A stable endogenous starch-lipid complex, one-step induced simultaneous preparation process and its high resistance special medical food

Abstract

The present application relates to a kind of stable, endogenous starch-lipid complex, its one-step efficient induction synchronous preparation process, and corresponding high resistance medical food with the characteristics of regulating blood sugar and intestinal probiotic properties.The present application innovatively proposes the formation of starch-lipid complex in the processing of instant noodles and other medical food, greatly improving the preparation efficiency of medical food containing starch-lipid complex resistant starch, the stability of the complex, and thus improving the overall resistance.Based on the efficient preparation of medical food containing starch-lipid complex resistant starch, it has lower glycemic index and excellent probiotic performance, and has the functions of regulating blood sugar and intestinal probiotic.

Description

Technical Field

[0001] This invention belongs to the field of food raw materials and processing technology, and relates to quality and nutritional regulation during food processing. Specifically, this invention relates to a stable, endogenous starch-lipid complex, its one-step efficient induction and simultaneous preparation process, and the corresponding high-resistance medical food, which simultaneously possesses glycemic regulation and intestinal probiotic properties. Background Technology

[0002] Diabetes and chronic kidney disease seriously endanger human health, and their incidence rates are on the rise this year. In December 2023, the International Diabetes Federation (IDF) released its 2023 Diabetes and Kidney Disease Report, which pointed out that diabetes is one of the main causes of chronic kidney disease (CKD), with as many as 30% to 40% of diabetic patients developing CKD.

[0003] Noodles, a representative of staple foods in Asia, are a popular wheat product in China. The steaming and boiling process causes the starch in noodles to gel, significantly increasing the content of rapidly digestible starch. This leads to a rapid rise in blood sugar levels after meals, classifying them as high-glycemic index (high GI) foods. Long-term consumption is believed to contribute to obesity and the development of chronic diseases such as diabetes, making them particularly unsuitable for diabetics. In recent years, developing low-glycemic index, nutritious, and healthy noodles to meet the needs of special populations like diabetics and to reduce the intake of easily digestible starches in the diets of the general population has become an important goal of the food industry, playing a significant role in preventing chronic diseases and improving public health.

[0004] Over the past 20 years, researchers have explored ways to reduce the rate of starch digestion without significantly affecting the quality of pasta products. For example, some studies have involved replacing a portion of wheat flour with high-amylose corn starch to increase the content of resistant starch in noodles, or adding bioactive substances such as catechins and extracts from Malayan cherry leaves to noodles to reduce starch digestibility through their inhibitory effects on enzyme activity.

[0005] Unfortunately, these products and methods all have some inherent drawbacks. On the one hand, while adding exogenous resistant starch can increase the resistant starch content in fresh noodles, the poor thermal stability and processing adaptability of traditional resistant starch lead to a significant reduction in resistant components after cooking, which also largely destroys the original quality of the noodles, resulting in a substantial decrease in their sensory quality. On the other hand, exogenous bioactive substances often have little effect on improving the digestibility and glycemic index of processed noodles due to their poor stability and bioavailability. Equally important, high amylose corn starch (RS2 type resistant starch) has a higher melting temperature (higher than RS5), but its sources are limited (currently it must be imported from Australia) and it is expensive.

[0006] Based on this predicament, the inventors proposed to change the traditional processing methods and conditions of foods such as noodles to achieve the simultaneous and one-step formation of resistant starch in the noodle preparation process, thereby regulating the starch digestibility and glycemic index in noodles. This has good application prospects and development potential, and is suitable for large-scale industrial production. At the same time, it is inexpensive and is expected to improve the problems faced by groups such as diabetics who need to strictly control their food intake and endure hunger.

[0007] RS: Resistant starch;

[0008] RS5: This refers to type 5 resistant starch, which is a starch-lipid complex.

[0009] Type I starch-lipid complex: Crystal melting temperature: 95~105℃;

[0010] Type II starch-lipid complex: Crystal melting temperature: 110~121℃. Summary of the Invention

[0011] To address the shortcomings of exogenous resistant starch and traditional resistant starch, such as poor thermal stability, poor processing adaptability, limited availability, and high price, this invention provides a stable, endogenous starch-lipid complex, its one-step efficient induction and simultaneous preparation process, and the corresponding highly resistant medical food that combines blood sugar regulation and intestinal probiotic properties.

[0012] This invention innovatively proposes a method to efficiently induce the formation of starch-lipid complexes during the processing of special medical foods such as instant noodles, which greatly improves the preparation efficiency and complex stability of special medical foods containing resistant starch with starch-lipid complexes, thereby enhancing overall resistance.

[0013] This invention involves adding a certain proportion of monoglycerides to wheat flour, followed by material mixing, dough preparation, and extrusion molding. This allows starch and lipids to fully interact during the extrusion heat processing, forming a starch-lipid complex. This one-step process efficiently produces medical foods (e.g., instant noodles) containing resistant starch with a starch-lipid complex. These foods exhibit low digestibility, a low glycemic index, and good sensory qualities, while also potentially improving gut microbiota. This invention develops a one-step process for preparing instant noodles with both blood sugar-regulating and gut-benefiting properties using a twin-screw extruder. This process not only overcomes the loss of resistant starch during traditional heat processing but also features high efficiency and sustainable production. The raw materials used are inexpensive, the process is simple, and it has broad application prospects.

[0014] This invention provides an endogenous starch-lipid complex, characterized in that it is formed simultaneously from starch and lipids during the extrusion processing of pasta. The endogenous starch-lipid complex of this invention has crystal forms including type I and / or type II.

[0015] The endogenous starch-lipid complex of the present invention comprises starch selected from wheat flour; and lipids selected from fatty acids and monoglycerides. Further, the lipids are selected from those with a carbon chain length of C8 to C99. 18 The monoglyceride, preferably glyceryl monolaurate.

[0016] The endogenous starch-lipid complex of the present invention can be formulated using the following raw material ratio:

[0017] 66-69 parts wheat flour

[0018] 1-4 parts of glyceryl monolaurate

[0019] 30-40 parts water.

[0020] The preparation steps of the endogenous starch-lipid complex of the present invention include:

[0021] (1) Take wheat flour and lipids, mix them well to obtain a mixture;

[0022] (2) Add water to the mixture, knead the dough, and let it rise and mature at room temperature;

[0023] (3) The matured dough is extruded using a twin-screw extruder to obtain the final product.

[0024] Furthermore, the preparation steps of the endogenous starch-lipid complex of the present invention include:

[0025] (1) Weigh out wheat flour and lipids, and mix them thoroughly with a mixer to obtain a mixture;

[0026] (2) Put the materials into the dough mixer and spray water evenly on the surface of the mixture at a constant rate; after the dough is kneaded, let it rise and mature at room temperature;

[0027] (3) The matured dough is fed into the feed port of a twin-screw extruder and extruded to obtain the final product.

[0028] Wherein: in step (2), the mixing time of the dough mixer is 5 minutes, and the room temperature proofing and maturation time is 30 minutes;

[0029] In step (3), the screw extruder consists of six temperature zones, the screw diameter is 2cm, and the length-to-diameter ratio (L / D) is 40:1. The operating parameters of the twin-screw extruder are as follows: the temperatures of zones 1, 2, 3, 4, 5, and 6 of the barrel are set to 40-50℃, 60-70℃, 80-90℃, 110-130℃, 110-130℃, and 110-130℃, respectively, and the screw speed is 300rpm.

[0030] The endogenous starch-lipid complex described in this invention can be used to prepare special medical foods, etc., and its preparation steps include:

[0031] (1) Take wheat flour and lipids, mix them well to obtain a mixture;

[0032] (2) Add water, knead the dough, and let it rise and mature at room temperature;

[0033] (3) The dough is extruded using a twin-screw extruder and shaped through a food mold to obtain the corresponding special medical food.

[0034] When the special medical food is presented as instant noodles, its characteristic is that the food mold in step (3) above is a noodle mold.

[0035] The application of the endogenous starch-lipid complex of the present invention is characterized in that the endogenous starch-lipid complex is used to prepare special medical foods that improve the composition of intestinal flora and promote the formation of metabolites such as short-chain fatty acids.

[0036] Furthermore, the present invention provides a convenient noodle with both blood sugar regulating and gut-benefiting properties, and its one-step preparation process, characterized by comprising the following steps:

[0037] (1) Weigh 66-69 parts by weight of wheat flour and 1-4 parts by weight of lipids, and mix them evenly with a mixer for 5 minutes to obtain a mixture;

[0038] (2) Spray 30-40 parts by weight of water into the mixture at a constant rate and mix with a dough mixer for 5 minutes. Let it rise and mature at room temperature for 30 minutes;

[0039] (3) The matured dough is fed to the feed port of the twin-screw extruder for extrusion and gelatinization. The dough is then formed into noodles in one step through the die head. The extruder consists of six temperature zones. The screw diameter is 2 cm and the length-to-diameter ratio (L / D) is 40:1. The operating parameters of the twin-screw extruder are as follows: the temperatures of zones 1, 2, 3, 4, 5, and 6 of the barrel are set to 40-50℃, 60-70℃, 80-90℃, 110-130℃, 110-130℃, and 110-130℃, respectively, and the screw speed is 300 rpm.

[0040] (4) Cut the noodles into lengths of 200-220 mm, then vacuum pack them in polyethylene bags and store them at 4°C.

[0041] Preferably, the wheat flour in step (1) is 68-69 parts by weight.

[0042] Preferably, the lipid in step (1) is a monoglyceride with a carbon chain length of C8 to C18 and a low irritating odor, and is 1 to 2 parts by weight of monolaurate glyceride.

[0043] Preferably, the lipids in step (1) are ground in a mortar and passed through a 100-mesh sieve.

[0044] Preferably, the water in step (2) is 30 parts by weight, added in the form of spraying at a constant rate, so that the water distribution is more uniform.

[0045] Preferably, the screw compressor in step (3) consists of six temperature components, with a screw diameter of 2cm, a length-to-diameter ratio (L / D) of 40:1, and barrel temperatures of 40℃, 60℃, 100℃, 120℃, 120℃, and 120℃, and a screw speed of 300rpm.

[0046] Preferably, the diameter of the screw press head mold in step (3) is 3mm, that is, the diameter of the noodles is 3mm.

[0047] An embodiment of the present invention provides an instant noodle that combines blood sugar regulation and intestinal probiotic properties. The instant noodle has low digestibility, and its digestibility can be further improved by adjusting the structure and content of its resistant starch through processing conditions.

[0048] An embodiment of the present invention provides an instant noodle product that combines blood sugar regulation and gut health benefits. The starch-lipid complex in the instant noodle can act as a novel dietary fiber to regulate the composition and metabolism of gut microbiota, such as increasing the relative abundance of beneficial bacteria such as Alistipes, Phascolarctobacterium, Megasphaera, and Bifidobacterium, and promoting the formation of related metabolites such as short-chain fatty acids, including acetic acid, acetic acid, and butyric acid, thereby improving gut health.

[0049] This invention includes, but is not limited to, the following advantages and advancements:

[0050] (1) To overcome the poor thermal stability and processing adaptability of exogenous resistant starch, this invention provides a new type of endogenous resistant starch;

[0051] (2) No repeated processing is required. The starch-lipid complex is generated simultaneously with the final products such as noodles, which reduces the impact of repeated heat processing on product stability. It has high thermal stability and strong processing adaptability.

[0052] (3) Simple process. The one-step method for efficient induction preparation of starch-lipid complexes is simple, low-cost, and suitable for large-scale industrial production.

[0053] (4) Resistance retention. Compared with exogenously added resistant starch, endogenous resistant starch is more uniform, and its resistance decreases less after cooking. Moreover, it largely retains the original quality of the noodles, resulting in better sensory quality.

[0054] (5) The present invention prepares a special medical food containing starch-lipid complex resistant starch, which can not only resist the digestion of amylase and reduce the glycemic index of noodles, but also enter the colon for fermentation to regulate the intestinal microecology, promote the production of short chain fatty acids in the intestine, and has the functions of regulating blood sugar and intestinal probiotics, which is of great significance for improving intestinal and human health.

[0055] Instruction manual illustrations

[0056] Figure 1 The X-ray diffraction patterns of Examples 1-4 and Comparative Example 1 are shown below.

[0057] Figure 2 The digestion curves of the freeze-dried noodle powder in Examples 1-4 and Comparative Example 1 are shown.

[0058] Figure 3 Differential scanning calorimeter spectra of noodles from Examples 1-4 and Examples 5-6;

[0059] Figure 4The in vitro digestion curves of noodle segments from Examples 1 to 4 are shown.

[0060] Figure 5 The heatmap shows the relative abundance of the first 20 different microorganisms at the genus level in the in vitro fermentation systems of Examples 5-6 and Comparative Examples 2-3;

[0061] Figure 6 The short-chain fatty acid content of the in vitro fermentation systems of Examples 5-6 and Comparative Examples 2-3;

[0062] Figure 7 This is a photograph of an instant noodle product that combines blood sugar regulation and gut health benefits according to the present invention. Detailed Implementation

[0063] The principles and features of the present invention are described below. The embodiments and comparative examples are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0064] Example 1: Preparation of Instant Noodles with Endogenous Resistant Starch

[0065] A type of instant noodles that combines blood sugar regulation and gut health benefits is prepared using the following steps:

[0066] (1) Weigh 69 parts by weight of wheat flour and 1 part by weight of food-grade monolaurate, and mix them evenly using a mixer for 5 minutes to obtain a mixture.

[0067] (2) Spray 30 parts by weight of water into the mixture at a constant rate and mix with a dough mixer for 5 minutes. Let it rise and mature at room temperature for 30 minutes.

[0068] (3) The cooked dough is extruded and gelatinized using a twin-screw extruder to obtain noodles. The extruder screw diameter is 2cm, the length-to-diameter ratio L / D is 40:1, the barrel temperature is set to 40℃, 60℃, 100℃, 120℃, 120℃, 120℃, and the screw speed is 300rpm.

[0069] (4) Cut the noodles into lengths of 200-220 mm, vacuum pack them in polyethylene bags, and store them at 4°C.

[0070] Example 2: Preparation of an Instant Noodle with Endogenous Resistant Starch

[0071] A type of instant noodles that combines blood sugar regulation and gut health benefits is prepared using the following steps:

[0072] (1) Weigh 68 parts by weight of wheat flour and 2 parts by weight of food-grade monolaurate glycerol, and mix them evenly with a mixer for 5 minutes to obtain a mixture.

[0073] (2) Spray 30 parts by weight of water into the mixture at a constant rate and mix with a dough mixer for 5 minutes. Let it rise and mature at room temperature for 30 minutes.

[0074] (3) The cooked dough is extruded and gelatinized using a twin-screw extruder to obtain noodles. The extruder screw diameter is 2cm, the length-to-diameter ratio L / D is 40:1, the barrel temperature is set to 40℃, 60℃, 100℃, 120℃, 120℃, 120℃, and the screw speed is 300rpm.

[0075] (4) Cut the noodles into lengths of 200-220 mm, vacuum pack them in polyethylene bags, and store them at 4°C.

[0076] Example 3: Preparation of Instant Noodles with Endogenous Resistant Starch

[0077] A type of instant noodles that combines blood sugar regulation and gut health benefits is prepared using the following steps:

[0078] (1) Weigh 67 parts by weight of wheat flour and 3 parts by weight of food-grade monolaurate glycerol, and mix them evenly with a mixer for 5 minutes to obtain a mixture.

[0079] (2) Spray 30 parts by weight of water into the mixture at a constant rate and mix with a dough mixer for 5 minutes. Let it rise and mature at room temperature for 30 minutes.

[0080] (3) The cooked dough is extruded and gelatinized using a twin-screw extruder to obtain noodles. The extruder screw diameter is 2cm, the length-to-diameter ratio L / D is 40:1, the barrel temperature is set to 40℃, 60℃, 100℃, 120℃, 120℃, 120℃, and the screw speed is 300rpm.

[0081] (4) Cut the noodles into lengths of 200-220 mm, vacuum pack them in polyethylene bags, and store them at 4°C.

[0082] Example 4: Preparation of Instant Noodles with Endogenous Resistant Starch

[0083] A preparation process for instant noodles that combines blood sugar regulation and gut health benefits is shown in the following steps:

[0084] (1) Weigh 66 parts by weight of wheat flour and 4 parts by weight of food-grade monolaurate glycerol, and mix them evenly with a mixer for 5 minutes to obtain a mixture.

[0085] (2) Spray 30 parts by weight of water into the mixture at a constant rate and mix with a dough mixer for 5 minutes. Let it rise and mature at room temperature for 30 minutes.

[0086] (3) The cooked dough is extruded and gelatinized using a twin-screw extruder to obtain noodles. The extruder screw diameter is 2cm, the length-to-diameter ratio L / D is 40:1, the barrel temperature is set to 40℃, 60℃, 100℃, 120℃, 120℃, 120℃, and the screw speed is 300rpm.

[0087] (4) Cut the noodles into lengths of 200-220 mm, vacuum pack them in polyethylene bags, and store them at 4°C.

[0088] Example 5 Preparation of Type I starch-lipid complex

[0089] A method for preparing a type I starch-lipid complex includes the following steps:

[0090] (1) Weigh 96 parts by weight of corn starch and 4 parts by weight of lauric acid, and mix them evenly using a mixer for 5 minutes to obtain a mixture.

[0091] (2) Add 25 parts by weight of water to the mixture at a constant rate and stir for 5 minutes. Place in a sealed bag at room temperature for 24 hours to equilibrate.

[0092] (3) The balanced mixture is discharged and conveyed to the feed port of a twin-screw extruder and extruded and gelatinized to obtain a type I composite sample. The screw extruder consists of six temperature components, with a screw diameter of 2 cm, a length-to-diameter ratio (L / D) of 40:1, and barrel temperatures of 40℃, 60℃, 90℃, 100℃, 100℃, and 100℃, and a screw speed of 300 rpm.

[0093] (4) Cut the extruded sample into strips of uniform size, dry them at 45°C for 24 hours, grind and sieve them to obtain the type I complex.

[0094] Example 6 Preparation of type II starch-lipid complex

[0095] A method for preparing a type II starch-lipid complex, comprising the following steps:

[0096] (1) Weigh 96 parts by weight of corn starch and 4 parts by weight of lauric acid, and mix them evenly using a mixer for 5 minutes to obtain a mixture.

[0097] (2) Add 45 parts by weight of water to the mixture at a constant rate and stir for 5 minutes. Place in a sealed bag at room temperature for 24 hours to equilibrate.

[0098] (3) The balanced mixture is discharged and conveyed to the feed port of a twin-screw extruder and extruded and gelatinized to obtain a type II composite sample. The screw extruder consists of six temperature components, with a screw diameter of 2 cm, a length-to-diameter ratio (L / D) of 40:1, and barrel temperatures of 40℃, 60℃, 90℃, 120℃, 120℃, and 120℃, and a screw speed of 300 rpm.

[0099] (4) Cut the extruded sample into strips of uniform size, dry them at 45°C for 24 hours, grind and sieve them to obtain the type II complex.

[0100] Comparative Example 1: Preparation of instant noodles without added lipids

[0101] A process for preparing lipid-free instant noodles is shown in the following steps:

[0102] (1) Weigh 70 parts by weight of wheat flour and 0 parts by weight of food-grade monolaurate, and mix them evenly using a mixer for 5 minutes to obtain a mixture.

[0103] (2) Spray 30 parts by weight of water into the mixture at a constant rate and mix with a dough mixer for 5 minutes. Let it rise and mature at room temperature for 30 minutes.

[0104] (3) The matured dough is fed into the feed port of a twin-screw extruder and extruded and gelatinized to obtain noodles. The extruder screw diameter is 2cm, the length-to-diameter ratio L / D is 40:1, the barrel temperature is set to 40℃, 60℃, 100℃, 120℃, 120℃, 120℃, and the screw speed is 300rpm.

[0105] (4) Cut the noodles into lengths of 200-220 mm, vacuum pack them in polyethylene bags, and store them at 4°C.

[0106] To demonstrate the probiotic effects of starch-lipid complexes in improving gut microbiota composition and promoting the formation of short-chain fatty acids and other related metabolites, type I starch-lipid complexes (Example 5) and type II starch-lipid complexes (Example 6) were prepared using the following processing techniques. Comparative Examples 2 and 3 were then subjected to in vitro fermentation experiments to verify the effects of starch-lipid complexes on gut microbiota.

[0107] Comparative Example 2: Preparation method of extruded corn starch without added lipids

[0108] A method for preparing extruded corn starch without added lipids, comprising the following steps:

[0109] (1) Weigh 100 parts by weight of corn starch and 0 parts by weight of lauric acid, and mix them evenly with a mixer for 5 minutes to obtain a mixture.

[0110] (2) Add 25 parts by weight of water to the mixture at a constant rate and stir for 5 minutes. Place in a sealed bag at room temperature for 24 hours to equilibrate.

[0111] (3) The balanced mixture is discharged and conveyed to the feed port of the twin-screw extruder and extruded and gelatinized to obtain extruded corn starch samples. The screw extruder consists of six temperature components, with a screw diameter of 2cm, a length-to-diameter ratio (L / D) of 40:1, and barrel temperatures set to 40℃, 60℃, 90℃, 100℃, 100℃, and 100℃, and a screw speed of 300rpm.

[0112] (4) Cut the extruded sample into strips of uniform size, dry them at 45℃ for 24 hours, grind and sieve them to obtain corn starch.

[0113] Comparative Example 3: Preparation of extruded corn starch without added lipids

[0114] A method for preparing extruded corn starch without added lipids, comprising the following steps:

[0115] (1) Weigh 100 parts by weight of corn starch and 0 parts by weight of lauric acid, and mix them evenly with a mixer for 5 minutes to obtain a mixture.

[0116] (2) Add 45 parts by weight of water to the mixture at a constant rate and stir for 5 minutes. Place in a sealed bag at room temperature for 24 hours to equilibrate.

[0117] (3) The balanced mixture is fed to the feed port of a twin-screw extruder and extruded and gelatinized to obtain a corn starch sample. The screw extruder consists of six temperature components, with a screw diameter of 2 cm, a length-to-diameter ratio (L / D) of 40:1, and barrel temperatures of 40℃, 60℃, 90℃, 120℃, 120℃, and 120℃, and a screw speed of 300 rpm.

[0118] (4) Cut the extruded sample into strips of uniform size, dry them at 45℃ for 24 hours, grind and sieve them to obtain corn starch.

[0119] Relevant test results for all examples and comparative examples prepared by the method of this invention:

[0120] Example 7: Thermodynamic properties of starch-lipid complex

[0121] The thermodynamic properties of starch-lipid complexes in noodles prepared under different processing conditions were measured using a differential scanning calorimeter (DSC). 3 mg of a mixture of starch and different types of lipids was accurately weighed into a 40 μL DSC crucible. Ultrapure water at a ratio of 1:3 (w / w) was added, and the crucible was sealed and left at room temperature overnight to equilibrate the moisture. During sample testing, the temperature was increased from 20 °C to 130 °C at a rate of 10 °C / min. An empty crucible served as a blank control. The thermodynamic transformation parameters of the complex, including the initial temperature (To), peak temperature (Tp), final temperature (Tc), and enthalpy of thermal transformation (ΔH), were calculated using the instrument's data recording software. The melting temperatures (To, Tp, Tc) represent the thermal stability of the complex, and the magnitude of the enthalpy (ΔH) represents the amount of starch-lipid complex. See Table 1. Figure 3 The data in the table shows that Example 5 detected a melting peak (Tp = 96.8℃), while Example 6 detected a melting peak in a higher temperature range (Tp = 114.2℃). These correspond to the melting of the type I complex and the type II complex, respectively. This indicates that the type II complex has a more ordered crystal structure and its thermodynamic stability is significantly higher than that of the type I complex.

[0122] Examples 1-4 are noodles containing starch-lipid complexes. The peak temperature (Tp1) of melting peak 1 ranges from 93.1 to 98.6 °C, and the enthalpy (ΔH1) ranges from 0.88 to 2.48 J / g. The peak temperature (Tp2) of melting peak 2 ranges from 112.2 to 115.9 °C, and the enthalpy (ΔH2) ranges from 0.98 to 4.08 J / g. This indicates that materials with different raw material ratios, after being processed by a one-step twin-screw extruder process at a specific temperature, form starch-lipid complexes of different quantities and stability. Figure 3 It can be visually observed that Examples 1-4 exhibit three melting peaks at approximately 50°C, 95°C, and 110°C, corresponding to glyceryl monolaurate, type I complex, and type II complex, respectively. The melting peaks of the lipids increase progressively from bottom to top, while the melting peaks and enthalpy values ​​of the complexes do not show a significant increase. This indicates that under the current conditions, increasing the amount of lipid added does not promote the formation of the starch-lipid complex; rather, the lipids tend to self-aggregate and crystallize due to hydrophobic interactions.

[0123] Example 8: Crystal structure of starch-lipid complex

[0124] The long-range crystalline order of the starch-lipid complexes in Examples 1, 2, 3, 4 and Comparative Example 1 was analyzed using X-ray diffraction (D8 Advance, Bruker, Germany). Analyses were performed at a scan rate of 2° / min and a step size of 0.02° within a scan range of 5°–30° (2θ). Figure 1Examples 1-4 all exhibited three distinct diffraction peaks at 7.5°, 12.8°, and 19.8°, indicating the formation of a V-type crystal structure. The figures clearly show that the diffraction intensity of the V-type crystals in Examples 1-4 initially increases and then decreases. This indicates that at this moisture content, as the amount of lipid added increases, it first promotes the aggregation of the starch-lipid complex into a more stable crystal structure. With excessive addition, lipids self-aggregate in the system, inhibiting the formation of the complex and preventing the formation of more and more stable type II complexes. This is consistent with the result of the lipid melting peaks in Examples 1-4 gradually increasing in size observed by differential scanning calorimetry.

[0125] Table 1. Thermodynamic properties of the compound in the noodles in the examples.

[0126]

[0127] Note: Data in the table are mean ± standard deviation; identical suffix letters indicate no significant difference, while different letters indicate a significant difference (p < 0.05); "ND" indicates no data detected.

[0128] Example 9: In vitro digestibility of starch

[0129] The noodles obtained in Examples 1-4 and Comparative Example 1 were dried at 45°C and ground into powder, passed through a 60-mesh sieve, and the sample (containing 100 mg of starch, dry basis) was accurately weighed and subjected to in vitro digestion experiments. 72.72 g of α-amylase (11 U / mg) was dispersed in 10 mL of deionized water at 37°C and magnetically stirred for 10 min to prepare a fresh porcine pancreatic α-amylase (PPA) solution. The sample (100 mg) was mixed with 9 mL of sodium acetate buffer (0.2 M, pH 6.8) containing 6.67 mmol / L CaCl2, and 1 mL of α-amylase (80 U) was added. At specified time points (0, 5, 10, 15, 20, 30, 45, 60, 90, and 120 min), equal aliquots (100 μL) were taken out, and 900 μL of sodium carbonate solution was added and the mixture was placed at 4°C to terminate the enzymatic digestion reaction. The suspension was centrifuged at 13,000 g for 3 min, and the reducing sugar content in the supernatant was determined using the PAHBAH-based method. The percentage of starch digested was expressed as the ratio of the amount of reducing sugar released to the total amount of starch. Starch digestibility was calculated using the following formula:

[0130]

[0131] ΔA is the absorbance of the sample, c and m are the intercept and slope of the maltose standard curve, D is the dilution factor, V is the total volume of the solution, 324 / 342 is the conversion factor from maltose to starch, and TS is the total starch content of the sample.

[0132] The results are as follows Figure 2As shown, after 0–120 minutes of in vitro digestion of noodle powder, Comparative Example 1 (~85%) was rapidly digested in the first 20 minutes and almost completely digested after 120 minutes. This indicates that 85% of the starch is rapidly broken down, suggesting significant fluctuations in blood sugar levels, which could potentially induce metabolic diseases such as type 2 diabetes in the long term. Examples 1–2, containing more type II starch-lipid complexes, showed significantly lower digestibility at 120 minutes compared to Comparative Example 1 (88% and 87%), with digestibility decreasing by 12% and 13%, respectively. Examples 3–4, containing more type I complexes, showed slightly lower final digestibility compared to Comparative Example 1 (94% and 97%).

[0133] This shows that starch-lipid complexes (especially type II complexes) have better enzyme resistance than gelled starch. Their more stable and compact crystal structure helps resist digestion in the small intestine, allowing more starch-lipid complexes to reach the large intestine for fermentation and improving the gut microbiota.

[0134] Example 10: Cooking loss of noodles

[0135] Weigh noodles of equal length and record their dry weight. Drain the cooked noodles in a funnel and rinse with 50 mL of distilled water for 30 seconds. Collect the cooking water and rinsing water and heat to a constant weight at 105 °C. Cooking loss (CL) is expressed as the percentage of the weight of dry solids in the cooking water relative to the weight of the dry noodles before cooking. The results are shown in Table 2.

[0136] Table 2 shows the cooking loss of noodles in the examples and comparative examples.

[0137]

[0138] The cooking loss rates of noodles in Examples 1-4 and Comparative Example 1 were 5.45%, 8.01%, 4.36%, 2.31%, and 4.62%, respectively. Among them, Example 2, which contained type II starch-lipid complex, had the highest cooking loss of 8.01%, while Example 4, which contained type I starch-lipid complex, had the lowest cooking loss of 2.31%. Compared with Comparative Example 1, Examples 1 and 2, which contained more type II complex, had higher cooking losses, increasing by 0.83% and 3.39%, respectively, while Examples 3 and 4, which contained more type I starch-lipid complex, had lower cooking losses, decreasing by 0.26% and 2.31%, respectively.

[0139] The above factors are mainly related to the structure of starch-lipid complexes. Type II starch-lipid complexes have a more stable crystal structure and a higher melting temperature, but their solubility is lower, making it difficult to form a dense network structure with gluten. Although this results in relatively greater losses during cooking, they are more effective in improving the digestibility of noodles. In contrast, Type I starch-lipid complexes have better solubility and can form a dense network structure with gluten, giving them an advantage in improving noodle quality.

[0140] Example 11 Texture properties of noodles

[0141] The cooked noodles were removed and placed in cold water for 30 seconds, then drained. Using a TA-XT Plus texture analyzer (StableMicro System, UK), three 5cm long noodles were placed on the testing platform. Two compression cycles were performed using a 12mm diameter P / 0.5 probe. The pre-test speed was 2mm / s, and the test speed was 1mm / s. The compression ratio was 70%, the trigger force was 5g, and the time interval between two compressions was 1 second. The texture determination of each sample was completed within 20 minutes. The results are shown in Table 3.

[0142] The results showed that, compared with the comparative example, Examples 1-2 containing the type II complex significantly reduced the hardness of the noodles, while Examples 3-4 containing the type I complex significantly increased the hardness of the noodles. Regarding noodle resilience, Examples 1-4 all significantly improved the resilience of the noodles compared with Comparative Example 1. In summary, noodles containing starch-lipid complexes prepared by a single-step process under specific temperature and processing conditions with different proportions of materials altered the quality of the noodles to varying degrees.

[0143] Table 3. Texture properties of noodles in the examples and comparative examples.

[0144]

[0145]

[0146] Note: Data in the table are mean ± standard deviation; identical suffix letters indicate no significant difference, while different letters indicate a significant difference (p < 0.05).

[0147] Example 12 eGI of noodles

[0148] It involves simulating the gastric digestion stage and the small intestinal digestion stage.

[0149] Each digestive fluid contains a gastric digestive buffer (pH=3) and a small intestinal digestive buffer (pH=6.8).

[0150] The specific steps are as follows:

[0151] Weigh 80 mg of the cooked sample, and use a blade to cut the cooked samples of Examples 1-4 and Comparative Example 1 into 2 mm pieces and add them to a 50 ml centrifuge tube. The cutting was intended to simulate oral chewing, and white bread was used as a control for glycemic index determination.

[0152] Add 3 ml of gastric digestion buffer to the centrifuge tube, incubate at 37°C for 30 min, and continuously stir at 150 rpm using a magnetic stirrer.

[0153] After the gastric digestion period ended, 100 μL of digestive juice from Examples 1-4, Comparative Example 1, and white bread digestive juice was added to 900 μL of sodium carbonate solution and placed at 4°C as the 0 point of the small intestinal digestion stage.

[0154] Add 6 ml of small intestinal digestion buffer to the centrifuge tube and incubate at 37°C for 5 h (5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240 and 300 min).

[0155] At each time point, 100 μL of the digest solution was added to sodium carbonate solution to terminate starch hydrolysis, and then centrifuged (12,000 rpm, 10 min). The reducing sugar in the supernatant was determined according to the PAHBAH method.

[0156] Starch digestibility is calculated using the following formula:

[0157]

[0158] ΔA is the absorbance of the sample, c and m are the intercept and slope of the maltose standard curve, D is the dilution factor, V is the total volume of the solution, 324 / 342 is the conversion factor from maltose to starch, and TS is the total starch content of the sample.

[0159] The hydrolysis index (HI) refers to the ratio between the area under the hydrolysis curve of samples from Comparative Example 1 and Examples 1-4 and the corresponding area of ​​white bread. Based on the obtained HI, the glycemic index (eGI) value is then estimated using an empirical formula as follows:

[0160] eGI = 8.198 + 0.862 * HI

[0161] The eGI of noodles from Examples 1, 2, 3, 4, and Comparative Example 1 was determined by in vitro simulated gastrointestinal digestion. The results are shown in Table 4. Figure 4 .

[0162] As shown in Table 4, the eGI of Comparative Example 1, Example 1, and Example 2 are all less than 55, classifying them as low glycemic index foods. Examples 3 and 4, however, have eGIs higher than 55, classifying them as high glycemic index foods. Although Comparative Example 1 has the lowest eGI, its main component is gelled starch. Compared to Examples 1 and 2, which are also low-GI, it lacks a starch-lipid complex and therefore does not possess the potential function of regulating gut microbiota similar to that of a complex. This conclusion can be verified by the fermentation experiment results in the following section.

[0163] Table 4. Glycemic index of noodles in the examples and comparative examples.

[0164]

[0165] Note: Data in the table are mean ± standard deviation; identical suffix letters indicate no significant difference, while different letters indicate a significant difference (p < 0.05).

[0166] Example 13 In vitro fermentation characteristics

[0167] The effects of type I and type II starch-lipid complexes on gut microbiota composition and short-chain fatty acid production were determined using an in vitro static bacterial fermentation model. The steps are as follows:

[0168] (1) Stool samples were collected from 6 healthy volunteers (aged 25 to 33 years and who had not taken antibiotics in the past 6 months) between 7:00 and 10:00 on the day of vaccination. The samples were placed in sterile bags and stored at 37°C.

[0169] (2) When inoculating, the collected samples are mixed together and diluted with sterile saline. The fecal residue is filtered out with gauze to obtain fecal liquid for inoculation.

[0170] (3) Add the samples from Examples 5-6 and Comparative Examples 2-3 to the sterile fermentation flask, and use fructooligosaccharide (FOS) as a positive control.

[0171] (4) Add the filtered fecal liquid to a serum bottle containing the substrate and culture medium. Take samples of the fermentation broth at different time points during fermentation for subsequent analysis of short-chain fatty acids and gut microbiota. Set up three replicates for each time point of each sample.

[0172] Methods for detecting short-chain fatty acid content: Gas chromatography was used to analyze short-chain fatty acids in the fermentation broth. Standard solutions with different concentrations of short-chain fatty acids were prepared, and standard curves for acetic acid, propionic acid, butyric acid, and valeric acid were plotted using the external standard method.

[0173] Figure 5-6 The results confirmed the claim that starch-lipid complexes have probiotic effects, such as improving gut microbiota composition and promoting the formation of short-chain fatty acids and related metabolites. Figure 6Examples 5-6, compared to Comparative Examples 2-3 and the FOS positive control, produced more total short-chain fatty acids, especially butyric acid, in in vitro fermentation experiments. This is related to... Figure 5 Example 6 promoted a more uniform relative abundance of butyric acid-producing bacteria, with the more structurally stable type II complex exhibiting a stronger acid-producing capacity than the type I complex. Figure 5 Examples 5-6, after fermentation, not only increased the diversity of intestinal microbiota but also increased the relative abundance of beneficial bacteria such as *Alistipes*, *Phascolarctobacterium*, *Megasphaera*, and *Bifidobacterium*. These results were not reflected in the fermentation results of gelled starch (Comparative Examples 2-3). This indicates that the starch-lipid complex can promote the proliferation of probiotics in the intestinal flora. Therefore, although the glycemic index of Comparative Example 1 and Examples 1-2 is similar, the main component of Comparative Example 1 is gelled starch, and its intestinal probiotic properties are significantly worse than those of the starch-lipid complex. Examples 1-4, after treatment with specific temperatures and material ratios and processed in a one-step method, all contain the starch-lipid complex found in Examples 5-6. Therefore, the noodles prepared in these examples should also possess probiotic properties. This proves that the noodles containing the starch-lipid complex developed in this invention not only have a low glycemic index but also possess potential probiotic properties.

[0174] In summary, this invention innovatively proposes a method for efficiently inducing the formation of starch-lipid complexes during the processing of medical foods such as instant noodles, which have a low glycemic index and excellent probiotic properties. This significantly improves the preparation efficiency and complex stability of medical foods containing resistant starch-lipid complexes, thereby enhancing overall resistance. Medical foods containing resistant starch-lipid complexes, prepared efficiently based on this invention, exhibit a low glycemic index and excellent probiotic properties, including blood sugar regulation and intestinal health benefits.

Claims

1. A pasta product processed by extrusion of an endogenous starch-lipid complex, characterized in that, Using starch and lipids as raw materials, a starch-lipid complex is simultaneously formed during the extrusion processing of pasta, characterized by the following raw materials: 66-69 parts wheat flour 1-4 parts of glyceryl monolaurate 30-40 parts water; Its preparation steps include: (1) Take wheat flour and lipids, mix them well to obtain a mixture; (2) Add water to the mixture, knead the dough, and let it rise and mature at room temperature; (3) The cooked dough is extruded using a twin-screw extruder and shaped through the die head to obtain the product; wherein, the twin-screw extruder consists of six temperature zones, the screw diameter is 2 cm, the length-to-diameter ratio (L / D) is 40:1, and the working parameters of the twin-screw extruder are: the temperatures of zones 1, 2, 3, 4, 5 and 6 of the barrel are set to 40~50 ℃, 60~70 ℃, 80~90 ℃, 110~130 ℃, 110~130 ℃, and 110~130 ℃ respectively, and the screw speed is 300 rpm.

2. The pasta processed from the endogenous starch-lipid complex according to claim 1, characterized in that, The crystalline forms of starch-lipid complexes include type I and / or type II.

3. The pasta processed from the endogenous starch-lipid complex according to claim 1, comprising the following preparation steps: (1) Weigh wheat flour and lipids, and mix them thoroughly with a mixer to obtain a mixture; (2) Put the materials into the dough mixer and spray water evenly on the surface of the mixture at a constant rate; after the dough is kneaded, let it rise and mature at room temperature; (3) The cooked dough is fed to the feed port of a twin-screw extruder and extruded to obtain the final product.

4. The pasta processed from the endogenous starch-lipid complex according to claim 3, characterized in that, In step (2), the mixing time of the dough mixer is 5 min, and the proofing and maturation time at room temperature is 30 min.

5. The pasta processed from the endogenous starch-lipid complex according to any one of claims 1 to 4, characterized in that... The pasta includes instant noodles, and step (3) the machine head mold is a noodle mold.

6. The application of a pasta product processed by extrusion of the endogenous starch-lipid complex according to any one of claims 1 to 4, characterized in that... Used to prepare special medical foods that improve the composition of intestinal flora and promote the formation of metabolites.

7. The application according to claim 6, wherein the metabolites include short-chain fatty acids.

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