Low-GI functional noodles based on biological enzymolysis-microwave puffing technology and preparation method of low-GI functional noodles

Abstract

The invention provides low-GI functional noodles based on a biological enzymolysis-microwave puffing technology and a preparation method of the low-GI functional noodles, and belongs to the technical field of food processing. The low-GI fermented tea functional noodles comprise the following raw materials in percentage by mass: 60%-80% of high gluten wheat flour, 10%-25% of resistant starch, 5%-15% of functional tea powder, 3%-8% of active wheat glutelin and 0.5%-1% of table salt. The functional tea powder is porous particles which are prepared from fermented tea through enzymolysis for regulating and controlling the viscoelastic state and microwave vacuum puffing and have a honeycomb-shaped open-type micropore structure. According to the invention, a'structured remodeling 'strategy is creatively adopted, so that the defects that a gluten network is damaged by traditional tea powder as a compact hard filler and the thermal stability of a liquid extract is poor are overcome. The functional tea powder is added, so that the noodles disclosed by the invention have excellent boiling fastness on one hand, and have excellent and stable low-GI characteristics on the other hand.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food processing, in particular to a low GI fermented tea functional noodle based on biological enzymatic hydrolysis-microwave puffing technology and a preparation method thereof. BACKGROUND

[0002] With the continuous rise of the incidence of metabolic syndromes such as diabetes and obesity worldwide, dietary intervention as a primary prevention and adjuvant therapy has become increasingly important. Glycemic index (GI) is a key indicator for measuring the postprandial blood glucose response of food. Traditional refined wheat flour made staple foods (such as noodles and bread) are usually high GI foods (GI>70), and their rapidly digestible starches can cause rapid fluctuations in postprandial blood glucose, increasing the risk of metabolic diseases with long-term intake. Therefore, there is an urgent need for staple products that have good taste and stable low GI (GI ≤ 55) characteristics.

[0003] Currently, the technical route for preparing low GI noodles mainly falls into two categories: Dietary fiber / Resistant starch (RS) physical barrier method: By adding high amylose corn starch, oat beta-glucan, etc., the viscosity of chyme is increased or the starch structure that is not easy to be enzymatically hydrolyzed is formed, thereby physically delaying digestion. However, this route often leads to hardening of noodle texture and deterioration of taste, and RS may undergo retrogradation during processing and storage, resulting in unstable GI reduction effect.

[0004] Digestive enzyme inhibitor chemical inhibition method: Using natural plant polyphenols (such as mulberry alkaloids and tea polyphenols) to inhibit the activity of α-amylase and α-glucosidase in the intestinal tract. Among them, tea polyphenols are widely studied due to their wide sources and high safety. Catechin is the main active ingredient of tea polyphenols, and the use of catechin and resistant starch in combination is a common technical solution. Although catechin has strong inhibitory activity on α-amylase, it is easily interfered by food matrix, and is prone to oxidation and thermal degradation during the heat processing of noodles such as steaming and drying, resulting in a significant decrease in activity. More importantly, catechin has relatively weak inhibitory effect on the key target enzyme α-glucosidase (located in the small intestinal brush border, which is more directly and effectively effective in reducing glucose absorption). In addition, the extraction process (extraction, filtration, concentration) of catechin is long and energy-consuming. Moreover, the extract composition is complex, and the active substance content varies greatly between batches, which is not conducive to the standardization and stability control of industrialized production. Moreover, the introduction of a large amount of aqueous extract seriously interferes with the water balance of the dough and the formation of gluten network, resulting in an increase in noodle cooking loss and a decrease in sticky elastic taste. SUMMARY

[0005] In view of this, the present application aims to provide a low GI functional noodle based on biological enzymatic-microwave puffing technology and a preparation method thereof. The present application uses the unique "enzyme-microwave coupling" pore forming mechanism, innovatively introduces "viscoelastic state regulation" pretreatment, uses enzymatic digestion to moderately cut the cellulose chain, and reduces the glass transition temperature (Tg) of the cell wall. The material can significantly expand in volume under the condition of microwave low temperature (<55℃), and form a unique honeycomb structure. Unlike the "high cooking loss rate" and "poor thermal stability" defects existing in the form of single water solution addition, and the "solid hard particles" of traditional tea powder which can cut the gluten network, the porous particles of the present application have strong water absorption and compression resilience. In the process of mixing, the gluten protein chain can penetrate and anchor inside the micropores of the tea powder, forming a stable "physical interlocking" structure. This "micro sponge" structure solves the problem of easy breaking of noodles, thereby increasing the tensile strength of the noodles by more than 20%, and the noodle breaking rate tends to be zero. The traditional hot air or steam puffing temperature is as high as 100℃ or above, which leads to the oxidation of tea flavonoids. The temperature of the present application is controlled below 55℃ during the whole preparation process of tea powder, and the product is in a vacuum anoxic environment, so that the retention rate of tea flavonoids in the finished product is as high as 96% or more, which is much better than that of common hot air or steam puffing.

[0006] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions: One of the technical solutions of the present application is a low GI fermented tea functional noodle, by mass percentage, the raw materials include: high gluten wheat flour 60%-80%, resistant starch (RS) 10%-25%, functional tea powder (F-TP) 5%-15%, active wheat gluten 3%-8%, and salt 0.5%-1%. The functional tea powder is a porous particle with honeycomb open micropore structure prepared by enzymatic regulation and microwave vacuum puffing of fermented tea, and the bulk density is 0.25-0.35 g / mL (significantly lower than 0.5-0.6 g / mL of ordinary tea powder), and the rehydration time is ≤5 seconds.

[0007] In the preferred embodiment of the present application, the preparation method of the functional tea powder includes the following steps: Step 1. Enzymatic viscoelastic state regulation: after the fermented tea is crushed, the water content is adjusted to 35%-45%, cellulase is added, and constant temperature limited enzymolysis is carried out at 40-50℃ for 30-50 minutes to regulate the viscoelastic state of the tea cell wall, and the wet base material suitable for puffing is obtained. The dosage of cellulase is 0.01%-0.05% of the mass of fermented tea.

[0008] In the present application, the cellulase can be a concentrated enzyme preparation with high purity and low carrier, or a compound enzyme with low GI substances (such as resistant starch) as a carrier, so as to avoid the introduction of additional digestible carbohydrates by enzyme preparation accessories and ensure the low GI characteristics of the product.

[0009] Step 2. Microwave vacuum cold puffing and shaping: the wet base material obtained in step (1) is placed in a microwave vacuum drying device, the vacuum degree is set to -0.08 MPa to -0.09 MPa, the microwave power density is 5-15 W / g, and the material is instantaneously expanded and dehydrated at a low temperature of 45-55℃ to build an aerogel-like skeleton; before the end of drying, a short microwave pulse is used to instantaneously raise the material temperature to 60-65℃ and maintain for 30-60 seconds to inactivate the enzyme and solidify the structure, and the material is dried to a water content of ≤6%.

[0010] In the present application, the microwave vacuum drying step can achieve a certain degree of cellulase inactivation effect, and the microwave field can destroy the secondary and tertiary structures of proteins; the subsequent HTST high-temperature short-time cooking step can completely inactivate the cellulase.

[0011] Step 3. Low-pressure flexible airflow depolymerization: a fluidized bed airflow crushing device is used, dry compressed air with a dew point lower than -40℃ is used as the working medium, the crushing pressure is controlled at 0.2-0.4 MPa, and the feeder frequency is 30-50 Hz, under the conditions of low-temperature flexible crushing, the material obtained in step 2 is crushed to obtain a honeycomb-shaped porous functional tea powder with a particle size distribution D90≤20μm and a natural bulk density of 0.25-0.35 g / mL.

[0012] Because of the "enzyme softening + microwave puffing" pretreatment, the material has become extremely brittle. Instantaneous breaking can be achieved without high-pressure airflow. Low-pressure airflow is used to "preserve the structure" - to avoid excessive impact force causing the collapse of the microporous structure, and to ensure that the final micropowder retains the complete "honeycomb-like fragment" morphology.

[0013] The functional tea powder prepared by the present application has the following physical and chemical properties: 1. Microstructure characteristics: the particles have continuous and open pores (Open-pore structure) inside, showing Aerogel-like skeleton characteristics; 2. Density characteristics: the natural bulk density is 0.25 g / mL to 0.35 g / mL (significantly lower than the 0.5-0.6 g / mL of ordinary ultrafine tea powder); 3. Hydration characteristics: the water holding capacity (WHC) is ≥5.5 g / g, and the rehydration time is ≤5 seconds; In the present application, the particle size distribution D90 of the functional tea powder is ≤20 μm (to ensure its uniform dispersion in the dough and high bioavailability during digestion), and the total content of theaflavins is ≥1.5% (to ensure its effective inhibitory activity on α-glucosidase). The functional tea powder under the above parameters ensures the high thermal stability of the active ingredient (theaflavins) and the high efficient inhibition on the key target enzyme α-glucosidase.

[0014] The functional tea powder prepared by biological enzymatic hydrolysis and microwave puffing is used in the noodles of the present application. The unique honeycomb microporous structure of the tea powder constructs a natural micro-reservoir system, which fundamentally solves the pain points of theaflavins easy loss and instability during high-temperature cooking. Specifically, the strong capillary force and structural steric effect generated by the micropores are used to encapsulate theaflavins and other water-soluble active ingredients in the deep pores in situ. Unlike the free liquid extract or ordinary solid tea powder, this porous structure limits the rapid replacement and penetration of water molecules in high-temperature cooking water, significantly inhibits the flash dissolution and oxidative degradation of the active ingredients. In addition, during the digestion process, the structure realizes the structured slow release of theaflavins, synchronizes its release kinetics with the enzymatic rate of starch, and avoids the defects of "too fast front-end release and insufficient back-end efficacy" in the liquid addition form, thereby showing a significant long-acting synergistic inhibition advantage in the GI control of the final product.

[0015] In the preferred embodiment of the present application, the functional tea powder is black tea powder or red tea powder.

[0016] In the present application, the resistant starch is provided by high-amylose corn starch (RS content ≥60%). Active wheat gluten is used to compensate for the dilution of F-TP and RS on wheat gluten, and to reshape the gluten network, which is the key to solving the quality problem of noodles.

[0017] The second technical solution of the present application is a preparation method of the above-mentioned low GI fermented tea functional noodles, comprising the following steps: Mixing high-gluten wheat flour, resistant starch, functional tea powder, active wheat gluten and salt uniformly to obtain a mixture; Adding water to the mixture, and then sequentially performing vacuuming, dough maturation, compound rolling and cutting, high-temperature short-time (HTST) cooking, gradient drying, cooling and packaging.

[0018] The amount of water used in the present application is not specially limited, and is adjusted according to the water absorption of the mixture, for example, the amount of water is 30%-35% of the mass of the mixture.

[0019] In the preferred embodiment of the present application, the dough maturation is carried out under vacuum at -0.05 ~ -0.07 MPa for 10-15 minutes, followed by a resting period of 20-30 minutes. The vacuum environment can effectively remove air bubbles and promote the formation of a dense and continuous gluten network.

[0020] In the preferred embodiment of the present application, the high-temperature short-time cooking is carried out in steam at 100-105℃ for 2-4 minutes. This condition is sufficient to gelatinize the starch (sterilization) and promote the interaction between tea polyphenols and starch molecules, which is conducive to the formation of more resistant complexes.

[0021] In the preferred embodiment of the present application, the gradient drying includes the following three stages to ensure the structural integrity of the functional tea powder and resistant starch matrix during dehydration: 1. Pre-drying stage: The temperature is set to 50℃~55℃, the relative humidity is maintained at 75%~80%, and the treatment time is 45~60 minutes. The main purpose of this stage is to remove surface free water under mild conditions to avoid the oxidation of theaflavins and the formation of a crust on the surface of the noodles due to rapid temperature rise.

[0022] 2. Main drying stage: The temperature gradient is set to rise to 55℃~65℃, the relative humidity is reduced to 55%~65%, and the treatment time is 90~120 minutes. In this stage, the internal water of the noodles diffuses outward in large quantities, and the controlled heating rate effectively relieves the internal stress caused by the difference in shrinkage rate between resistant starch and gluten protein.

[0023] 3. Final drying stage: The temperature is set to 65℃~70℃, the relative humidity is controlled to be below 50%, and the treatment time is 20~30 minutes. Since high temperature can cause the Maillard reaction to occur, this stage should be passed quickly, and the maximum drying temperature should not exceed 70℃ until the final product moisture content is ≤14%.

[0024] After drying, the noodles are slowly cooled to room temperature (about 25℃), and then measured and packaged. This gradient drying process significantly reduces the breakage rate of the finished product and maximizes the bioactivity of the fermented tea powder.

[0025] The present application discloses the following technical effects: Effectiveness target: The noodles product provided by the present application has significant and stable low GI effect, and a porous functional tea powder (F-TP) prepared by biological enzymatic regulation and microwave vacuum expansion is used to construct an enhanced sugar control mechanism of "structured micro-reservoir + enzyme adsorption trap". Unlike liquid extracts or ordinary dense tea powder, the F-TP of the present application has a unique honeycomb microporous structure. Micro-reservoir slow-release mechanism: The porous structure uses strong capillary force to in-situ encapsulate theaflavins in the deep pores, forming a natural "slow-release micro-reservoir". In the digestive process, the active ingredients are released in a structured manner with the enzymatic process of starch, achieving the synchronization of inhibitor release and substrate digestion kinetics, and completely overcoming the defects of "fast release at the front end and insufficient efficiency at the back end" of liquid extracts. Enzyme adsorption trap mechanism: The huge specific surface area of F-TP produces significant physical adsorption and steric effect on intestinal alpha-amylase and alpha-glucosidase, constructing an "enzyme adsorption trap" to effectively block the contact between enzymes and starch particles. Through the synergistic effect of "physical adsorption + chemical inhibition", combined with the protection of the low-temperature expansion process for heat-sensitive components, the product still has excellent and stable low GI characteristics after high-temperature processing and long shelf life.

[0026] Quality target: The liquid extract in the prior art can seriously dilute the gluten network, resulting in soft noodles; and the ordinary ultra-fine tea powder particles (tea powder prepared by directly pulverizing tea) are dense and hard in texture, and are easy to cut off the gluten network formed by disulfide bonds as "stress concentration points", resulting in rough and easy-to-break noodles. The F-TP of the present application has a unique honeycomb microporous structure constructed by enzymatic regulation and microwave expansion, achieving the structured remodeling of noodle quality. Physical interlocking enhancement mechanism: The porous structure of F-TP allows gluten protein molecular chains to penetrate into the pores during the mixing process, forming a stable physical anchoring effect. F-TP changes from a "network destroyer" to a "network enhancement node", reducing the cooking loss rate and giving the noodles excellent stretch elasticity and toughness. Micro-sponge moisturizing mechanism: The loose microporous structure has strong water holding capacity (micro-sponge effect), which can convert free water into bound water and lock it in the noodle skeleton. This not only delays the aging and retrogradation of starch, but also completely solves the dry and gritty taste of high-fiber functional noodles, giving the product a moist and not rotten, smooth and refreshing sensory quality, making its taste comparable to that of high-quality traditional wheat noodles.

[0027] Process target: A preparation method with simple and efficient process flow suitable for large-scale production is provided, which uses dry powder direct addition technology to save the complex liquid extraction step and uses the solid matrix of F-TP to provide in-situ thermal protection for heat-sensitive components (theaflavins). Experiments have proved that the thermal degradation rate of theaflavins in solid F-TP is significantly lower than that in liquid system during HTST cooking (100-105°C), ensuring the functional retention rate of the finished product after high-temperature processing. The cost is reduced and the efficiency is increased. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating the preparation process of the low-GI fermented tea functional noodles of the present invention. Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0033] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0034] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0035] The technical solutions of the present application are conventional solutions in the art, unless otherwise specified. The reagents or raw materials used are commercially available or have been disclosed, unless otherwise specified.

[0036] To better understand the present application, the following examples further illustrate the content of the present application, but the content of the present application is not limited to the following examples.

[0037] The raw materials used in the embodiments of the present application are all commercially available food-grade products. Among them, the fermented tea coarse powder is obtained by preliminary crushing of commercially available black tea through a 40-mesh sieve; the cellulase is a food-grade preparation (enzyme activity ≥10000 U / g); the resistant starch is high-amylose corn starch (RS2 type); and the active wheat gluten protein content is ≥75%.

[0038] The test methods of various performance indicators are as follows: The content of theaflavins is determined according to GB / T 30483-2013 "Determination of Theaflavins in Tea - High Performance Liquid Chromatography". The retention rate of theaflavins (%) = (theaflavins content in the prepared tea powder / theaflavins content in the raw material coarse powder) × 100%. The natural bulk density is determined by accurately weighing 10.00 g of the tea powder sample to be tested, slowly pouring it into a 100 mL graduated cylinder, without shaking, and reading the volume V (mL) after standing for 1 min. The bulk density ρ = 10.00 / V (g / mL). The water holding capacity (WHC) is determined by accurately weighing 1.00 g of the tea powder sample (M1) in a centrifuge tube, adding 20 mL of distilled water, thoroughly mixing and shaking, and then standing at room temperature for 30 min. Centrifuge at 3000 r / min for 15 min, discard the supernatant, and weigh the wet sample (M2) after absorbing the residual water with filter paper. WHC = (M2 - M1) / M1 (g / g). The noodle cooking loss rate is determined according to GB / T 35875-2018 "Grain and Oil Inspection - Sensory Evaluation Method for Noodle and Fine Noodle Cooking Quality". The noodle tensile properties are determined using a texture analyzer (TA-XT plus) with an A / SPR tensile probe. The cooked noodles are fixed on the probe, the test speed is 2.0 mm / s, the trigger force is 5 g, and the maximum tensile resistance (g) and tensile distance (mm) during the tensile process are recorded. In vitro simulated GI value determination: The in vitro digestion dialysis method using starch hydrolase (pancreatic alpha-amylase and glucosidase) simulates the human gastrointestinal digestion process, and the glucose release amount at different time points is determined. The white bread is used as a reference (GI=100) to calculate the estimated glycemic index (eGI).

[0039] Example 1 Preparation of honeycomb porous functional tea powder (F-TP) (1) Enzymatic viscoelasticity regulation: 1 kg of fermented black tea powder and cellulase (0.02% of the mass of the fermented black tea powder) were placed in a blender, and pure water was sprayed while stirring to adjust the total water content of the material to 40%. The wet material was placed in a sealed container and reacted at 45°C for 40 min in a constant temperature environment. At this time, the material felt soft and had obvious viscoelasticity.

[0040] (2) Microwave vacuum cold puffing and shaping: The wet material after enzymatic hydrolysis was placed on the tray of a microwave vacuum dryer (the thickness of the material was about 1.5 cm). The vacuum degree was set to -0.085 MPa, and the microwave heating was started, with the microwave power density controlled at about 8 W / g (based on the wet basis). The material rapidly expanded and dehydrated at low temperature (the material temperature was maintained at 50-55°C). Before the end of drying, a short high-power pulse treatment was performed to instantaneously raise the material temperature to 65°C and maintain it for 45 s to inactivate the enzyme preparation and solidify the structure. The final water content was controlled below 5%. The obtained dried material was observed to be a volumetrically expanded porous sponge-like block.

[0041] (3) Low-pressure flexible air flow depolymerization: A fluidized bed jet mill with an internal classification wheel was used to depolymerize the puffed block. Cold and dry compressed air with a dew point lower than -40°C was used as the working medium, the crushing pressure was set to low pressure 0.3 MPa, the feeding frequency was set to 40 Hz, and the classification wheel speed was set to 4000 rpm. The micropowder collected under the cyclone separator was the obtained porous functional tea powder, with a particle size distribution D90 = 18.5 μm.

[0042] Example 2 (1) 672 g of high-gluten wheat flour, 180 g of resistant starch, 80 g of porous functional tea powder prepared in Example 1, 60 g of active wheat gluten, and 8 g of salt (i.e. 67.2% high-gluten wheat flour, 18% resistant starch, 8% prepared functional tea powder, 6% active wheat gluten, and 0.8% salt) were mixed in a flour mixer at low speed for 8 minutes to ensure uniform distribution, obtaining a mixture; (2) Drinking water was added to the mixture (adjusted according to the water absorption), and the mixture was kneaded for 12 minutes, the dough was matured for 25 minutes, compound rolling and cutting were performed, the mixture was treated in steam at 102°C for 3 minutes, and gradient drying (the scheme is shown in Table 1 below) was performed to a final product moisture content ≤14%, and then the mixture was cooled to room temperature.

[0043] Table 1

[0044] The noodles prepared in this example were verified for the following effects: (1) Processing stability verification: Measurement index: The retention rate of theaflavins in the noodles after dough mixing and HTST cooking was 88.5%.

[0045] (2) In vitro simulated digestive kinetics: Test method: An in vitro digestion model was used to measure glucose release at 0, 30, 60, 90, 120 and 180 minutes, and the hydrolysis index (HI) and GI value were calculated.

[0046] GI value: GI=51.8; Starch hydrolysis rate at 120 min: HI=45%.

[0047] (3) Analysis of texture and cooking properties: Cooking loss rate: the solids content in the water used to cook noodles.

[0048] Texture analysis (TPA): assesses the hardness and stretch distance of cooked noodles and calculates their chewiness parameters (g).

[0049] Cooking loss rate: 5.6% Chewable weight = 2800 g.

[0050] Example 3 F-TP dosage verification By mass percentage, with fixed RS 15%, active wheat gluten 5%, salt 0.8%, and water (the amount of water adjusted according to water absorption), the properties of noodles prepared with F-TP dosages of 2%, 5%, 15%, and 20% were measured (high-gluten wheat flour was used to make up the balance). The noodle preparation method and parameters were the same as in Example 2.

[0051] in conclusion: (1) When the amount of F-TP was 2%, the performance of the noodles was measured: the GI value was too high (>60), the concentration of theaflavins was insufficient, the enzyme inhibition rate was low, and the low GI standard could not be achieved. This shows that when the amount of F-TP was less than 5%, the core objective of the low GI of this invention could not be achieved.

[0052] (2) When the amount of F-TP is 5%, the performance of the noodles was measured: the GI value reached ≤ 55, which just met the low GI requirement, and there was no obvious bitter taste. This proves that 5% is the minimum effective amount to achieve the technical effect.

[0053] (3) When the amount of F-TP was 15%, the performance of the noodles was measured: the GI value was excellent = 48, the sugar reduction effect was excellent, the dough formability was acceptable, and the bitterness was on the edge of acceptable. This proves that good processing and sensory quality can still be maintained at 15%.

[0054] (4) When the F-TP dosage is 20%, the performance of the noodles obtained is measured: the sensory score is extremely low. The noodles are too dark in color, with strong bitter taste, and the dough has a high breakage rate due to excessive powder content. It is proved that when the F-TP dosage is too high, although the GI is low, the product's sensory and processing performance is unacceptable.

[0055] Example 4 Verification of the dosage of resistant starch (RS) Fix F-TP 10%, gluten 5%, salt 0.8% and water (the dosage of water is adjusted according to the water absorption) by mass percentage, respectively, when the dosage of RS is 5%, 10%, 25% and 35% (the remaining amount is supplemented by high-gluten wheat flour), the performance of the noodles prepared is measured. The preparation method and parameters of the noodles are the same as those in Example 2.

[0056] Conclusion: (1) When the dosage of RS is 5%, the performance of the noodles obtained is measured: the GI value is slightly high (>55). The physical barrier is insufficient, and even with tea powder, the overall GI is still unstable. It is proved that tea powder alone is not enough to maintain stable low GI, and at least 10% RS must be used.

[0057] (2) When the dosage of F-TP is 10%, the performance of the noodles obtained is measured: the GI value meets the standard, and the noodles have strong toughness. It is proved that 10% is the starting point for producing a synergistic GI-lowering effect.

[0058] (3) When the dosage of F-TP is 25%, the performance of the noodles obtained is measured: the GI value is very low, and the cooking loss rate is slightly high but qualified (<8%). It is proved that 25% is the limit to ensure the integrity of the noodles.

[0059] (4) When the dosage of F-TP is 35%, the performance of the noodles obtained is measured: the cooking loss rate is seriously over-standard (>15%). The gluten network is seriously diluted, and the noodles are muddy after cooking, have no elasticity and are easy to break. It is proved that RS higher than 25% will completely destroy the eating quality of the noodles and cannot be formed.

[0060] Example 5 Verification of the HTST cooking time parameter According to high-gluten wheat flour 68.2%, resistant starch 15%, functional tea powder 10%, active wheat gluten 6% and edible salt 0.8%, the mixed powder is mixed in a low-speed mixer for 8 minutes to ensure uniform distribution; (2) Add drinking water (adjust according to water absorption) to the mixed powder, and mix for 12 minutes under a vacuum degree of -0.06 MPa, and the dough is matured for 25 minutes, then compound rolling and cutting are performed, and the noodles are treated in steam at 102°C (the treatment time is set to 1 minute, 2 minutes, 4 minutes and 8 minutes, respectively), dried according to the process gradient in Table 1 to a final product moisture content of ≤14%, and cooled to room temperature.

[0061] Conclusion: (1) When the processing time is 1 min, the gelatinization degree is insufficient (<70%). There is raw flour in the core of the noodles, not only the taste is raw, but also no protective layer is formed, which is easy to mold during storage. It is proved that the time is too short to complete the necessary gelatinization and sterilization.

[0062] (2) When the processing time is 2 min, the gelatinization degree is moderate, and the taste is smooth. It is proved that 2 minutes is the effective point of the process.

[0063] (3) When the processing time is 4 min, the gelatinization degree is sufficient, and the retention rate of theaflavins is high (75.3%). It is proved that 4 minutes can balance the cooking and the protection of active ingredients.

[0064] (4) When the processing time is 8 min, the noodles are seriously sticky. Overcooking leads to sticky surface, and the retention rate of theaflavins decreases significantly (<60%). It is proved that the time is too long to cause thermal degradation of active ingredients and product adhesion.

[0065] Comparative Example 1 The difference with Example 1 is that only pure water is added to adjust the moisture content to 40% in step (1), without adding cellulase. Then the same microwave vacuum drying and low-pressure air flow crushing are carried out. It is observed that the material does not expand obviously during microwave drying, and after drying, it is in the form of dense hard lump.

[0066] Comparative Example 2 The difference with Example 1 is that the wet material after enzymatic hydrolysis is placed in a hot air oven at 105°C for air drying to constant weight instead of microwave vacuum drying in step (2). Then low-pressure air flow crushing is carried out. It is observed that the color of the tea powder is obviously darkened.

[0067] Test Results (Table 2)

[0068] Comparative Example 3 The difference with Example 2 is that the low GI fermented tea functional noodle raw material formula is: high gluten flour 672 g, RS180 g, theaflavins aqueous solution (the active ingredient content is the same as Example 1, added with water), glutenin 60 g, cellulose powder (to make up the solid mass difference), edible salt 8 g, and other steps and parameters are the same as Example 2.

[0069] Comparative Example 4 The difference with Example 2 is that the low GI fermented tea functional noodle raw material formula is: high gluten flour 800 g, RS180 g, glutenin 60 g, edible salt 8 g (no tea component, as a blank control group), and other steps and parameters are the same as Example 2.

[0070] Test results (Table 3):

[0071] In summary, the porous aerogel-like functional tea powder (F-TP) prepared by the "biological enzymatic regulation-microwave vacuum puffing" coupling process utilizes its unique honeycomb microporous structure to construct an enhanced sugar control mechanism of "enzyme adsorption trap + micro-reservoir slow release". This mechanism forms a multi-dimensional synergy with the physical barrier effect of resistant starch (RS), achieving a more excellent and long-acting GI control effect, with a measured GI value as low as 52, far superior to the internationally recognized low GI standard (≤55).

[0072] The "structured microparticle" preparation technology of the present application not only discards the high-energy consumption and low stability of the liquid extraction step, but also realizes the dual improvement of production efficiency and activity retention by using low-temperature microwave puffing. Compared with traditional processes, the production efficiency is improved by more than 30%, and the retention rate of heat-sensitive components such as theaflavins in the tea powder preparation process is as high as 96% or more, greatly improving the quality stability of industrial production.

[0073] The F-TP dry powder prepared by the innovative process greatly improves the stability of active ingredients, with a polyphenol retention rate of up to 88% after storage, ensuring the functional consistency of the product throughout the shelf life.

[0074] More importantly, the present application utilizes the "micro-sponge effect" and "physical interlocking mechanism" of porous tea powder to transform tea powder into a "functional skeleton" with enhanced surface structure. This structural remodeling completely solves the industry problem of easy breaking and rough texture of high-fiber functional noodles, discards the liquid extraction method, reduces the cooking loss rate to below 5%, and endows the product with excellent texture of lubrication and toughness, with sensory quality comparable to high-quality traditional wheat noodles.

[0075] The above is only the preferred embodiment of the present application, and it should be noted that for ordinary skilled persons in the technical field, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A low-GI fermented tea functional noodle, characterized by, The raw materials include, by mass percentage, high-gluten wheat flour 60%-80%, resistant starch 10%-25%, functional tea powder 5%-15%, active wheat gluten 3%-8%, and salt 0.5%-1%. The functional tea powder is a porous particle with a honeycomb-like open microporous structure prepared from fermented tea through enzymatic regulation and microwave vacuum puffing, and has a bulk density of 0.25-0.35 g / mL and a rehydration time of ≤5 seconds.

2. The low-GI fermented tea functional noodle according to claim 1, characterized by, The preparation method of the functional tea powder comprises the following steps: Step 1. Enzymatic viscoelastic regulation: after the fermented tea is crushed, the water content is adjusted to 35%-45%, and cellulase is added for limited enzymolysis to soften the cell wall and achieve a suitable viscoelastic state; Step 2. Microwave vacuum cold puffing: the material obtained in step 1 is placed in a microwave vacuum drying device for drying; Step 3. Low-pressure flexible airflow depolymerization: a fluidized bed airflow crushing device is used to perform low-temperature flexible crushing on the material obtained in step 2, and the particle size D90 of the finished product is controlled to ≤20 μm.

3. The low-GI fermented tea functional noodle according to claim 2, characterized by, The temperature of the limited enzymolysis is 40-50°C, and the time is 30-50 minutes.

4. The low-GI fermented tea functional noodle according to claim 2, characterized by, The drying in the microwave vacuum drying device is specifically: instantaneous puffing and dehydration are performed under the conditions of a vacuum degree of -0.08~-0.09 MPa and a microwave power density of 5-15 W / g until the water content is ≤6%.

5. The low-GI fermented tea functional noodle according to claim 2, characterized by, The low-temperature flexible crushing is specifically: a fluidized bed airflow crushing device is used, dry compressed air with a dew point lower than -40°C is used as the working medium, and the material obtained in step 2 is crushed under the conditions of a crushing pressure of 0.2-0.4 MPa and a feeder frequency of 30-50 Hz.

6. The low-GI fermented tea functional noodle according to claim 1, characterized by, The functional tea powder is black tea powder or red tea powder.

7. A method of preparing the low-GI fermented tea functional noodle according to claim 1, characterized by, The method comprises the following steps: The high-gluten wheat flour, resistant starch, functional tea powder, active wheat gluten, and salt are mixed uniformly to obtain a mixture; Water is added to the mixture, and then vacuum mixing, dough maturation, composite rolling and cutting, high-temperature short-time steaming, gradient drying, cooling, and packaging are sequentially performed.

8. The preparation method according to claim 7, characterized in that, The vacuum mixing and dough maturation are: the dough is mixed for 10-15 minutes under a vacuum degree of -0.05 ~ -0.07 MPa, and then the dough is matured for 20-30 minutes under static conditions.

9. The preparation method according to claim 7, characterized in that, The high-temperature short-time steaming is: the dough is treated in 100-105°C steam for 2-4 minutes.

10. The preparation method according to claim 7, characterized in that, The gradient drying is: the relative humidity is 75%~80%, and the dough is treated at 50°C~55°C for 45~60 minutes, then the relative humidity is reduced to 55%~65%, and the dough is treated at 55°C~65°C for 90~120 minutes, finally the relative humidity is reduced to below 50%, and the dough is treated at 65°C~70°C for 20~30 minutes.

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