Method for increasing the resistant starch content of cyperus esculentus by ultra high pressure treatment
By using ultra-high pressure processing and polyphenol compounding, resistant starch from tiger nuts was prepared, which solved the problem of starch being converted into glucose too quickly. This method achieved more efficient and uniform starch structure modification, increased the content of resistant starch, and reduced the rate of postprandial blood glucose rise.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG UNIV
- Filing Date
- 2026-04-20
- Publication Date
- 2026-06-05
Smart Images
Figure CN122145655A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of starch processing technology, and in particular to a method for increasing the resistant starch content of tiger nuts through ultra-high pressure treatment. Background Technology
[0002] Starch is one of the most abundant sources of carbohydrates in the human diet, providing approximately 40%-60% of the basic energy needed for daily life. However, if starch is converted into glucose too quickly, it disrupts the body's blood sugar balance, potentially increasing the risk of obesity, type II diabetes, cardiovascular disease, and other chronic diseases in the long run. Therefore, controlling or reducing starch digestibility is a promising strategy for the prevention and treatment of metabolic diseases. Tiger nut starch is a nutrient-rich natural starch with numerous health benefits and broad application potential. To further diversify tiger nut products, the deep-processing industry system can be improved by regulating the resistant starch content in tiger nut starch, while simultaneously meeting market demand and aligning with consumers' health-conscious consumption concepts. Polyphenols, due to their unique antioxidant, anti-inflammatory, and enzyme-inhibiting properties, are considered beneficial functional components for human health and are widely found in fruits and vegetables. With the gradual elucidation of the interaction between phenols and starch, phenolic modification of starch to alter its digestibility has become a research hotspot. Existing techniques include hydrothermal processing, extrusion processing, microwave processing, and ultrasonic processing. These phenolic compounds primarily regulate starch digestibility by influencing enzyme activity or altering starch structure. Existing research indicates that phenolic compounds with different structures exhibit varying effects on starch. On one hand, phenolic compounds can enter the active sites of digestive enzymes or interact with specific amino acid residues at those sites, inhibiting enzyme activity and thus reducing starch digestibility. On the other hand, phenolic compounds can form complexes with starch through non-bonded and hydrophobic interactions, thereby affecting starch structure and digestibility. These changes are, to some extent, achieved through the formation of non-enclosed or enclosed amylose-polyphenol complexes.
[0003] Therefore, to solve the above-mentioned technical problems, a new technical solution is needed. Specifically, a method for increasing the resistant starch content of tiger nuts through ultra-high pressure treatment is required. Summary of the Invention
[0004] To address the technical problem of excessively rapid conversion of starch to glucose in existing methods, this invention provides a method for increasing the resistant starch content of tiger nuts through ultra-high pressure treatment.
[0005] To achieve the above objectives, the following technical solution is provided: A method for increasing the resistant starch content of tiger nuts through ultra-high pressure treatment, comprising the following steps: (1) Mix tiger nuts starch and polyphenols in a certain proportion and incubate in a water bath at 25°C for 30 min; (2) The mixture obtained in step (1) is subjected to ultra-high pressure treatment; (3) Freeze-dry the mixture after ultra-high pressure treatment to obtain tiger nuts resistant starch.
[0006] Preferably, the tiger nut starch is extracted by wet grinding and alcohol extraction. The specific steps are as follows: after washing the tiger nuts, soak them in deionized water at room temperature for 12 hours, drain and homogenize, pass through a 100-mesh sieve, let the filtrate stand overnight, discard the supernatant, extract the precipitate with anhydrous ethanol for 1 hour, repeat 3 times, collect the precipitate, dry, grind and sieve to obtain tiger nut starch; the material-to-liquid ratio in the homogenization process is 1:4 (w / v); the material-to-liquid ratio in the extraction process is 1:1 (v / v).
[0007] Preferably, the polyphenol is one of EGCG, quercetin, or ellagic acid.
[0008] Preferably, the amount of polyphenols added is 2% to 6% (w / w) of the starch mass.
[0009] Preferably, the pressure of the ultra-high pressure treatment is 100–500 MPa.
[0010] Preferably, the pressure of the ultra-high pressure treatment is 300 MPa.
[0011] Preferably, the ultra-high pressure treatment time is 10 minutes.
[0012] Preferably, the temperature of the ultra-high pressure treatment is 25°C.
[0013] Preferably, the freeze-drying conditions are: -50°C, 0.2 mbar freeze-drying for 48 h. Beneficial effects
[0014] Compared to traditional hydrothermal methods for increasing resistant starch content, this invention achieves a more efficient, uniform, and stable molecular complexation of polyphenols and starch through high-pressure forced action at low / room temperature, producing resistant starch with stronger digestibility and a denser structure. This process maximizes the preservation of the natural structure and bioactivity of polyphenols, resulting in a final product with excellent nutritional and physiological functions (such as slow digestion and probiotic effects). It provides a green, energy-saving, controllable, and uniform non-thermal processing method, resulting in a more natural sensory quality and broadening the development ideas and application scenarios for functional ingredients.
[0015] Effect of starch extraction purity on compounding effect: Tiger nut starch obtained by wet grinding and alcohol extraction has high purity and complete structure, which is conducive to the uniform adsorption and compounding of polyphenols.
[0016] The mechanism of ultra-high pressure treatment: High pressure promotes the dissociation and rearrangement of starch chains, forming more enzymatically resistant crystalline regions, while also promoting the uniform intercalation of polyphenols.
[0017] The necessity of freeze drying: Freeze drying can effectively prevent starch retrogradation, maintain polyphenol activity, and ensure the stability of the complex structure. Attached Figure Description
[0018] Fig. 1 The images are FT-IR images of tiger nut starch prepared in Examples 1-3 of this invention and natural tiger nut starch.
[0019] Fig. 2 The curves show the changes in resistant starch content under different pressures (100-500 MPa).
[0020] Fig. 3 Bar chart showing the resistant starch content at different polyphenol addition ratios (2%, 4%, 6%). Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.
[0022] In the description of this invention, it should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to or indirectly connected to the other element.
[0023] In the description of this invention, it should be noted that the terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.
[0024] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0025] The optimal implementation conditions for this patent are: EGCG as the polyphenol, added at 6% of the starch mass; ultra-high pressure treatment at 300 MPa; treatment time at 10 min; and temperature at 25℃. Under these conditions, the resistant starch content can reach 81.39%.
[0026] The present invention will be further illustrated by the following examples. These examples are for illustrative purposes and are not intended to limit the scope of the invention.
[0027] like Figs. 1 to 3 As shown, where Fig. 1 E-6-300 represents a sample treated with 6% EGCG and 300 MPa pressure; H-2-400 represents a sample treated with 2% quercetin and 400 MPa pressure; R-4-200 represents a sample treated with 4% ellagic acid and 200 MPa pressure.
[0028] Example 1: Optimal Condition Experiment (EGCG 6%, 300 MPa)
[0029] A method for increasing the resistant starch content of tiger nuts through ultra-high pressure treatment, comprising the following steps:
[0030] (1) Polyphenol compounding: Weigh 10 g tiger pea starch, disperse it evenly in 90 ml of deionized water, stir well, add 6% EGCG to the starch solution, mix thoroughly, and incubate in a 25℃ water bath for 30 min to form a stable mixed solution. Transfer the solution to a vacuum bag, leaving enough space inside the bag (about 1 / 3 to 1 / 2 of the total volume), and try to remove the air from the top of the bag, then seal it.
[0031] (2) Ultra-high pressure treatment: The starch sample obtained in step (1) was subjected to high pressure permeation at 300 MPa for 10 min using an HPP-600 / 20L ultra-high pressure treatment machine.
[0032] (3) Freeze-drying: The starch-EGCG complex obtained in step (2) was centrifuged at 4000×g and 20°C for 10 min, the supernatant was discarded, and the precipitate was freeze-dried at -50°C and 0.2 mbar for 48 h. The freeze-dried sample was crushed and passed through a 100-mesh sieve to obtain the sample to be tested, which was then stored in a desiccator.
[0033] (4) In vitro simulated digestion: 200 mg of starch-EGCG complex was suspended in 10 mL of sodium acetate buffer (0.1 M, pH 5.2) and incubated at 90 °C for 20 min with continuous stirring to ensure complete gelation of the complex. Then, the suspension was kept in a 37 °C water bath for 10 min, and 0.6 mL of mixed enzyme solution (120 U / mL α-amylase and 240 U / mL glucoamylase) was added. The reaction system was stirred at 180 r / min at 37 °C. At 0, 20, and 120 min, 0.2 mL of the simulated digest was aspirated and 1 mL of anhydrous ethanol was added to inactivate the enzyme. After centrifugation at 2000 xg for 10 min, the suspension (0.1 mL) was mixed with a dual-enzyme solution (0.4 mL) containing glucoamylase (32.5 U / mL) and invertase (112.5 U / mL) to ensure that all products were converted to glucose. The content of RS is determined using the following formulas: RDS = 0.9 × (G20 - G0); SDS = 0.9 × (G120 - G20); RS = TS - RDS - SDS, where 0.9 represents the conversion factor from starch to glucose, G0, G20 and G120 represent the glucose content at 0, 20 and 120 minutes, respectively, and TS is the initial total starch content.
[0034] Fourier transform infrared spectroscopy: The starch-EGCG complex was co-ground with KBr and pressed into disc-shaped particles. The absorption spectrum of the complex was obtained in the 4000-500 cm⁻¹ region with a resolution of 4 cm⁻¹.
[0035] Compared to the control group, the starch prepared in this example exhibits a broader peak at 3000-3600 cm⁻¹, indicating that some hydrogen bonds between starch chains were disrupted during the ultra-high pressure treatment. The absence of characteristic absorption peaks and absorption peak loss suggests no chemical bond modification or covalent bond formation. The starch prepared in this example contains a high resistant starch content of 81.39%, which is 64.45% higher than the 16.94% resistant starch content of the control group without polyphenols. Therefore, this method can effectively increase the resistant starch content without introducing new chemical bonds.
[0036] Example 2: Quercetin experiment (2%, 400 MPa)
[0037] A method for increasing the resistant starch content of tiger nuts through ultra-high pressure treatment, comprising the following steps:
[0038] (1) Compound polyphenols: Weigh 10 g tiger pea starch, disperse it evenly in 90 ml of deionized water, stir well, add 2% quercetin to the starch solution, mix thoroughly, and incubate in a 25℃ water bath for 30 min to form a stable mixed solution. Transfer the solution to a vacuum bag, leaving enough space inside the bag (about 1 / 3 to 1 / 2 of the total volume), and try to remove the air from the top of the bag, then seal it.
[0039] (2) Ultra-high pressure treatment: The starch sample obtained in step (1) was subjected to high pressure permeation at 400 MPa for 10 min using an ultra-high pressure treatment machine (HPP-600 / 20L).
[0040] (3) Freeze-drying: The starch-quercetin complex obtained in step (2) was centrifuged at 4000×g and 20°C for 10 min, the supernatant was discarded, and the precipitate was freeze-dried at -50°C and 0.2 mbar for 48 h. The freeze-dried sample was pulverized and passed through a 100-mesh sieve to obtain the sample to be tested, which was then stored in a desiccator.
[0041] (4) In vitro simulated digestion: The in vitro simulated digestion method and formula described in Example 1 were used for determination.
[0042] (5) Fourier transform infrared spectroscopy: The starch-quercetin complex was co-ground with KBr and pressed into disc-shaped particles. The absorption spectrum of the complex was obtained in the 4000-500 cm⁻¹ region with a resolution of 4 cm⁻¹.
[0043] Compared to the control group, the starch prepared in this example exhibits a broader peak at 3000-3600 cm⁻¹, indicating that some hydrogen bonds between starch chains were disrupted during the ultra-high pressure treatment. The absence of characteristic absorption peaks and the lack of absorption peak loss suggest the absence of chemical bond modification or covalent bond formation. The resistant starch content in the starch prepared in this example is approximately 47.30%, representing a 30.36% increase compared to the 16.94% resistant starch content in the control group without added polyphenols.
[0044] Example 3: Ellagic acid experiment (4%, 200 MPa)
[0045] A method for increasing the resistant starch content of tiger nuts through ultra-high pressure treatment, comprising the following steps:
[0046] (1) Polyphenol compounding: Weigh 10 g tiger pea starch and disperse it evenly in 90 ml of deionized water. After stirring evenly, add 4% ellagic acid to the starch solution and mix thoroughly. Incubate in a 25℃ water bath for 30 min to form a stable mixed solution. Transfer the solution to a vacuum bag, leaving enough space inside the bag (about 1 / 3 to 1 / 2 of the total volume) and removing as much air as possible from the top of the bag. Seal the bag.
[0047] (2) Ultra-high pressure treatment: The starch sample obtained in step (1) was subjected to high pressure permeation at 200 MPa for 10 min using an ultra-high pressure treatment machine (HPP-600 / 20L).
[0048] (3) Freeze-drying: The starch-ellagic acid complex obtained in step (2) was centrifuged at 4000×g and 20°C for 10 min, the supernatant was discarded, and the precipitate was freeze-dried at -50°C and 0.2 mbar for 48 h. The freeze-dried sample was crushed and passed through a 100-mesh sieve to obtain the sample to be tested, which was then stored in a desiccator.
[0049] (4) In vitro simulated digestion: The in vitro simulated digestion method and formula described in Example 1 were used for determination.
[0050] (5) Fourier transform infrared spectroscopy: The starch-ellagic acid complex was co-ground with KBr and pressed into disc-shaped particles. The absorption spectrum of the complex was obtained in the 4000-500 cm⁻¹ region with a resolution of 4 cm⁻¹.
[0051] Compared to the control group, the starch prepared in this example exhibits a broader peak at 3000-3600 cm⁻¹, indicating that some hydrogen bonds between starch chains were disrupted during the ultra-high pressure treatment. The absence of characteristic absorption peaks and the lack of absorption peak loss suggest the absence of chemical bond modification or covalent bond formation. The resistant starch content in the starch prepared in this example is approximately 53.66%, representing a 36.72% increase compared to the 16.94% resistant starch content in the control group without added polyphenols.
[0052] Example 4: Pressure optimization experiment (EGCG 6%, different pressures)
[0053] With an EGCG addition of 6%, the samples were treated with pressures of 100, 200, 300, 400, and 500 MPa for 10 min, respectively, and the RS content was measured. The results are as follows: Fig. 2 As shown, the RS content is highest at 300 MPa.
[0054] Example 5: Optimization experiment of polyphenol addition (EGCG, 300 MPa)
[0055] Under a pressure of 300 MPa, experiments were conducted with EGCG additions of 2%, 4%, and 6%, respectively, and the RS content was determined. The results are as follows... Fig. 3 As shown, the RS content was highest at an addition level of 6%.
[0056] Table 1. Comparison of resistant starch content under different polyphenol and pressure conditions.
[0057]
[0058] This invention utilizes ultra-high pressure, a green processing method, to efficiently modify starch chains. Specifically, high-pressure-driven physical forces synergistically work with polyphenols as functional ligands to induce partial dissociation and rearrangement of starch molecular chains, resulting in a novel, dense, highly ordered complex crystalline system with steric hindrance and inhibitory effects on digestive enzymes. This process simultaneously regulates starch gelatinization and retrogradation, yielding tiger nut starch with high resistant starch content. This preparation method improves the palatability of tiger nut starch while effectively controlling the slow degradation of its resistant components in the human body, thus effectively reducing the rate of postprandial blood glucose rise.
[0059] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.
Claims
1. A method for increasing the resistant starch content of tiger nuts through ultra-high pressure treatment, characterized in that, Includes the following steps: (1) Mix tiger nuts starch and polyphenols in a certain proportion and incubate in a water bath at 25°C for 30 min; (2) The mixture obtained in step (1) is subjected to ultra-high pressure treatment; (3) Freeze-dry the mixture after ultra-high pressure treatment to obtain tiger nuts resistant starch.
2. The method according to claim 1, characterized in that, The tiger nut starch was extracted by wet grinding and alcohol extraction. The specific steps were as follows: tiger nuts were washed, soaked in deionized water at room temperature for 12 h, drained, homogenized, passed through a 100-mesh sieve, the filtrate was left to stand overnight, the supernatant was discarded, the precipitate was extracted with anhydrous ethanol for 1 h, repeated 3 times, the precipitate was collected, dried, ground and sieved to obtain tiger nut starch; the material-to-liquid ratio in the homogenization process was 1:4 (w / v); the material-to-liquid ratio in the extraction process was 1:1 (v / v).
3. The method according to claim 1, characterized in that, The polyphenol is one of EGCG, quercetin, or ellagic acid.
4. The method according to claim 1, characterized in that, The amount of polyphenols added is 2% to 6% (w / w) of the starch mass.
5. The method according to claim 1, characterized in that, The pressure of the ultra-high pressure treatment is 100-500 MPa.
6. The method according to claim 5, characterized in that, The pressure for the ultra-high pressure treatment is 300 MPa.
7. The method according to claim 1, characterized in that, The ultra-high pressure treatment time is 10 minutes.
8. The method according to claim 1, characterized in that, The ultra-high pressure treatment temperature is 25℃.
9. The method according to claim 1, characterized in that, The freeze-drying conditions were: -50℃, 0.2 mbar freeze-drying for 48 h.