Slow-digestion high-nutrition starch-ham peptide compound and preparation method thereof

Abstract

The invention belongs to the technical field of food processing, and particularly discloses a slowly-digestible high-nutrition starch-ham peptide compound and a preparation method thereof. The preparation method comprises the following steps: S1, dispersing and dissolving purified ham peptide powder in deionized water, adjusting the pH value of the solution, and heating and stirring in a water bath until the ham peptide powder is completely dissolved to obtain a mixed solution; s2, adding potato starch into the mixed solution obtained in S1, and heating and stirring in a water bath to obtain a mixture; and S3, transferring the mixture obtained in S2 into a reaction kettle, drying, crushing, sieving, carrying out heat treatment, drying again, crushing and sieving to obtain the slowly-digestible high-nutrition starch-ham peptide compound. The invention discloses a slowly-digestible high-nutrition starch-ham peptide compound and a preparation method thereof. The starch-ham peptide compound has high nutritional value, increases the content of slowly-digestible starch and resistant starch, reduces the digestibility of starch, and is beneficial to controlling the postprandial blood sugar level.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and particularly relates to a slowly digestible and highly nutritious starch - ham peptide complex and a preparation method thereof. Background Art

[0002] A large amount of scraps are generated during the processing of ham, such as ham skins, fats, minced meats, etc. These scraps are usually discarded or not fully utilized, resulting in waste of resources and environmental pollution. Huizhou - style ham is famous for its unique flavor and aroma, but its processing cycle is long, the price is high, and the market sales volume is limited. The large amount of scraps accumulated during the processing of ham not only wastes resources but also burdens the environment.

[0003] The number of diabetic patients globally is increasing year by year and showing a trend of getting younger. Rational diet regulation is an important means of adjuvant treatment. Starch is the main source of human energy and is classified into rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) according to the digestion rate. Among them, SDS takes 20 - 120 minutes to be completely digested and absorbed in the small intestine, does not cause a sharp increase in blood glucose, and helps to maintain blood glucose homeostasis; RS cannot be digested in the human body, has high physiological activity, and can participate in blood glucose regulation by fermenting in the colon. Foods rich in SDS and RS have a low glycemic index (GI) and are suitable for diabetic patients to eat, having a certain preventive effect on diabetes.

[0004] Potato, as the fourth - largest crop globally, its starch is an important source of carbohydrates. However, after raw potato starch (PS) is cooked or heat - treated, the content of resistant starch (RS) decreases and the content of rapidly digestible starch (RDS) increases, becoming a high - GI food, which is not conducive to blood glucose control. Therefore, regulating the digestibility of potato starch by introducing exogenous additives, increasing the content of RS and reducing the proportion of RDS, is of great significance for improving its nutritional characteristics, developing potato staple food products, and maximizing economic and health benefits.

[0005] At present, the preparation of slowly digestible starch and resistant starch mostly uses natural starch and high - amylose starch as raw materials, but different modification methods have limitations. The chemical modification method uses chemical reagents such as acids, alkalis, or cross - linkers, which may introduce harmful residues, affecting food safety and environmental friendliness; although the enzymatic modification method has mild conditions, the cost of enzyme preparations is high, the reaction conditions are harsh, and the enzymatic hydrolysis process is difficult to precisely control, resulting in poor product stability; in the physical modification method, ultrasonic treatment and high - pressure homogenization can improve the starch structure, but the equipment investment is large, the energy consumption is high, and the modification effect is limited, making it difficult to significantly increase the content of resistant starch and slowly digestible starch. These methods all face challenges in practical applications. Summary of the Invention

[0006] The present invention aims to provide a slowly digestible and highly nutritious starch-ham peptide complex and its preparation method. The starch-ham peptide complex has high nutritional value, increases the content of slowly digestible starch and resistant starch, reduces the digestibility of starch, and helps to control the postprandial blood glucose level.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A preparation method of a slowly digestible and highly nutritious starch-ham peptide complex, comprising the following steps:

[0009] S1. Disperse and dissolve the purified ham peptide powder in deionized water, adjust the pH of the solution, and heat and stir in a water bath until completely dissolved to obtain a mixed solution;

[0010] S2. Add potato starch to the mixed solution obtained in S1, heat and stir in a water bath to obtain a mixture;

[0011] S3. Transfer the mixture obtained in S2 to a reaction kettle, dry, crush and sieve, perform heat treatment, dry again, crush and sieve to obtain a slowly digestible and highly nutritious starch-ham peptide complex.

[0012] Preferably, in S1, the preparation method of the purified ham peptide comprises the following steps:

[0013] A1. Grind the ham scraps and mix them with a 0.05 mol / L hydrochloric acid solution, and perform homogenization treatment in an ice bath for 8 min to obtain a homogenate;

[0014] A2. Centrifuge the homogenate obtained in A1 at a speed of 12,000 r / min for 20 min at 4°C, filter, discard the precipitate, add an ethanol solution with a mass fraction of 85%, and let it stand at 4°C for 20 h to obtain a deproteinized solution;

[0015] A3. Centrifuge the deproteinized solution obtained in A2 at a speed of 12,000 r / min for 20 min at 4°C, discard the precipitate, perform vacuum filtration, dialysis with an ultrafiltration membrane, collect the supernatant, divide the components into fractions of >4 kDa, 1-4 kDa, and <1 kDa, freeze-dry at -20 to -10°C for 48 h, and store at -30°C for later use.

[0016] Preferably, in S1, the purified ham peptide powder is dispersed and dissolved in deionized water, an alkali solution is added to adjust the pH of the solution to 8-9, heated in a water bath at 30°C, and stirred at a speed of 260 rpm until completely dissolved to obtain a mixed solution.

[0017] Preferably, the dissolution concentration of the purified ham peptide is 15-25 mg / mL.

[0018] Preferably, in S2, potato starch is added to the mixed solution obtained in S1, heated in a water bath at 30°C, and stirred at a speed of 300-450 rpm for 35 min to obtain a mixture.

[0019] Preferably, the dispersion ratio of the potato starch in the mixed solution obtained in S1 is 0.25-0.5 g / mL.

[0020] Preferably, in S3, the mixture obtained in S2 is transferred to a reaction kettle, dried at 50°C until the moisture content is 35%, and then crushed and sieved.

[0021] Preferably, in S3, the heat treatment temperature is 110°C and the heat treatment time is 4 h.

[0022] Preferably, in S3, it is dried again at 50°C until the moisture content is lower than 10%.

[0023] The present invention also provides a slowly digestible and highly nutritious starch-ham peptide complex prepared by the described preparation method.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] (1) The present invention discloses a slowly digestible and highly nutritious starch-ham peptide complex and its preparation method. The preparation method is simple, without the use of complex chemical modifications, the raw material sources are rich, and it can make full use of the processing by-product Huipai ham scraps, reduce costs, protect the environment and improve the utilization rate of by-products. At the same time, the contents of slowly digestible starch and resistant starch in the obtained complex are also relatively high.

[0026] (2) The present invention combines the health-care functional substances slowly digestible starch, resistant starch and Huipai ham peptide, not only reduces the enzymatic hydrolysis process of starch and controls the postprandial blood glucose level, but also the Huipai ham peptide is highly nutritious and highly absorbable, and can be used as a nutritional supplement, suitable for developing functional health foods for obese and diabetic populations.

[0027] (3) For the starch-ham peptide complex of the present invention, the ham peptide effectively promotes the short-range ordered structure of potato starch during the heat-moisture treatment process, forming more slowly digestible starch and resistant starch. Among them, in the group with 5% ham peptide added, after heat-moisture treatment for 5 h, the total content of slowly digestible starch and resistant starch in the complex is as high as 47.86%, endowing the potato starch food with the functional nutritional characteristics of regulating blood glucose level.

[0028] The technical solutions of the present invention will be further described in detail below with reference to the drawings and examples. Description of the Drawings

[0029] Figure 1SEM images of the starch-ham peptide complexes provided for Example 2, Example 4, Example 5 and Example 6, wherein, Figure 1 A in Figure 1 is the SEM image of the complex provided for Example 6, with a magnification of 500, Figure 1 B in Figure 1 is the SEM image of the complex provided for Example 6, with a magnification of 1000, Figure 1 C in Figure 1 is the SEM image of the complex provided for Example 5, with a magnification of 500, Figure 1 D in Figure 1 is the SEM image of the complex provided for Example 5, with a magnification of 1000,

[0030] Figure 2 FTIR test results of the starch-ham peptide complexes provided for Example 2, Example 3, Example 5 and Example 6;

[0031] Figure 3 Swelling degree measurement results of the starch-ham peptide complexes provided for Example 2, Example 3, Example 5 and Example 6;

[0032] Figure 4 Viscosity measurement results of the starch-ham peptide complexes provided for Example 2, Example 3, Example 5 and Example 6;

[0033] Figure 5 In vitro digestibility measurement results of the starch-ham peptide complexes provided for Example 2, Example 3, Example 5 and Example 6. Detailed implementation manners

[0034] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and examples.

[0035] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs.

[0036] In the present invention, unless otherwise specified, other test materials and instrument equipment are all conventional test materials in the art and can be obtained through commercial channels.

[0037] Example 1

[0038] Preparation method of purified ham peptides, comprising the following steps:

[0039] A1. After crushing 40 g of Anhui-style ham scraps for 20 min, add hydrochloric acid solution with a concentration of 0.05 mol / L according to a solid-liquid ratio of 1 g / 20 mL, mix in a stirrer, perform homogenization treatment for 8 min under ice bath conditions, and filter through two layers of gauze to obtain a homogenate;

[0040] A2. Centrifuge the homogenate obtained in A1 at 12,000 r / min for 20 min at 4 °C, filter through glass wool, discard the precipitate, add an ethanol solution with a mass fraction of 85%, wherein the added volume of the ethanol solution is three times that of the filtered supernatant, and let it stand at 4 °C for 20 h to obtain a deproteinized solution;

[0041] A3. Centrifuge the deproteinized solution obtained in A2 at 12,000 r / min for 20 min at 4 °C, discard the precipitate, take the supernatant and perform suction filtration using a vacuum suction filter, dialyze through a PES ultrafiltration membrane at 4 °C for 48 h, collect the supernatant, divide the ultrafiltration centrifuge tube components into fractions >4 kDa, 1 - 4 kDa, and <1 kDa, freeze-dry at -20 °C for 48 h to obtain freeze-dried powder of purified Anhui-style ham peptides (Huizhou ham peptides, HHP), and store at -30 °C for later use.

[0042] Example 2

[0043] A slow-digesting and highly nutritious starch-ham peptide complex HMT-PS-HHP 5％ , the preparation method comprises the following steps:

[0044] S1. Disperse and dissolve the purified Anhui-style ham peptide powder provided in Example 1 in deionized water, stir and dissolve at room temperature for 15 min to make the ham peptide concentration 20 mg / mL, add an alkali solution to adjust the solution pH to 8, heat in a water bath at 30 °C, and stir at 260 rpm until completely dissolved to obtain a mixed solution;

[0045] S2. Add potato starch to the mixed solution obtained in S1, wherein the dispersion ratio of potato starch in the mixed solution obtained in S1 is 0.5 g / mL, and the addition amount of purified Anhui-style ham peptide powder is 5% of the addition amount of potato starch, heat in a water bath at 30 °C, and stir at 360 rpm for 35 min to obtain a mixture;

[0046] S3. Transfer the mixture obtained in S2 to a reaction kettle, dry in a convection oven at 50 °C until the moisture content is 35%, crush and pass through a 100-mesh sieve, perform heat treatment at 110 °C for 4 h, dry again in a convection oven at 50 °C until the moisture content is less than 10%, crush and pass through a 100-mesh sieve to obtain a slow-digesting and highly nutritious starch-ham peptide complex HMT-PS-HHP 5％ .

[0047] Example 3

[0048] The preparation method is the same as that of Example 2, except that in S2, the addition amount of Huizhou-style purified ham peptide powder is 1% of the addition amount of potato starch, and a slowly digested and highly nutritious starch-ham peptide complex HMT-PS-HHP is obtained 1％ 。

[0049] Example 4

[0050] The preparation method is the same as that of Example 2, except that in S2, the addition amount of Huizhou-style purified ham peptide powder is 0% of the addition amount of potato starch, and a slowly digested and highly nutritious starch-ham peptide complex HMT-PS-HHP is obtained 0％ 。

[0051] Example 5

[0052] A slowly digested and highly nutritious starch-ham peptide complex PS-HHP 5％ ,The preparation method includes the following steps:

[0053] S1. Disperse and dissolve the Huizhou-style purified ham peptide powder provided in Example 1 in deionized water, stir and dissolve at room temperature for 15 min to make the ham peptide concentration 20 mg / mL, add an alkali solution to adjust the pH of the solution to 8, heat in a water bath at 30 °C, and stir at a speed of 260 rpm until completely dissolved to obtain a mixed solution;

[0054] S2. Add potato starch to the mixed solution obtained in S1. Among them, the dispersion ratio of potato starch in the mixed solution obtained in S1 is 0.5 g / mL, and the addition amount of Huizhou-style purified ham peptide powder is 5% of the addition amount of potato starch. Heat in a water bath at 30 °C and stir at a speed of 360 rpm for 35 min to obtain a mixture;

[0055] S3. Transfer the mixture obtained in S2 to a reaction kettle, dry it in a convection oven at 50 °C until the water content is 35%, crush it through a 100-mesh sieve to obtain the starch-ham peptide complex PS-HHP 5％ 。

[0056] Example 6

[0057] The preparation method is the same as that of Example 4, except that in S2, the addition amount of Huizhou-style purified ham peptide powder is 0% of the addition amount of potato starch, and a slowly digested and highly nutritious starch-ham peptide complex PS-HHP is obtained 0％ 。

[0058] The starch-ham peptide complexes provided in the above Examples 2-6 were verified for their effects through the following tests.

[0059] 1. Structural feature test:

[0060] Morphological properties: The electrostatic tape was attached to the stage of a scanning electron microscope (SU8020 type). A small amount of the composite sample was evenly adhered to the tape. The tape was placed under vacuum conditions and sputter-coated with gold for 5 min, and then placed into the scanning electron microscope. It was scanned and photographed at different magnifications under an accelerating voltage of 8 - 10 kV. The results are shown in Figure 1 .

[0061] As can be seen from Figure 1 , the PS-HHP 0％ sample provided in Example 6 presented various shapes, including circular, polygonal, and truncated shapes, with occasional cracks on the surface, and its structure was dense and smooth. In the PS-HHP 5％ sample provided in Example 5, the Huipai ham peptides were partially attached to the surface or around the potato starch granules. In comparison, under the condition of low moisture in the heat-moisture treatment, the aggregation phenomenon of the potato starch - ham peptide complex increased, which was attributed to the pressure and heat generated during the heat-moisture treatment causing the granules to aggregate into clusters. After the heat-moisture treatment, some potato starch granules swelled and gelatinized by absorbing water. For the potato starch and a series of Huipai ham peptide complexes, the added HHP was irregularly dispersed on the surface of the potato starch granules, making their surfaces rough. At the same time, most of the potato starch granules aggregated together to form larger aggregates, and as the HHP content increased, the number of large granules also increased.

[0062] Crystal properties: The crystal structure of the composite sample was measured using an X-ray diffractometer. The instrument was set at 40 kV and 20 mA, the scanning angle range was 5 - 50°, and the scanning speed was 5° / min. The relative crystallinity (RC) of the composite sample was calculated using Peakfit-v4.12 software to characterize the crystal structure of the sample. The results are shown in Table 1.

[0063] Table 1 Relative crystallinity of starch - ham peptide complexes

[0064]

[0065]

[0066] As can be seen from Table 1, the PS-HHP 0％It has a relatively high relative crystallinity, indicating that the crystal structure of potato starch is relatively complete, the starch molecules are arranged orderly, and there are many crystalline regions. After adding 5% Huipai ham peptide, the relative crystallinity of potato starch decreases. The reason may be that the Huipai ham peptide molecules attach to the surface of potato starch granules, hindering the orderly arrangement of starch molecules; at the same time, it is also possible that the hydrogen bond interaction between Huipai ham peptide and potato starch molecules destroys some crystalline regions and increases the amorphous regions. After heat-moisture treatment and with the increase of the composite content of Huipai ham peptide, the relative crystallinity of potato starch further decreases. Since the heat-moisture treatment is carried out under high temperature and high humidity conditions, it leads to the rearrangement of potato starch molecular chains and the destruction of some crystalline regions, increasing the amorphous regions. At the same time, the synergistic effect of heat-moisture treatment and the addition of Huipai ham peptide further destroys the crystal structure of potato starch. Generally speaking, heat-moisture treatment and the addition of Huipai ham peptide significantly affect the crystal structure of potato starch, resulting in a decrease in relative crystallinity. This change is mainly due to the fact that heat-moisture treatment destroys the orderly arrangement of starch molecules, and the addition of Huipai ham peptide further exacerbates this destructive effect. With the increase of Huipai ham peptide content, the relative crystallinity further decreases, indicating that the higher the content of Huipai ham peptide, the more significant the destructive effect on the crystal structure of potato starch.

[0067] Ratio of peak intensities at 1047 cm -1 and 1022 cm -1 : Take a small amount of composite sample and test it by an FTIR spectrometer (Bruker, Germany) in ATR mode, and calculate the ratio of peak intensities (R1047 / 1022) at 1047 cm -1 and 1022 cm -1 . The ratio is calculated by OMNIC software. The results are shown in Figure 2 .

[0068] As can be seen from Figure 2 , in the FTIR spectrum, the absorption peak positions of PS and PS-HHP composites do not shift significantly, indicating that HHP interacts with PS through non-covalent bonds; the infrared absorptions at 1022 cm -1 and 1047 cm -1 correspond to the amorphous structure and ordered crystalline structure of potato starch respectively. With the increase of HHP content, the R1047 / 1022 value gradually increases, indicating that the presence of HHP plays a crucial role in improving the degree of short-range ordered structure of starch. In addition, the R1047 / 1022 value after heat-moisture treatment further increases, indicating that heat-moisture treatment enhances the complexation ability between HHP and PS.

[0069] In vitro digestibility test: The in vitro digestibility was determined with reference to the method of Englyst et al. Weighed 0.6 g of the dry basis composite sample, added 20 mL of sodium acetate buffer solution, and vortexed for 5 min to mix well. The sample was placed in a boiling water bath and stirred for 30 min, and then placed in a water bath at 37 °C and shaken for 30 min. Added 5 mL of a mixed enzyme containing porcine pancreatin (3×103 U) and glucoamylase (40 U) to each centrifuge tube. Took out 0.25 mL of the enzymolysis solution at two time points of 30 min and 130 min, and mixed it with 10 mL of 66% (V / V) ethanol to inactivate the enzyme. The glucose contents of the hydrolyzed enzymolysis solutions were recorded as G30 and G130 in turn. Respectively pipetted 100 μL of the blank reagent, enzymolysis solution and standard glucose solution into 5 mL centrifuge tubes, added 3 mL of GOPOD solution respectively, vortexed to mix well, then developed color in the dark at 50 °C in a water bath for 30 min, and measured the absorbance value at a wavelength of 520 nm. The results are shown in Table 2 and Figure 5 。

[0070] Table 2 Results of in vitro digestibility determination of starch - ham peptide composite

[0071]

[0072]

[0073] As can be seen from Table 2 and Figure 5 it can be seen that the addition of HHP significantly reduced the sensitivity of PS to enzymolysis, and the RDS content decreased significantly from 80.67% to 60.34%. At the same time, the proportions of SDS and RS increased significantly, from 7.3% to 24.34% and from 12.03% to 15.32% respectively. The increase in the contents of SDS and RS after HMT may be related to the change of starch structure, due to the interaction between amylose chains and between amylose - amylopectin, as well as the rearrangement of the ordered crystal structure; in addition, under HMT conditions, the potato starch chains interacted with the side chain groups of HHP, resulting in an increase in the contents of SDS and RS. At the same time, with the increase in the proportion of HHP in the composite, the contents of SDS and RS in the PS - HHP composite increased, resulting in a gradual decrease in in vitro digestibility.

[0074] Food property test: Swelling degree determination: Weighed 0.2 g of the composite sample (dry basis), added deionized water to prepare a starch milk with a mass fraction of 10%, placed it in a water bath at 55, 75, 95 °C respectively and stirred for 30 min, then centrifuged at 3000 r / min for 15 min and poured out the supernatant, and calculated the swelling degree according to the remaining solid mass. The calculation formula is as follows:

[0075]

[0076] The results are shown in Figure 3 。

[0077] It can be seen from Figure 3 that for both the physically mixed samples and the complexes treated by hydrothermal treatment, their swelling degrees increase with the increase of temperature. Compared with the physically mixed samples, after hydrothermal treatment, the swelling degree of the potato starch-Huipai ham peptide complex decreases significantly. During the hydrothermal treatment process, the internal molecular chains of potato starch rearrange, and the interactions between amylose and amylose as well as between amylopectin and amylopectin are enhanced, making it form a more compact double helix structure. At the same time, it hinders the combination of potato starch granules and water molecules, thus limiting the hydration ability and swelling of potato starch. The ham peptides covering the surface of starch granules can bind part of the water, thus affecting the entry of water into the interior of starch granules and further affecting their swelling degree. In addition, during the hydrothermal treatment process, the negatively charged phosphate monoesters in potato starch may interact with the side chain groups in ham peptides, resulting in a significant decrease in the swelling degree of the potato starch-ham peptide complex.

[0078] Viscosity measurement: Weigh 6 g of the dry basis complex sample, add deionized water to prepare a starch milk with a mass fraction of 6%, and transfer it to a Brabender viscosity measuring cup. Set the parameters: the initial temperature is 30 °C, the heating rate is set at 6 °C / min, keep it for 5 min when the temperature rises to 95 °C, set the cooling rate at 7.5 °C / min, cool to 50 °C and keep it for 5 min to end, and record and save the viscosity-temperature curve. The results are shown in Figure 4 .

[0079] It can be seen from Figure 4 that compared with the physically mixed samples, the peak viscosity of the complex after hydrothermal treatment decreases significantly. This is attributed to the fact that during the HMT process, the mobility of starch chains increases, and the molecular chains rearrange and recombine to form ordered double helix amylopectin clusters. This rigid structure can limit starch swelling and improve the stability of starch during heating, which is consistent with the swelling degree results. The thermal energy during HMT promotes the breakage of long amylopectin chains, generating short chains closely related to amylose. At the same time, the cross-linking between particles enhances the action of hydrogen bonds, resulting in the leaching of amylose and increasing the heat resistance of starch, thus reducing the starch viscosity. And the addition of HHP further enhances the stability of potato starch molecules, hinders the penetration of water and the swelling of starch granules, and with the increase of HHP content, the viscosity further decreases.

[0080] In summary, the present invention provides a slowly digestible and highly nutritious starch-ham peptide complex and its preparation method. This method mixes purified Huipai ham peptides with potato starch and prepares the complex through hydrothermal treatment, significantly improving the contents of SDS and RS in the complex and simultaneously changing the multi-level structure of starch.

[0081] The composite prepared by the present invention has excellent low digestibility and high nutritional value, and is applicable to the fields of functional foods and health foods, especially suitable for diabetic patients to maintain stable blood sugar levels. This method uses the leftover materials of Huizhou ham as raw materials, which are low-cost, environmentally friendly and efficient, and do not require complex chemical modification, with high economic and social benefits. Through the synergistic effect of hydrothermal treatment and Huizhou ham peptides, the contents of SDS and RS in the composite are significantly increased, endowing it with the functional characteristics of regulating blood sugar and having broad application prospects.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions of the present invention or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a slowly digestible and highly nutritious starch-ham peptide complex, characterized in that: The following steps are involved: S1. Disperse and dissolve the purified ham peptide powder in deionized water, adjust the pH of the solution, heat in a water bath and stir until completely dissolved to obtain a mixed solution; S2, adding potato starch to the mixed solution obtained in S1, heating in a water bath with stirring to obtain a mixture; S3. The mixture obtained in S2 is transferred to a reactor, dried, crushed and sieved, heat treated, dried again, crushed and sieved, to obtain a slowly digestible and highly nutritious starch-ham peptide complex.

2. The preparation method according to claim 1, characterized in that: In S1, the method for preparing the purified ham peptide comprises the following steps: A1. Crush the ham scraps and mix them with a 0.05 mol / L hydrochloric acid solution, and homogenize them for 8 minutes under ice bath conditions to obtain a homogenate; A2, centrifuge the homogenate obtained in A1 at 12000 r / min for 20 min at 4°C, filter, discard the precipitate, add 85% ethanol solution by mass, and let stand at 4°C for 20 h to obtain a deproteinized solution; A3. Centrifuge the deproteinized solution obtained in A2 at 12000 r / min for 20 min at 4°C, discard the precipitate, vacuum filter, dialyze with ultrafiltration membrane, collect the supernatant, and separate the components into those >4 kDa, 1-4 kDa, and <1 kDa. Freeze-dry at -20--10°C for 48 h, and store at -30°C for later use.

3. The preparation method according to claim 1, characterized in that: In S1, the purified ham peptide powder is dispersed and dissolved in deionized water, an alkali solution is added to adjust the solution pH to 8-9, the solution is heated in a water bath at 30°C, and stirred at a speed of 260 rpm until it is completely dissolved to obtain a mixed solution.

4. The preparation method according to any one of claims 1 or 3, characterized in that The purified ham peptide has a dissolving concentration of 15 to 25 mg / mL.

5. The preparation method according to claim 1, characterized in that: In S2, potato starch is added to the mixed solution obtained in S1, heated in a water bath at 30°C, and stirred at a rotation speed of 300-450 rpm for 35 minutes to obtain a mixture.

6. The preparation method according to any one of claims 1 or 5, characterized in that: The dispersion ratio of the potato starch in the mixed solution obtained in S1 is 0.25-0.5 g / mL.

7. The preparation method according to claim 1, characterized in that: In S3, the mixture obtained in S2 is transferred to a reaction kettle, dried at 50° C. to a moisture content of 35%, and crushed and sieved.

8. The preparation method according to claim 1, characterized in that: In S3, the heat treatment temperature is 110° C. and the heat treatment temperature is 4 hours.

9. The preparation method according to claim 1, characterized in that: In S3, the re-drying is performed at 50°C until the moisture content is less than 10%.

10. The slowly digestible and highly nutritious starch-ham peptide complex prepared by the preparation method according to any one of claims 1 to 9.

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