enzymes selected from the group consisting of exoglucanases

(9) Alpha-trehalase (EC 3.2.1.28) and endo-1, 3-beta-glucanase (EC 3.2.1.39)

(10) Alpha-trehalase (EC 3.2.1.28) and glucoamylase (EC 3.2.1.3) and endo-1, 3-beta-glucanase (EC 3.2.1.39)

(11) Alpha-trehalase (EC 3.2.1.28) and endo-1, 6-beta-glucanase (EC 3.2.1.75)

(12) Alpha-trehalase (EC 3.2.1.28) and glucoamylase (EC 3.2.1.3) and endo-1, 6-beta-glucanase (EC 3.2.1.75)

(13) Alpha-trehalase (EC 3.2.1.28) and endo-1, 3(4) -beta-glucanase (EC3.2.1.6)

(14) Alpha-trehalase (EC 3.2.1.28) and glucoamylase (EC 3.2.1.3) and endo-1, 3(4) -beta-glucanase (EC 3.2.1.6)

(15) Any one of the above components (1) to (14) and an exoglucanase selected from the group consisting of glucan 1, 3-beta-glucosidase (EC 3.2.1.58), glucan 1, 6-beta-glucosidase and beta-glucosidase (EC 3.2.1.21)

(16) Any one of the above components (1) to (14) and glucan 1, 3-beta-glucosidase (EC3.2.1.58)

(17) Any one of the above components (1) to (14) and glucan 1,6- β -glucosidase (18) any one of the above components (1) to (14) and β -glucosidase (ec 3.2.1.21).

In a preferred embodiment, the yeast derivative produced by the process of the first aspect of the invention is a yeast autolysate. In the context of the present invention, "yeast autolysate" is defined according to the Food Chemical code as "concentrated, non-extracted, partially soluble digest obtained from Food grade yeast. Lysis is accomplished by enzymatic hydrolysis or autolysis of the yeast cells. Food grade salts and enzymes may be added. Autolysed yeast contains both soluble and insoluble components derived from whole yeast cells. It is composed mainly of amino acids, peptides, carbohydrates, fats and salts. "

In another preferred embodiment, the yeast derivative of the method of the first aspect of the invention is a yeast extract. In the context of the present invention, a "yeast extract" is defined according to the food chemistry code as a "yeast extract comprising water-soluble components of yeast cells, the composition of which is mainly amino acids, peptides, carbohydrates and salts. Yeast extracts are produced by the hydrolysis of peptide bonds by naturally occurring enzymes present in edible yeast or by the addition of food grade enzymes. "

In one embodiment, the process of the first aspect of the invention further comprises subjecting the yeast derivative to a solid-liquid separation step and removing insoluble matter

And (4) a sexual substance. Subjecting the yeast derivative, i.e. the resulting contacted solution, to a solid-liquid separation step and removing insoluble material may advantageously result in a more soluble, clearer and/or less coloured yeast derivative, which may be used in certain applications where these traits are desired. The yeast derivative from which the insoluble material is removed may be referred to as an extract; i.e. it can be considered as the soluble fraction of the yeast derivative.

We have surprisingly found that a yeast derivative enriched in reducing sugars can be produced by the process of the first aspect of the invention. Preferably, the reducing sugar is glucose. An advantage of the process of the invention is that a yeast derivative, such as a yeast autolysate or yeast extract, may contain a sufficient amount of a reducing sugar, such as glucose, to allow the direct use of the yeast derivative to prepare the flavour it produces without the need for the addition of an external reducing sugar such as glucose.

The yeast in the yeast-containing suspension of the method of the first aspect of the invention may be from any type of food grade yeast, such as baker's yeast, beer yeast or wine yeast. Preferably, the yeast belongs to the genus Saccharomyces, Kluyveromyces, Candida or Torula, more preferably to the genus Saccharomyces, i.e.Saccharomyces cerevisiae.

The suspension of yeast cells may be a fermentation broth, but is preferably a cream yeast. Cream yeast is well known in the art, such as the bakery industry, and refers to a yeast cell suspension obtained from a fermentation broth, optionally washed, with a total yeast dry matter content of between 18% and 24%.

In one embodiment, the method of the first aspect of the invention further comprises drying the contacted suspension or extract. This may result in a stable yeast derivative, e.g. during storage, and may be lighter in weight and more economical in transport.

The process of the first aspect of the invention advantageously allows to produce a high yield of dissolved dry matter (% w/w), expressed as yeast extract or yeast autolysate, preferably in yeast extract, in an amount of dissolved matter (dry weight) compared to the total dry weight of the yeast cell suspension. The yield is preferably higher than 70%, more preferably higher than 75%, higher than 80%, even more preferably higher than 85%, most preferably higher than 90%.

In a preferred embodiment, the method of the first aspect of the invention further comprises reducing the amount of free asparagine present in the yeast derivative. Preferably, the amount of free asparagine is reduced by an enzyme capable of reducing free asparagine, such as asparaginase, under conditions disclosed for example in WO 2007/073945.

Yeast derivatives containing reduced amounts of free asparagine are particularly advantageous for reactions in which the yeast derivative (e.g., yeast extract or yeast autolysate) is heated, for example when it is used to produce reaction flavours, and also when the yeast extract or yeast autolysate is added to prepared food that is heated prior to consumption. For example, if a yeast derivative obtained by the process of the first aspect of the invention, such as yeast extract or yeast autolysate, having said content of reducing sugars is added to soups, crisps (crisps) or chips (chips), or snacks (snacks), which are cooked (boiled), cooked (cooked) or baked (bated), a reduced amount of asparagine may reduce the formation of highly undesirable acrylamide in the food product. In the presence of yeast extracts or yeast autolysates known in the art, the risk of acrylamide formation may be lower due to their lower glucose content.

In a second aspect the present invention provides a yeast derivative obtainable by the process of the first aspect of the invention, comprising at least 1% w/w, based on total dry matter weight, of a reducing sugar, wherein the reducing sugar is derived from oligosaccharides and polysaccharides normally present in yeast cells used for the preparation of the yeast derivative. Preferably, the amount of reducing sugars in the yeast derivative is at least 1.5% w/w, more preferably at least 2% w/w, 3% w/w, 4% w/w, even more preferably at least 5% w/w, 6% w/w, 7% w/w, even more preferably at least 8% w/w, 9% w/w, 10% w/w, 11% w/w, most preferably at least 12% w/w, based on the total dry weight of the yeast derivative. The amount of reducing sugars of the yeast derivatives may be up to 30%, preferably less such as 25% or less or 20% or less, depending on the content of oligo-and polysaccharides in the yeast. For example, the yeast may comprise a high content of trehalose, preferably at least 1% or up to 30% based on the total dry weight of the yeast.

In the context of the present invention, a reducing sugar is any sugar having an aldehyde or ketone group in dissolved state. This allows the reducing sugar to act as a reducing agent in, for example, a maillard reaction and/or in a process for producing a reaction flavor, preferably a reaction flavor from a yeast derivative such as a yeast autolysate or yeast extract. In the maillard reaction and the process for producing reaction flavours, the first reaction is a reaction between a reducing sugar and an amino group, for example an amino acid. A highly preferred reducing agent in the context of the present invention is glucose. Glucose is a widely accepted food ingredient and is an effective maillard agent.

The yeast derivatives of the second aspect of the invention are preferably suitable for the production of reaction flavours. A preferred embodiment of the present invention is a yeast autolysate or yeast extract comprising at least 1% w/w reducing sugars based on the total dry matter weight, wherein the reducing sugars are derived from oligosaccharides and polysaccharides normally present in the yeast cells used for the preparation of the yeast autolysate or yeast extract. The yeast autolysate or yeast extract of the second aspect of the invention is preferably obtainable by the process of the first aspect of the invention.

Preferably, the amount of reducing sugars in the yeast autolysate or yeast extract is at least 1.5% w/w, more preferably at least 2% w/w, 3% w/w, 4% w/w, even more preferably at least 5% w/w, 6% w/w, 7% w/w, even more preferably at least 8% w/w, 9% w/w, 10% w/w, 11% w/w, most preferably at least 12% w/w based on the total dry matter weight of the yeast autolysate or yeast extract. The amount of reducing sugars of the yeast autolysate or yeast extract may be up to 30%, preferably less such as 25% or less or 20% or less, depending on the content of oligo-and polysaccharides in the yeast. For example, the yeast may contain a high content of trehalose, preferably at least 1% or up to 30% based on the total dry weight of the yeast.

A highly preferred reducing sugar in the context of the present invention is glucose. Glucose is a widely accepted food ingredient and is an effective maillard agent.

The yeast extract or yeast autolysate of the second aspect of the present invention may advantageously be dark in colour, which may be darker than yeast extracts or yeast autolysates known in the art. The color can be determined, for example, by measuring the absorbance, for example at 450 nm. If it is desired to further enhance the colour of the yeast extract or yeast autolysate of the second aspect of the invention, the yeast extract or yeast autolysate may be subjected to elevated temperatures, for example between 30 ℃ and 100 ℃.

Preferably, the reducing sugar in the yeast extract or yeast autolysate of the second aspect of the invention is glucose. Glucose is a widely accepted food ingredient and is an effective maillard agent.

In a third aspect the invention provides a method of producing a reaction flavour, comprising incubating as step (c) the yeast derivative of the second aspect of the invention and defined herein, under conditions of temperature and water content to obtain the reaction flavour. We have surprisingly found that reaction flavours can be produced by the process of the third aspect of the present invention without the addition of external reducing sugars such as glucose, and that the reaction flavours produced thereby can advantageously be labelled "natural" or "clean-label".

In a preferred embodiment, the process of the third aspect of the invention comprises all the steps of the process of the first aspect of the invention. This embodiment optionally includes a solid-liquid separation step and removal of insoluble material in the process of the first aspect of the invention. This step is optional and can therefore be omitted if desired. In one embodiment, the method of the third and first aspects of the invention does not comprise a solid-liquid separation step and removal of insoluble material. This may result in higher amounts of fatty substances originating from the yeast cell walls, which may result in more mouthfeel or additional aroma.

In another embodiment, the process of the third aspect of the invention comprises the addition of one or more additional components. This additional component may be added to the yeast derivative obtained by the process of the first aspect of the invention or the yeast derivative of the second aspect of the invention, such as a yeast extract or a yeast autolysate. Water is not considered an additional component in the context of the present invention. Likewise, the enzyme used in the process of the first aspect of the invention is not considered an additional component.

In a preferred embodiment, the additional component is a sulfur-containing component, such as cysteine or glutathione. In another preferred embodiment, the additional component is a yeast derivative. By "yeast-derived" is meant that the component is obtained from or produced by yeast. One advantage of the yeast-derived additional component is that it is generally considered safe and therefore well suited for preparing food grade reaction products, and consumers generally do not like reaction flavours from yeast that have any non-yeast derived component added to the final product and/or during its preparation.

In another preferred embodiment, the one or more additional components are selected from the group consisting of yeast extract, yeast autolysate, cysteine, glutathione, free amino acids and reaction flavours. Preferably, the one or more additional components are reaction flavours, more preferably reaction flavours produced from yeast derivatives comprising cysteine and/or yeast derivatives comprising glutathione (such as yeast extract or yeast autolysate), even more preferably reaction flavours produced in an extruder, for example as described in the examples of WO 2010/037783. The addition of a reaction flavour as one or more additional components may produce a reaction flavour with a particular flavour (e.g. beef flavour or roasted beef flavour), which may advantageously be concentrated.

One or more additional components may be added at any stage of the process of the first or third aspects of the invention. Which may be added before or after step (a) and/or before or after solid-liquid separation of the process of the first aspect of the invention. One or more additional components may also be added in multiple stages, for example before and after step (a), or before and after step (a) and solid-liquid separation, or before and after step (a) and after solid-liquid separation. The amount of the one or more additional components added is preferably such that the total amount of the one or more additional components in the yeast derivative obtained by the method of the first aspect of the invention or the yeast extract or yeast autolysate of the second aspect of the invention is between 0.1% w/w and 99% w/w, more preferably between 0.5% w/w and 95% w/w, between 1% w/w and 90% w/w, more preferably between 2% w/w and 80% w/w, between 3% w/w and 70% w/w, between 4% w/w and 60% w/w, most preferably between 5% w/w and 50% w/w, based on the total weight of the yeast derivative or yeast extract or yeast autolysate of the first aspect of the invention. Many types of fragrances can be obtained by varying the amount of one or more additional components. For example, the concentration of the perfume (strength) or the "degree of cure" of the perfume may be varied by varying the amount of one or more additional components, so that a person skilled in the art can, without unnecessary burden, determine an appropriate amount to obtain the desired type of perfume. The addition of one or more additional components to the process of the third aspect of the invention may increase the efficiency of the maillard reaction. This may also be advantageous because it may allow the production of specific reaction flavours, such as beef flavour, which cannot be produced or which may not be efficiently produced without the addition of additional components.

The water content in the yeast derivative of the second aspect of the invention or the yeast derivative obtained by the process of the first aspect of the invention is preferably between 1% w/w and 20% w/w, more preferably between 1.5% w/w and 10% w/w, even more preferably between 2% w/w and 5% w/w, based on the total weight of the yeast derivative or yeast extract or yeast autolysate.

The temperature in step (c) of the process of the third aspect of the invention is preferably between 50 ℃ and 180 ℃, more preferably between 75 ℃ and 170 ℃, even more preferably between 100 ℃ and 160 ℃. If the temperature is too high, e.g., above 180 ℃, the reaction flavours may burn. At higher temperatures, e.g. 180 ℃, the reaction time may be shorter than at lower temperatures, e.g. 50 ℃. At lower water contents, e.g. 2% w/w, the temperature may be higher, e.g. 180 ℃.

The incubation in step (c) may be carried out in equipment well known in the art, such as a reaction kettle, (vacuum) oven, digester, etc. Preferably, step (c) of the process of the third aspect of the present invention is carried out in an extruder. The extruder may be any type of extruder suitable for producing a reaction flavor, such as a twin screw extruder (twin extruder). Extruders, such as twin screw extruders, are well known in the art. The extruder may be of any capacity, which is the maximum capacity that the components can occupy within the extruder. Preferably, the capacity is between 1g and 1000 kg. More preferably, the capacity is between 5g and 100kg, more preferably between 10g and 10 kg. The yeast derivative obtained by the process of the first aspect of the invention or the yeast extract or yeast autolysate of the second aspect of the invention, and optionally water and/or oil, may be fed to the extruder by the same or different feeders. The reaction flavours may exit the extruder at different pressures, outside the extruder, from reduced pressure (e.g. 5 mbar) to atmospheric pressure (e.g. about 1 bar). The reaction flavours produced by the process of the third aspect of the present invention may be further cooled and/or dried using a cooling belt or any other method known in the art. An extruder may be advantageous in that the process according to the third aspect of the invention may be more reproducible and/or more stable, for example during storage. The use of an extruder in step (c) of the process of the third aspect of the invention may also be advantageous because it allows for a continuous process which may result in a higher yield of the reaction flavour. The use of an extruder in step (c) of the process of the third aspect of the invention may be advantageous because higher pressures and/or production temperatures may be achieved in step (c). Furthermore, the use of an extruder may be advantageous because it may allow for intimate mixing. This may be particularly important when one or more additional components are added, especially when a reaction fragrance is added as one or more additional components. In addition, the use of an extruder in step (c) of the process of the third aspect of the invention may be advantageous as it may result in a homogeneous reaction flavour, i.e. a reaction flavour that is evenly distributed in the product exiting the extruder. In addition, the use of an extruder in step (c) of the process of the third aspect of the present invention can advantageously produce a reaction flavor that is more concentrated than the reaction flavor produced in a vacuum oven. The use of an extruder in step (c) of the process of the third aspect of the invention may also be advantageous in that the reacted perfume may be free flowing after milling the extrudate. The use of an extruder in step (c) of the process of the third aspect of the invention may also be advantageous because it is simple. The use of an extruder in step (c) of the process of the third aspect of the invention may also be advantageous because it can produce a roast meat flavour.

The incubation in step (c) of the method of the third aspect of the invention preferably takes place in the presence of an enzyme capable of reducing the amount of free asparagine. Examples of such enzymes are described in WO2007073945, including asparaginase.

In a fourth aspect the present invention provides a reaction flavour obtainable by the process of the third aspect of the invention. The reactive perfume of the third aspect of the present invention may have any fragrance. The reaction flavours may have a vegetable flavour, for example cabbage such as cauliflower, broccoli, brussel sprout (Brussels sprut), Chinese kale (Chinese kale) or Chinese broccoli (Chinese broccoli), kale (kale) or green cabbage (spring greens), collard greens, kohlrabi, onions, cocoa, chocolate, peanuts, roasted peanuts, coffee, etc., or they may have a meat flavour. Meat flavors include, but are not limited to, poultry flavors such as chicken, turkey, pheasant, goose, swan, wild duck, or other meat flavors such as beef, lamb, sheep, goat, horse and pork. The reaction flavor may be a cooked (bouiled), stewed (braised), roasted (cooked), grilled (grilled), smoked (smoked), fried (fried) or bouillon flavor. Preferably, the reaction flavour is beef flavour. More preferably, the reaction flavor has a roasted meat flavor.

Materials and methods

Glucose and trehalose were determined by HPLC using an Aminex HPX-87G column (BioRad). The retention times for trehalose and glucose were 6.65 and 7.93 minutes, respectively.

The protein (i.e., the total mixture of amino acids, peptides and protein) was measured by Kjeldahl azotometry using a conversion factor of 6.25.

Filtrase(DSM Food Specialties, the Netherlands) is a non-transgenic liquid enzyme product for improving beer viscosity (viscisity) and filterability (filterability) and comprises a mixture of enzymes produced by selected strains of Talaromyces emersonii. The primary active agent is endo-1, 3(4) - β -glucanase (EC3.2.1.6), but there are also other enzymatic active agents such as xylanases and trehalases.

Examples

Example 1

Preparation of yeast extract containing reducing sugar

To Saccharomyces cerevisiae Zygomyces lactis (20% w/w dry matter) was added 10mg/g (on a dry matter basis) of Bacillus licheniformis endoprotease (Alcalase, Novozymes, Denmark). The conditions of the contact are: pH at 53 ℃ C6, 4 hours; then the temperature is 60 ℃, the pH is 6, and the time is 2 hours; then, the temperature is 53 ℃, the pH value is 5.3, and the time is 16 hours; the protease was then inactivated at 70 ℃ for 30 minutes. Next, the pH was lowered to 4.5, the temperature was lowered to 55 ℃ and 10mg/g enzyme mixture from Talaromyces (Filtrase) containing endo-1, 3-. beta. -glucosidase was addedDSM Food Specialties, the Netherlands), glucoamylase (Bakezyme AG800, DSM Food Specialties, the Netherlands, 1 mg/g) and fungal amylase (DSM Food Specialties, the Netherlands). This contact was continued for another 6 hours. The temperature was then lowered to 50 ℃ and a mixture of beta-glucanase, cellulase, protease and chitinase (lyase from Trichoderma harzianum, 1mg/g dry matter, Sigma Aldrich) was added at pH4.5 for 17.5 hours.

The enzyme mixture from Talaromyces also contained trehalase active agent, as shown in additional experiments by incubating pure trehalose with the enzyme mixture from Talaromyces and measuring residual trehalose and formed glucose with HPLC (see materials and methods).

A yeast extract (yeast extract A) is obtained by collecting and concentrating the centrifuged supernatant. A yeast extract powder of the yeast extract ("yeast extract a powder") was prepared by spray drying. The total dry matter of the cream yeast is defined as 100%. The results are shown in Table 1.

TABLE 1 results

ND = not determined

Example 2

Preparation of beef-type reaction spice

A mixture was prepared by mixing 28.7g of the yeast extract powder of example 1 (yeast extract A powder), 6.9g of a reaction flavor and 0.35g of high oleic sunflower oil (HOZOL, Brenntag, the Netherlands). The reaction flavours in the mixture were prepared by extrusion as described in the examples of WO2010/037783, the exact components and conditions being shown in table 2. Yeast extract powder: reaction of the perfume: the proportion of high oleic sunflower oil in the mixture was 79: 20: 1. the mixture was then heated in a twin screw extruder at a screw speed of 100rpm for three minutes at 125 ℃. After cooling to room temperature, the extrudate (reaction flavor) was ground to a fine dark brown powder and stored in plastic jars. The reaction flavours were evaluated by a trained panel of experts.

TABLE 2 Components

Five reaction flavours can be prepared by varying the ratio of yeast extract powder to reaction flavour in the mixture (the sunflower oil content in the mixture is always 1%) according to table 3.

TABLE 3 reaction fragrance

Reaction flavour	Yeast extract powder in mixture: proportion of reaction flavours
		Reaction fragrance 1	80:20
Reaction flavour 2	82.5:17.5
		Reaction flavor 3	85:15
Reaction fragrance 4	87.5:12.5
		Reaction flavor 5	90:10

The five reaction spices have different sensory properties (sensory profile), but all are beef. Mixtures containing more reaction flavours produce reaction flavours that are more sulfur coloured and also more intense.

Example 3

31.5g of the yeast extract powder of example 1 (glucose concentration 12%), 3.1gPlus (a yeast extract from Saccharomyces cerevisiae available from DSM Food Specialties, Delft, the Netherlands) and 0.35g high oleic sunflower oil (HOZOL) were mixed to make a mixture. Yeast extract powder:plus: the proportion of high oleic sunflower oil is 90: 9: 1. the mixture was then heated in a twin screw extruder at a screw speed of 150rpm for 3 minutes at 140 ℃. After cooling to room temperature, the extrudate (reaction flavor) was ground to a fine dark brown powder and stored in plastic jars. The reaction spice has barbecue flavor.

Example 4

Yeast extract B was prepared according to the procedure of example 1. The powder was prepared by spray drying as described in example 1. The dry weight content was 97.3% and the protein content was 50.1% w/w based on Kjehldahl nitrogen at 8% w/w.

About 10-20mg of spray dried Yeast extract B or comparative Yeast extract ((R))LS powder available from DSM Food Specialties, the Netherlands) in 1ml of D₂O。The LS powder is a standard commercial yeast extract prepared by a process comprising treatment of cream yeast with Alcalase, a Bacillus endoprotease available from Novozymes, Denmark, but which does not comprise treatment with endo-1, 3-beta-glucosidase, glucoamylase, fungal amylase, beta-glucanase, cellulase and/or chitinase.

Disodium maleate or disodium fumarate was added as an internal standard. NMR spectra were determined using BrukerAvance III at 600MHz, equipped with a 5mm cryoprobe.

The NMR spectrum showed that yeast extract B was rich in glucose and free of trehalose compared to the control yeast extract. This data shows that trehalose normally present in yeast extracts is converted to glucose by the trehalase active agent in the enzyme mixture from Talaromyces (example 1).

TABLE 4 Yeast extract composition (% on a dry matter basis)

	Comparative yeast extract	Yeast extract B
			Protein	65%	50.1%
Glucose	0%	8.9%
			Trehalose	5.5%	0%

Example 5

Saccharomyces cerevisiae cream yeast (20% w/w dry matter) was heat shocked (heat shock) at 60 ℃ for 5 minutes. Then, 10mg/g (on a dry matter basis) of Bacillus licheniformis endoprotease (Alcalase, Novozymes, Denmark) was added. The conditions of the contact are: 60 ℃, pH6, 4 hours, then 51.5 ℃, pH5.1, 16 hours.

Subsequently, the pH was lowered to 4.5, the temperature was lowered to 50 ℃ and 10mg/g of enzyme mixture from Talaromyces containing endo-1, 3-. beta. -glucosidase (Filtrase) was addedDSM food specialties, netherlands) for 18 hours. As a final step, the mixture was heat shocked at 65 ℃ pH4.5 for 1 hour. The results are shown in Table 5.

TABLE 5 Yeast derivative component (% on a dry matter basis)

Claims (20)

1. A method for producing a yeast derivative comprising the steps of:

a. contacting a suspension comprising yeast cells with an endoprotease to hydrolyze a yeast protein;

b. contacting the preparation obtained in step a with one or more enzymes selected from the group consisting of alpha-trehalase (EC 3.2.1.28), glucoamylase (EC 3.2.1.3), endoglucanases and exoglucanases.

2. The process according to claim 1, wherein the preparation obtained in step a is contacted with α - α -trehalase (EC 3.2.1.28).

3. The process according to claim 1, wherein the preparation obtained in step a is contacted with α - α -trehalase (EC 3.2.1.28) and glucoamylase (EC 3.2.1.3).

4. A process according to claim 1, wherein the preparation obtained in step a is contacted with α - α -trehalase (EC 3.2.1.28) and one or more enzymes selected from the group consisting of endoglucanases and exoglucanases.

5. The process according to any of the preceding claims, wherein the preparation obtained in step a is contacted with an alpha-trehalase (EC 3.2.1.28) and a glucoamylase (EC 3.2.1.3) and one or more enzymes selected from the group consisting of endoglucanases and exoglucanases.

6. A process according to any one of the preceding claims, wherein the endoglucanase is selected from the group consisting of endo-1, 3-beta-glucanase (EC 3.2.1.39), endo-1, 6-beta-glucanase (EC3.2.1.75) and endo-1, 3(4) -beta-glucanase (EC 3.2.1.6).

7. The method according to any one of the preceding claims, wherein the exoglucanase is selected from the group consisting of glucan 1,3- β -glucosidase (EC 3.2.1.58) and glucan 1,6- β -glucosidase.

8. The process according to any one of the preceding claims, further comprising subjecting the yeast derivative obtained in step b to a solid-liquid separation step and removing insoluble material.

9. The method according to any of the preceding claims, wherein the yeast derivative is a yeast autolysate.

10. The method according to any of the preceding claims, wherein the yeast derivative is a yeast extract.

11. The method according to any of the preceding claims, further comprising drying the yeast derivative.

12. A yeast derivative obtainable by the process of any one of claims 1 to 9 comprising at least 1% w/w and equal to or less than 30% reducing sugars on total dry matter weight basis, wherein the reducing sugars are derived from oligosaccharides and polysaccharides present in the yeast cells used to prepare the yeast derivative.

13. Yeast derivative according to claim 10, wherein said reducing sugar is glucose.

14. The yeast derivative according to claim 10 or 11, wherein the yeast derivative is a yeast autolysate or a yeast extract.

15. A method for producing a reaction flavour, comprising incubating a yeast derivative according to any one of claims 12-13 and obtainable by the method of any one of claims 1-11 under conditions of temperature and water content to obtain a reaction flavour.

16. The method of claim 13, comprising adding one or more additional components.

17. A method according to claim 13 or 14, wherein the one or more additional components are derived from yeast.

18. A method according to any one of claims 13 to 15, wherein the one or more additional components is a reaction flavour.

19. A method according to any one of claims 13 to 16, wherein the incubation in step c is performed in an extruder.

20. A reaction fragrance obtainable by the process according to any one of claims 13 to 17.