Preparation method of modified potato starch-glycerol trilaurate compound

Abstract

The invention provides a preparation method of a modified potato starch-glycerol trilaurate compound. The preparation method comprises the following steps: step 1, irradiation modification; step 2, construction of a water phase preparation system; step 3, gelatinization treatment; step 4, cooling treatment; step five, performing high-pressure homogenization treatment; step 6, removal of free lipid; and 7, drying the compound. Compared with a high-pressure homogenization preparation method, the starch-lipid compound prepared by the method provided by the invention has obviously enhanced dietary fiber characteristics and digestion resistance. The potato starch-triglyceride is creatively prepared by combining electron beam irradiation with a high-pressure homogenization technology, so that potato starch molecules are cracked, the dispersity of the triglyceride is improved, and the prepared starch-triglyceride compound has a relatively good compounding effect and can be used for preparing the potato starch-triglyceride compound. The preparation efficiency of the starch-triglyceride compound is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of food, relates to potato modification, and specifically relates to a preparation method of a modified potato starch-glycerol trilaurate complex. Background Art

[0002] Potato starch is a typical B-type crystalline structure, mainly containing branched starch, which is easily gelatinized during food thermal processing, which weakens its resistance to amylase and leads to a sharp rise in blood sugar levels after meals. Lipids, as another major nutrient in food, can form starch-lipid complexes with starch through hydrophobic interactions, hydrogen bonds and van der Waals forces. This effect transforms starch into a V-type crystalline structure, which has functional properties such as resistance to digestion and low glycemic index.

[0003] In the field of starch-lipid complex research and processing, potato starch has been widely studied with different types of fatty acids and monoglycerides that are easy to compound, and can form starch-lipid complexes with high compounding degree and good anti-digestion properties. However, in daily diet, the main component of edible lipids is in the form of "triglycerides" composed of different fatty acids and glycerol, but it is difficult to compound with starch and the preparation efficiency is low. Therefore, how to improve the compounding efficiency of potato starch and triglycerides is a difficult point for technicians in this field to study. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a modified potato starch-trilaurin complex to solve the technical problem that the dietary fiber properties and digestion resistance of the products prepared by the preparation methods in the prior art need to be further improved.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A method for preparing a modified potato starch-glycerol trilaurate complex, the method comprising the following steps:

[0007] Step 1, irradiation modification:

[0008] The potato starch is irradiated by using a high energy electron linear accelerator to obtain irradiated modified potato starch.

[0009] Step 2: Construction of aqueous phase preparation system:

[0010] The irradiated modified potato starch obtained in step 1 is uniformly mixed with water to prepare irradiated modified potato starch milk; trilaurin is fully dissolved in anhydrous ethanol to prepare a trilaurin / anhydrous ethanol solution.

[0011] Step 3: Gelatinization:

[0012] The irradiated modified potato starch emulsion prepared in step 2 is heated and stirred in an oil bath to be evenly dispersed, and then the trilaurin / anhydrous ethanol solution prepared in step 2 is poured into the irradiated modified potato starch emulsion, and the mixture is mixed and continued to be heated and stirred in an oil bath to obtain a mixed paste.

[0013] Step 4: Cooling:

[0014] The mixed paste obtained in step 3 is placed at room temperature to cool to obtain a cooled paste.

[0015] Step 5: High-pressure homogenization:

[0016] The cooled paste obtained in step 4 is subjected to high pressure homogenization treatment to obtain a homogeneous paste.

[0017] Step 6: Removal of free lipids:

[0018] The homogeneous paste obtained in step 5 is cooled to room temperature, n-hexane is added to the homogeneous paste and stirred, and after the stirring is completed, the supernatant is removed with a dropper, and this process is repeated three times to obtain a removed composite.

[0019] Step 7: Drying of the composite:

[0020] The removed complex obtained in step six is ​​subjected to low temperature drying to obtain a modified potato starch-trilaurin complex.

[0021] The present invention also has the following technical features:

[0022] In step 1, during the irradiation treatment, the electron beam output energy of the high-energy electron linear accelerator is 10 MeV, the maximum beam power is 20 kW, and the irradiation dose is 10 kGy to 40 kGy.

[0023] In step 2, the concentration of the irradiated modified potato starch emulsion is 5wt%; the mass of the trilaurin is 5wt% to 9wt% of the dry mass of the starch.

[0024] In step three, the temperature of the oil bath is 90° C. to 110° C., the heating time of the oil bath is 20 min; the stirring speed is 460 rpm; and the dispersion time of the irradiated modified potato starch emulsion is 30 s.

[0025] In step 4, the cooling paste needs to be cooled to 50°C.

[0026] In step 5, the conditions for high-pressure homogenization treatment are: homogenization temperature is 50° C., homogenization pressure is 20 MPa to 60 MPa, and the number of homogenization times is 1 to 3 times.

[0027] In step six, 40% of the volume of the mixed paste is added with n-hexane, and the stirring time is 3 minutes.

[0028] In step seven, the drying temperature is 40° C. to 45° C., and the drying time is 36 h to 48 h.

[0029] Compared with the prior art, the present invention has the following technical effects:

[0030] (I) The present invention creatively uses electron beam irradiation combined with high-pressure homogenization technology to prepare potato starch-trilaurin for the first time. Compared with the high-pressure homogenization preparation method, the dietary fiber properties and digestion resistance of the starch-lipid complex prepared by the provided method are significantly enhanced.

[0031] (II) The preparation method provided by the present invention is an organic combination of electron beam irradiation and high-pressure homogenization, which synergistically promotes the complexation of starch and triglycerides, improves the complexation efficiency with triglycerides as lipid objects, and can obtain a modified starch with dietary fiber functional properties. The obtained potato starch-trilaurin complex was experimentally studied and found to have properties such as high complexity, high digestion resistance and structural stability. This method changes the semi-crystalline structure of starch or competes with starch molecules for the active sites of digestive enzymes, reduces the hydrolysis efficiency of amylase, enhances the nutritional properties of starch foods, can control postprandial hyperglycemia caused by the rapid release of glucose in starch, and helps to alleviate chronic diseases such as diabetes, obesity and cardiovascular diseases. Therefore, the preparation method is applied to the modification and processing of potato starch, which can regulate the starch digestibility and develop functional starch that is beneficial to glucose metabolism, producing good health effects.

[0032] (III) The present invention creatively uses electron beam irradiation combined with high-pressure homogenization technology to prepare potato starch-trilaurin, so that the potato starch molecules are cracked and the dispersibility of trilaurin is improved. The prepared starch-triglyceride complex has a good composite effect and the preparation efficiency of the starch-triglyceride complex is improved.

[0033] (IV) The potato starch modified by irradiation of the present invention is subjected to high-pressure homogenization to prepare a starch-lipid complex, and the resistant starch content of the starch-lipid complex is increased compared with that of the unirradiated modified starch-lipid complex.

[0034] (V) The potato starch modified by irradiation of the present invention is subjected to high pressure homogenization treatment to prepare starch-lipid complexes, and the crystallinity thereof is different. Under a suitable irradiation dose, the crystallinity and structural stability of the starch-triglyceride complex are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1is the composite index of potato starch-trilaurin complex modified by different irradiation doses.

[0036] Figure 2 This is the RVA curve of potato starch-trilaurin complex modified by different irradiation doses.

[0037] Figure 3 The hydrolysis curve of potato starch-trilaurin complex modified by different irradiation doses.

[0038] Figure 4 FT-IR spectra of potato starch-trilaurin complex modified by different irradiation doses.

[0039] Figure 5 X-ray diffraction patterns of potato starch-trilaurin complex modified by different irradiation doses.

[0040] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0041] Electron beam irradiation uses a high-energy electron accelerator to generate an electron beam of specific energy to irradiate materials. It has the characteristics of high efficiency, greenness, and low carbon. When ionizing radiation acts on starch particles, the starch molecules are ionized and excited through the interaction between high-energy electrons and starch, which can change its crystallization and molecular chain structure, degrade amylopectin, and increase amylose, providing a good material basis for the inclusion reaction of starch and lipid guest molecules. High-pressure homogenization refers to the generation of mechanical shear, turbulence and cavitation effects under high pressure, which causes the material to collide at high speed and instantly reduce pressure, causing cavitation, thereby releasing strong energy. Under this action, the ordered structure of starch particles is further destroyed, releasing more amylose, and the aqueous phase system coexisting with lipids presents a good uniform distribution state, which can provide efficient compound conditions for the inclusion reaction of starch and triglycerides.

[0042] However, there is no method for preparing starch-lipid complexes by electron beam irradiation combined with high-pressure homogenization. The present invention is the first in the relevant field and provides an efficient compounding process condition for potato starch-trilaurin complexes. The technology is efficient and environmentally friendly, can solve the problem that triglycerides are difficult to compound with starch, realize the green preparation of starch-triglycerides, and provide a reference for improving the quality characteristics of starch-lipid complexes.

[0043] The obstacles in the preparation process of the potato starch-triglyceride complex of the present invention mainly include: on the one hand, the strong intermolecular and intramolecular hydrogen bonding in the potato starch granules makes it difficult to dissolve in water; on the other hand, due to the steric hindrance generated by the branched structure of amylopectin, the higher amylopectin content in potato starch. Therefore, the potato starch granules are structurally modified by electron beam irradiation technology, and the degradation of amylopectin by high-pressure homogenization technology is combined to weaken the intermolecular entanglement ability, so that the inclusion complex of starch and triglycerides can be better realized. The present invention emphasizes the synergistic effect of the application of electron beam irradiation technology and high-pressure homogenization technology, and the prepared potato starch-trilaurin complex can improve blood sugar control, prevent and regulate health problems such as diabetes, coronary heart disease and obesity.

[0044] Raw materials used in the present invention:

[0045] The potato starch (Aladdin, pharmacopoeia grade, potato starch moisture content of 10%wt-12wt%) and trilaurin (McLean, purity 98wt%) used in the specific implementation of the present invention, and the potato starch and trilaurin produced and sold by other manufacturers can be used in the present invention as long as they meet the requirements of the present invention.

[0046] The instruments and equipment used in the present invention are:

[0047] 10MeV / 20kW high energy electron accelerator, Yangling Hesheng Irradiation Technology Co., Ltd.

[0048] AH-PASIC high pressure homogenizer, Antos Nanotechnology (Suzhou) Co., Ltd.

[0049] HH.S21 8 Constant temperature electromagnetic stirring oil bath pot, Jiangsu Jinyi Instrument Technology Co., Ltd.

[0050] 114B swing type 4 liang high speed Chinese medicine pulverizer, Zhejiang Ruian Yongli Pharmaceutical Machinery Co., Ltd.

[0051] DHG 9423A Constant Temperature Blast Drying Oven, Beijing Songyuan Huaxing Technology Development Co., Ltd.

[0052] VERTEX 70 Fourier transform infrared spectrometer, Bruker Optics GmbH, Germany.

[0053] SmartLab SE X-ray diffractometer, Rigaku Corporation, Japan.

[0054] In accordance with the above technical scheme, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical scheme of this application fall within the protection scope of the present invention.

[0055] Comparative Example 1:

[0056] This comparative example provides a method for preparing a modified potato starch-trilaurin complex, which is basically the same as the method for preparing the modified potato starch-trilaurin complex in Example 1, with the only difference being that in step 1, during the irradiation treatment, the irradiation dose is 0 kGy, i.e., no irradiation treatment is performed.

[0057] The performance test results of this comparative example are as follows Figures 1 to 5 As shown in Tables 1 and 2.

[0058] Embodiment 1:

[0059] This embodiment provides a method for preparing a modified potato starch-glycerol trilaurate complex, which comprises the following steps:

[0060] Step 1, irradiation modification:

[0061] The potato starch is irradiated by using a high energy electron linear accelerator to obtain irradiated modified potato starch.

[0062] In step 1, during the irradiation treatment, the electron beam output energy of the high-energy electron linear accelerator is 10 MeV, the maximum beam power is 20 kW, and the irradiation dose is 10 kGy.

[0063] Step 2: Construction of aqueous phase preparation system:

[0064] The irradiated modified potato starch obtained in step 1 is uniformly mixed with water to prepare irradiated modified potato starch milk; trilaurin is fully dissolved in anhydrous ethanol to prepare a trilaurin / anhydrous ethanol solution.

[0065] In step 2, the concentration of the irradiated modified potato starch emulsion is 5wt%; the mass of trilaurin is 7wt% of the dry mass of starch.

[0066] Step 3: Gelatinization:

[0067] The irradiated modified potato starch emulsion prepared in step 2 is heated and stirred in an oil bath to be evenly dispersed, and then the trilaurin / anhydrous ethanol solution prepared in step 2 is poured into the irradiated modified potato starch emulsion, and the mixture is mixed and continued to be heated and stirred in an oil bath to obtain a mixed paste.

[0068] In step 3, the temperature of the oil bath is 100° C., the heating time of the oil bath is 20 min, the stirring speed is 460 rpm, and the dispersion time of the irradiated modified potato starch emulsion is 30 s.

[0069] Step 4: Cooling:

[0070] The mixed paste obtained in step 3 is placed at room temperature to cool to obtain a cooled paste.

[0071] In step 4, the paste needs to be cooled to 50°C.

[0072] Step 5: High-pressure homogenization:

[0073] The cooled paste obtained in step 4 is subjected to high pressure homogenization treatment to obtain a homogeneous paste.

[0074] In step 5, the conditions for high-pressure homogenization treatment are: homogenization temperature is 50° C., homogenization pressure is 40 MPa, and homogenization times are 3 times.

[0075] Step 6: Removal of free lipids:

[0076] The homogeneous paste obtained in step 5 is cooled to room temperature, n-hexane is added to the homogeneous paste and stirred, and after the stirring is completed, the supernatant is removed with a dropper, and this process is repeated three times to obtain a removed composite.

[0077] In step six, 40% of the volume of the mixed paste is added with n-hexane, and the stirring time is 3 minutes.

[0078] Step 7: Drying of the composite:

[0079] The removed complex obtained in step six is ​​poured into a culture dish and dried at low temperature to obtain a modified potato starch-trilaurin complex.

[0080] In step seven, the drying temperature is 45° C. and the drying time is 36 hours.

[0081] The performance test results of this embodiment are as follows Figures 1 to 5 As shown in Tables 1 and 2.

[0082] Embodiment 2:

[0083] This example provides a method for preparing a modified potato starch-trilaurin complex, which is basically the same as the method for preparing the modified potato starch-trilaurin complex in Example 1, except that in step 1, during the irradiation treatment, the irradiation dose is 20 kGy.

[0084] The performance test results of this embodiment are as follows Figures 1 to 5 As shown in Tables 1 and 2.

[0085] Embodiment 3:

[0086] This example provides a method for preparing a modified potato starch-trilaurin complex, which is basically the same as the method for preparing the modified potato starch-trilaurin complex in Example 1, except that in step 1, the irradiation dose is 30 kGy during the irradiation treatment.

[0087] The performance test results of this embodiment are as follows Figures 1 to 5 As shown in Tables 1 and 2.

[0088] Embodiment 4:

[0089] This example provides a method for preparing a modified potato starch-trilaurin complex, which is basically the same as the method for preparing the modified potato starch-trilaurin complex in Example 1, except that in step 1, the irradiation dose is 40 kGy during the irradiation treatment.

[0090] The performance test results of this embodiment are as follows Figures 1 to 5 As shown in Tables 1 and 2.

[0091] Performance Testing:

[0092] In order to illustrate the physicochemical and structural changes of potato starch-trilaurin glycerol complex after formation, the present application analyzes and detects the apparent morphology, physicochemical properties and structural characteristics of the potato starch-trilaurin glycerol complex, determines the composite index, gelatinization characteristics and in vitro digestion characteristics of the potato starch-trilaurin glycerol complex, scans the infrared spectrum and X-ray diffraction spectrum, and the specific experiments are described as follows.

[0093] The following experiments were carried out in sequence on the electron beam irradiated modified potato starch-trilaurin complexes prepared according to Comparative Example 1 and Examples 1 to 4 with irradiation doses of 0, 10, 20, 30 and 40 kGy.

[0094] First, the composite index of potato starch-trilaurin complex modified by different irradiation doses was compared:

[0095] The composite index determination method of potato starch-trilaurin complex prepared according to Comparative Example 1 and Examples 1 to 4 is as follows: 0.3 g potato starch-trilaurin complex is accurately weighed and dispersed in 4.7 ml distilled water to obtain a starch milk with a total concentration of 6% (w / w). The starch milk is then placed in boiling water and heated for 30 min to completely gelatinize the starch. After cooling to room temperature, the gelatinized sample is mixed with 25 mL distilled water and vortexed for 2 min, and then centrifuged at 4000 rpm for 15 min. The supernatant (0.2 mL) is mixed with 15 mL distilled water and 2 ml iodine solution (1.3% I 2and 2.0% KI). The absorbance of the sample was measured at 690 nm using a UV-visible spectrophotometer. The complex index (CI) was calculated as follows:

[0096] CI (%) = (A 1 -A 2 ) / A 1 ×100%

[0097] Where:

[0098] A 1 is the absorbance of starch without added lipid;

[0099] A 2 is the absorbance of the starch-lipid complex.

[0100] Depend on Figure 1 It can be seen that compared with the natural potato starch-trilaurin complex, the composite index of the irradiated potato starch-trilaurin complex increased by 9% to 38%, which may be due to the fact that the irradiation treatment destroyed the internal structure of potato starch, promoted the release of amylose, and thus increased the composite of starch and triglycerides. With the increase of irradiation dose, the composite index of potato starch-trilaurin complex showed a trend of first rising, then falling, and then rising again. The composite index reached the highest (46.61%) at 30kGy, and when the irradiation dose was 40kGy, its composite index decreased to 29.34%, which may be due to the excessive destruction of starch structure caused by excessive irradiation dose, which reduced its ability to bind to triglycerides.

[0101] Second, the gelatinization properties of potato starch-trilaurin complex modified by different irradiation doses were compared:

[0102] The method for determining the gelatinization properties of the electron beam irradiated modified potato starch-trilaurin complex prepared according to Comparative Example 1 and Examples 1 to 4 refers to GB / T24852-2010 "Rapid Viscometer Method for Determination of Gelatinization Properties of Rice and Rice Flour", and the gelatinization properties of the starch-lipid complex are determined using a rapid viscosity analyzer (RVA). Test method: In the sample weight calculator of the instrument test software, set the standard sample mass to 2.000g, the standard water weight to 25.000g, and the water basis to 12%, input the moisture content of the sample to be tested, and weigh the sample according to the corrected sample mass and water weight. Test procedure: The speed for the first 10s is 960r / min, and then the test is completed at a uniform speed of 160r / min. The temperature control step is to first balance at 50°C for 1min, heat to 95°C at a heating rate of 12°C / min, and then keep it for 2.5min, and then cool to 50°C at the same rate and keep it for 2min. At the same time, the peak viscosity (PV), minimum viscosity (TV), breakdown value (BV), final viscosity (FV) and setback value (SV) of the samples were recorded according to the viscosity change curve. The gelatinization characteristics of the potato starch-trilaurin complex modified with different irradiation doses are shown in Table 1.

[0103] Table 1 Gelatinization properties of potato starch-trilaurin complex modified by different irradiation doses

[0104]

[0105]

[0106] RVA is usually used to evaluate gelatinization properties and can reflect the changes in starch granule structure of starch or flour samples during food processing. Figure 2 It can be seen that with the increase of irradiation dose, the change trend of TV value and FV value is similar to that of PV value, both showing a trend of first increasing and then decreasing. In the range of 0-40kGy, the PV value gradually increases, and rises rapidly from 30 to 40kGy to reach a maximum value of 136.00cP. This may be due to the excessive destruction of starch structure by high-dose irradiation treatment, which increases the free starch chains and leads to an increase in peak viscosity, which corresponds to the composite index result. With the increase of irradiation dose, the BV value and SV value gradually decrease, reaching the minimum values ​​of 18.50 and 4.50cP at 40kGy, indicating that the viscosity of the composite after gelatinization during the cooling process is the smallest. In addition, the viscosity of the composites prepared by electron beam irradiation combined with high-pressure homogenization treatment is low and has good stability.

[0107] Third, the in vitro digestibility of potato starch-trilaurin complex modified by different irradiation doses was compared:

[0108] Determination and calculation method of in vitro digestion characteristics of potato starch-trilaurin complex prepared according to Comparative Example 1 and Examples 1 to 4: Accurately weigh the glucose standard to prepare a glucose standard solution with a concentration of 1 mg / mL, take 0, 0.2, 0.4, 0.6, 0.8, and 1 mL of the glucose standard solution in a 15 mL centrifuge tube, add 2 mL of DNS reagent, boil in a boiling water bath for 5 min, quickly cool to room temperature in an ice bath, make up to 15 mL with distilled water, measure the absorbance at a wavelength of 540 nm with a UV spectrophotometer, and draw a standard curve.

[0109] Mix 200 mg of sample with 15 mL of acetic acid-sodium acetate buffer (pH 5.2, 0.2 mol / L) and preheat in a 37°C water bath for 10 min. Then add 5 mL of enzyme solution (290 U / mL porcine pancreatic α-amylase and 15 U / mL of amyloglucosidase), incubate in a 37°C constant temperature water bath (200 rpm / min) for 2 h, and take 0.5 mL of enzymatic solution every 20 min to inactivate in a boiling water bath, then centrifuge (3000 g, 10 min). Take the supernatant and dilute it appropriately, take 1 mL of the diluted solution, and analyze its glucose content using the 3.5-dinitrosalicylic acid (DNS) method. Add 2 mL of DNS reagent to each tube, boil it in a boiling water bath for 5 min, cool it down quickly in an ice bath, and add distilled water to make it fixed to 15 mL. Use an ultraviolet spectrophotometer to measure the absorbance at a wavelength of 540 nm, and calculate the reducing sugar content in the sample according to the standard curve. According to the digestibility of starch at different times, starch can be defined as rapidly digestible starch (rapidly digestible starch, RDS) digested within 20 minutes, slowly digestible starch (slowly digestible starch, SDS) digested within 20-120 minutes and resistant starch (resistant starch, RS) not digested within 120 minutes.

[0110] Calculation of reducing sugar content:

[0111] a: Standard curve: record x as absorbance and y as concentration (mg / mL). Calculate the reducing sugar content in the sample according to the standard curve, that is, substitute ΔA (A test tube - A control tube) into x to calculate the y value.

[0112] b: Reducing sugar content G (mg) = y × 20 × 10

[0113] Where 20 is the volume and 10 is the dilution factor. The digestibility of starch is expressed as the ratio of the amount of glucose produced to the total amount of starch.

[0114] The specific calculation formula is as follows:

[0115] RDS(%)=(G20-G0)×0.9 / TS

[0116] SDS (%) = (G120-G20) × 0.9 / TS

[0117] RS(%)=100-RDS-SDS

[0118] Where:

[0119] G0 is the mass of glucose before enzymatic hydrolysis (mg);

[0120] G20 is the mass of glucose at 20 min of enzymatic hydrolysis (mg);

[0121] G120 is the mass of glucose at 120 min of enzymatic hydrolysis (mg);

[0122] TS is the total starch mass (mg).

[0123] The digestibility characteristics of potato starch-trilaurin complex modified with the same irradiation dose are shown in Table 2.

[0124] Table 2 Digestion characteristics of potato starch-trilaurin complex modified by different irradiation doses

[0125] RDS(%) SDS(%) RS(%) Comparative Example 1 47.00±0.42 21.83±0.25 31.17±0.68 Example 1 37.63±0.03 34.39±0.45 27.99±0.49 Example 2 42.32±0.13 22.84±0.49 34.85±0.63 Example 3 38.68±0.04 25.13±0.71 36.19±0.75 Example 4 44.85±0.13 18.35±0.64 36.80±0.78

[0126] From Table 2 and Figure 3 It can be seen that compared with the composite sample prepared by high-pressure homogenization without irradiation treatment, the RS content in the composite prepared by irradiation treatment increased significantly, and at 30-40 kGy, the RS content exceeded 36%. When the irradiation dose increased from 10 to 40 kGy, the RDS content first increased and then slightly decreased, and then increased significantly at 40 kGy, reaching a maximum value of 44.85%. The SDS content showed a trend of first decreasing, then increasing, and then decreasing with the increase of irradiation dose, and the sum of SDS content and RS content reached the highest (62.37%) at 10 kGy, and the sum of SDS content and RS content reached 61.32% at 30 kGy, which was close to the maximum value. It shows that the synergistic treatment of irradiation and high-pressure homogenization helps starch to combine with triglycerides to form a more stable starch structure that is more difficult to be enzymatically hydrolyzed. This may be the result of the combined effect of chemical changes (such as cross-linking, degradation, etc.) caused by electron beam irradiation and physical structure changes caused by high-pressure homogenization.

[0127] Fourth, comparison of infrared spectra of potato starch-glycerol trilaurate complex modified by different irradiation doses:

[0128] The infrared spectra of the potato starch-trilaurin complex prepared according to Comparative Example 1 and Examples 1 to 4 were analyzed by the following method.

[0129] The scanning test was performed using a German Bruker VERTEX 70 infrared spectrometer. An appropriate amount of sample was placed on the attenuated total reflectance (ATR) accessory for scanning. Blank KBr was used as the background for detection. The blank KBr background spectrum was scanned before the sample was measured. The spectral region was 4000-400 cm 1 , scanned 32 times, with a resolution of 16cm 1 The infrared spectra were analyzed using OMNIC8.0 software.

[0130] Fourier transform infrared spectroscopy (FT-IR) is an effective analytical method to study the formation of new bonds and structural changes during the formation of starch-lipid complexes. Figure 4 It can be seen that Comparative Example 1 and Examples 1 to 4 exhibit three absorption peaks at 2925, 2854 and 1746 cm-1. These absorption peaks correspond to the stretching vibration of -CH, the asymmetric stretching vibration of -CH and -CH fatty acids, and the vibration of C=O, respectively. Studies have confirmed that the formation of starch-lipid complexes will cause these three absorption peaks to appear in the FT-IR spectrum of natural starch, indicating that irradiation treatment and high-pressure homogenization treatment will cause potato starch and trilaurin to interact to form a starch-lipid complex. However, compared with Comparative Example 1 (natural potato starch-trilaurin complex), the irradiated modified potato starch-trilaurin has no absorption peaks at 2854 and 1746 cm-1. -1 The absorption intensity of the absorption peak at is strong, indicating that electron beam irradiation treatment can promote the formation of starch-triglyceride complex.

[0131] Fifth, comparison of X-ray diffraction (XRD) spectra of potato starch-glycerol trilaurate complex modified by different irradiation doses:

[0132] The potato starch-glycerol trilaurate complex prepared according to Comparative Example 1 and Examples 1 to 4 was measured using an X-ray diffractometer to determine the sample crystal structure. Test conditions: tube voltage 40 kV, current 40 mA, scanning rate 5 ° / min, measurement angle 2θ 5 ° -60 °, step length 0.02 °. The relative crystallinity (Rc) of the sample was calculated using Origin2021 software:

[0133] Calculation formula:

[0134] Rc(%)=Ac / (Ac+Aa)

[0135] Where:

[0136] Ac is the area of ​​the crystal region;

[0137] Aa is the area of ​​the amorphous region.

[0138] XRD is used to detect the crystal structure and crystallinity of the samples, which helps to explore the interaction between lipids and starch molecules. Figure 5 It can be seen that the potato starch-glyceryl trilaurate complex prepared in Comparative Example 1 and Examples 1 to 4 all have diffraction peaks near a diffraction angle 2θ of 20.0°, wherein the diffraction peaks at diffraction angles 2θ of 7.6°, 13.0° and 20.0° are V-type crystallization peaks, which indicates that potato starch and glyceryl trilaurate form a V-type crystalline complex through high-pressure homogenization. The irradiation-modified potato starch-glyceryl trilaurate complex prepared in Examples 1 to 4 has a diffraction peak near a diffraction angle 2θ of 17.5°, and the diffraction peak near a diffraction angle 2θ of 17.5° is the retrogradation crystallization peak of amylose, indicating that electron beam irradiation modification can promote the release of amylose in potato starch.

[0139] When the irradiation dose increased from 0 kGy to 10 kGy, the crystallinity increased (from 6.75% to 8.17%), indicating that low-dose irradiation may promote the interaction between starch and triglycerides, making the crystalline structure of the complex more ordered. However, with the further increase of irradiation dose (from 20 kGy to 30 kGy), the crystallinity first decreased and then increased (from 5.82% to 9.87%), which may be due to the high-dose irradiation causing chain breakage and rearrangement of starch molecules, thereby affecting the crystalline structure of the complex. At 30 kGy, both the crystallinity and the composite index reached their maximum values, which may mean that at this dose, the interaction between starch and lipids reached an optimal state.

[0140] In the composite of irradiated modified starch and trilaurin, the change of irradiation dose not only affects the crystallinity of starch, but also may affect the composite effect and gelatinization properties of the composite.

[0141] At 30 kGy, the crystallinity of the composite was the highest, indicating that the composite under this condition may have a better composite effect and form a more stable composite structure. Higher crystallinity is often related to the mechanical strength and gelatinization properties of the material. Therefore, the potato starch-trilaurin composite treated with 30 kGy has better structural stability and has broad application prospects in the food industry and biomedicine.

Claims

1. A method for preparing a modified potato starch-glyceryl trilaurate complex, characterized in that: The method comprises the following steps: Step 1, irradiation modification: Using a high-energy electron linear accelerator to irradiate potato starch to obtain irradiated modified potato starch; Step 2: Construction of aqueous phase preparation system: The irradiated modified potato starch obtained in step 1 is uniformly mixed with water to prepare irradiated modified potato starch milk; trilaurin is fully dissolved in anhydrous ethanol to prepare a trilaurin / anhydrous ethanol solution; Step 3: Gelatinization: The irradiated modified potato starch emulsion prepared in step 2 is heated and stirred in an oil bath to be evenly dispersed, and then the trilaurin / anhydrous ethanol solution prepared in step 2 is poured into the irradiated modified potato starch emulsion and mixed, and the mixture is continuously heated and stirred in an oil bath to obtain a mixed paste; Step 4: Cooling: The mixed paste obtained in step 3 is placed at room temperature to cool to obtain a cooled paste; Step 5: High-pressure homogenization: The cooled paste obtained in step 4 is subjected to high pressure homogenization to obtain a homogenous paste; Step 6: Removal of free lipids: The homogenous paste obtained in step 5 is cooled to room temperature, n-hexane is added to the homogenous paste and stirred, and after the stirring is completed, the supernatant is removed with a dropper, and this process is repeated three times to obtain a removed composite; Step 7: Drying of the composite: The removed complex obtained in step six is ​​subjected to low temperature drying to obtain a modified potato starch-trilaurin complex.

2. The method for preparing the modified potato starch-trilaurin complex according to claim 1, characterized in that: In step 1, during the irradiation treatment, the electron beam output energy of the high-energy electron linear accelerator is 10 MeV, the maximum beam power is 20 kW, and the irradiation dose is 10 kGy to 40 kGy.

3. The method for preparing the modified potato starch-trilaurin complex according to claim 1, characterized in that: In step 2, the concentration of the irradiated modified potato starch emulsion is 5wt%; the mass of the trilaurin is 5wt% to 9wt% of the dry mass of the starch.

4. The method for preparing the modified potato starch-trilaurin complex according to claim 1, characterized in that: In step three, the temperature of the oil bath is 90° C. to 110° C., the heating time of the oil bath is 20 min; the stirring speed is 460 rpm; and the dispersion time of the irradiated modified potato starch emulsion is 30 s.

5. The method for preparing the modified potato starch-trilaurin complex according to claim 1, characterized in that: In step 4, the cooling paste needs to be cooled to 50°C.

6. The method for preparing the modified potato starch-trilaurin complex according to claim 1, characterized in that: In step 5, the conditions for high-pressure homogenization treatment are: homogenization temperature is 50° C., homogenization pressure is 20 MPa to 60 MPa, and the number of homogenization times is 1 to 3 times.

7. The method for preparing the modified potato starch-trilaurin complex according to claim 1, characterized in that: In step six, 40% of the volume of the mixed paste is added with n-hexane, and the stirring time is 3 minutes.

8. The method for preparing the modified potato starch-trilaurin complex according to claim 1, characterized in that: In step seven, the drying temperature is 40° C. to 45° C., and the drying time is 36 h to 48 h.

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