Preparation method of nanoscale sorghum starch-polyphenol compound and product

Abstract

The invention relates to a preparation method of a nanoscale sorghum starch-polyphenol compound and a product, and belongs to the technical field of starch deep processing and nanoparticle preparation, and the preparation method comprises the following steps: (1) carrying out enzymolysis treatment on sorghum starch to obtain sorghum starch with different amylose contents and chain length distribution; (2) compounding the sorghum starch subjected to enzymolysis with different types of polyphenol substances to prepare a sorghum starch-polyphenol compound; and (3) adopting an absolute ethyl alcohol precipitation method to obtain the nanoscale sorghum starch-polyphenol compound. The prepared nanoscale sorghum starch-polyphenol compound is small in size and good in digestion resistance, has important significance in regulating postprandial blood sugar balance of a human body, and meanwhile can achieve delivery of micromolecular active substances such as polyphenol and the like.

Description

Technical Field

[0001] The invention belongs to the field of starch deep processing and nano-particle preparation, and specifically relates to a method for preparing a nano-level sorghum starch-polyphenol complex. Background Art

[0002] Nano-sized starch particles are widely used in the food industry because of their small size, large specific surface area, and cheap and readily available raw materials. At the same time, nano-sized starch particles can also be used as carriers of functional factors to protect unstable bioactive substances. Polyphenols have multiple biological activities such as antioxidant, anti-cancer, anti-inflammatory and antibacterial. However, some hydrophobic polyphenols have low bioavailability and low stability in the gastrointestinal tract, which limits the application of polyphenols in the food industry.

[0003] Starch can form a complex with polyphenols, and the properties of the starch such as the content of amylose in the starch will affect the properties of the complex. When the content of amylose is high, polyphenols can enter the interior of the starch spiral structure, which is of great significance for regulating the body's postprandial blood sugar balance. The nano-scale starch-polyphenol complex can not only maintain the body's postprandial blood sugar balance, but also help to achieve the protection and delivery of polyphenols. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for preparing a nano-scale sorghum starch-polyphenol complex. The nano-scale sorghum starch-polyphenol complex prepared by the method has a small size, a high yield, and a high digestion resistance, and can also increase the added value of sorghum.

[0005] The specific technical solutions of the present invention are as follows:

[0006] A method for preparing a nano-scale sorghum starch-polyphenol complex comprises the following steps:

[0007] (1) Enzymatic hydrolysis of sorghum starch: prepare 3-10 g / 100 mL sorghum starch solution, gelatinize it in a boiling water bath, and then add pullulanase at a ratio of 20-80 U per gram of starch to perform enzymatic hydrolysis for 2-12 hours;

[0008] (2) Preparation of sorghum starch-polyphenol complex: adding an anhydrous ethanol solution of polyphenols to the sorghum starch solution after enzymatic hydrolysis in step (1), and carrying out a complex reaction at a temperature of 30 to 90° C. for 30 min to obtain a sorghum starch-polyphenol complex suspension;

[0009] (3) Preparation of nano-scale sorghum starch-polyphenol complex: 3 to 10 times the volume of anhydrous ethanol was added dropwise to the sorghum starch-polyphenol complex suspension, the polyphenols that did not participate in the reaction were removed by centrifugation, and the precipitate was freeze-dried to obtain the nano-scale sorghum starch-polyphenol complex.

[0010] The polyphenols described in step (2) are preferably one or more of resveratrol, quercetin or proanthocyanidins, and the amount used is 5% to 30% of the mass of the sorghum starch.

[0011] The present invention also claims to protect the nano-scale sorghum starch-polyphenol complex prepared by the method.

[0012] Beneficial effects:

[0013] Compared with the prior art, the nano-scale sorghum starch-polyphenol complex prepared by the present invention has the beneficial effects of small size, good digestibility, etc. The prepared nano-scale sorghum starch-polyphenol complex of the present invention is of great significance for regulating the postprandial blood sugar balance of the human body, and can also realize the delivery of small molecular active substances such as polyphenols. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The size and PDI of sorghum starch-resveratrol complex in Example 2.

[0015] Figure 2 The resistant starch content in the sorghum starch-resveratrol complex of Example 3. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with reference to specific embodiments and accompanying drawings.

[0017] Example 1

[0018] 2.5 g of sorghum starch was weighed and dissolved in 50 mL of sodium acetate buffer, and gelatinized in a 90° C. water bath pot for 30 min; when the temperature of the sorghum starch paste solution was reduced to 58° C., 100 U of pullulanase was added for different enzymatic hydrolysis times; after enzymatic hydrolysis, the enzyme was inactivated at 100° C. The amylose content in the sorghum starch after different enzymatic hydrolysis times is shown in Table 1 (the sorghum starch after enzymatic hydrolysis for 0 h, 2 h, 4 h, 6 h, 8 h, and 12 h was named SS0, SS2, SS4, SS6, SS8, and SS12, respectively); the temperature of the starch paste solution after enzymatic hydrolysis was maintained at 30° C., a resveratrol solution with a concentration of 100 mg / mL was added dropwise, and a sorghum starch-resveratrol complex suspension was obtained after maintaining at 30° C., an ethanol solution with a volume 3 times that of the suspension was added dropwise, centrifuged at 4000 g for 5 min, washed twice with anhydrous ethanol, and the precipitate was freeze-dried to obtain a nano-scale sorghum starch-resveratrol complex. The contents of amylose in sorghum starch obtained by enzymatic hydrolysis at different times are shown in Table 1.

[0019] Table 1 Amylose content in sorghum starch at different enzymatic hydrolysis times

[0020]

[0021] Example 2

[0022] 2.5 g of sorghum starch was weighed and dissolved in 50 mL of sodium acetate buffer, and gelatinized in a 90° C. water bath for 30 min; when the temperature of the sorghum starch paste solution was reduced to 58° C., 100 U of pullulanase was added, and the starch paste solution after enzymatic hydrolysis for 8 h was subjected to enzyme inactivation treatment at 100° C., and then the temperature was maintained at 90° C., and an ethanol solution of resveratrol was added dropwise, wherein the ethanol solution of resveratrol was obtained by dissolving 5%-30% of resveratrol by weight of starch in 5 mL of ethanol, and the sorghum starch-resveratrol complex suspension was obtained after maintaining the temperature at 90° C. for 30 min, and then 3 times the volume of the suspension was added with an ethanol solution, centrifuged at 4000 g for 5 min, washed twice with anhydrous ethanol, and the precipitate was freeze-dried to obtain a nano-scale sorghum starch-resveratrol complex named (SS8-R5, SS8-R10, SS8-R20, SS8-R25, SS8-R30), and its size and PDI were as follows Figure 1 As shown. Figure 1 It can be seen that the size of the obtained sorghum starch-resveratrol complexes is all nanoscale. At the same time, resveratrol enters the interior of the helical structure of amylose in sorghum starch through hydrophobic interactions. As the resveratrol content increases, the particle size gradually increases.

[0023] Example 3

[0024] Weigh 2.5g sorghum starch and dissolve it in 50mL sodium acetate buffer, and gelatinize it in a 90℃ water bath for 30min; when the temperature of the sorghum starch paste solution drops to 58℃, add 100U pullulanase, and the starch paste solution after 8h of enzymolysis is treated with enzyme inactivation at 100℃, then the temperature is maintained at 90℃, and resveratrol (5%-30%) of different starch masses is added dropwise. After maintaining at 90℃ for 30min, a sorghum starch-resveratrol complex is obtained, and 3 times the volume of ethanol solution is added, centrifuged at 4000g for 5min, washed twice with anhydrous ethanol, and the precipitate is freeze-dried to obtain a nanoscale sorghum starch-resveratrol complex named (SS8-R5, SS8-R10, SS8-R20, SS8-R25, SS8-R30), respectively. Sorghum starch nanoparticles prepared without resveratrol are used as blanks. The resistant starch content of the obtained complex after adding resveratrol is as follows: Figure 2 As shown. Figure 2 It can be seen that the addition of resveratrol promoted the formation of sorghum starch-resveratrol complex, increased the content of resistant starch in sorghum starch, and thus improved the digestion resistance of sorghum starch.

Claims

1. A method for preparing a nano-scale sorghum starch-polyphenol complex, comprising the following steps: (1) Enzymatic hydrolysis of sorghum starch: prepare 3-10 g / 100 mL sorghum starch solution, gelatinize it in a boiling water bath, and then add pullulanase at a ratio of 20-80 U per gram of starch to perform enzymatic hydrolysis for 2-12 hours; (2) Preparation of sorghum starch-polyphenol complex: adding an anhydrous ethanol solution of polyphenols to the sorghum starch solution after enzymatic hydrolysis in step (1), and carrying out a complex reaction at a temperature of 30 to 90° C. for 30 min to obtain a sorghum starch-polyphenol complex suspension; (3) Preparation of nano-scale sorghum starch-polyphenol complex: 3 to 10 times the volume of anhydrous ethanol was added dropwise to the sorghum starch-polyphenol complex suspension, the polyphenols that did not participate in the reaction were removed by centrifugation, and the precipitate was freeze-dried to obtain the nano-scale sorghum starch-polyphenol complex.

2. The method for preparing a nano-scale sorghum starch-polyphenol composite according to claim 1, characterized in that: The polyphenols described in step (2) are one or more of resveratrol, quercetin or proanthocyanidins, and the amount used is 5% to 30% of the mass of the sorghum starch.

3. A nano-scale sorghum starch-polyphenol composite, characterized in that: The method is prepared by any one of claims 1 to 2.

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