1. A plant-based grilled beef flavoring, characterized in that the grilled beef flavoring is formed by mixing a flavor composition, a secondary Maillard reaction product, and auxiliary materials in a mass ratio of (10~20):(450~1000):(20~100);

The secondary Maillard reaction product is obtained by mixing and reacting a main material, a primary Maillard reaction product I, a primary Maillard reaction product II, and a soybean protein isolate enzymatic hydrolysate in a mass ratio of (140~420):(15~20):(20~50):(300~500); wherein,
the reaction base material of the primary Maillard reaction product I comprises cysteine, serine, and reducing sugar; and the molar concentration of cysteine is 6~10 mol/L, the molar concentration of serine is 10~15 mol/L, and the molar ratio of cysteine to the reducing sugar is 1:(1~2);
the reaction base material of the primary Maillard reaction product II comprises lysine and reducing sugar; and the molar concentration of lysine is 3~6 mol/L, and the molar ratio of lysine to the reducing sugar is 1:(1~5);
and, the flavor composition comprises the following raw materials in parts by weight: dimethyl disulfide 0.06~0.50 parts, hexanal 8.70~18.21 parts, heptanal 2.31~10.26 parts, 2-pentylfuran 0.21~4.53 parts, octanal 4.18~10.71 parts, 1-octen-3-ol 0.62~4.85 parts, 2-ethyl-3,5-dimethylpyrazine 0.11~1.86 parts, 2-heptenal 0.83~8.52 parts, 2-methyl-3-furanthiol 4.89~30.0 parts, 2-octenal 2.39~10.77 parts, 3-(methylthio)propanal 1.16~11.93 parts, 2,4-hexadienal 0.93~12.25 parts, decanal 1.04~8.75 parts, 2-nonenal 0.08~2.87 parts, benzaldehyde 0.12~4.01 parts, 2,4-nonadienal 0.80~5.79 parts, octanol 0.71~6.39 parts, 2-decenal 0.10~1.89 parts, 2,4-octadienal 0.06~4.02 parts, 2,4-decadienal 3.03~40.21 parts, phenylacetaldehyde 0.11~15.62 parts, 2-undecenal 0.12~5.91 parts, 12-methyltridecanal 0.02~3.57 parts, 4-hydroxy-2,5-dimethyl-3(2H)-furanone 0.04~6.39 parts, p-cresol 0.44~9.02 parts and a solvent 827~932 parts; wherein the solvent is vegetable oil, and the vegetable oil is palm oil, sunflower oil, rapeseed oil or corn oil;
and, the preparation method of the plant-based grilled beef flavoring specifically comprises the following steps:
(1) preparing the flavor composition: diluting the flavor substances with the solvent to a solution with a mass concentration of 1%, and formulating into a composition according to the parts by weight to obtain product A;
(2) primary Maillard reaction (I): adding cysteine, serine and reducing sugar into a phosphate buffer solution to react, and vacuum concentrating to obtain product B;
(3) primary Maillard reaction (II): adding lysine and reducing sugar into a phosphate buffer solution to react, and vacuum concentrating to obtain product C;
(4) directed biological enzymatic hydrolysis: sequentially adding trypsin, papain and flavourzyme to soybean protein isolate for biological enzymatic hydrolysis reaction, then inactivating the enzymes to obtain product D;
(5) secondary Maillard reaction: reacting the product B, the product C, the product D with the main material, then cooling, subsequently adding the product A and mixing uniformly to obtain product E;
(6) mixing and homogenizing: adding auxiliary materials to the product E, and high-speed homogenizing to obtain the plant-based grilled beef flavoring.

2. The plant-based grilled beef flavoring according to claim 1, characterized in that the auxiliary materials comprise the following components in parts by weight: starch 20~80 parts, xanthan gum 0.2~2 parts and carboxymethyl cellulose 0.5~2 parts.

3. The plant-based grilled beef flavoring according to claim 1, characterized in that the main material comprises the following components in parts by weight: vegetable oil 10~20 parts, yeast extract 20~50 parts, cysteine 2~8 parts, glycine 5~10 parts, glutamic acid 5~12 parts, leucine 8~10 parts, phenylalanine 3~7 parts, proline 3~5 parts, alanine 4~8 parts, methionine 3~10 parts, thiamine 2~4 parts, glucose 10~30 parts, xylose 8~24 parts, water 50~200 parts and salt 15~20 parts.

4. The plant-based grilled beef flavoring according to any one of claims 1~3, characterized in that the reducing sugar is xylose, ribose, glucose, galactose or L-arabinose. (Continued from page 2, completed on page 3)

4 (completed). The plant-based grilled beef flavoring according to claim 1, characterized in that the reducing sugar is xylose, ribose, glucose, galactose or L-arabinose.

5. The plant-based grilled beef flavoring according to claim 1, characterized in that in step (2), the pH value of the phosphate buffer solution is 5~6, the reaction temperature is 45°C~60°C, and the reaction time is 0.5~3 h; in step (3), the pH value of the phosphate buffer solution is 6~7, the reaction temperature is 80°C~100°C, and the reaction time is 5 min~2 h.

6. The plant-based grilled beef flavoring according to claim 1, characterized in that in step (4), the process steps for the directed biological enzymatic hydrolysis of soybean protein isolate are: adding water to the soybean protein isolate at a solid-to-liquid ratio of 1:(5~10) (g:mL), and under conditions of a temperature of 55°C and pH of 6.0~7.0, first adding trypsin at an enzyme-to-substrate ratio of 0.5~1% for enzymatic hydrolysis for 1~1.5 h, then adding papain at an enzyme-to-substrate ratio of 0.2~0.5% for enzymatic hydrolysis for 0.5~1 h, and then adding flavourzyme at an enzyme-to-substrate ratio of 0.5~1% for enzymatic hydrolysis for 0.5~1.5 h, finally heating to 85°C to inactivate the enzymes for 10 min, obtaining product D.

7. The plant-based grilled beef flavoring according to claim 1, characterized in that in step (5), the reaction pH value is 6~7, the reaction temperature is 100°C~140°C, and the reaction time is 0.5~2 h; and the mixing temperature is 60°C~90°C, and the mixing time is 5~15 min.

8. Use of the plant-based grilled beef flavoring according to claim 1 in food processing.