Bread based on super-fine bamboo shoot powder and kappa-carrageenan composite gel and preparation method thereof

Abstract

This invention belongs to the field of food processing technology, specifically relating to a bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel and its preparation method. The preparation method includes the following steps: (1) dissolving κ-carrageenan in water and adding bamboo shoot ultrafine powder to obtain bamboo shoot ultrafine powder and κ-carrageenan composite gel; (2) mixing the composite gel with flour, then adding yeast, sugar, water and auxiliary materials, and stirring to form a dough; (3) baking the dough obtained in step (2) after proofing to obtain bread. The beneficial effects of this invention are: by combining bamboo shoot ultrafine powder prepared from bamboo shoot processing by-products with κ-carrageenan in the presence of calcium ions to form a gel, and then applying it to bread making. On the one hand, it enhances flavor generation; on the other hand, the three-dimensional network structure formed by κ-carrageenan and bamboo shoot ultrafine powder can selectively inhibit the release of unpleasant odor substances such as inorganic sulfides, while promoting the generation or retention of nitrogen oxide-like baking characteristic flavor substances.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel and its preparation method. Background Technology

[0002] As a typical baked food, the flavor quality of bread is of paramount importance. It mainly depends on the volatile flavor compounds such as pyrazines, furans, and aldehydes generated during the Maillard reaction and Strecker degradation reaction. These compounds give bread its unique baked aroma, nutty aroma, and caramel aroma.

[0003] In the prior art, methods to improve bread flavor mainly include: (1) directly adding sugars, dairy products or flavorings; (2) controlling flavor precursors through fermentation processes; and (3) introducing natural plant powders such as whole grain powder and vegetable powder. However, these methods have obvious drawbacks: the addition of exogenous flavoring substances can easily lead to a single and unnatural flavor; while the introduction of natural plant powders can improve nutritional value, it may often introduce unpleasant odors (such as sulfide odors), or damage the gluten network due to its rough fiber structure, resulting in poor bread texture and a rough mouthfeel.

[0004] To address the adverse effects of plant fibers, ultrafine grinding technology has been used to reduce fiber particle size. For example, Chinese patent CN109090183A discloses a method for making bread by adding ultrafine bamboo shoot dietary fiber powder. This method extracts bamboo shoot dietary fiber through physical and enzymatic treatments and then performs ultrafine grinding to improve the nutritional value and texture of the bread. However, this method simply mixes the ultrafine powder with flour and other raw materials, failing to address the potential release of unpleasant odors such as sulfides introduced by plant powders, nor does it address how to actively regulate the generation and release of flavor compounds through system construction.

[0005] Chinese patent CN121176593A discloses a method for producing konjac-based food products. This method utilizes various colloids such as carrageenan and gellan gum to form a gel system with konjac micropowder, and uses β-cyclodextrin to encapsulate flavor substances to improve the product's flavor. This technical solution focuses on adding and slow-release flavors through external encapsulation technology and improving texture through the combination of multiple colloids. However, its purpose is to mask and compensate for the undesirable flavors of konjac itself, rather than promoting and regulating the generation of characteristic flavors required for baked goods from the source. Furthermore, its complex enzymatic hydrolysis and multi-colloid system increase cost and processing difficulty.

[0006] Therefore, how to utilize natural plant resources, especially processing by-products such as bamboo shoot husks and shoot tips, to construct a simple composite system that can significantly enhance the characteristic baking flavor of bread while effectively suppressing unpleasant odors introduced by plant powders has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, as well as a method for its preparation. This method can not only effectively improve the flavor and quality of bread and reduce unpleasant odors, but also regulate moisture and extend shelf life, achieving a synergistic enhancement of multiple benefits.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, comprising the following steps: (1) Dissolve κ-carrageenan in water. After it is completely dissolved, add bamboo shoot ultrafine powder and stir to mix evenly. Then add calcium ion solution and stir to promote the formation of gel network. Cool to obtain bamboo shoot ultrafine powder and κ-carrageenan composite gel. (2) Mix the composite gel obtained in step (1) with flour, then add yeast, sugar, water and auxiliary materials, and stir into dough; (3) The dough obtained in step (2) is proofed and then baked to make bread.

[0009] Another technical solution of the present invention is to provide a bread prepared by the above-mentioned method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel.

[0010] The beneficial effects of this invention are as follows: The method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel involves combining bamboo shoot ultrafine powder (a byproduct of bamboo shoot processing) with κ-carrageenan in the presence of calcium ions to form a gel, which is then applied to bread making. Compared with the prior art of directly adding plant powder to bread, the composite gel system constructed by this method can synergistically regulate bread flavor from multiple levels, including "flavor precursor generation, reaction pathway regulation, and volatile release behavior." On the one hand, the proteins, amino acids, and reducing sugars released by the bamboo shoot ultrafine powder provide rich precursors for the Maillard reaction, enhancing flavor generation from the source. On the other hand, the three-dimensional network structure formed by κ-carrageenan and bamboo shoot ultrafine powder can selectively inhibit the release of unpleasant odor substances such as inorganic sulfides, while promoting the generation or retention of nitrogen oxide-based baking characteristic flavor substances, thus solving the problem of unpleasant odors introduced by natural plant powders. Attached Figure Description

[0011] Figure 1 This is a comparison chart of the water-holding capacity of composite gels with different particle sizes and compounding ratios in Example 3 of a specific embodiment of the present invention; Figure 2 Fourier transform infrared spectra of composite gels with different particle sizes and compounding ratios in Example 3 of this invention; Figure 3 Fourier transform infrared spectra of different composite gels in Example 3 of a specific embodiment of the present invention; Figure 4 This is a schematic diagram showing the water loss rate of bread after storage with different amounts of composite gel added in Example 3 of this invention. Figure 5 Radar images of bread-shaped electronic noses with different amounts of composite gel added in Example 3 of this invention; Figure 6 This is a comparison chart of the flavor of bread with different amounts of composite gel added in Example 3 of the present invention. Figure 7 This is a comparison chart of the flavor of bread electronic tongue with different amounts of composite gel added in Example 3 of the specific implementation of the present invention; Figure 8 This is a comparison of the different metabolites in bread with different amounts of composite gel added in Example 3 of a specific embodiment of the present invention; Figure 9 This is a comparison of the different metabolites in bread with different amounts of composite gel added in Example 3 of a specific embodiment of the present invention; Figure 10 This is a comparison of the different metabolites in bread with different amounts of composite gel added in Example 3 of a specific embodiment of the present invention; Figure 11 This is a comparison of the different metabolites in bread with different amounts of composite gel added, as described in Example 3 of this invention. Detailed Implementation

[0012] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0013] Bamboo shoots, a plant resource rich in dietary fiber, amino acids, and various functional components, have long suffered from low utilization rates of their processing byproducts (such as bamboo shoot husks and tips). Processing bamboo shoots into ultrafine powder significantly increases their specific surface area, making it easier to release active ingredients. This provides abundant nitrogen and carbon precursors for the Maillard reaction, potentially enhancing flavor. However, bamboo shoots may also produce undesirable flavor compounds such as sulfides, limiting their application in baked goods.

[0014] κ-carrageenan is a natural polysaccharide derived from red algae, possessing excellent gelling and water-holding properties, enabling it to form a three-dimensional network structure in food systems. Existing research indicates that κ-carrageenan can influence food texture by regulating moisture state and system structure, but its mechanism of action in flavor formation regulation, particularly in controlling the release of volatile flavor compounds, remains unclear.

[0015] This invention provides a method for regulating bread flavor by constructing a composite gel system of bamboo shoot ultrafine powder and κ-carrageenan. By adjusting the proportion of the composite gel added, the release of volatile flavor substances, taste properties, and Maillard reaction pathways in bread can be synergistically regulated, thereby improving the overall flavor quality of the bread.

[0016] This invention provides a method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, comprising the following steps: (1) Dissolve κ-carrageenan in water. After it is completely dissolved, add bamboo shoot ultrafine powder and stir to mix evenly. Then add calcium ion solution and stir to promote the formation of gel network. Cool to obtain bamboo shoot ultrafine powder and κ-carrageenan composite gel. (2) Mix the composite gel obtained in step (1) with flour, then add yeast, sugar, water and auxiliary materials, and stir into dough; (3) The dough obtained in step (2) is proofed and then baked to make bread.

[0017] As described above, this invention involves combining ultrafine bamboo shoot powder (a byproduct of bamboo shoot processing) with κ-carrageenan in the presence of calcium ions to form a gel, which is then applied to bread making. Compared to existing technologies that directly add plant powder to bread, this method constructs a composite gel system that can synergistically regulate bread flavor from multiple levels: flavor precursor generation, reaction pathway regulation, and volatile release behavior. On the one hand, the proteins, amino acids, and reducing sugars released by the ultrafine bamboo shoot powder provide abundant precursors for the Maillard reaction, enhancing flavor generation from the source. On the other hand, the three-dimensional network structure formed by κ-carrageenan and ultrafine bamboo shoot powder can selectively inhibit the release of unpleasant odor substances such as inorganic sulfides, while promoting the generation or retention of nitrogen oxide-based baking characteristic flavor substances, thus solving the problem of unpleasant odors introduced by natural plant powders.

[0018] Furthermore, in step (1) of the above-mentioned method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, the bamboo shoot ultrafine powder is obtained by ultrafine grinding of bamboo shoot processing by-products to D50≤1.5μm.

[0019] As described above, limiting the particle size of bamboo shoot powder to the ultrafine level of D50≤1.5μm significantly increases the specific surface area of ​​the bamboo shoot powder, exposing more active groups such as hydroxyl and carboxyl groups. This is beneficial for forming a denser composite gel network with κ-carrageenan molecules through hydrogen bonding and electrostatic interaction, while also promoting the release of Maillard reaction precursors such as amino acids and reducing sugars in the bamboo shoot powder.

[0020] Furthermore, in step (1) of the above-mentioned method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, the mass-volume percentage of κ-carrageenan to water is 0.5%-1.2%, and the mass-volume percentage of bamboo shoot ultrafine powder to water is 0.5%-2.4%.

[0021] As described above, this concentration range is crucial for the formation of a stable composite gel. When the concentration of κ-carrageenan is below 0.5%, it is difficult to form an effective gel network, while above 1.2%, the system viscosity is too high, which is not conducive to the uniform dispersion of bamboo shoot powder. When the concentration of ultrafine bamboo shoot powder is below 0.5%, the flavor precursors are insufficient, and above 2.4%, the continuity of the gel network will be disrupted.

[0022] Furthermore, in step (1) of the above-mentioned method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, the mass-volume percentage of κ-carrageenan to water is 0.7%, and the mass-volume percentage of bamboo shoot ultrafine powder to water is 0.7%.

[0023] As described above, when the addition amount of both κ-carrageenan and bamboo shoot ultrafine powder is 0.7%, Fourier transform infrared spectroscopy shows that the hydrogen bond interaction between the two is the strongest, forming a composite structure with the largest intermolecular non-covalent binding force and the densest gel network, which can maximize the selective regulation of flavor substances.

[0024] Furthermore, in step (2) of the above-mentioned method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, the amount of the composite gel added is 5%-30% of the flour mass.

[0025] Furthermore, in the above-mentioned method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, the amount of the composite gel added is 15%-20% of the flour mass.

[0026] As described above, within this preferred addition range (especially 15%, as verified in Example 3), the bread exhibits the lowest water loss rate during storage, indicating that the composite gel at this addition level performs optimally in terms of water retention capacity. This not only delays bread aging but also provides a more suitable moisture microenvironment for the Maillard reaction in the early stages of baking, resulting in more complete generation of characteristic flavor compounds.

[0027] Furthermore, in the above method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, the calcium ion solution in step (1) is a calcium chloride solution.

[0028] Furthermore, in the above-mentioned method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, the bamboo shoot processing by-products include bamboo shoot shells, bamboo shoot tips, bamboo shoot sheaths, or combinations thereof.

[0029] As described above, using bamboo shoot processing by-products as the raw material source for bamboo shoot ultrafine powder achieves high-value utilization of waste, reduces raw material costs, and solves the environmental problems caused by by-product disposal, making this method both economical and environmentally friendly.

[0030] The present invention also provides a method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel.

[0031] Example 1 A method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel includes the following steps: A composite gel was formed by combining bamboo shoot ultrafine powder with κ-carrageenan: Distilled water was heated in a water bath until the water temperature reached 60°C. 0.7% (by mass of water) of κ-carrageenan was dissolved in the water and stirred for 5 minutes to ensure complete dissolution. Then, 0.7% (by mass of water) of bamboo shoot ultrafine powder was added. The bamboo shoot ultrafine powder was prepared by ultra-fine grinding of bamboo shoot processing by-products to a D50 ≤ 1.5 μm. After stirring for 20 minutes, calcium chloride solution (0.1 mol / L) was added, and the mixture was stirred for another 10 minutes to promote the formation of a gel network between the bamboo shoot ultrafine powder and κ-carrageenan. After stirring, the mixture was cooled to room temperature (25°C) to obtain the composite gel of bamboo shoot ultrafine powder and κ-carrageenan.

[0032] Add the above-mentioned composite gel to the bread system; Add 15% by weight of bamboo shoot ultrafine powder and κ-carrageenan complex gel to 100g of flour, mix thoroughly, then add 1g of yeast powder, 10g of white sugar, and 60ml of warm water (30℃). Pour into a mixer and mix until there is no dry powder. Then add 7g of butter and 0.6g of salt, and continue mixing until a smooth dough is formed. Take it out and divide it into even small dough balls. Place them in a proofing box to proof for 45 minutes, then bake for 10 minutes (top heat 180℃, bottom heat 160℃). Through fermentation and baking, a bread product with optimized flavor characteristics is obtained.

[0033] Example 2 A method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel includes the following steps: A composite gel was formed by mixing bamboo shoot ultrafine powder and κ-carrageenan in a certain proportion: distilled water was heated in a water bath until the water temperature reached 60℃. 0.5%-1.2% (by mass of water) of κ-carrageenan was dissolved in the water and stirred for 5 minutes to completely dissolve the κ-carrageenan. Then, 0.5%-2.4% (by mass of water) of bamboo shoot ultrafine powder was added. The bamboo shoot ultrafine powder was obtained by ultra-fine grinding of bamboo shoot processing by-products to D50≤1.5μm. After stirring for 20 minutes, calcium chloride solution (0.1mol / L) was added and stirred for another 10 minutes to promote the formation of a gel network between the bamboo shoot ultrafine powder and κ-carrageenan. After stirring, the mixture was cooled to room temperature (25℃) to obtain the composite gel of bamboo shoot ultrafine powder and κ-carrageenan.

[0034] Add the above-mentioned composite gel to the bread system; Add 5%-30% by weight of bamboo shoot ultrafine powder and κ-carrageenan complex gel to 100g of flour, mix thoroughly, then add 1g of yeast powder, 10g of white sugar, and 60ml of warm water (30℃). Pour into a mixer and mix until there is no dry powder. Then add 7g of butter and 0.6g of salt, and continue mixing until a smooth dough is formed. Take it out and divide it into even small dough balls. Place them in a proofing box to proof for 45 minutes, then bake for 10 minutes (top heat 180℃, bottom heat 160℃). Through fermentation and baking, a bread product with optimized flavor characteristics is obtained.

[0035] Example 3 This embodiment aims to illustrate the screening and application process of composite gel raw materials.

[0036] In this embodiment, bamboo shoot ultrafine powder is obtained using bamboo shoot shells as raw material. The shells are pulverized using a high-speed pulverizer and sieved to obtain 40-mesh and 80-mesh bamboo shoot powder. The 40-mesh bamboo shoot powder is fed into the ultrafine pulverizer at a rate of 500g per batch and pulverized for 15 minutes to obtain ultrafine bamboo shoot powder with a D50 ≤ 1.5μm. The bamboo shoot powder is then compounded with κ-carrageenan in a certain proportion to form a more stable composite gel network structure, constructing a bamboo shoot powder and κ-carrageenan composite gel system. The particle size with the best effect is screened to obtain ultrafine powder. Bamboo shoot ultrafine powder-κ-carrageenan composite gels with different compounding ratios are prepared to obtain bamboo shoot ultrafine powder-κ-carrageenan composite gels that can regulate the release of small molecules.

[0037] This invention utilizes ultrafine pulverization technology, a novel fine pulverization processing technique that can pulverize materials to the micron level, making it an excellent physical modification technology. Compared to ordinary pulverization techniques, ultrafine pulverization can exert a stronger force to break the long chains of dietary fiber, exposing more active groups. This effectively improves the water-holding capacity, swelling capacity, and other physicochemical properties of dietary fiber, and helps promote the combination of bamboo shoot powder and κ-carrageenan to form a three-dimensional network structure under calcium ion induction, thereby better regulating the release of small molecule substances.

[0038] 1. Preparation of bamboo shoot powder-κ-carrageenan composite gels with different particle sizes and compounding ratios; Different particle sizes of bamboo shoot powder and κ-carrageenan were compounded in a certain proportion to form a composite gel: distilled water was heated in a water bath until the water temperature reached 60℃. 0.7% κ-carrageenan was dissolved in the water and stirred for 5 minutes to completely dissolve the κ-carrageenan. 40 mesh, 80 mesh and bamboo shoot ultrafine powder were added and stirred for 20 minutes. Calcium ions were added and stirred for another 10 minutes to promote the formation of a gel network between the bamboo shoot ultrafine powder and κ-carrageenan. After stirring, the mixture was cooled to room temperature (25℃) to obtain the bamboo shoot powder-κ-carrageenan composite gel, which were named S-40-0.7 (40 mesh), S-80-0.7 (80 mesh), and S-ultrafine-0.7 (bamboo shoot ultrafine powder), respectively.

[0039] Bamboo shoot ultrafine powder and κ-carrageenan were compounded in different proportions to form composite gels: distilled water was heated in a water bath until the water temperature reached 60℃. 0.5%, 0.7%, and 1.2% κ-carrageenan were dissolved in water and stirred for 5 minutes to completely dissolve the κ-carrageenan. 0.5%, 0.7%, and 2.4% bamboo shoot ultrafine powder were added respectively, and stirred for 20 minutes. Calcium ions were added, and the mixture was stirred for another 10 minutes to promote the formation of a gel network between the bamboo shoot ultrafine powder and κ-carrageenan. After stirring, the mixture was cooled to room temperature (25℃) to obtain bamboo shoot ultrafine powder-κ-carrageenan composite gels, which were named S-ultrafine-0.5 (0.5% by mass / volume percentage of water), S-ultrafine-0.7 (0.7% by mass / volume percentage of water), and S-ultrafine-2.4 (2.4% by mass / volume percentage of water), respectively.

[0040] (1) Water retention of composite gels with different particle sizes and compounding ratios Please see Figure 1 , Figure 1 A comparison of the water-holding capacity of composite gels with different particle sizes and compounding ratios (Figure 1) Figure 1 Different lowercase letters in the text indicate significant differences between different data points (P < 0.05). Depend on Figure 1 It can be seen that for composite gels with different particle sizes, the smaller the particle size, the higher the water-holding capacity. Under the same particle size, the S-ultrafine-0.7 group of composite gels has the best water-holding capacity, indicating that the smaller bamboo shoot powder can be better dispersed in the κ-carrageenan network, forming a denser gel network structure, thereby restricting the flow of water molecules.

[0041] (2) Structural characteristics of composite gels with different particle sizes and compounding ratios Please see Figure 2 , Figure 2 The figures show the Fourier transform infrared (FTIR) spectra of composite gels with different particle sizes and mixing ratios. As can be seen from the figures, the infrared spectra are concentrated at 3400 cm⁻¹. 1 Absorption peaks appeared in the vicinity, mainly due to The stretching vibration of OH, with smaller particle sizes at 3400 cm⁻¹ 1 The broad peak at 2920 cm⁻¹ shifts towards higher wavenumbers, indicating enhanced hydrogen-bonding interactions between bamboo shoot powder and κ-carrageenan. The absorption peak intensities of the S-ultrafine-0.5 and S-ultrafine-2.4 groups are lower than those of the S-ultrafine-0.7 group, suggesting that when the compound ratio is 0.7% κ-carrageenan and 0.7% bamboo shoot ultrafine powder, intermolecular interactions are more likely to occur, forming more intermolecular hydrogen bonds. Furthermore, all samples show peak intensities at 2920 cm⁻¹. 1 and 1655 cm 1The presence of weak absorption peaks in both samples is related to the stretching vibrations of CH and -COOH, indicating that hydrophobic interactions or molecular chain rearrangement may occur after bamboo shoot powder is combined with κ-carrageenan. In summary, it can be determined that a mixture of 0.7% κ-carrageenan and 0.7% bamboo shoot ultrafine powder is more effective in forming a novel composite gel network structure.

[0042] 2. Application of the above-mentioned bamboo shoot powder-κ-carrageenan composite gel; (1) The structural characteristics of the composite gel system of bamboo shoot ultrafine powder and κ-carrageenan when the compounding ratio in 1 above is 0.7% κ-carrageenan and 0.7% bamboo shoot ultrafine powder; Please see Figure 3 , Figure 3 Fourier transform infrared spectra of different composite gels. Figure 3 The ingredients are KC-S (0.7% κ-carrageenan and 0.7% bamboo shoot ultrafine powder), KC (κ-carrageenan), and S (bamboo shoot ultrafine powder).

[0043] Preparation of KC-S (bamboo shoot ultrafine powder-κ-carrageenan composite gel): Heat distilled water in a water bath until the water temperature reaches 60℃. Dissolve 0.7% κ-carrageenan in the water and stir for 5 minutes until the κ-carrageenan is completely dissolved. Then add 0.7% bamboo shoot ultrafine powder and stir for 20 minutes. Add calcium chloride solution and stir for another 10 minutes to promote the formation of the bamboo shoot ultrafine powder and κ-carrageenan gel network. After stirring, cool to room temperature (25℃) to obtain the bamboo shoot ultrafine powder-κ-carrageenan composite gel matrix.

[0044] Preparation of KC (κ-carrageenan): Heat distilled water in a water bath until the water temperature reaches 60℃, then dissolve 0.7% κ-carrageenan in the water and stir for 5 minutes until completely dissolved. After stirring, cool to room temperature (25℃) to obtain κ-carrageenan gel.

[0045] Preparation of S (bamboo shoot ultrafine powder): Bamboo shoot shells are used as raw materials. After being crushed and sieved by a high-speed pulverizer, coarse bamboo shoot shell powder is obtained. The coarse bamboo shoot shell powder is fed into the ultrafine pulverizer at a rate of 500g each time and crushed for 15min to obtain bamboo shoot ultrafine powder with D50≤1.5μm.

[0046] Depend on Figure 3 It can be seen that the infrared spectrum is at 3400 cm⁻¹ 1 Strong and sharp absorption peaks appeared in the vicinity, mainly due to The increased absorption peak intensity due to the stretching vibration of OH may be due to the formation of intermolecular hydrogen bonds between κ-carrageenan and substances such as cellulose and hemicellulose in bamboo shoot ultrafine powder. Furthermore, all samples showed an increase in absorption peak intensity at 2920 cm⁻¹. 1Weak absorption peaks were observed in the vicinity, which is related to the CH stretching vibrations of methyl and methylene groups in the polysaccharide. The peak shape of the KCS group changed and shifted, indicating that hydrophobic interactions or molecular chain rearrangement may occur after the bamboo shoot ultrafine powder is combined with κ-carrageenan. Additionally, at 1655 cm⁻¹... 1 The presence of a weak absorption peak indicates the bending vibration of -COOH. The broadening of the peak in the KCS group suggests that the carboxyl groups in the bamboo shoot ultrafine powder may interact ionicly with the sulfate or hydroxyl groups of κ-carrageenan. In summary, bamboo shoot ultrafine powder and κ-carrageenan form a novel composite gel network structure through non-covalent forces, primarily hydrogen bonding and secondarily electrostatic interactions, which helps to regulate the release of flavor compounds in bread.

[0047] 3. Application of the composite gel system of bamboo shoot ultrafine powder and κ-carrageenan in bread when the compound ratio in 1 above is 0.7% κ-carrageenan and 0.7% bamboo shoot ultrafine powder; Bamboo shoot ultrafine powder and κ-carrageenan composite gel were added to bread at mass percentages of 5%, 10%, 15%, and 20% (based on 100g of flour), respectively, according to the bread preparation method in Example 2.

[0048] (1) Regulation of water content Please see Figure 4 , Figure 4 The water loss rate of bread after storage was measured for different amounts of composite gel added. Among them, KCS-0, KCS-5, KCS-10, KCS-15, and KCS-20 represent 0%, 5%, 10%, 15%, and 20% composite gel added to bread, respectively; KC represents bread with carrageenan added alone; and S represents bread with bamboo shoot ultrafine powder added alone.

[0049] Depend on Figure 4 It can be seen that the water loss rate of all samples increased during the storage period. The water loss rate of bread with added composite gel showed a trend of first decreasing and then increasing with the increase of the addition amount. KCS-15 had the lowest water loss rate and the best water retention during storage. During storage, moisture migrates from the inside of the bread to the crust and is lost. Amylose also absorbs moisture and recrystallizes, leading to a reduction in free water. This indicates that the composite gel network formed by κ-carrageenan and bamboo shoot ultrafine powder can effectively control moisture migration. In summary, when the addition amount of bamboo shoot ultrafine powder and κ-carrageenan composite gel is 5%-15%, it can effectively reduce the water loss rate of bread and extend its shelf life. Among them, 15% bamboo shoot ultrafine powder and κ-carrageenan composite gel has the best effect.

[0050] (2) Regulation effect on nitrogen oxide flavor compounds Please see Figure 5-6 , Figure 5 Radar graphs of bread electronic noses with different amounts of composite gel added; Figure 6Comparison of bread flavors with different amounts of composite gel added by electronic nose; Studies have shown that the addition of bamboo shoot ultrafine powder and κ-carrageenan composite gel significantly increases the volatile nitrogen oxide components (W5S class) in bread. These substances mainly impart roasted, nutty, and caramelized aromas to the product.

[0051] Nitrogen oxides (W5S): impart roasted, nutty, and caramelized aromas. High levels result in a rich, toasted bread and nutty flavor; low levels lead to a milder flavor and a lack of roasted notes. However, excessively high levels can quickly transform the roasted aroma into a burnt, bitter taste. Typical substances include pyrazines, some aldehydes, and alcohols. The reasons for this may include: ① Introduced from raw materials: the proteins, amino acids, and nitrates naturally present in bamboo shoots; ② Enhanced Maillard reaction: the amino acids and reducing sugars in ultrafine bamboo shoot powder, under high-temperature baking, intensify the Maillard reaction, producing more flavor compounds but also potentially generating nitrogen oxides as a byproduct; ③ Moisture regulation and promotion: carrageenan itself does not produce nitrogen oxides, but its water-holding capacity alters the system's water activity, delays starch gelatinization, and makes the bread more moist, heats more evenly, and promotes a more complete Maillard reaction. In conclusion, when the addition amount of ultrafine bamboo shoot powder and κ-carrageenan composite gel is 5%-20%, it can effectively enrich the aroma components of bread and improve its flavor.

[0052] (3) Inhibition and regulation of inorganic sulfides Please see Figure 5-6 Studies have found that the composite gel system can effectively regulate the release levels of inorganic sulfides (W1W type, sulfur aroma, caramel aroma, slight spiciness / irritation). The ultrafine bamboo shoot powder and κ-carrageenan form a three-dimensional network structure, which significantly encapsulates and fixes volatile sulfides, thereby reducing their migration and release into the gas phase. This inhibits the release of undesirable flavor substances such as hydrogen sulfide, reduces the risk of rancid and putrid odors, retains an appropriate amount of sulfur aroma, and enhances the fermentation base aroma and baking complex aroma. In summary, when the addition amount of ultrafine bamboo shoot powder and κ-carrageenan composite gel is 5%-20%, it can effectively inhibit the release of undesirable volatile components in bread, thereby improving the aroma components of bread and benefiting its flavor.

[0053] (4) Regulatory effect on taste attributes (sweet, sour, bitter) Please see Figure 7 , Figure 7 Comparison of the flavor of bread with different amounts of compound gel added using electronic tongue.

[0054] from Figure 7The results show that the addition of bamboo shoot ultrafine powder and κ-carrageenan composite gel significantly affects the sourness, sweetness, and bitterness of bread, significantly reducing these flavors. Specifically, the sweetness decreases noticeably with increasing composite gel content, indicating that the gel network structure formed by the bamboo shoot ultrafine powder and κ-carrageenan restricts the diffusion of small-molecule flavor compounds and reduces the release rate of sweet substances. In conclusion, when the addition amount of bamboo shoot ultrafine powder and κ-carrageenan composite gel is 5%-20%, it can effectively reduce the sourness, sweetness, and bitterness of bread.

[0055] (5) Promoting effect on key flavor precursors (small molecule peptides) Please see Figures 8 to 11 A comparison of the different metabolites in breads with different amounts of composite gel added; among them... Figure 8 (a) KCS-0 and KCS-5; Figure 9 (b) KCS-0 and KCS-10; Figure 10 (c) KCS-0 and KCS-15; Figure 11 (d) KCS-0 and KCS-20 (red bars represent upward adjustment, blue bars represent downward adjustment, and the length of the bar represents the logarithm of the upward or downward adjustment multiple.) from Figure 8 The results show that the upregulated differential metabolites mainly fall into the following categories: terpenes / glycosides, phenolic acids, fatty acid derivatives, and peptides. Upregulated peptides in several sample groups include small molecule peptides such as Trp-Met-Ser, Glu-Glu-Glu, Gln-lle-Trp, and lle-Leu-lle. During baking, these small molecule peptides participate in the Maillard reaction, generating pyrazines, furans, and other roasted, nutty, and caramel aroma compounds. Furthermore, the Strecker aldehydes released during Strecker degradation (such as 3-methylbutyraldehyde from leucine, which has a malty aroma) are important components of typical bread aromas. The increased content of small molecule peptides also indicates that the addition of complex gels helps to create a richer and more prominent bread flavor.

[0056] In summary: (1) Moisture regulation Figure 4 During the storage period, the water loss rate of all breads with added KCS complex gel (KCS-5 to KCS-20) was lower than that of the blank group KCS-0 and the groups with added KC and S alone. Among them, the KCS-15 group had the strongest water-holding capacity and the lowest water loss rate. This is because the three-dimensional network formed by the KCS complex gel can effectively bind water molecules and slow down the migration and loss of moisture, thereby helping to maintain the softness of the bread and extend its shelf life.

[0057] (2) Flavor regulation Figure 5 and Figure 6Electronic nose analysis showed that, compared to the control, bread with added KCS composite gel exhibited a significantly enhanced signal in response to nitrogen oxides (W5S sensor). These substances mainly include pyrazines and aldehydes, which are key flavor compounds that impart toasty and nutty aromas to bread. The enhanced signal indicates a richer Maillard reaction product and a more prominent characteristic flavor. Meanwhile, the signal in response to inorganic sulfides (W1W sensor) was significantly lower in the KCS group than in the S group with added bamboo shoot powder alone, and even lower than in the blank group. This demonstrates the selective encapsulation and inhibition of release of unpleasant odor substances such as hydrogen sulfide by the composite gel network, successfully solving the "fishy" and "earthy" taste problems associated with adding plant powders.

[0058] (3) Improved taste ( Figure 7 The electronic tongue results showed that adding KCS complex gel significantly reduced the response values ​​of sourness, sweetness, and bitterness in bread. This means that the complex gel can coordinate and improve the overall taste profile of bread, making its texture more mellow and refreshing, and reducing any possible cloying sweetness or fermented sourness.

[0059] (4) Flavor precursor enhancement ( Figures 8-11 Metabolomics analysis showed that, compared with blank bread KCS-0, bread with different proportions of KCS composite gel showed significantly upregulated expression levels of various small peptides. These small peptides are important precursors of Maillard reaction and Strecker degradation, and can be directly converted into various aroma compounds during baking. Their increased content proves from the "source" that the composite gel of this invention not only regulates the release of flavor compounds, but also fundamentally enhances the flavor potential of bread by promoting the generation of flavor precursors.

[0060] The invention successfully constructed a composite gel of bamboo shoot ultrafine powder and κ-carrageenan. When applied to bread, it can synergistically enhance the characteristic baking flavor of bread through multiple mechanisms of "source enhancement, path regulation, and environmental optimization," effectively suppress unpleasant odors, improve taste properties, and regulate moisture. It has good application value in the field of baked goods.

[0061] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel, characterized in that, Includes the following steps: (1) Dissolve κ-carrageenan in water. After it is completely dissolved, add bamboo shoot ultrafine powder and stir to mix evenly. Then add calcium ion solution and stir to promote the formation of gel network. Cool to obtain bamboo shoot ultrafine powder and κ-carrageenan composite gel. (2) Mix the composite gel obtained in step (1) with flour, then add yeast, sugar, water and auxiliary materials, and stir into dough; (3) The dough obtained in step (2) is proofed and then baked to make bread.

2. The method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel according to claim 1, characterized in that, In step (1), the bamboo shoot ultrafine powder is obtained by ultrafine grinding of bamboo shoot processing by-products to D50≤1.5μm.

3. The method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel according to claim 1, characterized in that, In step (1), the mass-volume percentage of the κ-carrageenan to the water is 0.5%-1.2%, and the mass-volume percentage of the bamboo shoot ultrafine powder to the water is 0.5%-2.4%.

4. The method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel according to claim 3, characterized in that, In step (1), the mass-volume percentage of the κ-carrageenan to the water is 0.7%, and the mass-volume percentage of the bamboo shoot ultrafine powder to the water is 0.7%.

5. The method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel according to claim 1, characterized in that, In step (2), the amount of the composite gel added is 5%-30% of the flour mass.

6. The preparation method according to claim 5, characterized in that, In step (2), the amount of the composite gel added is 15%-20% of the flour mass.

7. The method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel according to claim 1, characterized in that, The calcium ion solution mentioned in step (1) is a calcium chloride solution.

8. The method for preparing bread based on bamboo shoot ultrafine powder and κ-carrageenan composite gel according to claim 1, characterized in that, The bamboo shoot processing by-products include bamboo shoot shells, bamboo shoot tips, bamboo shoot sheaths, or combinations thereof.

9. A type of bread prepared by the method of any one of claims 1-8 based on bamboo shoot ultrafine powder and κ-carrageenan composite gel.

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