Method for regulating enrichment of 2-acetyl-1-pyrroline in germinated brown rice and application

Abstract

The invention discloses a method for regulating and controlling enrichment of 2-acetyl-1-pyrroline in germinated brown rice and application of the method. And performing soaking treatment on the brown rice by using an L-proline solution. According to the invention, an L-proline treatment technology and a germination process are combined for the first time, the industrial pain point that the germinated brown rice has nutrition and low aroma is successfully solved, and a high-end product with excellent nutrition and flavor is created.

Description

Technical Field

[0001] This invention belongs to the field of functional agricultural product processing technology, specifically relating to a method and its application for significantly increasing the content of 2-acetyl-1-pyrrolline (2-AP), a characteristic aroma substance in germinated brown rice, by precisely controlling the concentration of L-proline treatment and germination time. Background Technology

[0002] The market for sprouted brown rice, which combines high nutritional value with functional benefits, is experiencing rapid growth. The sprouting process activates the enzyme system within brown rice, making it rich in gamma-aminobutyric acid (GABA), dietary fiber, inositol, and other health-promoting active substances, earning it the reputation of "living rice." However, compared to refined white rice, sprouted brown rice has significant shortcomings in terms of cooking quality, especially aroma. Its inherent "bran taste" and insufficient aroma have become key bottlenecks restricting consumer acceptance and the enhancement of industry value.

[0003] Aroma is the soul of rice quality and a core basis for pricing. 2-Acetyl-1-pyrrolline (2-AP) is internationally recognized as the decisive compound in the characteristic aroma of fragrant rice (such as Thai jasmine rice and Indian Basmati rice). Studies have shown that when the 2-AP content in rice reaches 0.1 mg / kg (100 μg / kg) or higher, it can be clearly perceived by the human sense of smell. Therefore, increasing the 2-AP content is a direction for creating high-end germinated brown rice products and breaking through the homogeneous competition in the market, enabling it to achieve a perfect unity of "nutrition" and "flavor," thereby gaining extremely high market premium.

[0004] Currently, there are several challenges and limitations in improving the aroma of rice:

[0005] 1. Dependence on fragrant rice varieties: Traditionally, 2-AP is obtained by directly planting fragrant rice varieties. However, many famous fragrant rice varieties have problems such as low yield, poor resistance, and limited planting area. Moreover, their aroma components are easily lost during processing and storage.

[0006] 2. Limited effects of agronomic and processing control: The effects of cultivation measures (such as silicon fertilizer and water management) or post-processing (such as milling and heat treatment) on aroma enhancement are unstable and limited, making it difficult to achieve targeted and significant enrichment.

[0007] 3. Immature application of biotechnology: Although some aroma-related genes (such as BADH2) have been cloned, the process of cultivating new fragrant rice varieties through transgenic or gene editing technology is lengthy and subject to strict regulation. It is also difficult to rapidly improve existing high-quality fragrant rice varieties (such as "Meixiangzhan 2" used in this experiment).

[0008] 4. Lack of research on the regulation of germination process: How to accurately regulate the biosynthetic pathway of 2-AP through safe and low-cost exogenous intervention to improve the aroma of germinated brown rice remains an unsolved technical problem in this field.

[0009] Therefore, the market urgently needs an innovative method to stably and significantly increase the 2-AP content in germinated brown rice through green and safe processing technology without altering the genetic background of the variety. This method can not only directly produce germinated brown rice products with high aroma quality to meet the demands of high-end consumers, but also serve as a powerful tool for rapidly screening and cultivating new rice germplasm with both excellent agronomic traits and high aroma potential, possessing enormous commercial value and social benefits.

[0010] In view of this, the present invention is hereby proposed. Summary of the Invention

[0011] The purpose of this invention is to provide a method that can significantly, stably and controllably increase the 2-AP content in germinated brown rice, overcoming the shortcomings of the prior art.

[0012] The first objective of this invention is to provide a method for increasing the content of 2-acetyl-1-pyrrolidone (2-AP) in germinated brown rice by soaking the brown rice in an L-proline solution.

[0013] Preferably, the working concentration of the L-proline solution is 20-60 mmol / L.

[0014] Preferably, the working concentration of the L-proline solution is 40 mmol / L.

[0015] Preferably, the working concentration of the L-proline solution is 20 mmol / L.

[0016] Preferably, the soaking treatment time is 48 hours.

[0017] Preferably, the germinated brown rice germinates for 5 to 6 days.

[0018] Preferably, the brown rice is the Meixiangzhan No. 2 variety.

[0019] A second objective of this invention is to provide the application of L-proline in the preparation of germinated brown rice products with high 2-AP content.

[0020] A third objective of this invention is to provide the application of L-proline in the 2-AP content of germinated brown rice.

[0021] The fourth objective of this invention is to provide a germinated brown rice product with high aroma quality prepared by the above method.

[0022] The fifth objective of this invention is to provide a method for screening high-aroma rice germplasm, comprising treating brown rice of different rice varieties with the above-described method of increasing the content of 2-acetyl-1-pyrroline (2-AP) in germinated brown rice, and screening varieties with high aroma quality by comparing their 2-AP content.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. Innovatively enhances the sensory quality of germinated brown rice: For the first time, L-proline treatment technology is combined with the germination process, successfully solving the industry pain point of germinated brown rice being "nutritious but lacking aroma", creating a high-end product with both excellent nutrition and flavor.

[0025] 2. Precise and controllable technology with clear concentration effects: For the first time, it was clearly demonstrated that the L-proline treatment concentration range of 20-60 mmol / L significantly promotes the enrichment of 2-AP, with 40 mmol / L being the optimal concentration. In the late germination stage (day 6), the 2-AP content reached 620.88 μg / kg, significantly higher than the control. This achieved precise control over the 2-AP synthesis process, with stable and reliable results.

[0026] 3. Clear time-series control: It revealed the dynamic relationship between 2-AP enrichment and germination time, and found that the treatment effect was most significant in the middle and late stages of germination (days 5-6), thus determining the optimal harvest window for production practice.

[0027] 4. Immense commercial value: This invention can not only be used to produce high-aroma germinated brown rice, directly enhancing product added value and market competitiveness, but also serve as a standard technology for the efficient screening and identification of rice germplasm resources with high 2-AP synthesis potential.

[0028] 5. High applicability and safety: This method is applicable to existing germinated brown rice production lines, is simple to operate, and has low cost. L-proline is a naturally occurring amino acid, is safe and harmless, and does not introduce chemical residues.

[0029] 6. Stable and reliable results: Based on rigorous biological replication and statistical analysis, the method is proven to be stable across different replicates, with small standard errors and reliable conclusions. Attached Figure Description

[0030] Figure 1 Effects of different concentrations of L-proline at different germination stages on the 2-AP content of Meixiangzhan brown rice. CK: control group (0 mmol / L); C1: 20 mmol / L; C2: 40 mmol / L; C3: 60 mmol / L. The standard error sample size was 3 replicates. Different letters indicate significant differences at the P < 0.05 (LSD) level.

[0031] Figure 2 Effects of different concentrations of L-proline on the morphology of germinated brown rice on days 1-3 after germination. 4th: Day 1 after germination; 5th: Day 2 after germination; 6th: Day 3 after germination; CK: Control group (0 mmol / L); C1: 20 mmol / L; C2: 40 mmol / L; C3: 60 mmol / L. Detailed Implementation

[0032] The following embodiments are further illustrations of the present invention, but not limitations thereof. Specific experimental conditions and methods are not specified in the following embodiments, and the technical means employed are conventional methods well known to those skilled in the art.

[0033] Example 1: Effect of L-proline concentration gradient treatment on 2-AP enrichment in germinated brown rice

[0034] I. Experimental Methods

[0035] 1. Materials and disinfection: Take Meixiangzhan No. 2 brown rice, soak it in 0.1% (w / v) sodium hypochlorite solution for 30 minutes for surface disinfection, and then wash it with sterile water.

[0036] 2. Solution preparation: Weigh out L-proline and dilute to 500 mL with sterile water to prepare L-proline working solutions of 0 (CK), 20 (C1), 40 (C2), and 60 (C3) mmol / L.

[0037] 3. Soaking and Germination: The sterilized brown rice was placed in L-proline working solutions of different concentrations and soaked for 48 hours in a dark environment at 30ºC. Then it was transferred to a sterilized germination incubator and germinated at 30°C, with alternating light and dark conditions of 12h and 12h, and 95% humidity.

[0038] 4. Sampling and Measurement: Samples were taken at six time points: 30 min after disinfection (1st), 1 day after soaking (2nd), 2 days after soaking (3rd), and 1-3 days after germination (4th-6th). The 2-AP content in the samples was determined by gas chromatography-mass spectrometry (GC-MS), and the moisture content of the samples was determined for data calibration.

[0039] II. Experimental Results:

[0040] As shown in Table 1 below, Figure 1 and Figure 2 As shown, L-proline treatment significantly affected the accumulation dynamics and final content of 2-AP in germinated brown rice. Figure 2As shown, brown rice treated with L-proline germinated earlier and faster than untreated rice, especially C1 and C2 treatments. Among them, C2 treatment (40 mmol / L) had the longest germination length and the best condition on the third day (6th) of germination.

[0041] Table 1: Average 2-AP content (μg / kg) of germinated brown rice at different stages under different treatments

[0042] Note: The standard error sample size is 3 replicates. At the same time, between different treatments, P ≥ 0.05 (LSD) indicates no significant difference between those labeled with the same lowercase letter, while P < 0.05 (LSD) indicates a significant difference between those labeled with different lowercase letters.

[0043] 1. Concentration effect: The C2 (40 mmol / L) treatment group showed the highest 2-AP content in the later stage of germination (days 5 and 6), which were 513.24 μg / kg and 620.88 μg / kg, respectively, significantly higher than the CK group.

[0044] 2. Time effect: The 2-AP content of all treatment groups showed an increasing trend with the extension of germination time, but the increase was greater in the L-proline treatment group (especially C1 and C2), and it remained at a high level in the later stage.

[0045] 3. Optimal combination: Overall, soaking the germinated brown rice in 40 mmol / L L-proline and culturing it until day 6 of germination yields the germinated brown rice product with the highest 2-AP content.

[0046] In summary, by controlling the treatment concentration of L-proline (20-60 mmol / L, preferably 40 mmol / L) and the germination time (preferably 5-6 days), this invention achieves precise and efficient enhancement of the content of 2-AP, a characteristic aroma compound in germinated brown rice. It provides an application of L-proline in the preparation of high-aroma germinated brown rice products and offers a new, reliable, and effective technical solution for the development of high-quality fragrant rice products.

Claims

1. A method for increasing the content of 2-acetyl-1-pyrrolline (2-AP) in germinated brown rice, characterized in that, Brown rice was soaked in an L-proline solution.

2. The method according to claim 1, characterized in that, The working concentration of the L-proline solution is 20-60 mmol / L, preferably 40 mmol / L or 20 mmol / L.

3. The method according to claim 1 or 2, characterized in that, The soaking treatment time is 48 hours.

4. The method according to claim 1 or 2, characterized in that, The germinated brown rice has a germination time of 5 to 6 days.

5. The method according to claim 1 or 2, characterized in that, The brown rice mentioned is the Meixiangzhan No. 2 variety.

6. Application of L-proline in the preparation of germinated brown rice products with high 2-AP content.

7. Application of L-proline in increasing the 2-AP content in germinated brown rice.

8. A germinated brown rice product with high aroma quality prepared by any of the methods described in claims 1-5.

9. A method for screening high-aroma rice germplasm, characterized in that, This includes methods for treating brown rice of different rice varieties with the method described in any of claims 1-5 to increase the 2-AP content in germinated brown rice, and screening for varieties with high aroma quality by comparing their 2-AP content.

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