Plasma treatment method for germination promotion and quality improvement of sorghum seeds and application

Abstract

The invention provides a plasma treatment method for promoting germination and improving quality of sorghum seeds and application, and belongs to the technical field of plant physiology. The method comprises the following steps: carrying out dielectric barrier discharge low-temperature plasma treatment on sorghum seeds; the input voltage of the dielectric barrier discharge low-temperature plasma treatment is 20-60 V, and the treatment time is 3-15 min. Through DBD-CP treatment with specific parameters, the germination efficiency of the sorghum seeds can be remarkably improved, accumulation of functional components is promoted, the technical problems that in the prior art, the sorghum germination treatment efficiency is low, and nutrient substance accumulation is insufficient are solved, and a new technical approach is provided for high-value processing and utilization of sorghum.

Description

Technical Field

[0001] This invention belongs to the field of plant physiology technology, and in particular relates to a plasma treatment method and its application for promoting germination and improving the quality of sorghum seeds. Background Technology

[0002] Sorghum, as a globally important food, feed, and energy crop, is characterized by its drought resistance, tolerance to poor soil, and strong adaptability, playing a crucial role in agricultural production in arid and semi-arid regions. However, sorghum seeds have a low natural germination rate and a slow germination process, severely impacting planting efficiency and yield. Furthermore, sorghum grains contain high levels of tannins, which inhibit the digestion and absorption of protein and starch, reducing their nutritional value and palatability. In addition, the content of γ-aminobutyric acid (GABA), a functional component, is low in natural sorghum.

[0003] Currently, traditional methods for improving the germination rate and nutritional quality of sorghum seeds mainly include: physical treatment – ​​such as soaking seeds in warm water and ultrasonic treatment, but these methods suffer from low efficiency and unstable effects, and it is difficult to simultaneously promote germination and regulate nutrition; chemical treatment – ​​such as using reagents like gibberellin and potassium nitrate, which can promote germination to some extent, but may lead to chemical residues, affecting food safety, and are also costly; and biological treatment – ​​such as fermentation or germination regulation, but the fermentation process is easily contaminated by miscellaneous bacteria, has a long germination cycle, and has limited efficiency in tannin degradation and GABA accumulation.

[0004] Low-temperature plasma technology, as a novel non-thermal physical treatment technology, boasts advantages such as short processing time, high efficiency, no pollution, and low-temperature energy saving, showing great application potential in food, biology, and agriculture. The plasma generated by this technology consists of electrons, ions, free radicals, photons, ultraviolet radiation, active substances, and molecules in their ground or excited states, effectively improving seed vigor indicators. Currently, low-temperature plasma technology has some applications in grain treatment, but existing technologies have not yet disclosed specific low-temperature plasma treatment methods for sorghum seeds, particularly lacking specific technical solutions regarding the optimal combination of treatment parameters and how to utilize this technology to enhance the accumulation of functional nutrients during sorghum germination. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a plasma treatment method and application for promoting germination and improving the quality of sorghum seeds, thereby improving the germination efficiency of sorghum seeds and promoting the accumulation of functional components.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A plasma treatment method for promoting germination and improving the quality of sorghum seeds involves treating sorghum seeds with dielectric barrier discharge low-temperature plasma; the input voltage for the dielectric barrier discharge low-temperature plasma treatment is 20-60V, and the treatment time is 3-15min.

[0008] Preferably, the input voltage for the dielectric barrier discharge low-temperature plasma treatment is 25-50V, and the treatment time is 5-10min.

[0009] Preferably, the atmosphere gas for the dielectric barrier discharge low-temperature plasma treatment is argon gas, and the flow rate is 3-8 L / min.

[0010] Preferably, the center frequency of the dielectric barrier discharge low-temperature plasma treatment is 10 kHz, and the input power is 50-100 W.

[0011] Preferably, the output voltage of the dielectric barrier discharge low-temperature plasma treatment is 3-6KV.

[0012] Preferably, the duty cycle of the dielectric barrier discharge low-temperature plasma treatment is 40%, and the discharge distance is 0.4 cm.

[0013] Preferably, the device for generating dielectric barrier discharge low-temperature plasma treatment consists of a high-frequency AC power supply, a voltage regulator, and a DBD plasma reactor; the DBD plasma reactor consists of two metal electrodes with an inner diameter of 55 mm and a thickness of 8 mm and a circular quartz dish with a cover.

[0014] More preferably, sorghum seeds are evenly spread in the circular quartz dish.

[0015] Preferably, the process also includes soaking and germination after the dielectric barrier discharge low-temperature plasma treatment is completed.

[0016] The present invention also provides the application of sorghum seeds treated by the above method in food manufacturing, feed raw material manufacturing, pharmaceutical or seed production.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention uses DBD-CP treatment with specific parameters (input voltage 20-60V, processing time 3-15min) to etch grooves and cracks on the surface of sorghum seed coat, increasing seed coat permeability, promoting water absorption and enzyme activity activation, accelerating the seed germination process, and thus significantly improving the germination rate of sorghum seeds. At the same time, the root length, seedling length, fresh weight and vitality index of seedlings are also significantly improved.

[0019] The DBD-CP treatment of this invention can also reduce the tannin content of sorghum seeds in combination with germination treatment, effectively reducing its inhibitory effect on protein digestion and improving its edible and feed value; it can also enhance the accumulation of functional component γ-aminobutyric acid by regulating the activity of glutamate decarboxylase (GAD) and amino acid metabolism pathways, laying the foundation for the development of health-promoting sorghum products.

[0020] This invention uses physical plasma treatment, which eliminates the need for chemical reagents and avoids pesticide residues and environmental pollution. The treatment time is short, and when combined with subsequent standardized soaking and germination processes, the germination cycle can be shortened to 3 days, significantly improving production efficiency. Attached Figure Description

[0021] Figure 1 This is a diagram of the DBD-CP device.

[0022] Figure 2 Scanning electron microscope images of the sorghum seed coat surface before and after processing;

[0023] Figure 3 Figure 1 shows the effect of DBD-CP on the germination morphology of sorghum seeds.

[0024] Figure 4 The figure shows the effect of DBD-CP on the germination rate of sorghum grains.

[0025] Figure 5 The figure shows the effect of DBD-CP on the root length and seedling length of sorghum seedlings.

[0026] Figure 6 Figure showing the effect of DBD-CP on the fresh weight of sorghum seedlings;

[0027] Figure 7 The graph shows the effect of DBD-CP on the grain vigor index of sorghum.

[0028] Figure 8 The figure shows the effect of DBD-CP on tannin content before and after sorghum germination.

[0029] Figure 9 Scanning electron micrographs of sorghum starch before and after germination treated with DBD-CP;

[0030] Figure 10 X-ray diffraction patterns of sorghum starch before and after DBD-CP treatment and germination;

[0031] Figure 11 Fourier transform infrared spectra of sorghum starch before and after germination treated with DBD-CP;

[0032] Figure 12 This study investigated the biosynthetic pathways of amino acid metabolism, glycolysis, and TCA cycle in sorghum treated with DBD-CP. Detailed Implementation

[0033] This invention provides a plasma treatment method for promoting germination and improving the quality of sorghum seeds, which involves treating sorghum seeds with dielectric barrier discharge low-temperature plasma. The input voltage for the dielectric barrier discharge low-temperature plasma treatment is 20-60V, and the treatment time is 3-15 minutes. Preferably, the input voltage is 25-50V, and the treatment time is 5-10 minutes.

[0034] The preferred atmosphere for the dielectric barrier discharge low-temperature plasma treatment in this invention is argon gas, with a flow rate of 3-8 L / min, more preferably 5 L / min; the center frequency is 10 kHz, the input power is 50-100 W, the output voltage is 3-6 KV, the duty cycle is 40%, and the discharge distance is 0.4 cm.

[0035] The preferred device for generating dielectric barrier discharge low-temperature plasma treatment in this invention consists of a high-frequency AC power supply, a voltage regulator, and a DBD plasma reactor; the DBD plasma reactor consists of two metal electrodes with an inner diameter of 55 mm and a thickness of 8 mm and a circular quartz dish with a lid; more preferably, sorghum seeds are evenly spread in the circular quartz dish.

[0036] After the dielectric barrier discharge low-temperature plasma treatment is completed, the sorghum seeds are soaked and germinated. More preferably, the soaking treatment includes soaking the sorghum seeds in distilled water overnight to remove dirt and the outer shell; then soaking them in a 7.0% H2O2 solution for 15 minutes to slow down mold growth during germination; then washing the soaked sorghum seeds with distilled water and soaking them in water for 20 minutes to remove residual H2O2 solution; and more preferably, the germination treatment includes spreading the sorghum seeds flat between two layers of gauze, allowing the grains to germinate in the dark, and replenishing moisture as needed.

[0037] The present invention also provides the application of sorghum seeds treated by the above method in food manufacturing, feed raw material manufacturing, pharmaceutical or seed production, including but not limited to as functional food raw materials (such as making biscuits, bread, etc.), fermentation industry raw materials (such as brewing), nutritionally fortified foods (such as infant complementary food, elderly nutritional products), feed raw materials (such as protein feed, aquatic feed), functional extract raw materials (such as extracting high-purity GABA), dietary fiber products and excellent seeds.

[0038] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1

[0040] A plasma treatment method for promoting germination and improving the quality of sorghum seeds, comprising the following steps:

[0041] A dielectric barrier discharge low-temperature plasma treatment device is prepared, consisting of a high-frequency AC power supply, a voltage regulator, and a DBD plasma reactor. The DBD plasma reactor consists of two metal electrodes with an inner diameter of 55 mm and a thickness of 8 mm, and a circular quartz dish with a cover.

[0042] Sorghum seeds were evenly spread in the circular quartz dish. Argon was used as the atmosphere gas, with a flow rate of 5 L / min, a center frequency of 10 kHz, an input power of 50 W, an input voltage of 25 V, an output voltage of 3 KV, a duty cycle of 40%, a discharge distance of 0.4 cm, and a discharge time of 5 min for DBD-CP treatment.

[0043] After DBD-CP treatment, the sorghum seeds are disinfected, soaked, and germinated.

[0044] Example 2

[0045] A plasma treatment method for promoting germination and improving the quality of sorghum seeds differs from Example 1 in the following ways:

[0046] The input power is 100W, the input voltage is 50V, the output voltage is 6KV, and the discharge time is 10min.

[0047] Example 3

[0048] A plasma treatment method for promoting germination and improving the quality of sorghum seeds differs from Example 1 in the following ways:

[0049] The input power is 50W, the input voltage is 20V, the processing time is 15min, and the output voltage is 3KV.

[0050] Example 4

[0051] A plasma treatment method for promoting germination and improving the quality of sorghum seeds differs from Example 1 in the following ways:

[0052] The input power is 100W, the input voltage is 60V, the processing time is 3min, and the output voltage is 6KV.

[0053] Experimental Example 1

[0054] 1. Experimental Methods

[0055] 1.1 DBD-CP treatment of sorghum

[0056] The plasma generator used in this invention consists of a high-frequency AC power supply (CTP-2000K), a voltage regulator, and a DBD plasma reactor (DBD-100). The DBD plasma reactor comprises two metal electrodes with an inner diameter of 55 mm and a thickness of 8 mm, and a covered circular quartz dish. Figure 1 As shown.

[0057] The sorghum stalks to be treated were evenly spread in the quartz dish of the plasma reactor, using argon as the atmosphere gas at a flow rate of 5 L / min. The center frequency of the treatment was 10 kHz, the input power was 50 W and 100 W, the input voltage was 25 V and 50 V, the corresponding output voltages were 3 KV and 6 KV, the duty cycle was 40%, the discharge distance was 0.4 cm, and the discharge time was 5 min and 10 min. After treatment, the sorghum was germinated.

[0058] 1.2 DBD-CP treatment of sorghum seed coat appearance and structural characteristics

[0059] The sorghum seed coats of the four DBD-CP treatment groups and the control group were fixed to short columns with conductive tape. The samples were examined using a scanning electron microscope (JSM-7800F, JEOLLtd. Japan) at an accelerating voltage of 3.0 kV. Representative photomicrographs of each sample were acquired at magnifications of 500× and 1000×.

[0060] 1.3 Preparation of Germinated Sorghum and Seed Vigor Analysis

[0061] Soak 600g of sorghum grains in distilled water overnight to remove dirt and husks. Then soak in a 7.0% H2O2 solution for 15 minutes to slow mold growth during germination. Wash the soaked sorghum grains with distilled water and soak in the solution for 20 minutes to remove residual H2O2. Spread the sorghum grains evenly between two layers of gauze and allow them to germinate in the dark at room temperature for 3 days, spraying water on the grains if necessary. Measure the germination rate, root length and seedling length, fresh weight, and vigor index.

[0062] Germination rate: The standard is that the sprout length exceeds half the length of the seed. The number of sprouts is recorded daily, and the calculation formula is as follows:

[0063] G R =G n / m×100%

[0064] In the formula G R Germination rate; G n denoted as germination rate on day n; m represents the total number of seeds tested.

[0065] Root length and seedling length: On the third day of seedling cultivation, 20 wheat seedlings were randomly selected from each culture dish. After rinsing with distilled water, the root length and seedling length of the wheat seedlings were measured with a ruler. The maximum and minimum values ​​of each parameter were removed, and the average value was calculated.

[0066] Fresh weight: The seedlings were selected from the same root and seedling length. The roots and grains of 20 wheat seedlings were removed, and after rinsing with distilled water, the surface moisture was absorbed with filter paper and the fresh weight was measured.

[0067] Vitality Index VI:

[0068] G I =∑G n / D n

[0069] V I =G I ×S

[0070] In the formula G I Germination index; G n D is the number of germinations on day n; n V represents the number of days since germination. I S represents the vitality index; S represents seedling length, in mm.

[0071] 1.4 Determination of Tannin Content

[0072] The tannin content in sorghum was determined according to the national standard GB / T 15686-2008. First, tannins were extracted from sorghum using 75% dimethylformamide solution and stirred for 60 min. Then, the mixture was centrifuged at 3000×g for 10 min. The supernatant was collected and mixed with 6 mL of water and 1 mL of ammonia solution. Another supernatant was collected and mixed with 5 mL of water, 1 mL of ferric ammonium citrate solution, and 1 mL of ammonia solution. The difference in absorbance between the two mixtures was the tannin content in the sample. Water was used as a blank control, and the absorbance was measured at 525 nm using a spectrophotometer. A standard curve for tannins was plotted using tannic acid.

[0073] 1.5 Extraction and determination of physicochemical properties of starch

[0074] 1.5.1 Extraction of sorghum starch

[0075] Sorghum powder was soaked in a 0.2% NaOH solution (w / w) at 25℃ and reacted in a constant temperature water bath shaker for 4 hours. Subsequently, the sample was centrifuged at 2500×g for 15 minutes, the supernatant was discarded, the precipitate was filtered, the filtrate was placed in a beaker, hydrochloric acid was added until neutral, and the mixture was centrifuged three more times, discarding the supernatant. The precipitate was then dried in a 40℃ oven for 24 hours to obtain sorghum starch. This starch was then ground into powder and stored at 4℃.

[0076] 1.5.2 Microstructure

[0077] The extracted sorghum starch samples were allowed to air dry in a cool, well-ventilated environment. Subsequently, the sorghum starch samples were fixed to short columns with conductive tape and analyzed using a TESCAN field emission scanning electron microscope (TESCAN MIRA) at an accelerating voltage of 10.0 kV. Representative micrographs of each sample were acquired at 10000× magnification.

[0078] 1.5.3 X-ray diffraction analysis

[0079] X-ray diffraction patterns of DBD-CP-treated sorghum starch were obtained using an X-ray diffractometer (D8 ADVANCE, Bruker, Germany). The diffraction rate was 4° min. -1 The scanning rate was from 5° to 40° (2θ) for sorghum starch. The relative crystallinity (RC, %) of the starch sample was determined by calculating the percentage of the total crystalline peak area relative to the total diffraction pattern (including crystalline peak area and amorphous peak area), and the analysis was performed using Origin software.

[0080] 1.5.4 Fourier Transform Infrared Spectroscopy Analysis

[0081] Fourier transform infrared (FT-IR) spectra of sorghum starch samples were obtained using a Nicolet IS50 (Thermo Nicolet Corporation, USA). The FT-IR spectra were recorded from 4000 to 525 cm⁻¹. -1 Within the wavenumber range, each sample underwent a cumulative 64 scans, with a resolution of 4 cm⁻¹. -1 And through 1047cm -1 / 1022cm -1 The short-range ordered structure of starch was calculated.

[0082] 1.5.5 Thermal Properties

[0083] The thermal properties of sorghum starch were studied using a differential scanning calorimeter (DSC 3, Mettler Toledo, Switzerland). 3.0 mg of sorghum starch (dry basis) and 7.5 μL of distilled water were placed in a small crucible. The crucible was sealed and equilibrated at room temperature for 4 h before heating. The temperature was increased from 25 °C to 100 °C at a rate of 10 °C / min. The initial temperature (T0) was determined from the endothermic peak observed in the DSC thermal analysis plot using Proteus thermal analysis software (Version 8.0.1, NETZSCH-Geratebau, GmbH, Germany). o Peak temperature (T) p ), End temperature (T) c) and endothermic enthalpy (ΔH).

[0084] 1.6 Metabolomics Analysis

[0085] Sample preparation: Hydrophilic compounds were extracted from sorghum powder samples using a previously reported method (Kim et al., 2021). 200 mg of lyophilized sorghum powder was placed in a 2 mL centrifuge tube. Then, 0.7 mL of pre-chilled 100% methanol and 60 μL of ribitol aqueous solution (2 mg / mL, internal standard) were added. After vortexing for 30 s, the sample was incubated at 40 °C with shaking at 900 rpm for 10 min. The mixture was then centrifuged at 11000 × g for 20 min. The supernatant was transferred to a new 2 mL centrifuge tube, and 300 μL of chloroform (-20 °C) and 500 μL of deionized water were added. After vortexing for 20 s, the sample was centrifuged again at 2200 × g for 20 min, and 300 μL of the supernatant was transferred to another new 2 mL tube. The solvent was completely evaporated in a centrifuge concentrator (ZLS-2, Hunan Herexi Instrument & Equipment Co., Ltd., China) at 37 °C. For derivatization, 80 μL of methoxyamine hydrochloride solution (20 mg / mL) prepared with pyridine was added to each sample, and the sample was incubated at 37 °C with shaking at 900 rpm for 2 h in a hot mixer (JXH-100, Tuohe Electromechanical Technology Co, Ltd., China). Then, 80 μL of LMSTA was added, and the sample was incubated at 37 °C with shaking at 900 rpm for another 30 min. The derivatized samples were then transferred to the glass insert in the GC autosampler vial. Six biological replicates were performed for each sample.

[0086] GC-MS analysis: A DB-5 fused silica capillary column (30 m × 0.25 mm × 0.25 μm; Agilent Technologies, Santa Clara CA, USA) was used. Instrument parameters were set according to the previously described method.

[0087] Quality Control (QC): QC samples were prepared by mixing equal volumes (1 g) of all sorghum flour samples from this test case. QC samples were periodically incorporated into the analytical sequence of actual samples to assess the reproducibility of the analytical methods and detect potential laboratory contamination.

[0088] 2. Results and Analysis

[0089] 2.1 Effects of DBD-CP treatment on the morphology and structure of sorghum husks

[0090] Figure 2The surface morphology of sorghum seed coats before and after DBD-CP treatment is shown. The untreated control group had a smooth and flat surface, while the DBD-CP treated samples showed obvious grooves and cracks. These surface changes were caused by high-energy particle etching and energy radiation generated by DBD-CP. The most significant changes in seed coat surface structure were observed under the treatment condition of 25V for 10 min. These microstructural changes increased the seed coat surface area, improved seed hydrophilicity, and promoted water absorption, thereby increasing seed germination rate and seedling growth.

[0091] 2.2 Effects of DBD-CP treatment on sorghum grain vigor

[0092] Figure 3 This study demonstrates the morphological changes of sorghum seeds during the early germination stages (days 1-3). Observations on day 1 showed that the radicle of the seeds in the 25V-10min treatment group was significantly more prominent, indicating better germination than other treatment groups. On day 2, the seedling vigor of the 25V-10min group was higher than that of the control group and other treatment groups. On day 3, the root length of the seedlings in this group further extended, and the overall seedling vigor continued to increase, indicating strong germination activity and early growth capacity. These morphological observations confirm that the 25V-10min treatment condition has a good effect on accelerating sorghum seed germination and promoting early seedling growth.

[0093] like Figure 4 As shown, the germination rate of the control group was 69%, while the germination rate of sorghum grains treated with DBD-CP increased to 74% (25V-5min), 77% (50V-5min), 82% (25V-10min), and 78% (50V-10min), respectively. The highest germination rate, reaching 82%, was observed under the 25V-10min treatment. These results indicate that DBD-CP treatment promoted sorghum grain germination, and the treatment effect was correlated with voltage and time parameters.

[0094] like Figure 5 , Figure 6 , Figure 7 As shown, DBD-CP treatment also increased root length, seedling length, fresh weight, and vigor index of sorghum seedlings. Compared with the control group, under different treatment conditions, root length increased from 6.3 mm to a maximum of 29.7 mm (25V-10min); seedling length increased from 4.0 mm to a maximum of 11.0 mm (25V-10min); fresh weight increased from 2.8 mg to a maximum of 11.2 mg (25V-10min); and vigor index increased from 192.40 to a maximum of 913.00 (25V-10min). These data demonstrate that the DBD-CP treatment method of this invention can effectively promote sorghum grain germination and early seedling growth. DBD-CP treatment alters grain surface characteristics, increases seed coat permeability, and promotes seed metabolism and nutrient utilization.

[0095] 2.3 Effects of DBD-CP treatment and germination on tannin content in sorghum

[0096] This invention investigated the effects of DBD-CP treatment and germination process on the tannin content of sorghum. Tannins, as the main polyphenolic compounds in sorghum, can bind with proteins to form indigestible complexes, affecting the nutritional value and eating quality of sorghum. Figure 8 As shown, DBD-CP treatment had little effect on the tannin content of sorghum, while germination treatment significantly reduced the tannin content, decreasing it from 0.3 mg / g to 0.2 mg / g. Combined with the observed changes in seed surface structure, although DBD-CP treatment does not directly reduce tannin content, it facilitates the dissolution and removal of tannins during subsequent processing by altering the seed coat structure. The mechanisms by which tannin content decreases during germination include: partial dissolution of water-soluble tannins during soaking, changes in sorghum protein structure leading to the formation of tannin-protein complexes, and the activation of metabolic enzymes such as polyphenol oxidase during germination promoting tannin degradation. The experimental results indicate that germination treatment is an effective method for reducing the tannin content of sorghum, thereby improving its nutritional value and eating quality.

[0097] 2.4 Determination of the physicochemical properties of sorghum starch

[0098] 2.4.1 Microstructure Analysis of Sorghum Starch

[0099] The microstructural changes of sorghum starch under different treatment conditions were observed using scanning electron microscopy. For example... Figure 9 As shown, sorghum starch granules exhibit irregular, hexagonal, and polyhedral shapes. After germination and DBD-CP treatment, the surface structure of the starch granules changes to varying degrees. The germination process primarily results in needle-like structures on the starch granule surface, due to the erosive action of amylases on the granule surface, making it rough and forming pinholes. Starch hydrolysis during germination begins with enzyme adsorption on the granule surface, subsequently forming small pores that expand into channels, ultimately creating indentations on the granule surface.

[0100] Meanwhile, DBD-CP treatment primarily induces microcracks and pores on the surface of some starch granules through etching, but does not destroy the basic morphology or granule integrity of the starch. Compared with the control group, the starch granules treated with DBD-CP maintained their original integrity, and their basic structure did not change significantly. This indicates that while promoting sorghum seed germination, DBD-CP treatment does not damage the basic structure of starch; however, changes in the surface microstructure may affect the functional properties of starch, such as water absorption and gelatinization properties.

[0101] 2.4.2 X-ray diffraction and Fourier transform infrared spectroscopy analysis of sorghum starch

[0102] Figure 10 XRD patterns of sorghum starch from each treatment group are shown. All samples exhibited diffraction peaks with typical type A crystal structure at 2θ angles of 15°, 17°, 18°, and 23°. The positions and shapes of the diffraction peaks did not change significantly among the treatment groups, indicating that germination and DBD-CP treatment did not alter the crystal type of the starch. However, the relative crystallinity (RC) of germinated sorghum starch increased from 26.0% in the control group to 54.0% in the 25V-10min treatment group. This was mainly due to the preferential degradation of amorphous regions by enzymes during germination and the promotion of starch amylose-side chain recombination by DBD-CP treatment, resulting in more crystalline regions. The increased RC value also indicates that starch gelatinization requires more energy, confirming that the crystalline regions are more complete and stable.

[0103] Figure 11 The FT-IR spectral analysis shown indicates that DBD-CP treatment did not result in the appearance of new absorption peaks (4000-525 cm⁻¹). -1 (Region), ruling out the possibility of covalent interactions. Sorghum starch exhibits three characteristic absorption peaks (3100-3600 cm⁻¹). -1 3000-2800cm -1 and 1640cm -1 This corresponds to the tensile vibrations of OH, CH, and CH2. 1047 cm⁻¹ -1 and 1022cm -1 absorption peak intensity ratio (R) 1047 / 1022 The ratio reflects short-range orderliness. DBD-CP treatment increases this ratio, indicating that the starch surface structure is more ordered. This is consistent with the trend of RC value change, further confirming that DBD-CP treatment enhances the structural stability of starch.

[0104] As shown in Table 1, the relative crystallinity of the control group before germination was 0.20±0.02. After treatment with 25V-5min, 50V-5min, 25V-10min, and 50V-10min, the relative crystallinity increased to 0.32±0.02, 0.42±0.01, 0.38±0.04, and 0.41±0.01, respectively. After germination, the relative crystallinity of the control group was 0.26±0.02, while the 25V-10min treatment group reached the highest value of 0.54±0.03. Furthermore, the Rc of each treatment group... 1047 / 1022 The values ​​also showed corresponding changes, clearly reflecting the influence of DBD-CP treatment on the crystallization characteristics and short-range ordered structure of sorghum starch.

[0105] Table 1 Results of crystallinity and short-range ordering of sorghum starch

[0106]

[0107] 2.4.3 Analysis of Gelatinization Characteristics

[0108] Table 2 shows the gelatinization characteristics of germinated sorghum starch in each treatment group. Although DBD-CP treatment did not alter the basic stability of the starch crystal structure, it significantly affected the gelatinization enthalpy (ΔH), with the highest value (9.47 J / g) observed in the 25V-10min post-germination treatment group, indicating enhanced thermal stability, possibly due to DBD-CP-induced cross-linking. While the peak temperature and gelatinization enthalpy decreased relative to the highest value with increasing treatment voltage and time, they remained higher than the control group, suggesting that cross-linking and depolymerization may coexist at higher treatment intensities, but the cross-linking effect still dominates. Compared to the control group, the gelatinization enthalpy increased in all DBD-CP treatment groups, which may be related to the increased amylose content after treatment, indicating a more stable starch structure and stronger resistance to heat and shear stress. This finding demonstrates that by precisely controlling the DBD-CP treatment parameters, the characteristics of sorghum starch can be specifically regulated, providing an effective method to meet specific industrial application needs.

[0109] Table 2 Results of thermal properties of sorghum starch

[0110]

[0111]

[0112] 2.5 Metabolomics analysis of sorghum after germination

[0113] MetaboAnalyst 5.0 and the KEGG database were used for metabolic pathway analysis. Figure 12 The main metabolic pathways (glycolysis, amino acid metabolism, and TCA cycle) involving key metabolites were described. The heatmap color bars represent the relative content of corresponding compounds in each group of sorghum (lighter colors indicate higher content). From left to right, the groups are Control, 25V-5min, 25V-10min, 50V-5min, and 50V-10min. DBD-CP treatment significantly altered the accumulation levels of key intermediates such as glucose and pyruvate in the glycolysis pathway, affecting energy metabolism. In the TCA cycle, the relative contents of fumaric acid, succinic acid, and malic acid decreased with increasing treatment voltage and time. Furthermore, DBD-CP treatment led to changes in the levels of amino acids such as glutamate, alanine, and valine. These changes are related to amino acid transamination and branched-chain amino acid degradation pathways, affecting the carbon-nitrogen balance in sorghum.

[0114] Experiments showed that GABA (γ-aminobutyric acid) content was significantly affected by DBD-CP treatment parameters. Within the experimental conditions, when the DBD-CP treatment parameters were 25V for 10 min, the GABA content in sorghum was significantly increased compared to the control group. When the treatment voltage was increased to 50V, the GABA content decreased accordingly. This change was related to changes in glutamate content and glutamate decarboxylase (GAD) activity. The results indicate that regulating the DBD-CP treatment parameters can effectively control the content of functional components such as GABA in sorghum, providing a new technical approach for developing functional sorghum foods.

[0115] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A plasma treatment method for promoting germination and improving the quality of sorghum seeds, characterized in that, Sorghum seeds were subjected to dielectric barrier discharge low-temperature plasma treatment; the input voltage of the dielectric barrier discharge low-temperature plasma treatment was 20-60V, and the treatment time was 3-15min.

2. The method according to claim 1, characterized in that, The input voltage for the dielectric barrier discharge low-temperature plasma treatment is 25-50V, and the treatment time is 5-10min.

3. The method according to claim 1, characterized in that, The atmosphere for the dielectric barrier discharge low-temperature plasma treatment is argon gas, with a flow rate of 3-8 L / min.

4. The method according to claim 1, characterized in that, The center frequency of the dielectric barrier discharge low-temperature plasma treatment is 10KHz, and the input power is 50-100W.

5. The method according to claim 1, characterized in that, The output voltage of the dielectric barrier discharge low-temperature plasma treatment is 3-6KV.

6. The method according to claim 1, characterized in that, The duty cycle of the dielectric barrier discharge low-temperature plasma treatment is 40%, and the discharge distance is 0.4 cm.

7. The method according to claim 1, characterized in that, The device for generating dielectric barrier discharge low-temperature plasma treatment consists of a high-frequency AC power supply, a voltage regulator, and a DBD plasma reactor; the DBD plasma reactor consists of two metal electrodes with an inner diameter of 55 mm and a thickness of 8 mm and a circular quartz dish with a cover.

8. The method according to claim 7, characterized in that, Spread the sorghum seeds evenly in the circular quartz dish.

9. The method according to claim 1, characterized in that, It also includes soaking and germination after the dielectric barrier discharge low-temperature plasma treatment is completed.

10. The use of sorghum seeds treated by the method of any one of claims 1-9 in food manufacturing, feed ingredient manufacturing, pharmaceutical manufacturing or seed production.

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