A method for synergistic modification of gluten protein matrix and residual microcrystal by dual heterogeneous nucleation

Abstract

The application discloses a method for synergistically modifying gluten protein framework and residual microcrystal double heterogeneous nucleation, and belongs to the technical field of deep processing of grains. The gluten protein-containing grain raw material is conditioned to 20%-35% of moisture, and the three-dimensional network of the gluten protein is completely retained as a first heterogeneous nucleation framework, and part of the natural starch microcrystal is retained as a second heterogeneous nucleation seed in the annealing temperature window lower than the critical temperature of thermal denaturation of the gluten protein; the double-framework synergistically induces the ordered rearrangement of gelatinized amylose molecules, and forms high-melting-point RS3 type resistant starch with a melting temperature of greater than or equal to 120 DEG C; and then gradient slow cooling, shaping and low-temperature drying are carried out. The application is a pure physical zero-addition process, and the annealing time is only 8-20 minutes; the obtained product has high gluten strength and low GI characteristics, and is suitable for high-end flour products, such as bread, noodles, dumpling wrappers and the like, which require high gluten strength.

Description

Technical Field

[0001] This invention belongs to the field of deep grain processing technology, specifically relating to a modification method that uses a purely physical process to simultaneously retain the gluten protein backbone and residual starch microcrystals in grains, and utilizes the synergistic effect of the dual backbone to induce orderly crystallization of starch. Background Technology

[0002] High-gluten flour is a fundamental ingredient in making bread, ramen, dumpling wrappers, and other wheat products that require strong gluten. Traditional high-gluten flour typically has a glycemic index (GI) between 70 and 85, classifying it as a high-GI food. Existing methods for lowering the GI of flour present inherent contradictions: adding whole wheat or dietary fiber can damage the gluten network, leading to loss of stretchiness and a coarse texture; chemical modification or enzymatic treatment can introduce ingredients not properly labeled; and traditional wet heat treatment, requiring high temperatures and long durations, can completely destroy the gluten protein structure, resulting in the product losing all its high-gluten properties.

[0003] The applicant's prior art discloses a modification method using an endogenous protein scaffold as a heterogeneous nucleation template, which can reduce the GI value while preserving the gluten network. Another prior art disclosed an annealing method using residual starch microcrystals as heterogeneous nucleation seeds, which can significantly shorten the annealing time. However, the prior art has never proposed the synergistic use of the above two heterogeneous nucleation mechanisms in the same process to achieve technical effects superior to using either scaffold alone. Summary of the Invention

[0004] Purpose of the invention

[0005] The purpose of this invention is to provide a purely physical, zero-additive synergistic modification method. By simultaneously retaining and utilizing the gluten protein backbone and residual starch microcrystals in the same process, the dual backbone synergistically induces ordered starch crystallization, thereby maximizing the reduction of GI value while maintaining high gluten content. The overall performance of the resulting product is superior to processes that use protein backbones or microcrystal backbones alone.

[0006] Technical solution

[0007] This invention adopts a novel technical approach of "synergistic nucleation of gluten protein backbone and residual microcrystals in a dual heterogeneous phase," and includes the following steps:

[0008] (1) Conditioning: Add water to the grain raw materials containing gluten protein to condition to a moisture content of 20%-35% and a temperature of 45-50℃, so that the starch absorbs water and swells, while the three-dimensional network of gluten protein and some ungelatinized natural starch microcrystals are completely preserved (gelatinization degree 20%-65%, crystallinity retention rate ≥50%).

[0009] (2) Dual-framework synergistic annealing: In a constant humidity environment with a relative humidity of 80%-95%, keep at 50-55℃ for 8-20 minutes, so that the partially gelatinized linear starch molecules can simultaneously attach and rearrange their lattice along the gluten protein network and the surface of the residual microcrystals.

[0010] (3) Cooling and shaping: The annealed material is cooled to below 35°C using a gradient slow cooling method.

[0011] (4) Low temperature drying: Dry at no more than 60℃ to safe moisture content.

[0012] Core Mechanism

[0013] This invention is the first to discover and utilize an important synergistic effect: when the three-dimensional gluten protein network and residual starch crystals coexist, they spatially interpenetrate, forming a heterogeneous nucleation site network that is denser than either framework alone. Gelatinized amylose molecules can not only attach to the ordered side chains of the gluten protein network but also simultaneously align in an ordered manner on the surface of the residual crystals interpenetrating within this network. This dual-framework synergy results in a significantly higher nucleation density for RS3-type resistant starch compared to using either framework alone, leading to a denser crystalline structure, higher thermal stability, and superior GI reduction effect.

[0014] Strictly controlling the annealing temperature window within 50-55℃ (i.e., below the critical temperature for thermal denaturation of gluten protein, 54.7℃) is the core condition for simultaneously achieving the aforementioned dual-skeleton functions. Above 55℃, the gluten protein network undergoes irreversible denaturation and collapse, and the most important protein skeleton in the dual-skeleton system loses its function; below 50℃, the starch molecular chain mobility is insufficient, and the lattice repair efficiency is too low, making it impossible to complete the effective generation of RS3 within an industrially feasible time of 8-20 minutes.

[0015] Based on the mechanism disclosed in this invention, those skilled in the art can reasonably foresee that the product obtained by using the dual-skeleton synergistic method of this invention, because it utilizes both protein and microcrystalline dual heterogeneous nucleation skeletons, will inevitably have better RS3 generation efficiency and GI reduction effect than the process using only a single skeleton. At the same time, the intact gluten network ensures the high gluten processing performance of the product.

[0016] Beneficial effects

[0017] (1) Synergistic effect: For the first time, two heterogeneous nucleation frameworks, gluten protein and residual microcrystals, are used in the same process. The RS3 generation efficiency and GI reduction effect are better than either single framework method.

[0018] (2) High gluten content and low GI: wet gluten retention rate ≥85%, GI value ≤65, RS3 melting temperature ≥120℃, perfectly solving the industry problem that high gluten flour cannot reduce GI.

[0019] (3) Extremely short process: annealing time is 8-20 minutes, which is fully compatible with industrial continuous production.

[0020] (4) Pure physical zero additives: The ingredient list contains only grains themselves, which meets the global clean label standard. Detailed Implementation

[0021] Example 1 (Hard Red Winter Wheat Flour, Dual-Skeleton Synergy)

[0022] Take 1000g of hard red winter wheat flour (14.2% protein, 33% wet gluten), add water to adjust to 28%, temperature 48℃, gelatinization degree approximately 30%, crystallinity retention approximately 72%. Anneal at 51℃ and 85% humidity for 14 minutes. Gradual cooling: first stage at 3.5℃ / min from 51℃ to 40℃; second stage at 1.5℃ / min from 40℃ to 33℃. Dry at 42℃ until moisture content is 12.0%, sieve to obtain the product.

[0023] The resulting product exhibits high wet gluten retention, a significantly reduced GI value, an RS3 melting temperature exceeding 120℃, and a significantly increased resistant starch content. The resulting toast bread demonstrates excellent stretching properties, showing no significant difference from untreated high-gluten flour, and remains soft even after being left at room temperature.

[0024] Comparative Example 1 (using only protein backbone, without microcrystalline backbone)

[0025] The conditioning conditions of Example 1 were changed to high-temperature cooking, resulting in a gelatinization degree of 92% and a crystallinity retention rate of less than 5% (complete destruction of microcrystals), while the other conditions remained unchanged. Only the gluten protein backbone remained during annealing.

[0026] The resulting product had a high wet gluten retention rate and a lower GI value, but the resistant starch content and RS3 melting temperature were both lower than in Example 1, with the RS3 melting temperature below 120°C. This demonstrates that using only a protein backbone is less effective than a dual-backbone synergy.

[0027] Comparative Example 2 (using only microcrystalline framework, without protein framework)

[0028] The annealing temperature in Example 1 was changed to 58°C (exceeding the 55°C denaturation point of gluten protein, causing the protein network to collapse), while other conditions remained unchanged. Only residual microcrystalline framework remained during annealing.

[0029] The resulting product had an increased resistant starch content, but a significantly decreased wet gluten retention rate, loss of stringiness, and collapsed toast. This demonstrates that using only a microcrystalline framework cannot preserve the product's processing properties.

[0030] Comparative Example 3 (neither skeleton is retained)

[0031] The conditioning conditions of Example 1 were changed to high-temperature cooking (92% gelatinization, complete destruction of microcrystals), and the annealing temperature was changed to 58°C (gluten protein denaturation and collapse), while the other conditions remained unchanged.

[0032] The resulting product showed a significant decrease in wet gluten retention, low resistant starch content, and no significant reduction in GI value. This demonstrates that annealing is almost ineffective when the dual framework is completely lost.

[0033] Comparative Example 4 (annealing temperature exceeds 55℃ red line)

[0034] The annealing temperature in Example 1 was changed to 58°C, while the other conditions remained unchanged.

[0035] The resulting product showed a significant decrease in wet gluten retention and deterioration in fiber-drawing properties. This demonstrates that even if the microcrystalline framework still exists, temperatures above 55°C will irreversibly destroy the gluten protein framework, causing the loss of the synergistic effect of the dual framework.

[0036] Comparative Example 5 (annealing temperature below the lower limit of 50℃)

[0037] The annealing temperature in Example 1 was changed to 48°C, while the other conditions remained unchanged.

[0038] The resulting product had a low resistant starch content, no significant decrease in GI value, and an RS3 melting temperature below 120℃. This demonstrates that below 50℃, starch molecules lack sufficient mobility, and the synergistic effect of the dual-skeletal structure cannot be effectively exerted.

[0039] Summary of comparative verification of synergistic effects

[0040] Process conditions: gluten protein skeleton, microcrystalline skeleton, wet gluten retention rate, RS3, melting temperature determination.

[0041] Example 1: Complete and intact, temperature ≥120℃, qualified.

[0042] (Dual-skeleton collaboration) Optimal

[0043] Comparative Example 1: Intact but damaged, high temperature <120℃, second best.

[0044] (Protein backbone only) RS3 not up to standard

[0045] Comparative Example 2

[0046] Comparative Example 2: Denatured and intact, significantly reduced at ≥120℃. Not usable.

[0047] (Microcrystalline framework only) No processing properties

[0048] Comparative Example 3

[0049] (Both skeletons lost) Degenerated and damaged, significantly reduced to <120℃. Unqualified.

[0050] Comparative Example 4: Denatured and intact, significantly reduced at ≥120℃. Not usable.

[0051] (Annealing temperature exceeds the red line) No machinability

[0052] Comparative Example 5: Complete and intact, temperature <120℃, unqualified.

[0053] Insufficient efficiency (annealing temperature below the lower limit)

[0054] The table above clearly demonstrates that only when both the protein backbone and the microcrystalline backbone are completely preserved, and the annealing temperature is within the effective window of 50-55℃, can the product simultaneously meet the dual requirements of high gluten processing performance and low GI. The absence of either backbone or deviation from the annealing conditions will lead to a significant deterioration in product performance. This fully demonstrates the core and irreplaceable role of the dual-backbone synergistic effect in this invention.

[0055] Detection methods

[0056] Wet gluten content and retention rate: determined by the gluten analyzer method or hand washing method according to GB / T 14608.

[0057] GI value: based on the ISO 26642:2010 standard method.

[0058] RS3 melting temperature: Differential scanning calorimetry (DSC) was used, with a heating rate of 10℃ / min, nitrogen atmosphere, and a temperature range of 10-180℃.

[0059] Resistant starch content: AOAC 2002.02 standard method was used.

[0060] Gelatinization degree: determined by enzymatic hydrolysis method (GB / T 24403-2009).

[0061] Crystallinity retention rate: determined by X-ray diffraction (XRD) with Cu target, scanning range 2θ = 5°-40°, scanning speed 2° / min, and crystallinity was calculated using the peak separation method.

[0062] Industrial applications

[0063] The method of this invention can be implemented on existing continuous grain conditioning-annealing-cooling-drying production lines. The core equipment includes a dual-shaft differential high-pressure atomizing continuous conditioning tank, a closed mesh belt continuous annealing tower with a temperature control accuracy of ±0.5℃ across the entire range, a multi-stage air-cooled conveyor belt, and a low-temperature airflow drying device.

Claims

1. A method for synergistic modification of gluten protein backbone and residual microcrystals through biphasic nucleation, characterized in that, The following steps are performed sequentially: a. Conditioning: Add water to the grain raw materials containing gluten protein to condition to a moisture content of 20%-35%, and control the temperature at 45-50℃, so that the starch absorbs water and swells, while completely preserving the natural three-dimensional network structure of gluten protein and some ungelatinized natural starch microcrystals; b. Dual-skeletal synergistic annealing: The conditioned material is kept in a constant humidity environment with a relative humidity of 80%-95% for 8-20 minutes within an annealing temperature window below the critical temperature for thermal denaturation of the grain gluten protein. This allows the partially gelatinized amylose molecules to simultaneously adhere and rearrange their crystal lattice along the intact three-dimensional network of gluten protein and the surface of the residual natural starch microcrystals, forming a high-melting-point RS3 type resistant starch with a melting temperature ≥120℃. c. Cooling and shaping: The annealed material is cooled to below 35°C using a gradient slow cooling method; d. Low-temperature drying: Dry the cooled material at a temperature not exceeding 60°C until the moisture content is below 13%.

2. The method according to claim 1, characterized in that, The gluten-containing grain raw material mentioned in step a is any one or more of the following: wheat, rye, barley, spelt wheat, and triticale, including grains, broken particles, coarse flour, fine flour, or dough.

3. The method according to claim 1, characterized in that, The annealing temperature window mentioned in step b is 50-55℃, and the temperature at any temperature measurement point during the annealing process does not exceed 54℃.

4. The method according to claim 3, characterized in that, When the raw material is durum wheat flour, the annealing temperature is 51-52℃ and the annealing time is 13-15 minutes.

5. The method according to claim 1, characterized in that, The gradient cooling in step c is as follows: the first stage cools from the annealing temperature to 40-42℃ at a rate of 3-5℃ / min, and the second stage cools from 40-42℃ to below 35℃ at a rate of 1-2℃ / min.

6. The method according to claim 1, characterized in that, In step b, the dual-framework synergistic annealing makes the RS3 resistant starch formation efficiency higher than that of annealing methods that use gluten protein framework alone or residual microcrystalline framework alone.

7. The method according to claim 1, characterized in that, The starch gelatinization degree of the grain raw material mentioned in step a is 20%-65%, and the crystallinity retention rate of the ungelatinized portion is ≥50%.

8. A high-gluten, low-glycemic index cereal powder with dual-skeletal synergistic modification, characterized in that, The cereal powder prepared by the method according to any one of claims 1-7 simultaneously satisfies the following conditions: wet gluten retention rate ≥85%, GI value ≤65, RS3 type resistant starch melting temperature ≥120℃, and the ingredient list contains only the cereal raw material itself; the cereal powder simultaneously contains a three-dimensional network of gluten protein and a dual heterogeneous nucleation framework of residual starch microcrystals.

9. The grain flour according to claim 8, characterized in that, RS3-type resistant starch grows orderly along the gluten protein network and microcrystalline surface.

10. The use of the cereal flour of claim 8 or 9 in the preparation of high-gluten, low-glycemic index noodle products, wherein the noodle products include, but are not limited to, toast, ramen, dumpling wrappers, frozen pizza bases, and frozen dough.