Method for preparing sesamol-canna edulis ker RS5 type resistant starch by utilizing hydration-co-gelatinization

Abstract

The invention relates to preparation of raw materials / auxiliary materials of food, in particular to a preparation method of RS5 type resistant starch, canna edulis ker starch is used as an optimal carrier of sesamol, the RS5 type resistant starch with excellent composite index, loading capacity and RS starch content can be obtained by combining a specific hydration-co-gelatinization technology with the sesamol, the loading capacity of the sesamol reaches 3.85 mg / g, and the loading capacity of the sesamol reaches 3.85 mg / g. The composite index reaches 76.76%, and the RS content reaches 87.84%. The method has the advantages of simple process, no need of adding other reagents / assistants and other auxiliary technical means, low cost and no pollution. The prepared RS5 type resistant starch has the advantages of high digestion resistance, high oxidation resistance, capability of promoting intestinal health and the like, and can be applied to the fields of medicines and feeds as raw materials and auxiliary materials.

Description

Technical Field

[0001] This application relates to the technical field of food raw material / auxiliary material processing, and specifically relates to a method for preparing sesamol-Canna indica RS5 type resistant starch by using a hydration-coprecipitation technology. The prepared RS5 type resistant starch can also be applied to the fields of medicine and feed. Background Art

[0002] Starch is the second largest carbohydrate in nature, composed of amylose and amylopectin. It is the most important dietary macronutrient for humans, providing more than 50% of the energy for the human body. Starch is a biopolymer with a semi-crystalline structure and has a multi-scale structure, including molecular structure, helical structure, crystal structure, lamellar structure, growth ring structure, and granular structure. As an abundant, low-cost, edible, and biodegradable natural polymer, starch can be used as a delivery carrier and shows great potential in the development of delivery systems. Resistant starch (RS) is recognized as an important dietary fiber component. Increasing the intake of resistant starch is considered an effective method to delay the increase in blood glucose levels and the corresponding insulin response. RS5 generally refers to the complex formed by starch and guest molecules represented by starch-fatty acid complexes. Due to its unique V-type structure and the physiological activity of the guest molecules, it has attracted the attention of researchers. Polyphenols have also been used for starch modification, thereby changing the digestion characteristics of starch, reducing rapidly digestible starch (RDS), increasing resistant starch (RS), and forming starch-polyphenol complexes is regarded as an innovative method to increase the RS content and optimize nutrition. Polyphenols and starch are mainly combined in two ways: one is that the left-handed single helix cavity of amylose loads small molecule guests to form an inclusion complex; the other is to form a non-inclusion complex through non-covalent interactions with starch molecules through hydrogen bonds, hydrophobic interactions, and electrostatic interactions.

[0003] Starch has a wide source in nature, and its multi-level structure has diversity. The structural differences will affect its interaction with polyphenols, and the structural characteristics are crucial for the functional properties of starch. For example, the crystal form of starch has a certain influence on its digestion. The V-type crystal, that is, the single helix amylose complex, has anti-digestibility. In the presence of guests such as polyphenols, starch can form a single helix structure, thereby loading small molecule substances such as polyphenols to form RS5 type resistant starch. The starch-based sustained-release carrier can also protect polyphenols from the digestive environment.

[0004] Sesamol, also known as 3,4-methylenedioxyphenol, is a natural extract of sesame plants and the main aroma component and antioxidant in sesame oil. The phenolic hydroxyl group and benzodioxy ring in its molecular structure give sesamol super antioxidant properties and free radical scavenging ability. Sesamol also has excellent anti-inflammatory, antioxidant, anti-apoptotic and immunomodulatory functions. Sesamol has good thermal stability, but it is unstable under acidic conditions of pH <5. In order to deliver sesamol to the target site to exert biological activity and avoid gastric acid degradation, it is very necessary to construct a natural carrier loaded with sesamol. However, there has been no research on sesamol RS5 resistant starch products at home and abroad. From the many starches, how to find a starch carrier with a high loading capacity for sesamol, maximize the loading capacity of sesamol, and improve the physiological activity and digestibility of the product are problems that need to be solved urgently. Summary of the invention

[0005] Purpose of the invention: The present application provides a method for preparing RS5 resistant starch loaded with sesamol by using hydration-co-gelatinization technology, and at the same time provides a new RS5 resistant starch product, in which sesamol and taro are effectively utilized at the same time.

[0006] Technical problem: Find a starch carrier that matches sesamol from a variety of starches. How to maximize the sesamol loading based on the properties of the raw materials and how to use technical means, while also effectively improving the product's physiological activity and resistance to digestion.

[0007] Technical solution:

[0008] A method for preparing sesamol-cano RS5 resistant starch by hydration-cogelatinization, characterized in that it comprises the following steps:

[0009] (1) Defatting of taro starch;

[0010] (2) Hydration-co-gelatinization: Add sesamol, distilled water, and defatted yam starch obtained in step (1) to a pre-prepared aluminum can, mix well at 25-35° C., and hydrate for 0.5 h; heat the hydrated mixture to 45-55° C., equilibrate at 45-55° C. for 1-2 min, heat the mixture to 90-95° C., and maintain the temperature for 20-30 min, then cool the mixture to 45-55° C. and maintain the temperature for 2-3 min, take out the mixture, and gradually cool it to 20-25° C. to obtain a sesamol-yam starch complex;

[0011] (3) Drying and washing: Place the sesamol-canna starch complex obtained in step (2) in a refrigerator at -18 - 20 °C and freeze it for 12 - 15 h, then place it in a freeze dryer for drying; Wash the freeze-dried sample three times with an ethanol solution of 50 - 55% to remove free sesamol, and obtain sesamol-canna RS5 type resistant starch.

[0012] Preferably, in step (2): The heating-up, the heating, and the cooling are all carried out at a rate of 10 °C / min.

[0013] Preferably, for the hydration-cogelling in step (2): Add sesamol, distilled water, and the defatted canna starch obtained in step (1) into a pre-prepared aluminum can, mix them evenly at 30 °C and hydrate for 0.5 h; Heat up the hydrated mixture to 50 °C, after equilibration at 50 °C for 1 min, heat the mixture to 95 °C and hold at this temperature for 25 min, then cool to 50 °C and hold for 2 min, take it out and let it cool gradually to 25 °C to obtain the sesamol-canna starch complex;

[0014] Preferably, in step (1), a Soxhlet extraction device is used for the defatting treatment. Preferably, the mass-volume ratio of the canna starch (dry basis) to petroleum ether is 1:5 (m / v), and the defatting time is 15 h.

[0015] In step (2), the mass ratio of sesamol, distilled water, and the defatted canna starch is 0.01 - 0.1:10:1, where the defatted canna starch is based on dry basis.

[0016] Obtain an RS5 type resistant starch product with excellent composite index, sesamol loading amount, and resistant starch content.

[0017] In this application, canna starch is effectively applied. In improving the sesamol loading amount, compared with phloroglucinol and tea polyphenols, the sesamol loading amount can reach 3.85 mg / g.

[0018] In the above scheme, the starch can be replaced with mung bean starch, pea starch, or sweet potato starch.

[0019] Technical effects:

[0020] 1. It is unexpectedly found among numerous starches that canna starch can be used as the best carrier for sesamol, and an RS5 type resistant starch with excellent composite index, loading amount, and RS starch content can be obtained. The sesamol loading amount reaches 3.85 mg / g, the composite index reaches 76.76%, and the RS content reaches 87.84% (see Figures 1-4)。Meanwhile, the optimal mass ratio of sesamol, distilled water, and defatted canna starch is determined to be 0.01 - 0.1:10:1. Canna starch itself has many advantages such as high raw material yield, low fat, low total sugar content, and strong anti - enzymatic hydrolysis. The prepared sesamol - canna RS5 - type resistant starch product can be widely used as raw and auxiliary materials in the fields of food, medicine, and feed.

[0021] 2. Utilize the characteristics of canna starch, such as relatively high amylose content, relatively short and regularly arranged amylopectin branches, and relatively low gelatinization temperature. At the same time, utilize the relatively small skeleton structure of sesamol. Combine the two through a specific hydration - co - gelatinization technology. The moderate hydration treatment before gelatinization causes the canna starch with a lower gelatinization temperature to undergo mild swelling. With temperature and time control, the effective gelatinization during the whole process promotes the release of a large amount of amylose in the canna starch granules. Most of the sesamol is nested in the hydrophobic helical cavity of the starch to form a V - type inclusion complex, reducing the contact opportunity between starch and starch - hydrolyzing enzymes, lowering the enzymatic hydrolysis efficiency of starch, and enabling sesamol to be transmitted to the colon to exert its biological activity. Another small part forms a non - V - type complex through hydrogen bonds, van der Waals forces, hydrophobic interactions, electrostatic interactions, etc. between the hydroxyl groups of sesamol and canna starch. The amylopectin of canna starch has an appropriate chain length, degree of branching, and arrangement, reducing the steric hindrance between amylopectin molecules. The reduction of steric hindrance is conducive to the formation of a non - inclusion complex between sesamol molecules and amylopectin. The appropriate ratio of the V - type inclusion complex and the non - V - type complex ultimately results in the sesamol RS5 - type resistant starch complex having the characteristics of high complex index, high loading capacity, and high RS content. And the whole reaction process is simple, without adding other reagents / auxiliaries, and without relying on other means (such as ultra - high pressure, microwave, ultrasonic wave, etc.). Compared with the prior art, the process is simple, low - cost, and pollution - free.

[0022] 3. The formation of the sesamol - starch complex increases the content of resistant starch. The content of resistant starch in the complex increases from 24.00% - 45.00% to 40.00% - 85.00%. The RS contents of Example 1 (mung bean), Example 2 (pea), and Example 3 (canna) are 88.14%, 91.84%, and 87.84% respectively (see Figure 3 ), which also indicates that the B + V - type starch - sesamol complex has the potential to stabilize post - meal blood glucose levels. The local ordered structure of the B + V crystal blocks the catalytic sites of digestive enzymes. During digestion, the starch - sesamol complex gradually releases sesamol, and then shows an inhibitory ability to amylase. This inhibition of enzyme activity slows down the hydrolysis of starch into glucose, thus helping to reduce post - meal blood glucose levels and promoting intestinal health at the same time.

[0023] 4. The starch-sesamol complex has strong antioxidant ability. The DPPH radical scavenging ability and ABTS radical scavenging ability of the complex are positively correlated with the concentration. When the concentration of the complex is 10 mg / mL, the scavenging abilities of DPPH and ABTS radicals are respectively in the range of 59.86% - 69.52% and 62.69% - 71.40%. The difference in antioxidant ability among different starches is attributed to the content of loaded sesamol and the exposure degree of the active groups of sesamol in the complex. The binding degree of starch and sesamol affects its antioxidant ability. Compounds with a higher amylose content can form more V-type structures. This compact structure leads to stronger intramolecular interactions, limits the exposure of active groups, and thus reduces its biological activity. On the contrary, compounds with a higher amylopectin content form more non-V-shaped structures, in which the binding of sesamol is less tight, thereby enhancing its scavenging ability in antioxidant assays.

[0024] Index determination method:

[0025] Determination of the complex index (CI):

[0026] The CI of the starch-sesamol complex indicates the degree of complex formation. Weigh 100 mg of starch and starch-sesamol complex samples respectively, and then disperse the samples in 10 mL of slightly boiling water and heat them in boiling water for 30 min. Subsequently, add 150 mL of distilled water to make the final solution concentration reach 0.625 mg / mL. Take 0.9 mL of this solution, mix it with 0.1 mL of iodine reagent (consisting of 0.2% I2 and 2% KI), and make up the volume to 10 mL with deionized water. Stir the mixture quickly and evenly and let it stand for 10 min. Then scan the absorbance in the range of 500 - 900 nm, and calculate the CI value of the sample according to the absorbance measured at 620 nm. See formula 1 for details.

[0027]

[0028] In the formula: ABS 淀粉 —Absorbance of the starch sample, ABS 复合物 —Absorbance of the corresponding complex sample.

[0029] Determination of the loading amount of sesamol:

[0030] The content of sesamol was evaluated using the Folin-Ciocalteu method. 40 mg (dry weight) of the starch-sesamol complex was dissolved in 4 mL of dimethyl sulfoxide, and then centrifuged at 4000×g for 10 min. 2 mL of the supernatant was taken and mixed with 1 mL of 0.25 mol / L Folin-Ciocalteu reagent and mixed well. Subsequently, 4 mL of 10% (w / w) sodium carbonate solution was added, and the mixture was stored in the dark at room temperature for 120 min. The absorbance of the solution was measured at 765 nm using a microplate reader. A standard curve of sesamol was established, using the equation Y = 0.1513X + 0.0895, with an R 2 value of 0.9908, and then this equation was used to calculate the actual content of sesamol in the complex.

[0031] DPPH radical scavenging ability:

[0032] The DPPH radical scavenging ability of the starch-sesamol complex was evaluated. DPPH was dissolved in absolute ethanol to prepare a DPPH solution with a concentration of 0.1 mmol / L. The test samples were diluted with deionized water to a concentration of 2 - 10 mg / mL. 1.0 mL aliquots of the sample solution were mixed with 5.0 mL of the DPPH solution, mixed well, and reacted in the dark at room temperature for 30 minutes. Subsequently, the absorbance was measured at 517 nm. The DPPH radical scavenging rate was calculated using formula (3).

[0033]

[0034] where, A 0 — Absorbance measured with deionized water instead of the sample, A — Absorbance measured of the sample.

[0035] ABTS radical scavenging ability:

[0036] 0.1 g of ABTS and 0.029 g of potassium persulfate (K2O8S2) were weighed and then dissolved in deionized water to prepare 100 mL of the ABTS radical stock solution. The stock solution was stored in the dark at 4 °C for 12 h. The stock solution was diluted with PBS (0.1 mol / L, pH 7.4) until the absorbance at 734 nm reached 0.700 ± 0.005. The test samples were diluted with deionized water to a concentration of 2 - 10 mg / mL. 0.1 mL of the sample solution was mixed well with 2 mL of the ABTS solution, and then the absorbance was measured at 734 nm. The ABTS radical scavenging rate was calculated using formula (4).

[0037]

[0038] where, A0 — Absorbance with deionized water instead of the sample, A1 — Absorbance of the sample; A2 — Absorbance with deionized water instead of the ABTS solution.

[0039] Determination of RDS, SDS, and RS:

[0040] For the digestibility of starch and the complex, an enzyme solution was prepared by mixing equal volumes of freshly prepared α - amylase (100 U / mL) and amyloglucosidase (100 U / mL). To simulate the digestion process, 200 mg (dry basis) of the sample was weighed, dispersed in sodium acetate buffer solution (15 mL, 0.5 mol / L, pH 5.2), boiled in boiling water for 30 min, and then equilibrated in a shaking incubator at 37 °C for 30 min. Subsequently, 5 mL of the mixed enzyme solution was added. The oscillation frequency during digestion was set to 150 r / min, and the total digestion process lasted for 180 minutes. At 5, 10, 15, 20, 60, 120, and 180 min during digestion, 0.5 mL of the digestion solution was sampled and placed in 4 mL of 75% (v / v) ethanol solution to inactivate the enzyme. Then, the DNS reagent was used to detect the released glucose content. The starch digestibility (%) and the contents of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) were calculated using the following formula:

[0041]

[0042] In the formula, 0.9 is the conversion coefficient of starch to glucose, G 20 and G 120 represent the glucose contents at 20 min and 120 min, respectively.

[0043] The above - mentioned determination method can also adopt other conventional methods. Brief Description of the Drawings

[0044] Figure 1 : The loading capacity of various starches for sesamol;

[0045] Figure 2 : The complex index of sesamol and various starches;

[0046] Figure 3 : The RDS, SDS, and RS contents of each RS5 - type resistant starch complex;

[0047] Figure 4 : The loading capacity of various starches for sesamol, phloroglucinol, and tea polyphenols. Detailed Description of the Invention

[0048] The following specific examples are used to further explain the present invention, but the examples do not limit the present invention in any form.

[0049] Sesamol, phloroglucinol, and tea polyphenols can be purchased commercially or extracted by conventional methods. Other raw materials and equipment can be purchased and used conventionally, which will not be elaborated here. The experiments were carried out in parallel under scientific and reasonable designs.

[0050] Example 1

[0051] 1. A method for preparing sesamol-mung bean RS5 type resistant starch by hydration-copasting, which is characterized by comprising the following steps:

[0052] (1) Degreasing treatment of mung bean starch: Mix the mung bean starch (dry basis) with petroleum ether in a mass-to-volume ratio of 1:5 (m / v) for degreasing, and the degreasing time is 15 h;

[0053] (2) Hydration-copasting: Add sesamol, distilled water, and the degreased mung bean starch obtained in step (1) into a pre-prepared aluminum can. The mass ratio of sesamol, distilled water, and the degreased mung bean starch is 0.05:10:1, where the degreased mung bean starch is based on dry basis. Mix well at 30 °C and hydrate for 0.5 h; Heat the hydrated mixture to 50 °C, balance for 1 min at 50 °C, then heat the mixture to 95 °C and hold at this temperature for 25 min, then cool to 50 °C and hold for 2 min, take out and gradually cool to 25 °C to obtain a sesamol-mung bean starch complex; The heating-up, the heating, and the cooling are all carried out at a rate of 10 °C / min;

[0054] (3) Drying and washing: Place the sesamol-mung bean starch complex obtained in step (2) in a -20 °C refrigerator and freeze for 12 h, then dry it in a freeze dryer; Wash the freeze-dried sample three times with a 50% ethanol solution to remove free sesamol, and obtain sesamol-mung bean RS5 type resistant starch.

[0055] Example 2

[0056] 1. A method for preparing sesamol-pea RS5 type resistant starch by hydration-copasting, which is characterized by comprising the following steps:

[0057] (1) Degreasing treatment of pea starch: Mix the pea starch (dry basis) with petroleum ether in a mass-to-volume ratio of 1:5 (m / v) for degreasing, and the degreasing time is 15 h;

[0058] (2) Hydration-copasting: Add sesamol, distilled water, and the defatted pea starch obtained in step (1) into a pre-prepared aluminum can. The mass ratio of sesamol, distilled water, and the defatted pea starch is 0.05:10:1, where the defatted pea starch is calculated on a dry basis. Mix well at 30°C and hydrate for 0.5 h; heat the hydrated mixture to 50°C, balance for 1 min at 50°C, then heat the mixture to 95°C and hold at this temperature for 25 min, then cool to 50°C and hold for 2 min, take out and gradually cool to 25°C to obtain the sesamol-pea starch complex; the heating-up, the heating, and the cooling are all carried out at a rate of 10°C / min;

[0059] (3) Drying and washing: Place the sesamol-pea starch complex obtained in step (2) in a -20°C refrigerator and freeze for 12 h, then place it in a freeze dryer for drying; wash the freeze-dried sample three times with a 50% ethanol solution to remove free sesamol, and obtain sesamol-pea RS5 type resistant starch.

[0060] Example 3

[0061] A method for preparing sesamol-canna RS5 type resistant starch by hydration-copasting, which is characterized by comprising the following steps:

[0062] (1) Defatting treatment of canna starch: The mass-volume ratio of the canna starch (calculated on a dry basis) to petroleum ether is 1:5 (m / v), and the defatting time is 15 h;

[0063] (2) Hydration-copasting: Add sesamol, distilled water, and the defatted canna starch obtained in step (1) into a pre-prepared aluminum can. The mass ratio of sesamol, distilled water, and the defatted canna starch is 0.05:10:1, where the defatted canna starch is calculated on a dry basis. Mix well at 30°C and hydrate for 0.5 h; heat the hydrated mixture to 50°C, balance for 1 min at 50°C, then heat the mixture to 95°C and hold at this temperature for 25 min, then cool to 50°C and hold for 2 min, take out and gradually cool to 25°C to obtain the sesamol-canna starch complex; the heating-up, the heating, and the cooling are all carried out at a rate of 10°C / min;

[0064] (3) Drying and washing: Place the sesamol-canna starch complex obtained in step (2) in a -20°C refrigerator and freeze for 12 h, then place it in a freeze dryer for drying; wash the freeze-dried sample three times with a 50% ethanol solution to remove free sesamol, and obtain sesamol-canna RS5 type resistant starch.

[0065] Example 4

[0066] 1. A method for preparing sesamol - potato RS5 - type resistant starch by hydration - co - gelatinization, characterized by comprising the following steps:

[0067] (1) Degreasing treatment of potato starch: The mass - to - volume ratio of the potato starch (on a dry - basis) to petroleum ether is 1:5 (m / v), and the degreasing time is 15 h;

[0068] (2) Hydration - co - gelatinization: Add sesamol, distilled water, and the degreased potato starch obtained in step (1) into a pre - prepared aluminum can. The mass - fraction ratio of sesamol, distilled water, and the degreased potato starch is 0.05:10:1, where the degreased potato starch is on a dry - basis. Mix well at 30 °C and hydrate for 0.5 h; Heat the hydrated mixture to 50 °C, balance for 1 min at 50 °C, then heat the mixture to 95 °C and hold at this temperature for 25 min, then cool to 50 °C and hold for 2 min, take out and gradually cool to 25 °C to obtain a sesamol - potato starch complex; The heating - up, the heating, and the cooling are all carried out at a rate of 10 °C / min;

[0069] (3) Drying and washing: Place the sesamol - potato starch complex obtained in step (2) in a - 20 °C refrigerator and freeze for 12 h, then dry it in a freeze - dryer; Wash the freeze - dried sample three times with a 50% ethanol solution to remove free sesamol, and obtain sesamol - potato RS5 - type resistant starch.

[0070] Example 5

[0071] 1. A method for preparing sesamol - wheat RS5 - type resistant starch by hydration - co - gelatinization, characterized by comprising the following steps:

[0072] (1) Degreasing treatment of wheat starch: The mass - to - volume ratio of the wheat starch (on a dry - basis) to petroleum ether is 1:5 (m / v), and the degreasing time is 15 h;

[0073] (2) Hydration - co - gelatinization: Add sesamol, distilled water, and the degreased wheat starch obtained in step (1) into a pre - prepared aluminum can. The mass - fraction ratio of sesamol, distilled water, and the degreased wheat starch is 0.05:10:1, where the degreased wheat starch is on a dry - basis. Mix well at 30 °C and hydrate for 0.5 h; Heat the hydrated mixture to 50 °C, balance for 1 min at 50 °C, then heat the mixture to 95 °C and hold at this temperature for 25 min, then cool to 50 °C and hold for 2 min, take out and gradually cool to 25 °C to obtain a sesamol - wheat starch complex; The heating - up, the heating, and the cooling are all carried out at a rate of 10 °C / min;

[0074] (3) Drying and washing: Place the sesamol - wheat starch complex obtained in step (2) in a refrigerator at -20°C for 12 h, and then dry it in a freeze dryer; Wash the lyophilized sample three times with a 50% ethanol solution to remove free sesamol, obtaining sesamol - wheat RS5 resistant starch.

[0075] Example 6

[0076] 1. A method for preparing sesamol - corn RS5 resistant starch by hydration - co - gelatinization, characterized by comprising the following steps:

[0077] (1) Degreasing treatment of corn starch: The mass - to - volume ratio of the corn starch (on a dry basis) to petroleum ether is 1:5 (m / v), and the degreasing time is 15 h;

[0078] (2) Hydration - co - gelatinization: Add sesamol, distilled water, and the degreased corn starch obtained in step (1) to a pre - prepared aluminum can. The mass ratio of sesamol, distilled water, and the degreased corn starch is 0.05:10:1, where the degreased corn starch is on a dry basis. Mix well at 30°C and hydrate for 0.5 h; Heat the hydrated mixture to 50°C, balance for 1 min at 50°C, then heat the mixture to 95°C and hold at this temperature for 25 min, then cool to 50°C and hold for 2 min, take out and gradually cool to 25°C to obtain a sesamol - corn starch complex; The heating - up, heating, and cooling are all carried out at a rate of 10°C / min;

[0079] (3) Drying and washing: Place the sesamol - corn starch complex obtained in step (2) in a refrigerator at -20°C for 12 h, and then dry it in a freeze dryer; Wash the lyophilized sample three times with a 50% ethanol solution to remove free sesamol, obtaining sesamol - corn RS5 resistant starch.

[0080] Example 7

[0081] 1. A method for preparing sesamol - sweet potato RS5 resistant starch by hydration - co - gelatinization, characterized by comprising the following steps:

[0082] (1) Degreasing treatment of sweet potato starch: The mass - to - volume ratio of the sweet potato starch (on a dry basis) to petroleum ether is 1:5 (m / v), and the degreasing time is 15 h;

[0083] (2) Hydration - co - gelatinization: Add sesamol, distilled water, and the defatted sweet potato starch obtained in step (1) into a pre - prepared aluminum can. The mass - part ratio of sesamol, distilled water, and the defatted sweet potato starch is 0.05:10:1, where the defatted sweet potato starch is based on dry basis. Mix well at 30°C and hydrate for 0.5 h; heat the hydrated mixture to 50°C, balance for 1 min at 50°C, then heat the mixture to 95°C and hold at this temperature for 25 min, then cool to 50°C and hold for 2 min, take out and gradually cool to 25°C to obtain the sesamol - sweet potato starch complex; the heating - up, the heating, and the cooling are all carried out at a rate of 10°C / min.

[0084] (3) Drying and washing: Place the sesamol - sweet potato starch complex obtained in step (2) in a - 20°C refrigerator and freeze for 12 h, then place it in a freeze - dryer for drying; wash the freeze - dried sample three times with a 50% ethanol solution to remove free sesamol, and obtain sesamol - sweet potato RS5 - type resistant starch.

[0085] Example 8

[0086] 1. A method for preparing sesamol - cassava RS5 - type resistant starch by hydration - co - gelatinization, characterized by comprising the following steps:

[0087] (1) Defatting treatment of cassava starch: The mass - volume ratio of the cassava starch (based on dry basis) to petroleum ether is 1:5 (m / v), and the defatting time is 15 h.

[0088] (2) Hydration - co - gelatinization: Add sesamol, distilled water, and the defatted cassava starch obtained in step (1) into a pre - prepared aluminum can. The mass - part ratio of sesamol, distilled water, and the defatted cassava starch is 0.05:10:1, where the defatted cassava starch is based on dry basis. Mix well at 30°C and hydrate for 0.5 h; heat the hydrated mixture to 50°C, balance for 1 min at 50°C, then heat the mixture to 95°C and hold at this temperature for 25 min, then cool to 50°C and hold for 2 min, take out and gradually cool to 25°C to obtain the sesamol - cassava starch complex; the heating - up, the heating, and the cooling are all carried out at a rate of 10°C / min.

[0089] (3) Drying and washing: Place the sesamol - cassava starch complex obtained in step (2) in a - 20°C refrigerator and freeze for 12 h, then place it in a freeze - dryer for drying; wash the freeze - dried sample three times with a 50% ethanol solution to remove free sesamol, and obtain sesamol - cassava RS5 - type resistant starch.

[0090] Example 9

[0091] 1. A method for preparing sesamol - indica rice RS5 - type resistant starch by hydration - co - gelatinization, which is characterized by comprising the following steps:

[0092] (1) Degreasing treatment of indica rice starch: The mass - volume ratio of the indica rice starch (dry basis) to petroleum ether is 1:5 (m / v), and the degreasing time is 15 h;

[0093] (2) Hydration - co - gelatinization: Add sesamol, distilled water, and the degreased indica rice starch obtained in step (1) into a pre - prepared aluminum can. The mass - portion ratio of sesamol, distilled water, and the degreased indica rice starch is 0.05:10:1, where the degreased indica rice starch is based on dry basis. Mix well and hydrate at 30 °C for 0.5 h; heat the hydrated mixture to 50 °C, after equilibrating for 1 min at 50 °C, heat the mixture to 95 °C and hold at this temperature for 25 min, then cool to 50 °C and hold for 2 min, take out and gradually cool to 25 °C to obtain a sesamol - indica rice starch complex; the heating up, the heating, and the cooling are all carried out at a rate of 10 °C / min;

[0094] (3) Drying and washing: Place the sesamol - indica rice starch complex obtained in step (2) in a - 20 °C refrigerator and freeze for 12 h, then place it in a freeze - dryer for drying; wash the freeze - dried sample three times with a 50% ethanol solution to remove free sesamol, and obtain sesamol - indica rice RS5 - type resistant starch.

[0095] Comparative Examples 1 - 9

[0096] Degreased starch not complexed with sesamol: Degreasing treatment of starch: The mass - volume ratio of starch (dry basis) to petroleum ether is 1:5 (m / v), and the degreasing time is 15 h; The starches are successively selected as mung bean starch, pea starch, canna starch, potato starch, wheat starch, corn starch, sweet potato starch, cassava starch, and indica rice starch.

Claims

1. A method for preparing sesamol-canna RS5 resistant starch by hydration-cogelatinization, characterized in that: The following steps are involved: (1) Defatting of taro starch; (2) Hydration-co-gelatinization: Add sesamol, distilled water, and defatted yam starch obtained in step (1) to a pre-prepared aluminum can, mix well at 25-35° C., and hydrate for 0.5 h; heat the hydrated mixture to 45-55° C., equilibrate at 45-55° C. for 1-2 min, heat the mixture to 90-95° C., and maintain the temperature for 20-30 min, then cool the mixture to 45-55° C. and maintain the temperature for 2-3 min, take out the mixture, and gradually cool it to 20-25° C. to obtain a sesamol-yam starch complex; (3) Drying and washing: The sesamol-canna starch complex obtained in step (2) is placed in a -18--20°C refrigerator for 12-15 hours, and then dried in a freeze dryer; the freeze-dried sample is washed three times with a 50-55% ethanol solution to remove free sesamol, thereby obtaining sesamol-canna RS5 resistant starch.

2. The method according to claim 1, characterized in that: In step (2): the temperature increase, the heating and the cooling are all performed at a rate of 10°C / min.

3. The method according to any one of claims 1 to 2, characterized in that: Step (2) hydration-co-gelatinization: add sesamol, distilled water and the defatted yam starch obtained in step (1) into a pre-prepared aluminum can, mix them thoroughly and hydrate them at 30° C. for 0.5 h; heat the hydrated mixture to 50° C., balance at 50° C. for 1 min, heat the mixture to 95° C. and keep it at this temperature for 25 min, then cool it to 50° C. and keep it at this temperature for 2 min, take it out and gradually cool it to 25° C. to obtain a sesamol-yam starch complex.

4. The method according to any one of claims 1 to 2, characterized in that: In step (1), the degreasing treatment is carried out using a Soxhlet extraction apparatus, preferably the mass volume ratio of canna starch (on a dry basis) to petroleum ether is 1:5 (m / v), and the degreasing time is 15 hours.

5. The method according to any one of claims 1-2, characterized in that: In step (2), the mass ratio of sesamol, distilled water and the defatted taro starch is 0.01-0.1:10:1, wherein the defatted taro starch is calculated on a dry basis.

6. A sesamol RS5 type resistant starch having excellent composite index, loading amount and resistant starch content, characterized in that: Prepared by the method according to any one of claims 1 to 5, the loading amount of sesamol is 3.85 mg / g, the composite index is 76.76%, and the RS starch content is 87.84%.

7. The application of yam starch in increasing the loading amount of sesamol is characterized in that: In the process of preparing RS5 resistant starch using the method described in any one of claims 1 to 5, the loading amount of sesamol can reach 3.85 mg / g compared with maliphenol and tea polyphenols.

8. Use of the RS5 resistant starch according to claim 6 in the preparation of functional foods, medicines and feeds.

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