Two-component flavor enhancer for enhancing flavor of rice as well as preparation method and application of two-component flavor enhancer

Abstract

The invention belongs to the technical field of crop cultivation, and particularly discloses a two-component flavor enhancer for rice flavor enhancement as well as a preparation method and application of the two-component flavor enhancer for rice flavor enhancement, and the two-component flavor enhancer is prepared from a component A and a component B in a weight ratio of 1: (0.9-1.1), wherein the component A is prepared from the following raw materials in parts by weight: 80 to 120 parts of proline and 180 to 220 parts of ornithine; the component B is prepared from 2 to 5 parts of colloidal chitosan nano-selenium and 350 to 450 parts of zinc oxide quantum dots. The flavor enhancer developed in the invention is helpful for efficiently increasing the content of free proline and proline dehydrogenase, increasing the accumulation of 2-AP in rice grains, and effectively improving the rice fragrance.

Description

Technical Field

[0001] This invention belongs to the field of crop cultivation technology, specifically a two-component aroma enhancer for rice, its preparation method, and its application. Background Technology

[0002] Aroma is one of the important quality traits of rice. High-quality fragrant rice, characterized by its good palatability, strong stickiness, and fragrant aroma during cooking, is highly favored by the market and consumers. Research shows that the main component of aroma is 2-acetyl-1-pyrroline (2-AP), and the synthesis of 2-AP is not only controlled by genes but also easily regulated by environmental factors and cultivation practices. Therefore, improving the cultivation techniques of fragrant rice can synergistically enhance its aroma, quality, and yield.

[0003] Currently, common methods for enhancing rice aroma include the breeding of fragrant rice varieties, microbial regulation, physical induction, and the addition of aroma enhancers at key stages. However, the breeding of fragrant rice varieties is characterized by long breeding cycles, and the enhancement of aroma substances cannot simultaneously guarantee rice yield and quality. Microbial regulation results in instability, while physical induction is difficult to implement in the field due to high equipment costs. Currently, most methods for adding aroma enhancers use inorganic or organic chemical reagents individually, without considering their combined application to improve utilization or plant absorption efficiency. For example, Chinese patent CN119257125A discloses an organic aroma enhancer for regenerated rice, whose raw materials include 6-8 parts EDTA-Zn, 3-5 parts monosodium glutamate residue, 1-3 parts hair extract, 85 parts potassium nitrate, 0.5-1.5 parts ammonium dihydrogen phosphate, and 0.5-1.5 parts amino acid ester. Although it contains various organic substances, its composition is complex and not conducive to plant absorption.

[0004] Therefore, there is an urgent need for a flavor enhancer that can synergistically promote the accumulation of 2-AP in rice by combining organic and inorganic substances, while also being easily absorbed by rice. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a two-component flavor enhancer for rice and its preparation method, which combines organic and inorganic materials to prepare the flavor enhancer, promotes rice absorption, and increases the 2-AP content of rice grains at maturity.

[0006] The objective of this invention is achieved through the following technical solution: A two-component flavor enhancer for rice, consisting of component A and component B in a weight ratio of 1:0.9~1.1; Component A is made from the following raw materials in parts by weight: 80-120 parts proline and 180-220 parts ornithine. Component B consists of 2-5 parts of colloidal chitosan nano-selenium and 350-450 parts of zinc oxide quantum dots.

[0007] Specifically, the preparation method of the colloidal chitosan nano-selenium in component B includes the following steps: S11: Add chitosan powder to a weak acid aqueous solution and stir until the chitosan is completely dissolved to obtain a chitosan stock solution; S12: Dilute NaSeO3 and the chitosan stock solution with water to obtain a mixed solution; S13: Stir and shake the mixture while adding a reducing agent dropwise. The mixture turns bright red to obtain selenium nanoparticles. S14: The selenium nanoparticles are purified by dialysis to obtain colloidal chitosan nano-selenium.

[0008] Specifically, in step S1, the weak acid aqueous solution includes either acetic acid or citric acid, with a concentration of 0.5%; in step S3, the reducing agent includes either ascorbic acid, glutathione, or sodium borohydride. Specifically, the preparation method of the zinc oxide quantum dots in component B includes the following steps: S21: Dissolve Zn(CH3COO)2 in an organic solvent, heat and stir until completely dissolved to obtain a zinc solution; S22: Slowly add an alkali metal hydroxide solution to the zinc solution and stir to obtain an alkaline zinc solution; S23: Add a silane coupling agent to the alkaline zinc solution for surface modification. After the reaction, separate the precipitate, wash and dry it to obtain amino-functionalized zinc oxide quantum dots.

[0009] Specifically, in step S5, the organic solvent includes one of ethanol, methanol, and isopropanol, and the heating and stirring temperature is 70~85℃. In step S6, the alkali metal hydroxide includes one of potassium hydroxide, sodium hydroxide, and lithium hydroxide; In step S7, the silane coupling agent includes one of APTES, APTMS, and AEAPTMS.

[0010] Specifically, it is applied to enhance the aroma of rice by spraying.

[0011] Preferably, the two-component flavor enhancer is prepared into a working solution of component A by mixing component A with water at a mass ratio of 1:200; and a working solution of component B is prepared by mixing component B with water at a mass ratio of 1:200. Specifically, the concentration of proline in the working solution of component A is 0.4~0.6 g / kg, and the concentration of ornithine is 0.9~1.1 g / kg; Specifically, and / or, the concentration of colloidal chitosan nano-selenium in the working solution of component B is 10~25 mg / kg; the concentration of zinc oxide quantum dots is 1.75~2.25 g / kg.

[0012] Preferably, the working solution of component A is sprayed at the heading stage, and the application rate is 1000 kg / mu. Preferably, the working solution of component B is sprayed during the heading stage, and the application rate is 1000 kg / mu.

[0013] Preferably, the rice aroma enhancement method involves increasing the 2-AP content in mature rice grains.

[0014] Specifically, the applicable varieties of the two-component flavor enhancer include indica rice, japonica rice, hybrid rice or their derivative varieties; Preferably, the two-component flavoring agent for rice developed in this application can be used as a flavoring agent for Rosa rice.

[0015] The beneficial effects of this invention are: 1. The two-component rice aroma enhancer provided in this application helps to promote the accumulation of the aroma substance 2-acetyl-1-pyrrolline (2-AP) in rice and improve the aroma of rice.

[0016] 2. The two-component rice flavor enhancer provided in this application is more easily absorbed by rice and can effectively increase the content of free proline and proline dehydrogenase in rice, thereby promoting the formation of 2-AP and effectively increasing the 2-AP content in rice.

[0017] 3. The two-component rice flavor enhancer provided in this application helps to improve the quality of rice after application. Attached Figure Description

[0018] Figure 1 These are field application experiments of the embodiments and comparative examples 1-5 of this application. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0020] The experimental material used in the following examples and comparative examples is Luosha rice, a local specialty rice germplasm resource of Luzhou City, Sichuan Province, which is a fragrant soft rice variety. The planting area was the Wenjiang Gaoshan Village Rice Experimental Base of Sichuan Agricultural University.

[0021] Example The preparation method of the rice nano-two-component flavor enhancer of this application is as follows: (1) Preparation method of nano-selenium: Colloidal chitosan nano-selenium (SeNPs) were prepared by a process with improvements in individual steps. First, 1.0 g of chitosan powder was added to a 1% (w / w) acetic acid solution and stirred continuously at room temperature until the chitosan was completely dissolved to obtain a 10 mg / mL chitosan stock solution, which was stored at 4℃ for later use. Then, 1 mL of 50 mM Na2SeO3 solution and 0.08 mL of chitosan stock solution were quickly transferred into an EP tube and diluted with double-distilled water to 8 mL. Then, 2 mL of 100 mM ascorbic acid (Vc) solution was slowly added dropwise to the mixture under stirring and shaking. The color of the mixture changed from colorless to bright red, indicating that SeNPs had been formed. Subsequently, the colloid was dialyzed using a dialysis bag with a molecular weight cutoff of 3500 for 24 h, with distilled water replaced every 5 h to obtain SeNPs with a concentration of 5 mM, which were stored at 4℃.

[0022] (2) Preparation method of zinc oxide quantum dots ZnO QDs were synthesized via the sol-gel method. First, 55 g of zinc acetate was added to 1.5 L of anhydrous ethanol solution and stirred at 78 °C for 30 min. After cooling, 300 mL of anhydrous ethanol solution containing 29.3 g of potassium hydroxide was slowly added while stirring, and the mixture was stirred for 5 min. Finally, 43.2 mL of APTES solution diluted with water (5:1 volume ratio) was added dropwise. At this point, a large amount of white flocculent material was produced. After stirring for 10 min, the mixture was centrifuged (3500 r / min for 5 min), the supernatant was discarded, and the mixture was washed twice with anhydrous ethanol and dried at 60 °C for 12 h to obtain ZnO QDs.

[0023] (3) Method for compounding rice nano-two-component flavor enhancers: ① Preparation method of working solution of component A: Prepare the raw materials according to the mass parts: 100 parts of proline and 200 parts of ornithine, add water and mix. The concentration of proline is 0.5 g / kg and the concentration of ornithine is 1 g / kg.

[0024] ② Preparation method of working solution of component B: Prepare the raw materials according to the mass fraction, 3 parts of nano selenium and 400 parts of zinc oxide quantum dots, add water to mix and prepare, wherein the concentration of nano selenium is 15 mg / kg and the concentration of zinc oxide quantum dots is 2 g / kg.

[0025] Seeds were disinfected before sowing, and sparse sowing was used to cultivate strong seedlings. Sowing took place in late April, with seedlings approximately 30 days old. Transplanting was carried out in mid-May. The planting specifications were 16.67×26.67 cm per row, with one seedling per hill and 10 seedlings per row. In terms of fertilization management, both early and late application of fertilizer were emphasized, with balanced fertilization, using a multi-element formula, combining late and early application, stabilizing nitrogen, increasing phosphorus and potassium, and supplementing micronutrients. Nitrogen fertilizer application should follow the principle of "heavy application at the beginning, controlled application in the middle, and supplemental application at the end," with the following fertilizer ratio: 60.0% basal fertilizer, 30.0% tillering fertilizer, 5.0% panicle fertilizer, and 5.0% grain fertilizer. In terms of water management, shallow water was used for transplanting, with a small amount of water for greening, and thin water for tillering. In the middle stage, when seedlings were strong enough, the field was dried, and deep water was used for heading. In the later stage, alternating between dry and wet conditions and drainage were used to promote ripening. Premature dehydration should be avoided to prevent affecting rice quality.

[0026] In this embodiment, the working solution of component A of the flavor enhancer is sprayed at 1 day and 7 days after the rice heading stage, with an application rate of 1000 kg / mu. The working solution of component B is sprayed at 1 day and 7 days after the heading stage, with an application rate of 1000 kg / mu.

[0027] Inorganic flavor enhancers are sprayed during the heading stage, while organic flavor enhancers are sprayed during the full heading stage. A second spray after 7 days is to prevent re-spraying if the product was missed due to rain, wind, or other reasons.

[0028] Comparative Example 1 Comparative Example 4 was a blank control group. The specific rice planting method was the same as in Example 1, but no rice flavor enhancer was added.

[0029] Comparative Example 2 The preparation method of the organic flavor enhancer for rice in Comparative Example 2 is as follows: Preparation method of rice organic flavor enhancer: The raw materials are prepared according to the mass parts, including 1 part proline and 2 parts ornithine, and mixed to a concentration of 0.5 g / kg and 1 g / kg, respectively.

[0030] The rice planting method is the same as in Example 1. The flavor enhancer in this comparative example is applied at 1 day and 7 days after the rice heading stage, and the application rate is 1000 kg / mu.

[0031] Comparative Example 3 The preparation method of the inorganic flavor enhancer for rice in Comparative Example 3 is as follows: (1) Preparation method of nano-selenium: Colloidal chitosan nano-selenium (SeNPs) were prepared by a process with improvements in individual steps. First, 1.0 g of chitosan powder was added to a 1% (w / w) acetic acid solution and stirred continuously at room temperature until the chitosan was completely dissolved, resulting in a 10 mg / mL chitosan stock solution, which was stored at 4°C for later use. Then, 1 mL of a 50 mM Na2SeO3 solution and 0.08 mL of the chitosan stock solution were quickly transferred into an EP tube and diluted with double-distilled water to 8 mL. Then, 2 mL of a 100 mM ascorbic acid (Vc) solution was slowly added dropwise to the mixture under stirring and shaking. The color of the mixture changed from colorless to bright red, indicating that SeNPs had been formed. Subsequently, the colloid was dialyzed using a dialysis bag with a molecular weight cutoff of 3500 (for a total of 24 h, with distilled water replaced every 5 h) to obtain SeNPs with a concentration of 5 mM, which were stored at 4°C.

[0032] (2) Preparation method of zinc oxide quantum dots ZnO QDs were synthesized via the sol-gel method. First, 55 g of zinc acetate was added to 1.5 L of anhydrous ethanol solution and stirred at 78 °C for 30 min. After cooling, 300 mL of anhydrous ethanol solution containing 29.3 g of potassium hydroxide was slowly added while stirring, and the mixture was stirred for 5 min. Finally, 43.2 mL of APTES solution diluted with water (5:1 volume ratio) was added dropwise. At this point, a large amount of white flocculent material was produced. After stirring for 10 min, the mixture was centrifuged (3500 r / min for 5 min), the supernatant was discarded, and the mixture was washed twice with anhydrous ethanol and dried at 60 °C for 12 h to obtain ZnO QDs.

[0033] (3) Preparation method of inorganic flavor enhancer for rice: The raw materials are prepared according to the mass parts, including 3 parts of Na2SeO3 and 2400 parts of Zn(CH3COO)2, and mixed and prepared with concentrations of 15 mg / kg and 2 g / kg, respectively.

[0034] The rice planting method is the same as in Example 1. The flavor enhancer in this comparative example is applied at 1 day and 7 days after the rice heading stage, and the application rate is 1000 kg / mu.

[0035] Comparative Example 4 In Comparative Example 4, the inorganic components in the rice inorganic flavor enhancer were not prepared into the form of nanomaterials.

[0036] Preparation method: Rice flavor enhancer compounding method: The raw materials are prepared according to the mass parts, and 3 parts of Na2SeO3 and 400 parts of Zn(CH3COO)2 are mixed and prepared, with concentrations of 15 mg / kg and 2.0 g / kg, respectively.

[0037] The rice planting method is the same as in Example 1. The flavor enhancer in this comparative example is applied at 1 day and 7 days after the rice heading stage, and the application rate is 1000 kg / mu.

[0038] Comparative Example 5 The preparation method of the rice flavor enhancer in Comparative Example 5 is as follows: Rice flavor enhancer compounding method: ① Preparation method of component A working solution: Prepare the raw materials according to the mass parts, 100 parts of proline and 200 parts of ornithine, add water and mix, wherein the concentration of proline is 0.5 g / kg and the concentration of ornithine is 1 g / kg.

[0039] ② Preparation method of component B working solution: Prepare the raw materials according to the mass fraction: 3 parts Na2SeO3, 400 parts Zn(CH3COO)2, add water and mix. The concentration of nano selenium is 15 mg / kg and the concentration of zinc oxide quantum is 2 g / kg.

[0040] The rice planting method and application are the same as in Example 1.

[0041] The contents of free proline and proline dehydrogenase in rice leaves during the grain-filling stage were measured in Example 1 and Comparative Examples 1-3, respectively. At the same time, the contents of 2-AP in mature rice grains were measured. The contents of 2-AP in mature rice grains were measured in Comparative Examples 4-5. The specific data are shown in Table 1.

[0042] Table 1. Aromatic substance content of Luosha Gong rice Note: Data are expressed as mean ± standard error.

[0043] Analysis of experimental data showed that the highest level of free proline was found in the leaves of the example. Simultaneously, the content of proline dehydrogenase in the leaves of the example was significantly increased, by 66.13% compared to Comparative Example 1, 47.55% compared to Comparative Example 2, and 29.69% compared to Comparative Example 3. This indicates that this application not only promotes the accumulation of free proline in leaves but also increases the content of proline dehydrogenase, converting the accumulated proline into pyrroline-5-carboxylic acid (P5C). P5C is then catalyzed by pyrroline-5-carboxylic acid reductase to form 1-pyrroline. Under the action of pyrroline acetyltransferase, 1-pyrroline and acetyl-CoA synthesize 2-AP, which is currently considered the most likely pathway for 2-AP synthesis. The content of free proline and proline dehydrogenase in rice is positively correlated with the content of 2-AP in rice. Therefore, spraying a foliar fragrance enhancer when Luosha rice reaches the heading stage can enable Luosha rice to accumulate more aroma substances. Compared to the control group in Comparative Example 1, all flavor enhancer treatments significantly increased the content of the aroma compound 2-AP. Comparative Examples 2, 3, and 4 showed that the inorganic mineral treatment was more effective than the organic material treatment. Furthermore, it was found that converting inorganic minerals into nanomaterials increased the accumulation of 2-AP in the grains. The treatment described in this application showed the most significant increase in aroma compound accumulation; spraying a mixture of nanomineral materials and organic matter resulted in an approximately 44% increase in the 2-AP content of mature rice grains compared to the control group.

[0044] In summary, the two-component aroma enhancer for rice developed in this application can effectively accumulate 2-AP in rice and improve its aroma.

[0045] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A two-component flavor enhancer for rice, characterized in that, It consists of component A and component B in a weight ratio of 1:0.9~1.1; Component A is made from the following raw materials in parts by weight: 80-120 parts proline and 180-220 parts ornithine. Component B consists of 2-5 parts of colloidal chitosan nano-selenium and 350-450 parts of zinc oxide quantum dots.

2. The two-component flavor enhancer according to claim 1, characterized in that: The preparation method of the colloidal chitosan nano-selenium in component B includes the following steps: S11: Add chitosan powder to a weak acid solution and stir until the chitosan is completely dissolved to obtain a chitosan stock solution; S12: Dilute NaSeO3 and the chitosan stock solution with water to obtain a mixed solution; S13: Stir and shake the mixture while adding a reducing agent dropwise. The mixture turns bright red to obtain selenium nanoparticles. S14: The selenium nanoparticles are purified by dialysis to obtain colloidal chitosan nano-selenium.

3. The two-component flavor enhancer according to claim 2, characterized in that: In S11, the weak acid solution includes either an aqueous solution of acetic acid or an aqueous solution of citric acid, with a concentration of 0.5% vol. In S13, the reducing agent includes one of ascorbic acid, glutathione, and sodium borohydride.

4. The two-component flavor enhancer according to claim 1, characterized in that: The preparation method of the zinc oxide quantum dots in component B includes the following steps: S21: Dissolve Zn(CH3COO)2 in an organic solvent, heat and stir until completely dissolved to obtain a zinc solution; S22: An alkali metal hydroxide solution is slowly added to the zinc solution and stirred to obtain an alkaline zinc solution; S23: Add a silane coupling agent to the alkaline zinc solution for surface modification. After the reaction, separate the precipitate, wash and dry it to obtain amino-functionalized zinc oxide quantum dots.

5. The two-component flavor enhancer according to claim 4, characterized in that: In S21, the organic solvent includes one of ethanol, methanol, and isopropanol, and the heating and stirring temperature is 70~85°C. In S22, the alkali metal hydroxide includes one of potassium hydroxide, sodium hydroxide, and lithium hydroxide; In S23, the silane coupling agent includes one of APTES, APTMS, and AEAPTMS.

6. The application of a two-component flavor enhancer according to any one of claims 1-5, characterized in that: It is used to enhance the aroma of rice and is applied by spraying.

7. The application according to claim 6, characterized in that, The two-component flavor enhancer is prepared into a working solution of component A by mixing component A with water at a mass ratio of 1:200; and a working solution of component B is prepared into a working solution of component B by mixing component B with water at a mass ratio of 1:

200. The concentration of proline in the working solution of component A is 0.4~0.6 g / kg, and the concentration of ornithine is 0.9~1.1 g / kg; And / or, the concentration of colloidal chitosan nano-selenium in the working solution of component B is 10~25 mg / kg; the concentration of zinc oxide quantum dots is 1.75~2.25 g / kg.

8. The application according to claim 6, characterized in that, The working solution of component A is sprayed at the heading stage, and the application rate is 1000 kg / mu. And / or, the working solution of component B is sprayed during the heading stage, and the application rate is 1000 kg / mu.

9. The application according to claim 6, characterized in that, The two-component flavor enhancer is used to increase the 2-AP content in mature rice grains.

10. The application according to claim 6, characterized in that, The applicable varieties of the two-component flavor enhancer include indica rice, japonica rice, hybrid rice or their derivative varieties.

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