WO2024227945A1

WO2024227945A1 - Reaction flavour for egg analogue products

Info

Publication number: WO2024227945A1
Application number: PCT/EP2024/062347
Authority: WO
Inventors: Alicia GIRARDI; Sonia Manganiello; Walter Matthey-Doret
Original assignee: Société des Produits Nestlé S.A.
Priority date: 2023-05-04
Filing date: 2024-05-03
Publication date: 2024-11-07

Abstract

The present invention relates to a method of making a flavour composition, said method comprising the steps of (a) preparing a solution, wherein said solution comprises (i) a reducing sugar, preferably glucose; (ii) a sulphur-containing amino acid, preferably cysteine or salt thereof; and (iii) ascorbic acid or salt thereof; (b) adjusting the pH of the solution to 6.5 or greater; and (c) heating the solution. A plant based egg analogue product comprising the flavour composition is also provided.

Description

Reaction flavour for egg analogue products

Introduction

The volatile profile of cooked eggs is well known to be influenced by several factors. These include chicken feed composition, egg storage duration, and the method of cooking, such as boiling and scrambling. It has been shown that all of these can affect the aroma of cooked eggs by changing its volatile composition and therefore the sensory perception. Carbonyl compounds such as aldehydes and ketones, as well as alcohols, furans, esters and sulfur-containing compounds also play a role. The real contribution of each is still not clear, but it is likely to be a combination of all of them which is responsible of the characteristic sulfuric, creamy, dairy, and sweet notes of cooked eggs.

Current solutions for eggy flavours are typically complex mixtures of volatile compounds which are partially or completely lost during heat treatment, for example during UHT, pasteurization, and cooking in the pan. The aroma is often considered too artificial by consumers. The only natural ingredient commonly used to deliver sulfuric notes which tastes like eggs is Kala Namaksalt, otherwise known as Black salt. However, as it is mainly composed of sodium chloride, its usefulness is limited due to sensory and/or health constraints.

Summary of invention

The invention relates to a method of making a flavour composition. The composition is suitable for egg analogue products and avoids the drawbacks of prior art egg flavour compositions.

In particular, the method comprises the steps of preparing a solution of (i) a reducing sugar; (ii) a sulphur-containing amino acid; and (iii) ascorbic acid or an ascorbate.

In particular, the method comprises the steps of preparing a solution of (i) a reducing sugar, for example glucose; (ii) cysteine or salt thereof; and (iii) ascorbic acid or an ascorbate, for example sodium ascorbate. The method employs a Maillard reaction system and the resulting flavour is suitable for use in plant based egg products.

It was surprisingly found that when pre-reacting precursors under specific conditions to initiate the Maillard reaction, a more complex egg flavour is obtained. This reaction system, which can be added as such to any plant-based preparation, has the advantage to react and further develop the flavour during heating. The invention further relates to a Ma ilia rd reaction system comprising cysteine, a reducing sugar and sodium ascorbate which are heated to between 90 to 100°C in water at pH between 6.5 and 8 for 15 to 90 minutes. The resulting mixture can be used as such to impart egg flavour or could be dried and used as a powder. It was found that the addition of ascorbates promotes the formation of sulfur- containing compounds and delivers a much stronger egg flavour.

Brief description of the figures

Figure 1 shows the frequency of samples selected as presenting the "closest to egg" odour by sensory assessment of the flavour compositions made at different pH.

Figure 2 shows the frequency of the sensory scores of the egg odour intensity.

Figure 3 shows the level of three sulfur-containing compounds (2-methylfuran-3-thiol; methyl furfuryl thiol; 2-furfurylthiol) in the reaction flavours performed at pH 5, 6, 7, and 8 with 24.4 wt% ascorbate.

Figure 4 shows the level of 3-Mercapto-2-butanone in the reaction flavours performed at pH 5, 6, 7, and 8 with 24.4 wt% ascorbate.

Figure 5 shows the level of hydrogen sulfide in the reaction flavours performed at pH 5, 6, 7, and 8 with 24.4 wt% ascorbate.

Figure 6 shows the level of ketones and lactones in the reaction flavours performed at pH 5, 6, 7, and 8 with 24.4 wt% ascorbate.

Figure 7 shows the average sensory scores of the reaction flavours with 9.9 wt% ascorbate on the three key attributes for egg. The letters above the bars indicate the result of the Duncan test: products sharing a common letter are not significantly different.

Figure 8 shows the level of three sulfur-containing compounds (2-methylfuran-3-thiol; methyl furfuryl thiol; 2-furfurylthiol) in the reaction flavours performed at pH 5, 6, 7, and 8 with 9.9 wt% ascorbate.

Figure 9 shows the level of 3-mercapto-2-butanone in the reaction flavours performed at pH 5, 6, 7, and 8 with 9.9wt% ascorbate.

Figure 10 shows the level of hydrogen sulfide in the reaction flavours performed at pH 5, 6, 7, and 8 with 9.9 wt% ascorbate.

Figure 11 compares the sulphur (S)-containing compounds in the reaction flavour performed at pH=7.8 with and without ascorbate. Figure 12 compares the level of hydrogen sulfide in the reaction flavour performed at pH=7.8 with and without ascorbate.

Figure 13 compares the level of 3-mercapto-2-butanone in the reaction flavour performed at pH=7.8 with and without ascorbate.

Embodiments of the invention

The present invention relates to a method of making a flavour composition, said method comprising the step of preparing a solution, wherein said solution comprises a reducing sugar and a sulphur containing amino acid.

The invention further relates to a method of making a flavour composition, said method comprising the steps of (a) preparing a solution, wherein said solution comprises (i) a reducing sugar (ii) a sulphur- containing amino acid; and (iii) ascorbic acid or salt thereof; (b) adjusting the pH of the solution; and (c) heating the solution.

The invention further relates to a method of making a flavour composition, said method comprising the steps of (a) preparing a solution, wherein said solution comprises (i) a reducing sugar, preferably glucose; (ii) a sulphur-containing amino acid, preferably cysteine or salt thereof; and (iii) ascorbic acid or salt thereof; (b) adjusting the pH of the solution to 6.5 or greater; and (c) heating the solution.

In one embodiment, said method comprises the steps of (a) preparing a solution, wherein said solution comprises (i) glucose; (ii) cysteine or salt thereof; and (iii) ascorbic acid or salt thereof; (b) adjusting the pH of the solution to 6.5 or greater; and (c) heating the solution to a temperature of 90°C or greater.

In one embodiment, step (a) comprises preparing a solution, wherein said solution comprises (i) glucose; (ii) cysteine or cysteine salt; and (iii) at least 0.1 wt% ascorbic acid or at least 0.1 wt% ascorbate salt.

In one embodiment, step (a) comprises preparing a solution, wherein said solution comprises (i) glucose; (ii) cysteine or cysteine salt; and (iii) at least 5 wt% ascorbic acid or at least 5 wt% ascorbate salt.

In one embodiment, step (a) comprises preparing a solution, wherein said solution comprises (i) glucose; (ii) cysteine or cysteine salt; and (iii) between 0.1 to 30 wt% ascorbic acid or between 0.1 to 30 wt% ascorbate salt. In one embodiment, step (a) comprises preparing a solution, wherein said solution comprises (i) glucose; (ii) cysteine or cysteine salt; and (ill) about 9.9 wt% ascorbic acid or about 9.9 wt% ascorbate salt.

In one embodiment, step (a) comprises preparing a solution, wherein said solution comprises (i) glucose; (ii) cysteine or cysteine salt; and (ill) about 24.4 wt% ascorbic acid or about 24.4 wt% ascorbate salt.

In one embodiment, the molar ratio of reducing sugar:sulphur containing amino acid:ascorbic acid or salt thereof in the solution in step (a) is 0.8-1.2:0.8-1.2:0.8-1.2.

In one embodiment, the molar ratio of glucose:cysteine:ascorbic acid in the solution in step (a) is about 1:1:1.

In one embodiment, the pH of the solution is adjusted in step (b) to between 6.5 to 9.0.

In one embodiment, the pH of the solution is adjusted in step (b) to between 7.4 to 8.2, preferably to about pH 7.8.

In one embodiment, the method further comprises step (d) adjusting the pH of the solution to 6.5 or greater during or after step (c).

In one embodiment, the solution in step (a) is pre-heated to about 40°C before the addition of one or more of (i) a reducing sugar; (ii) sulphur containing amino acid or salt thereof; and (ill) ascorbic acid or salt thereof.

In one embodiment, the pH of the solution is adjusted in step (b) with potassium hydroxide or sodium hydroxide.

The invention further relates to a flavour composition made by a method according to the invention.

The invention further relates to a flavour composition, wherein said composition comprises 3- mercapto-2-butanone and 2-methylfuran-3-thiol.

In one embodiment, the ratio of the peak area of 3-mercapto-2-butanone to 2-methylfuran-3-thiol is at least 1:1, preferably at least 10:1.

The invention further relates to a plant-based egg analogue product comprising a flavour composition according to the invention.

The invention further relates to the use of a flavour composition according to the invention in a plantprotein based egg analogue product. Detailed description of the invention

Preparation of flavour composition

The flavour composition may be prepared substantially as described in the examples. Typically, the flavour composition is prepared by mixing a reducing sugar, cysteine or salt thereof, and ascorbic acid or salt thereof. Preferably, the ingredients are wet mixed, preferably in water to form a solution. Preferably, the water is pre-heated, for example to about 40°C. Preferably, about 64mmol of each ingredient is mixed. Preferably, the pH of the mixture is adjusted, for example to between pH 6.5 to 8.0. The mixture is then heated, for example to at least 80°, for example to between 90 to 100°C, or to about 95°C, for example for about 15 to 30 minutes. The pH can be adjusted again to between pH 6.5 to 8.0 during or after heating.

Reducing sugar

Preferably, the reducing sugar is glucose, for example glucose anhydrous. Alternatively, the reducing sugar can be, for example, ribose, xylose, or fructose.

Sulphur-containing amino acid

Preferably, the sulphur-containing amino acid is cysteine or salt thereof. Preferably, the sulphur- containing amino acid is L-cysteine. Alternatively, the sulphur-containing amino acid may be methionine or salt thereof.

Ascorbic acid or salt thereof

The flavour composition can be made by preparing a solution comprising between 0.1 to 35 wt% ascorbic acid or salt thereof. Preferably, the ascorbate salt is sodium ascorbate. Alternatively, the ascorbate salt is potassium ascorbate. For example, the flavour composition can be made by preparing a solution comprising between 0.1 to 20 wt% ascorbic acid or salt thereof, or between 5 to 15 wt%, or between 7.5 to 12.5 wt%, or about 9.9 wt% ascorbic acid or salt thereof. For example, the flavour composition can be made by preparing a solution comprising between 15 to 35 wt% ascorbic acid or salt thereof, or between 20 to 30 wt% ascorbic acid or salt thereof, or between 22.5 to 27.5 wt%, or about 24.4 wt% ascorbic acid or salt thereof.

Flavour composition

Preferably, the flavour composition comprises sulphur containing compounds. Preferably, the flavour composition comprises 2-methylfuran-3-thiol. Preferably, the flavour composition comprises methyl furfuryl thiol. Preferably, the flavour composition comprises 2-furfu rylthiol.

Preferably, at least 15% of the sulphur containing ingredients of the flavour composition are comprised of 2-furfu rylthiol and methyl furfuryl thiol, preferably at least 25%.

Preferably, the flavour composition comprises 3-mercapto-2-butanone. Preferably, the flavour composition comprises one or more ketones. Preferably, the flavour composition comprises one or more lactones.

Preferably, the flavour composition comprises 2,3-pentandione. Preferably, the flavour composition comprises 2-undecanone. Preferably, the flavour composition comprises 2-decanone. Preferably, the flavour composition comprises 2-nonanone. Preferably, the flavour composition comprises 2- hexanone. Preferably, the flavour composition comprises y-butyrolactone.

Preferably, the flavour composition comprises 3-methyl-2-butanone. Preferably, the flavour composition comprises hydrogen sulfide.

Preferably, the flavour composition comprises 2-methylfuran-3-thiol, methyl furfuryl thiol, and 2- fu rfu rylthiol . pH adjustment

The pH may be adjusted during the method of making the flavour composition. Preferably, the pH is adjusted using an alkali solution, for example sodium hydroxide or potassium hydroxide. The pH may be adjusted to pH 5.5 or greater. Preferably, the pH is adjusted to pH 6.5 or greater. More preferably, the pH is adjusted to pH 6.6 or greater, or pH 6.7 or greater, or pH 6.8 or greater, or pH 6.9 or greater, or pH 7.0 or greater, or pH 7.1 or greater, or pH 7.2 or greater, or more preferably pH 7.3 or greater. The pH may be adjusted to pH 9.0 or less. Preferably, the pH is adjusted to pH 8.5 or less. More preferably, the pH is adjusted to pH 8.4 or less, or pH 8.3 or less, or pH 8.2 or less, or pH 8.1 or less, or pH 8.0 or less, or more preferably pH 7.9 or less. Preferably, the pH is adjusted to between pH 7.0 to 8.2, or adjusted to between pH 7.1 to 8.1, or adjusted to between pH 7.2 to 8.0, or adjusted to between pH 7.3 to 7.9, or more preferably adjusted to between pH 7.4 to 7.8. The pH may be adjusted before the heating step. The pH may be adjusted during the heating step. The pH may be adjusted after the heating step.

Egg analogue product

The egg analogue product may be vegan or vegetarian. Preferably, the egg analogue product comprises soy protein, for example soy protein isolate or soy protein concentrate. The egg analogue product may comprise soy protein and canola protein, or soy protein and pea protein.

Definitions

When a composition or product is described herein in terms of wt%, this means a mixture of the ingredients on a wet basis, unless indicated otherwise.

As used herein, the term "about" is understood to refer to numbers in a range of numerals, for example the range of -30% to +30% of the referenced number, or -20% to +20% of the referenced number, or -10% to +10% of the referenced number, or -5% to +5% of the referenced number, or -1% to +1% of the referenced number. All numerical ranges herein should be understood to include all integers, whole or fractions, within the range.

As used herein, the term "analogue" is considered to be an edible substitute of a substance in regard to one or more of its major characteristics. An "egg analogue" as used herein is a substitute of egg in the major characteristics of purpose and usage. Preferably, the egg analogue product is an analogue of chicken egg.

As used herein, the term "vegan" refers to an edible composition which is entirely devoid of animal products, or animal derived products, for example eggs, milk, honey, fish, and meat.

As used herein, the term "vegetarian" relates to an edible composition which is entirely devoid of meat, poultry, game, fish, shellfish or by-products of animal slaughter.

As used herein, a "protein isolate" comprises at least 70 wt% protein, more preferably at least 80 wt% protein, or about 87 wt.% protein, or about 91.5 wt% protein.

Soy protein isolate may comprise about 87 wt% protein, about 3.5 wt% fat, about 3.5 wt% fiber.

Those skilled in the art will understand that they can freely combine all features of the present invention disclosed herein. In particular, features described for the compositions of the present invention may be combined with the method or uses of the present invention and vice versa. Further, features described for different embodiments of the present invention may be combined. Where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred to in this specification.

Further advantages and features of the present invention are apparent from the figures and nonlimiting examples.

Examples

Example 1

Preparation of flavour composition

In a 150mL 2 necks flat-bottomed flask equipped with a reflux condenser and magnetic stirring, a mixture of L-Cysteine (7.74g, 64 mmol), Glucose anhydrous (11.52g, 64mmol) and sodium ascorbate (12.67g, 64mmol) were dissolved in 20 mL of water pre-heated at 40°C. The pH of the mixture was then adjusted to 7.8 by the slow addition of ION KOH solution. The mixture was heated to between 90 and 100°C in an oil bath, with stirring. After 15 to 30 minutes, the pH was adjusted again to 7.8 by the slow addition of 10N KOH solution and left stirring for an additional 15 to 90 minutes to between 90 and 100°C. After cooling at room temperature, the mixture was transferred to an appropriate container and stored at -20°C. Following the same procedure, reactions at pH 6, pH 7, and pH 8 were performed. For the reaction at pH 5, HCI 36% was used to adjust the pH. The procedure was repeated as above but with 9.9 wt% of sodium ascorbate, and then without sodium ascorbate.

Example 2

Odour sensory evaluation of flavour composition

Sensory evaluation of the flavour composition was performed with a panel (n=16-17) that received no specific training on the use of the intensity scales and were naive to the egg product category. They were asked to perform Rate All That Apply (RATA) sensory methodology (Ares et al., Food Quality and Preference, 2014, 36, 87-95). A 4-pt scale was used with "1-slight", "2-medium" and "3-high" labelling. In this method, no tick corresponds to a non-perceived attribute.

Panelists used the glossary shown in Table 1. This glossary has been selected based on a glossary generation session performed with a trained panel to characterize the sensory profile of chicken egg based on eggs from different suppliers. Data were collected using EyeQuestion® software (Logic 8, Elst, the Netherlands) in individual sensory booths.

Samples were identified using a 3-digit random code. Sensory evaluation was performed on the odour dimension only. To avoid saturation effect, one minute pause was set between the samples during which panelists were requested to smell their skin (wrist area) as an odour neutralizer.

Example 3

Sample preparation and aroma compounds analyses by SPME/GC-MS Triple Quad/FPD Volatile compounds were analyzed by headspace solid phase micro-extraction (SPME) headspace coupled with gas chromatography (Model 7890B, Agilent Technologies, Basel, Switzerland) and mass spectrometry Triple Quad (Model 7010, Agilent Technologies, Basel, Switzerland).

A mixture of 1 g of sample (Maillard reaction flavour) and lg of water was placed into a 10 mL headspace-vial closed with a magnetic cap (VWR) and septum (silicone lined PTFE septum, 20 mm, VWR). Samples were kept at 6°C during the analysis.

Pal RCT 120 autosampler was used to sample the headspace using SPME technique. The fiber used was a PDMS/DVB 65um, 1 cm length (Agilent). The vials were incubated at 40°C for lOmin and extraction was performed at 40 °C for 10 min. SPME fiber was then desorbed into the GC-MS inlet at 250 °C during 5 min. The GC was equipped with a DB-WAX capillary column (30 m long, 0.25 mm internal diameter and 0.25 um film thickness, J & W). Helium was used as carrier gas at constant flow rate of 1 ml/min. The oven temperature was held 5 min at 35 °C then increased at 4 °C/min until 230 °C for 10 min. The inlet injector, heated at 250 °C, was on splitless mode during 3 min then the split was open at 50 ml/min.

After the GC, a split was set up between FPD and MS at an expected ratio 1:1. The FPD detector was set at a temperature of 230 °C and emission block at 150 °C. Hydrogen flow, air flow and makeup flow (N2) at 60 ml/min, 70 ml/min and 60 ml/min respectively.

The MS operated in electron impact mode at a scanning range from m/z 29 to m/z 300 at 2.68 scans/s. Temperature of the ion source, quadrupole and transfer line were set at 230 °C, 150 °C and 250°C respectively.

MS Data processing was performed using MS-Dial software for chromatogram alignment, automatic extraction of the features (m/z measured and retention time) and peak integration. Compounds were tentatively identified by comparison of mass spectrum with mass spectral libraries (WileyllNist20, and internally developed libraries) and Kovats Indices.

As FPD data could not provide identification of the compound in contrast to the MS approach, the retention time was used as the key parameter for distinguishing different sulphur compounds and identification via MS data.

Example 4

Sample preparation and hydrogen sulfide analyses by headspace GC-MS Hydrogen sulfide was measured by headspace and was sampled using an HTC PAL system autosampler fitted with a gas-tight syringe 2.5 ml. 1 g of sample (Maillard reaction flavour) poured into a 10 mL headspace-vial closed with a magnetic cap (VWR) and septum (silicone lined PTFE septum, 20 mm, VWR).

The vial was transferred into the incubator for 10 minutes at 40 °C, shaker time 0.3 on / 0.5 off (sec) to allow the headspace to reach equilibrium. The gas-tight syringe temperature was 35°c and the fill gas volume 0.5 mL. Injection speed 100 pL/sec and then pullup gas injection (0.5 ml / 10 sec) in the GC injector at 240°C in splitless mode (50.0 ml/min at 3.0 min).

A GC capillary column DB-WAX (60 m, ID 0.25 mm, 0.25pm film thickness, J & W) was used for the chromatographic separation. The column was installed on an Agilent GC 6890A, equipped with an Agilent 5973 mass spectrometer detector. The oven temperature was held at 35°C for 5 minutes, raised to 240 °C at 4 °C/min and then held at 240 °C for 10 minutes. Helium was the carrier gas and ran at a constant flow rate of 1.2 mL/min.

MS acquisitions were achieved in El ionization mode at 70 eV from m/z 29 to 300 amu with 7.54 scans per second.

Example 5

Odour sensory and volatile compound evaluation

The assessed samples were split into two groups: below and above pH 7. The results show that products above pH 7 were more frequently selected by panelists as "odour closest to egg" among all samples (Figure 1).

Figure 2 shows the distribution of the intensity score of egg odour on samples with pH 5, pH 6, pH 7 and pH 8. The results show that at pH 8, more than 58% perceived the egg odour, and the intensity was significantly increased compared to all other samples. It is slightly lower for pH 7, with more than 52%. Below pH 7, less than 36% of the panel perceived an egg odour. Chicken odour was perceived in all samples but was significantly decreased in the sample at pH 8, as well as the roasted note. It is the opposite trend for the sulfuric odour perception, with pH 8 being the most intense. The pH 5 sample was an outlier with low egg odour, but also low chicken and more intense sulphur odour, as if the aromatic profile was unbalanced below pH 6.

Figure 3, Figure 4 and Figure 5 show the level of the major sulfur-containing compounds which have been identified in the reaction flavours performed at pH 5, 6, 7, and 8. The odour of the three compounds shown in Figure 4 (2-methylfuran-3-thiol; methyl furfuryl thiol; 2-f u rfu rylth iol ) is generally described as sulfurous, onion, meaty, roasted and associated with meaty flavour. The volatile compound 3-Methyl-2-butanone shown in Figure 4 has a very particular flavour description, with powerful eggy, alliaceous, boiled meat tonalities and also with creamy and dairy character depending on the concentration. Hydrogen sulfide is an important volatile compound identified in heated egg whites. The important increase of the eggy-related compounds 3-methyl-2-butanone and hydrogen sulfide from pH 5 to pH 8 explains the increase of eggy flavour perception in the reaction flavours performed at pH greater than 7. On the other hand, the important decrease of the meaty, roasted- associated volatile compounds (in particular 2-methylfuran-3-thiol) from pH 5 to pH 8 confirms the decrease of the chicken note at pH 8 as assessed by sensory evaluation. Ketones and lactones are important volatile compounds associated with creamy, buttery, dairy notes. Figure 5 shows that the level of ketones identified (for example 2,3-pentandione, 2-undecanone, 2-decanone, 2-nonanone, 2- hexanone, y-butyrolactone), is higher in reaction flavours performed at pH greater than 7. It was found that these volatile compounds contribute to delivering a more complex and balanced eggy flavour which is characterized not only by sulfuric notes typical of the egg white part, but also by the creamy and dairy notes typical of the egg yolk.

A second set of reaction flavours was produced under the same conditions as above, with 9.9 wt% ascorbate. Both sensory evaluation and volatile compounds analysis confirm that the eggy flavour is higher at pH 7 and 8 compared to pH 5 and 6.

In Figure 7 are displayed significant sensory differences between the four pH values. As observed in the first set of products, pH 7 and pH 8 are significantly higher in egg flavour and significantly lower in grilled flavour than pH 5. In addition, pH 8 is also lower in chicken flavour than pH 5.

Figures 8, 9 and 10 show that the levels of the sulfur-containing compounds identified at the four pH values follow exactly the same trend than in the first set of reaction flavours. A reaction flavour was produced without sodium ascorbate to ensure that every single ingredient was required to achieve the desired flavour. The sample without ascorbate was described as less overall intense than the full recipe at pH 7.8.

In addition to the sensory perception, figures 11, 12 and 13 highlight the impact of sodium ascorbate on volatile compounds. When the reaction flavour is performed at pH 7.8 without ascorbate, the level of S-containing compounds (Figure 11) and hydrogen sulfide (Figure 12) is much lower than in the same reaction with ascorbate. In addition, without ascorbate, the compound 3-mercapto-2-butanone is not formed at all (Figure 13).

Claims

1. A method of making a flavour composition, said method comprising the steps of (a) preparing a solution, wherein said solution comprises (i) a reducing sugar, preferably glucose; (ii) a sulphur- containing amino acid, preferably cysteine or salt thereof; and (iii) ascorbic acid or salt thereof; (b) adjusting the pH of the solution to 6.5 or greater; and (c) heating the solution.

2. A method of making a flavour composition according to claim 1, said method comprising the steps of (a) preparing a solution, wherein said solution comprises (i) glucose; (ii) cysteine or salt thereof; and (iii) ascorbic acid or salt thereof; (b) adjusting the pH of the solution to 6.5 or greater; and (c) heating the solution to a temperature of 90°C or greater.

3. The method of making a flavour composition according to any one of claims 1 and 2, wherein step (a) comprises preparing a solution, wherein said solution comprises (i) glucose; (ii) cysteine or cysteine salt; and (iii) at least 0.1 wt% ascorbic acid or at least 0.1 wt% ascorbate salt.

4. The method of making a flavour composition according to any one of claims 1 to 3, wherein the molar ratio of reducing sugar:sulphur containing amino acid:ascorbic acid or salt thereof in the solution in step (a) is 0.8-1.2:0.8-1.2:0.8-1.2.

5. The method of making a flavour composition according to any one of claims 1 to 4, wherein the molar ratio of glucose:cysteine:ascorbic acid in the solution in step (a) is about 1:1:1.

6. The method according to any one of claims 1 to 5, wherein the pH of the solution is adjusted in step (b) to between 6.5 to 9.0.

7. The method according to any one of claims 1 to 6, wherein the pH of the solution is adjusted in step (b) to between 7.4 to 8.2, preferably to about pH 7.8.

8. The method according to any one of claims 1 to 7, further comprising step (d) adjusting the pH of the solution to 6.5 or greater during or after step (c).

9. The method according to any one of claims 1 to 8, wherein the solution in step (a) is pre-heated to about 40°C before the addition of one or more of (i) a reducing sugar; (ii) sulphur containing amino acid or salt thereof; and (iii) ascorbic acid or salt thereof.

10. The method according to any one of claims 1 to 9, wherein the pH of the solution is adjusted in step (b) with potassium hydroxide or sodium hydroxide.

11. A flavour composition made by a method according to any one of claims 1 to 10.

12. A flavour composition according to claim 11, wherein said composition comprises 3-mercapto-2- butanone and 2-methylfuran-3-thiol.

13. A flavour composition according to claim 12, wherein the ratio of the peak area of 3-mercapto-2- butanone to 2-methylfuran-3-thiol is at least 1:1, preferably at least 10:1.

14. Plant-based egg analogue product comprising a flavour composition according to any one of claims 11 to 13.

15. Use of a flavour composition according to any one of claims 11 to 14 in a plant-protein based egg analogue product.