A fermentation powder-based food preservative compound and a method of preparing the same

Abstract

This invention relates to the field of food preservative technology, and particularly to a food preservative complex based on baking powder and its preparation method. Using whey baking powder, sucrose baking powder, and vinegar powder as core raw materials, the complex achieves dual stability of acetic acid through intermolecular hydrogen bonds formed between starch acetate and acetic acid, and hydrophobic encapsulation by hydrogenated palm oil. A composite gel network is constructed using whey protein, sucrose fermentation polysaccharide, and sodium octenyl succinate starch. Microspheres are prepared and modified with HPMC temperature-responsive coating to form a double moisture barrier under steaming conditions, trapping antibacterial components. During room temperature storage, the antibacterial components are slowly released in response to moisture, achieving broad-spectrum antibacterial activity, effectively improving the preservative's resistance to damp heat, and significantly extending the shelf life of steamed foods.

Description

Technical Field

[0001] This invention relates to the field of food preservative technology, and in particular to a food preservative complex based on baking powder and its preparation method. Background Technology

[0002] Steamed foods are an indispensable core category in the daily diet of Chinese residents, encompassing traditional staple foods such as steamed buns, dumplings, shumai, steamed dumplings, and steamed cakes, as well as various pre-prepared steamed dishes. In recent years, with the explosive growth of the pre-prepared food industry, the market size of industrialized steamed foods has continued to expand, becoming an important growth point for the food industry. However, steamed foods generally have high moisture content and rich nutrient matrix, making them extremely prone to the growth of various microorganisms such as bacteria, mold, and yeast. Moreover, conventional steaming processes can only kill most of the nutrients and cannot completely eliminate heat-resistant spores, resulting in short product shelf life and problems such as mold, sourness, and deterioration in taste, which seriously restricts the large-scale development of the industry. With the increasing health awareness of consumers, the use of chemically synthesized preservatives is subject to increasingly strict restrictions. Bio-based preservation technologies, represented by baking powder, have received widespread attention due to their natural safety and wide availability. However, existing baking powder-based preservation technologies mostly use a single baking powder, which has a limited antibacterial spectrum and insufficient inhibitory effect on molds, acid-resistant bacteria, and Bacillus. They require high-dose addition, which can easily lead to deterioration of food flavor. At the same time, their preservation time is not long enough, and fermentation metabolites are easily diluted and degraded by the food system, resulting in a short action cycle that is difficult to meet the long-term preservation requirements of steamed foods. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a food preservative complex based on baking powder and its preparation method. Using whey baking powder, sucrose baking powder, and vinegar powder as core raw materials, the complex achieves dual stability of acetic acid through intermolecular hydrogen bonds formed between starch acetate and acetic acid, and hydrophobic encapsulation by hydrogenated palm oil. A composite gel network is constructed using whey protein, sucrose fermentation polysaccharide, and sodium octenyl succinate starch. Microspheres are prepared and modified with HPMC temperature-responsive coating to form a double moisture barrier under steaming conditions, trapping antibacterial components. During room temperature storage, the antibacterial components are slowly released in response to moisture, achieving broad-spectrum synergistic antibacterial activity, effectively improving the preservative's resistance to damp heat, and significantly extending the shelf life of steamed foods.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] In a first aspect, the present invention provides a method for preparing a food preservative complex based on baking powder, comprising the following steps:

[0006] S1. Mix whey baking powder, sucrose baking powder and deionized water, and then ball mill and sieve to obtain a baking powder suspension;

[0007] S2. After sterilizing and cooling the baking powder suspension, add sodium octenyl succinate starch, microcrystalline cellulose, trehalose and Tween 80 in sequence and mix. Add starch acetate and hydrogenated palm oil powder, disperse, add vinegar powder, adjust pH and obtain a mixture.

[0008] S3. The mixture is heated and kept at the temperature to obtain a pregel solution, which is then spray-dried and sieved to obtain microspheres;

[0009] S4. Mix calcium lactate with deionized water to obtain an aqueous solution of calcium lactate; mix hydroxypropyl methylcellulose (HPMC), polyethylene glycol (PEG) 400 and deionized water to obtain a coating solution; crosslink microspheres through fluidized bed crosslinking of calcium lactate aqueous solution, atomize and spray the coating solution, and fluidize to obtain coated microspheres; add fumed silica and mix to obtain a food preservative complex based on baking powder.

[0010] Further, the whey yeast has a particle size ≤150μm; the sucrose yeast has a particle size ≤150μm; the microcrystalline cellulose has a particle size of 20-40μm; the hydrogenated palm oil micron powder has a particle size of 30-50μm; the acetate starch has a particle size ≤125μm; the vinegar powder has a particle size ≤150μm; the HPMC has a viscosity of 50mPa·s in a 2% aqueous solution at 20℃; and the fumed silica is hydrophilic fumed silica with an average particle size of 12-16nm and a specific surface area of ​​180-220m². 2 / g.

[0011] In one feasible implementation, in S1, the mass-to-volume ratio of the whey yeast, sucrose yeast, and deionized water is (19-21) g: (9.5-10.5) g: 100 mL; the ball milling conditions are: a first-stage ball milling speed of 1700-1900 r / min and a first-stage ball milling time of 35-45 min, and a second-stage ball milling speed of 2100-2300 r / min and a second-stage ball milling time of 55-65 min; the sieving conditions are: a mesh size of 120 mesh and a vibration frequency of 28-32 Hz.

[0012] Whey baking powder and sucrose baking powder contain functional components such as proteins, polysaccharides, and antibacterial active substances. Whey baking powder uses bacteriocinoid peptides, propionic acid, lactic acid, and other organic acids produced by fermentation metabolism as its core antibacterial components. The antibacterial activity of sucrose baking powder mainly comes from antibacterial peptides and lactic acid produced by lactic acid bacteria metabolism. Together, they constitute the source of antibacterial activity of non-acetic acid fermentation sources in the system.

[0013] The initial particle size of whey and sucrose baking powder is relatively large, which is not conducive to the uniform mixing with other raw materials and the construction of a gel network. Wet ball milling refines the baking powder particles using the impact and shear force of the grinding media. The two-stage ball milling process results in a more concentrated particle size distribution. Low-temperature control throughout the process inhibits heat accumulation and prevents high temperatures from damaging the heat-sensitive fermenting source antibacterial components and polysaccharide activity in the baking powder. The wet system avoids powder dust and secondary particle agglomeration. The pulverized suspension is then screened by a vibrating sieve to remove a small amount of incompletely refined large particles, resulting in a uniform and fine baking powder suspension. The refined particles significantly increase the specific surface area of ​​the raw materials, allowing various functional components to be fully exposed and promoting interactions between subsequent components. Furthermore, it provides a good particle size basis for the formation of hydrogen bonds between acetate starch and acetic acid, and for the uniform formation of the composite gel network.

[0014] In one feasible implementation, in step S2, the sterilization step is as follows: heating in a water bath to 58-62℃ and holding for 28-32 minutes; the target cooling temperature is 38-42℃; the mass ratio of the yeast suspension, sodium octenyl succinate starch, microcrystalline cellulose, trehalose, Tween 80, acetate starch, hydrogenated palm oil powder, and vinegar powder is (118-131):(4.8-5.2):(1.9-2.1):(0.9-1.1):(0.45-0.55):(14.5-15.5):(2.9-3.1):(8.5-9.5); the dispersion speed is 9000-11000 r / min, and the dispersion time is 4-6 minutes; the pH adjustment step is as follows: adding a 10wt% dilute acetic acid solution at a rate of 0.3-0.5 mL / min to adjust the pH of the system to 4.1-4.3.

[0015] Sodium octenyl succinate starch is a hydrophobically modified starch with both hydrophilic and hydrophobic groups in its molecules. It can interweave with whey protein and sucrose fermentation polysaccharides to jointly build a complex gel network. Microcrystalline cellulose acts as a rigid filler to enhance the strength of the gel structure, while trehalose can protect heat-sensitive antibacterial peptides and active proteins during processing, maintaining their bioactivity. Tween 80, as a nonionic surfactant, can both emulsify and disperse hydrogenated palm oil micropowder and improve the interfacial compatibility of the components in the system, preventing material stratification and agglomeration.

[0016] Acetate starch is the core material for stabilizing acetic acid. The acetyl carbonyl groups on its molecules form intermolecular hydrogen bonds with the carboxyl groups of free acetic acid, anchoring acetic acid to the starch chain and inhibiting its volatilization and migration. In aqueous systems, water molecules compete for hydrogen bond binding sites, weakening the interaction. However, the numerous hydrophobic acetyl groups carried by acetate starch can spontaneously form localized hydrophobic microregions, reducing the accumulation of water molecules near the binding sites and weakening the competitive interference from water. The added hydrogenated palm oil micropowder, after high-speed dispersion, is uniformly suspended in the system as solid particles and pre-adsorbed onto the composite matrix surface through hydrophobic interactions. Upon subsequent heating and melting, it spreads on the matrix surface to form a continuous and dense hydrophobic barrier film, isolating water intrusion and protecting the hydrogen bond binding sites. These two components synergistically achieve chemical anchoring and physical barrier of acetic acid. The vinegar powder added to the system is rich in natural acetic acid and trace amounts of associated organic acids, which can supplement antibacterial components that target and inhibit molds and yeasts.

[0017] Because the organic acid content of acetic acid powder fluctuates from batch to batch and the pH adjustment precision is limited, further addition of dilute acetic acid can replenish the total amount of acetic acid, ensuring stable antibacterial effect, and also regulate the pH of the system. Adjusting the system to a weakly acidic environment, this pH range is close to the isoelectric point of whey protein, which weakens the electrostatic repulsion between protein molecules, facilitating the aggregation and cross-linking of proteins after thermal denaturation. Simultaneously, it protects the molecular structure of sodium octenyl succinate starch, preventing hydrolysis of starch glycosidic bonds and modified groups, ensuring the smooth formation of a structurally complete composite pregel from proteins, starch, and polysaccharides. From a chemical equilibrium perspective, acetic acid is a weak acid; this weakly acidic environment inhibits its dissociation, allowing acetic acid to exist primarily in an electrically neutral molecular form. Hydrophobic acetic acid molecules are more easily enriched within the hydrophobic microdomains of acetyl groups, further enhancing hydrogen bonding efficiency and ensuring the stability of the hydrogen bond between it and starch acetate.

[0018] In one feasible implementation, in step S3, the target heating temperature is 63-67℃; the holding time is 4-6 min; the spray drying step is as follows: setting the inlet air temperature to 83-87℃, the outlet air temperature to 43-47℃, the atomizing disc rotation speed to 24000-26000 r / min, the feed rate to 16-20 mL / min, and using compressed air to pulse-purge the tower wall every 4-6 min at a pressure of 0.18-0.22 MPa; the sieving step is as follows: using a two-stage sieve of 500 mesh and 700 mesh, setting the vibration frequency to 28-32 Hz, and continuously sieving for 8-12 min; the particle size distribution of the microspheres is 20 μm-30 μm.

[0019] After being heated and kept at a moderate temperature in a water bath, the mixture underwent pre-gelation transformation. During this process, whey protein underwent mild denaturation, breaking its inherent disulfide bonds and covalently cross-linking through intermolecular thiol exchange, thus building a continuous and stable network framework. Sodium octenyl succinate starch was fully gelatinized under heating conditions, its coiled molecular chains fully unfolding and activating, exhibiting excellent interweaving and binding capabilities. Sucrose fermentation polysaccharide molecules were uniformly interwoven and entangled in the gaps between the protein cross-linking framework, intertwining with the denatured whey protein and gelatinized modified starch segments to form a highly stable composite gel network. The pre-dispersed hydrogenated palm oil micropowder within the system melted upon heating and spontaneously spread under the drive of interfacial tension and hydrophobic association, forming a continuous liquid hydrophobic film on the acetic acid-loaded starch matrix surface, thereby hydrophobically encapsulating the active components and hydrogen bond sites. Meanwhile, microcrystalline cellulose, acting as a rigid inorganic filler, is uniformly distributed within the gel network, effectively filling network pores and constraining macromolecular chain deformation, significantly enhancing the overall mechanical strength and resistance to damp heat deformation of the gel. Trehalose continuously exerts its bioprotective effect: during the water-containing heating stage, the bioactivity of antibacterial peptides and active proteins is highly dependent on their specific spatial folding conformation, while the stability of the conformation depends on the synergistic maintenance of various non-covalent forces, such as the hydrogen bond network formed by the polar amino acid residues on the molecular surface and the surrounding water molecules in the hydration layer. When the system is heated, the heat weakens the non-covalent forces such as hydrogen bonds and hydrophobic interactions that maintain the protein conformation. At the same time, the increased thermal motion of water molecules causes them to gradually detach from the hydration layer on the protein surface. Trehalose molecules can form hydrogen bonds with the polar groups on the surface of antibacterial peptides and active proteins through hydroxyl groups, replacing water molecules to maintain the natural spatial conformation of the active components. During the spray drying dehydration process, an amorphous glassy matrix is ​​further formed, embedding and fixing the active molecules, effectively avoiding the destruction of the activity of the heat-sensitive fermentation source antibacterial components during the heating process. This composite gel network can uniformly encapsulate and load the two core active components in the system: acetic acid and fermentation-derived antibacterial active components. This achieves uniform dispersion of active substances in the matrix, avoids component aggregation and localized uneven concentration, and provides a homogeneous carrier for subsequent stable controlled release.

[0020] The pregel liquid is dispersed into uniformly sized microdroplets under high-speed centrifugal atomization, significantly increasing the specific surface area of ​​the droplets. This allows for full contact with hot air, enabling rapid dehydration and drying. During the drying process, there is a significant difference in mass transfer rates between the inside and outside: the surface of the droplets directly contacts the high-temperature hot air, causing the moisture to evaporate rapidly. The surface gel macromolecules quickly dehydrate, shrink, and solidify, forming a dense microsphere shell. Meanwhile, the heat conduction and moisture migration rates inside the droplets lag far behind those on the surface, resulting in a slow dehydration rate. This allows the internal gel macromolecules to fully expand, ultimately forming a loose and porous microsphere core. This differentiated gradient structure endows the microspheres with bidirectional functional properties: the dense outer layer has excellent water vapor barrier capabilities, which can prevent external moisture from penetrating the interior of the microspheres under high temperature and humidity conditions, effectively preventing the internal gel network from swelling and rupturing prematurely, and significantly inhibiting the high-temperature loss and inactivation of acetic acid and fermentation-derived antibacterial components; the loose and porous inner layer can not only stably load high-content active components, but also reserve permeable channels for water diffusion, hydrogen bond dissociation, and slow gel swelling during room temperature storage, providing structural conditions for the continuous and stable release of antibacterial components.

[0021] In one feasible implementation, in step S4, the mass-to-volume ratio of calcium lactate to deionized water is (0.14-0.16) g: 3 mL; the mass-to-volume ratio of HPMC, PEG400, fumed silica, and deionized water is (0.95-1.05) g: (0.09-0.11) g: (0.28-0.32) g: 8.9 mL; the fluidization crosslinking conditions are: spray rate 2.8-3.2 mL / min, inlet air temperature 38-42℃, bed height 1.1-1.3 m, airflow velocity 1.7-1.9 m / s, and time 18-22 min; the atomization spraying conditions are: spray rate 1.3-1.7 mL / min, inlet air temperature 43-47℃, and time 13-17 min; and the fluidization time is 4-6 min.

[0022] First, uniformly sieved microspheres undergo fluidized bed crosslinking treatment with calcium lactate. The composite gel network on the surface and shallow interior of the microspheres is rich in carboxyl active groups. The sprayed calcium lactate aqueous solution dissociates into divalent calcium ions, which can undergo a uniform ionic crosslinking reaction with the gel carboxyl groups, forming a dense ionic crosslinking network on the surface of the microspheres. This process not only strengthens the microsphere skeleton and significantly improves the mechanical strength and resistance to damp heat, preventing the microspheres from swelling and rupturing during subsequent coating fluidization and high-temperature steaming, but also effectively seals the micropores on the surface of the microspheres, shortens surface defect gaps, and further prevents acetic acid molecules from evaporating and leaking from the pores, achieving secondary locking. At the same time, it provides a smooth and dense adhesion substrate for the subsequent coating film layer, ensuring coating uniformity.

[0023] A temperature-responsive functional membrane was constructed by uniformly spraying a composite coating solution containing HPMC and PEG400. HPMC serves as the core temperature-sensitive film-forming substrate, exhibiting reversible temperature-responsive sol-gel transition characteristics: it solidifies at room temperature in a dry state to form a continuous polymer film with basic water vapor barrier capabilities; upon contact with water, its molecular chains expand and disperse, exhibiting good water solubility and allowing it to spread uniformly on the surface of microspheres to form a thin, water-permeable structure; in a high-temperature and humid environment, the methoxy and hydroxypropyl groups on the HPMC molecular chains synergistically undergo intermolecular hydrophobic association, rapidly crosslinking to form a continuous, dense, and water-impermeable gel barrier membrane. PEG400, as a food-grade polymeric plasticizer, can be embedded between HPMC molecular chains, effectively releasing internal stress in the membrane, improving membrane flexibility, avoiding the defects of single HPMC membranes being brittle and prone to cracking and detachment, while also enhancing the wetting and spreading properties of the coating solution.

[0024] The formed HPMC functional membrane and the dense outer layer of the microspheres form a dual moisture protection system, which works synergistically with the humidity response characteristics of the internal gel network: Under high-temperature steaming conditions, HPMC thermally gels to form a dense water barrier, which, together with the outer structure of the microspheres, provides double protection against the intrusion of external high-temperature moisture, preventing premature swelling of the internal gel network and loss or inactivation of active components, thus ensuring the stable retention of antibacterial components during processing; Under normal temperature storage conditions, after contact with trace amounts of moisture in the food environment, the HPMC membrane gradually returns to a loose state that allows for water and air permeability, allowing trace amounts of moisture in the food to slowly permeate through the membrane layer into the interior of the microspheres, gradually triggering the dissociation of starch-acetic acid hydrogen bonds and the gentle swelling of the gel network, allowing for the continuous and stable release of acetic acid and fermentation-derived antibacterial components. Hydrophilic fumed silica, acting as an anti-caking agent, under gentle shearing, has its nano-sized particles adsorbed onto the outer surface of the coated microspheres through hydrogen bonds formed between the surface silanol groups and the hydroxyl groups on the HPMC coating film. The fumed silica nanoparticles attached to the surface of the microspheres form a physical isolation layer between the microspheres. Their steric hindrance effect prevents direct contact between the surfaces of adjacent microspheres. At the same time, their huge specific surface area can adsorb trace amounts of moisture in the powder, preventing moisture from forming liquid bridges between the microspheres. This effectively prevents the microspheres from agglomerating and clumping during storage, ensuring the flowability and uniform dispersion of the product.

[0025] Secondly, the present invention provides a food preservative complex based on baking powder.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This solution uses whey baking powder, sucrose baking powder, and vinegar powder as core raw materials. Acetic acid is loaded onto acetate starch and hydrophobically encapsulated with hydrogenated palm oil. A composite gel network is constructed using whey protein, sucrose fermentation polysaccharide, and sodium octenyl succinate starch. Microspheres are prepared and coated with HPMC to obtain a baking powder-based food preservative complex. This complex exhibits both resistance to steaming and humid heat and broad-spectrum antibacterial properties, making it suitable for long-term preservation of steamed foods. Acetic acid starch forms intermolecular hydrogen bonds with the carboxyl groups of free acetic acid through acetyl carbonyl groups, anchoring acetic acid to the starch chain and reducing its volatility and migration. Simultaneously, hydrogenated palm oil adheres to the starch chain surface through hydrophobic association. After melting upon heating, it spreads evenly to form a continuous and dense hydrophobic barrier layer, isolating water from competing for hydrogen bond sites and preventing premature release of acetic acid. This synergistic approach achieves dual stability through chemical anchoring and physical barrier of acetic acid.

[0028] After being denatured by heat, whey protein in whey yeast powder forms a cross-linked network backbone. Sucrose fermentation polysaccharides in sucrose yeast powder intertwine and entangle within the backbone, interweaving with the gelatinized segments of sodium octenyl succinate starch to form a stable composite gel network, providing structural support for the microspheres. A spray-drying process imparts a gradient structure to the microspheres, with a dense outer layer and a sparse inner layer. Relying on the temperature-responsive reversible change of the coating layer and the humidity-responsive swelling mechanism of the gel network, the controlled release of antibacterial components is achieved: Under high-temperature steaming conditions, HPMC thermally gelles to form a dense gel film, which, together with the dense outer structure of the microspheres, constitutes a double moisture barrier, resisting moisture intrusion and preventing premature swelling and rupture of the internal gel network, ensuring that the antibacterial components are retained inside the microspheres. Under normal temperature storage conditions, the coating layer returns to a permeable state, allowing free water in the food to slowly permeate through the micropores of the coating layer and the outer layer of the microspheres, penetrating into the inner layer and triggering the gradual dissociation of starch-acetic acid hydrogen bonds and the slow swelling of the gel network, thus continuously releasing the antibacterial components into the food. The released antibacterial components exert their antibacterial effect through the combined action of fermentation-derived antibacterial components and acetic acid. The fermentation-derived antibacterial components mainly include bacteriocins, antibacterial proteins, and other active metabolites, which can inhibit a variety of Gram-positive and Gram-negative putrefactive pathogens. Acetic acid has a significant inhibitory effect on molds and yeasts, maintaining an effective antibacterial concentration during storage, thereby significantly extending the shelf life of steamed foods. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the preparation process of a food preservative complex based on baking powder according to the present invention.

[0030] Figure 2 This is a graph showing the cumulative release rate of acetic acid in a food preservative complex based on baking powder according to the present invention. Detailed Implementation

[0031] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the application will be further described in detail below with reference to embodiments. However, this should not be construed as limiting the scope of this application to the following examples. All other embodiments obtained by those skilled in the art without creative effort without departing from the above-described methodological spirit of this application are within the scope of protection of this application.

[0032] The singular forms “for,” “or,” “a,” “any,” and “described” used in this application are intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, the terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] The whey baking powder, sucrose baking powder, and vinegar powder were all purchased from Shanghai Yinong Biotechnology Co., Ltd.

[0034] Example 1

[0035] like Figure 1 As shown, a method for preparing a food preservative complex based on baking powder includes the following steps:

[0036] S1. Mix 20g of whey yeast powder with a particle size ≤150μm, 10g of sucrose yeast powder with a particle size ≤150μm, and 100mL of deionized water evenly to obtain a suspension. Transfer the suspension to a horizontal wet ball mill. Set the first-stage ball mill speed to 1800r / min and the ball milling time to 40min. Set the second-stage ball mill speed to 2200r / min and the ball milling time to 60min. Maintain the system temperature <35℃ throughout the process. After ball milling, pass the suspension through a 120-mesh vibrating sieve with a vibration frequency of 30Hz to obtain a yeast suspension.

[0037] S2. Heat 124.5g of yeast suspension to 60℃ in a water bath and keep it at that temperature for 30min. After cooling to 40℃, add 5.0g of sodium octenyl succinate starch, 2.0g of microcrystalline cellulose with a particle size of 30μm, 1.0g of trehalose, and 0.5g of Tween 80 in sequence. Stir at 300r / min until completely dissolved. Add 15.0g of acetate starch with a particle size ≤125μm and stir for 10min. Then add 3.0g of hydrogenated palm oil micropowder with a particle size of 40μm. Disperse the mixture in a 40℃ water bath using a high-speed disperser at 10000r / min for 5min. Then add 9g of acetic acid powder with a particle size ≤150μm and continue stirring for 15min. Add a 10wt% dilute acetic acid solution dropwise at a rate of 0.4mL / min to adjust the pH of the system to 4.2. Let it stand for 10min to remove bubbles and obtain the mixture.

[0038] S3. Heat the mixture in a water bath to 65℃ and hold for 5 minutes to obtain a pregelation solution. Introduce the pregelation solution into a centrifugal spray dryer, set the inlet air temperature to 85℃, the outlet air temperature to 45℃, the atomizing disc speed to 25000r / min, and the feed rate to 18mL / min. Use compressed air to pulse-purge the tower wall every 5 minutes at a pressure of 0.2MPa until all the pregelation solution has been fed and the drying process is complete. Collect the dried powder. Transfer the powder to a vibrating screen, using a two-stage sieve of 500 mesh and 700 mesh, set the vibration frequency to 30Hz, and continuously sieve for 10 minutes. Collect the material between the two sieves to obtain microspheres with a particle size distribution of 20-30μm.

[0039] S4. Mix 0.15g of calcium lactate with 3mL of deionized water and stir at 500r / min until completely dissolved to obtain a calcium lactate aqueous solution. Mix 1g of HPMC (2% aqueous solution viscosity is 50mPa·s at 20℃), 0.10g of PEG400 and 8.9mL of deionized water and stir at 250r / min for 30min until completely dissolved to obtain a coating solution. Transfer the microspheres to a conventional bottom-spray fluidized bed and atomize the calcium lactate aqueous solution at a spray rate of 3.0mL / min. Fluidize and crosslink for 20min at an inlet air temperature of 40℃, a bed height of 1.2m, and an airflow velocity of 1.8m / s. Atomize and spray the coating solution at a spray rate of 1.5mL / min and fluidize and coat for 15min at an inlet air temperature of 45℃. After coating, continue fluidizing for 5min to solidify the film layer to obtain coated microspheres. Add 0.3g of a substance with an average particle size of 14nm and a specific surface area of ​​200m² to the coated microspheres. 2 / g of hydrophilic fumed silica was placed in a three-dimensional mixer and mixed at 150r / min for 5min to obtain a food preservative complex based on baking powder.

[0040] Example 2

[0041] like Figure 1 As shown, a method for preparing a food preservative complex based on baking powder includes the following steps:

[0042] S1. Mix 19g of whey yeast powder with a particle size ≤150μm, 9.5g of sucrose yeast powder with a particle size ≤150μm, and 100mL of deionized water evenly to obtain a suspension. Transfer the suspension to a horizontal wet ball mill. Set the ball mill speed to 1700r / min and the ball milling time to 35min for the first stage, and set the ball mill speed to 2100r / min and the ball milling time to 55min for the second stage. Maintain the system temperature <35℃ throughout the process. After ball milling, pass the suspension through a 120-mesh vibrating sieve with a vibration frequency of 28Hz to obtain a yeast suspension.

[0043] S2. Heat 118g of yeast suspension to 58℃ in a water bath and keep it at that temperature for 28min. After cooling to 38℃, add 4.8g of sodium octenyl succinate starch, 1.9g of microcrystalline cellulose with a particle size of 20μm, 0.9g of trehalose, and 0.45g of Tween 80 in sequence. Stir at 280r / min until completely dissolved. Add 14.5g of acetate starch with a particle size ≤125μm and stir for 8min. Then add 2.9g of hydrogenated palm oil micropowder with a particle size of 30μm. Disperse the mixture in a water bath at 38℃ using a high-speed disperser at 9000r / min for 4min. Then add 8.5g of acetic acid powder with a particle size ≤150μm and continue stirring for 13min. Add a 10wt% dilute acetic acid solution dropwise at a rate of 0.3mL / min to adjust the pH of the system to 4.1. Let it stand for 8min to remove bubbles and obtain a mixed solution.

[0044] S3. Heat the mixture in a water bath to 63℃ and hold for 4 minutes to obtain a pregel solution. Introduce the pregel solution into a centrifugal spray dryer, set the inlet air temperature to 83℃, the outlet air temperature to 43℃, the atomizing disc speed to 24000 r / min, and the feed rate to 16 mL / min. Use compressed air to pulse-purge the tower wall every 4 minutes at a pressure of 0.18 MPa until all the pregel solution has been fed and the drying process is complete. Collect the dried powder. Transfer the powder to a vibrating screen, using a two-stage sieve of 500 mesh and 700 mesh, set the vibration frequency to 28 Hz, and continuously sieve for 8 minutes. Collect the material between the two sieves to obtain microspheres with a particle size distribution of 20-30 μm.

[0045] S4. Mix 0.14g of calcium lactate with 3mL of deionized water and stir at 400r / min until completely dissolved to obtain an aqueous solution of calcium lactate; add 0.95g... HPMC (viscosity of 50 mPa·s in 2% aqueous solution at 20℃), 0.09 g PEG400, and 8.9 mL deionized water were mixed and stirred at 200 r / min for 28 min until completely dissolved to obtain a coating solution. Microspheres were transferred to a conventional bottom-spray fluidized bed, and calcium lactate aqueous solution was atomized and sprayed at a spray rate of 2.8 mL / min. Fluidization and crosslinking were performed for 18 min at an inlet air temperature of 38℃, a bed height of 1.1 m, and an airflow velocity of 1.7 m / s. The coating solution was then atomized and sprayed at a spray rate of 1.3 mL / min, and fluidization and coating were performed for 13 min at an inlet air temperature of 43℃. After coating, fluidization was continued for 4 min to solidify the film, resulting in coated microspheres. 0.28 g of a material with an average particle size of 12 nm and a specific surface area of ​​180 m² was added to the coated microspheres. 2 / g of hydrophilic fumed silica was placed in a three-dimensional mixer and mixed at 140r / min for 4min to obtain a food preservative complex based on baking powder.

[0046] Example 3

[0047] like Figure 1 As shown, a method for preparing a food preservative complex based on baking powder includes the following steps:

[0048] S1. Mix 21g of whey yeast powder with a particle size ≤150μm, 10.5g of sucrose yeast powder with a particle size ≤150μm and 100mL of deionized water evenly to obtain a suspension. Transfer the suspension to a horizontal wet ball mill. Set the ball mill speed to 1900r / min and the ball milling time to 45min for the first stage, and set the ball mill speed to 2300r / min and the ball milling time to 65min for the second stage. Maintain the system temperature <35℃ throughout the process. After ball milling, pass the suspension through a 120-mesh vibrating sieve with a vibration frequency of 32Hz to obtain a yeast suspension.

[0049] S2. Heat 131g of baking powder suspension to 62℃ in a water bath and keep it at that temperature for 32min. After cooling to 42℃, add 5.2g of sodium octenyl succinate starch, 2.1g of microcrystalline cellulose with a particle size of 40μm, 1.1g of trehalose, and 0.55g of Tween 80 in sequence. Stir at 320r / min until completely dissolved. Add 15.5g of acetate starch with a particle size ≤125μm and stir for 12min. Then add 3.1g of hydrogenated palm oil micropowder with a particle size of 50μm. Disperse the mixture for 6min at 11000r / min using a high-speed disperser under 42℃ water bath conditions. Then add 9.5g of acetic acid powder with a particle size ≤150μm and continue stirring for 17min. Add a 10wt% dilute acetic acid solution dropwise at a rate of 0.5mL / min to adjust the pH of the system to 4.3. Let it stand for 12min to remove bubbles and obtain a mixed solution.

[0050] S3. Heat the mixture in a water bath to 67℃ and hold for 6 minutes to obtain a pregelatinized liquid. Introduce the pregelatinized liquid into a centrifugal spray dryer, set the inlet air temperature to 87℃, the outlet air temperature to 47℃, the atomizing disc speed to 26000 r / min, and the feed rate to 20 mL / min. Use compressed air to pulse-purge the tower wall every 6 minutes at a pressure of 0.22 MPa until all the pregelatinized liquid has been fed and the drying process is complete. Collect the dried powder. Transfer the powder to a vibrating screen, using a two-stage sieve of 500 mesh and 700 mesh, set the vibration frequency to 32 Hz, and continuously sieve for 12 minutes. Collect the material between the two sieves to obtain microspheres with a particle size distribution of 20-30 μm.

[0051] S4. Mix 0.16g of calcium lactate with 3mL of deionized water and stir at 600r / min until completely dissolved to obtain an aqueous solution of calcium lactate; add 1.05g... HPMC (viscosity of 50 mPa·s in 2% aqueous solution at 20℃), 0.11 g PEG400, and 8.9 mL deionized water were mixed and stirred at 300 r / min for 32 min until completely dissolved to obtain a coating solution. Microspheres were transferred to a conventional bottom-spray fluidized bed, and calcium lactate aqueous solution was atomized and sprayed at a spray rate of 3.2 mL / min. Fluidization and crosslinking were carried out for 22 min at an inlet air temperature of 42℃, a bed height of 1.3 m, and an airflow velocity of 1.9 m / s. The coating solution was then atomized and sprayed at a spray rate of 1.7 mL / min, and fluidization and coating were carried out for 17 min at an inlet air temperature of 47℃. After coating, fluidization was continued for 6 min to solidify the film, resulting in coated microspheres. 0.32 g of a material with an average particle size of 16 nm and a specific surface area of ​​220 m² was added to the coated microspheres. 2 / g of hydrophilic fumed silica was placed in a three-dimensional mixer and mixed at 160r / min for 6min to obtain a food preservative complex based on baking powder.

[0052] Comparative Example 1

[0053] A method for preparing a food preservative complex based on baking powder, the implementation steps and parameters of which differ from those of Example 1 are as follows: hydrogenated palm oil powder is not added in step S2, while the remaining steps and parameters are the same as those of Example 1.

[0054] Comparative Example 2

[0055] A method for preparing a food preservative complex based on baking powder differs from Example 1 in that the coating solution is not prepared in step S4 and HPMC coating treatment is not performed; the remaining steps and parameters are the same as in Example 1.

[0056] Comparative Example 3

[0057] A method for preparing a food preservative complex based on baking powder, the implementation steps and parameters of which differ from those of Example 1 are as follows: in step S2, starch acetate is not added, while the remaining steps and parameters are the same as those of Example 1.

[0058] Performance testing:

[0059] Acetic acid retention rate test: 5g of the food preservative complex based on baking powder prepared in Examples 1-3 and Comparative Examples 1-3 were uniformly dispersed in 100g of unfermented dough to simulate steamed food matrix and formed into regular small dough balls. The prepared dough balls were placed in a steamer and continuously treated with saturated steam at 100℃ for 20min to complete the simulated steaming process. After steaming, the dough balls were removed, 50mL of deionized water was added, and the mixture was homogenized at 10000r / min for 5min. The mixture was then filtered, and the acetic acid content in the clear filtrate was detected by high-performance liquid chromatography. A blank control sample that had not undergone steaming was simultaneously set up. An equal mass of the test sample was directly extracted with water, and the initial acetic acid content was detected. The acetic acid retention rate (%) was calculated as (amount of acetic acid extracted after steaming / amount of acetic acid extracted without steaming) × 100%. All samples were measured in triplicate, and the arithmetic mean of the three results was taken.

[0060] Non-acetic acid antibacterial activity retention rate test: 2g of the food preservative complexes based on baking powder prepared in Examples 1-3 and Comparative Examples 1-3 were placed in containers and continuously treated with saturated steam at 100℃ for 20min to completely simulate the high-temperature environment of food steaming. Samples were taken before and after steaming. To eliminate the interference of acetic acid in the samples on the inhibition zone detection results, the pH of the sample dilution was first adjusted to 7.0 with sterile sodium hydroxide solution to completely convert acetic acid to sodium acetate and eliminate its antibacterial contribution. Then, the neutralized samples were diluted tenfold with sterile deionized water, and the antibacterial activity of the samples was detected by agar diffusion method. Escherichia coli and Staphylococcus aureus were evenly spread on the surface of LB agar plates in advance. Holes were evenly punched on the plates using a 6mm diameter punch, and 50μL of the prepared sample dilution was added to the holes. All plates were incubated at 37℃ in the dark for 24h. After incubation, the diameter of the inhibition zone in each group was measured. The initial non-acetic acid antibacterial activity was represented by the diameter of the inhibition zone corresponding to the sample dilution without steaming treatment. The retention rate of the non-acetic acid antibacterial component in the steamed sample against different bacterial species was calculated. Three parallel test plates were set up for each group of samples, and the average value of the parallel tests was finally taken.

[0061] Simulated release curve test during room temperature storage: 1g of the food preservative complex based on baking powder prepared in Examples 1-3 and Comparative Examples 1-3 was placed in an 8000Da dialysis bag and sealed tightly. The sealed dialysis bag was completely immersed in 200mL of phosphate buffer solution with a pH of 6.5 to simulate the food storage medium. The entire bag was placed in a constant temperature water bath at 25℃ and continuously oscillated at a rate of 100r / min. Samples were taken at time points of 0.5h, 1h, 2h, 4h, 8h, 12h, 24h, 48h, 72h, and 120h, with 10μL of release medium taken each time. The acetic acid content in the medium was detected by high performance liquid chromatography. Using the initial total amount of acetic acid in the whey baking powder as a baseline, the cumulative release rate of acetic acid at different time points was calculated. Based on the release data corresponding to each time group, a dynamic release curve of acetic acid components during room temperature storage of the samples was plotted.

[0062] Accelerated shelf-life testing of steamed foods: Based on flour quality, the food preservative complexes based on baking powder prepared in Examples 1-3 and Comparative Examples 1-3 were added to steamed bun dough at a mass ratio of 0.5%. Standard test steamed buns were made using uniform raw materials and processes, while a blank control group sample without any preservatives was also included. After the steamed buns were naturally cooled, they were vacuum-sealed and placed in a constant temperature and humidity incubator at 30°C and 75% relative humidity for accelerated storage testing. During the test, the appearance of each sample of steamed buns was observed at fixed times every day, and the time when mold first appeared in each group of steamed buns was accurately recorded as the number of days since mold growth began. The pH value and acidity changes of each group of steamed buns were also tested periodically. Ten parallel steamed bun samples were set up for each group of tests, and the average value of all parallel samples was taken as the final test result. Based on the data obtained from the accelerated test, the expected shelf life of the samples at room temperature (25°C) was calculated according to the temperature coefficient Q10=2.

[0063] Table 1. Performance test results of the food preservative complexes based on baking powder prepared in Examples 1-3 and Comparative Examples 1-3.

[0064]

[0065] As shown in Table 1, the acetic acid retention rate, the activity retention rate of the non-acetic acid antibacterial component against Escherichia coli, the activity retention rate of the non-acetic acid antibacterial component against Staphylococcus aureus, the number of days since mold growth began, the pH at the storage endpoint, and the estimated shelf life at room temperature of the food preservative complexes prepared in Examples 1-3 were higher than those in Comparative Examples 1-3, and the acidity at the storage endpoint was lower than that in Comparative Examples 1-3. This indicates that the high-temperature processing stability, room-temperature controllable slow-release performance, and long-term food preservation performance of the food preservative complexes prepared in Examples 1-3 are better than those in Comparative Examples 1-3.

[0066] Depend on Figure 2 It can be seen that the acetic acid release curves of the food preservative complexes based on baking powder prepared in Examples 1-3 all show a gradual upward trend with no obvious burst release phenomenon in the early stage. However, the release rate of the food preservative complex based on baking powder prepared in the comparative example is significantly accelerated in the early stage, and the burst release phenomenon is prominent. This indicates that the acetic acid dual-stabilized system and temperature-sensitive coating structure constructed in this invention can effectively delay the release of active components and achieve controllable sustained release.

[0067] Comparative Example 1, without the addition of hydrogenated palm oil micropowder, lacked the crucial physical hydrophobic barrier structure of the system. This structure was originally designed to prevent moisture from penetrating the microspheres under high-temperature and humid conditions during steaming, reducing the volatilization and migration of acetic acid, while also helping to stabilize the gel network and weaken the indirect damage to antibacterial components caused by high temperatures. As a result, the acetic acid retention rate in this group was significantly lower than that in the example, and the retention rate of non-acetic acid antibacterial components also decreased simultaneously. In the in vitro release test at room temperature, after the outer hydrophobic barrier disappeared, the resistance to the outward diffusion of acetic acid was greatly reduced, and the cumulative release rate of components at each time point was significantly higher than that in the example, with an overall faster release rate. In practical food applications, the premature and large-scale release of antibacterial components will cause rapid consumption of effective ingredients and a continuous decline in antibacterial efficacy. Ultimately, this manifests as a shortened start date for mold growth in steamed buns, a significant increase in acidity at the end of storage, and a significant shortening of the shelf life estimated at room temperature. This directly demonstrates the important supporting role of the hydrophobic structure formed by hydrogenated palm oil in the two major stages of high-temperature component retention and room-temperature slow release.

[0068] Comparative Example 2 did not undergo HPMC fluidized bed coating, thus lacking the core temperature-responsive barrier and controlled-release structure of this invention. Under high steaming temperatures, the HPMC membrane undergoes thermal gelation to form a dense protective layer, which is a crucial barrier protecting the antibacterial components of the heat-sensitive fermentation source and preventing their high-temperature denaturation and inactivation. It also further locks in the acetic acid components, reducing loss. The absence of coating resulted in a low acetic acid retention rate, and a precipitous drop in the retention rate of non-acetic acid antibacterial components, indicating that the high-temperature and humid environment directly caused the inactivation of a large number of non-acetic acid antibacterial components. Figure 2 In the in vitro release curves, after losing the constraint of the coating film, the antibacterial components inside the microspheres were no longer limited by the controlled release mechanism, resulting in a significant burst release phenomenon. The cumulative release of components in the early stage of the experiment was much higher than that of other groups. When applied to steamed bun samples, the antibacterial components were released in a concentrated manner in the early stage, and the effective concentration was insufficient in the later stage. Coupled with the double problem of a significant loss of activity of non-acetic acid antibacterial components, the sample's ability to resist microbial growth was significantly reduced. Not only did the mold growth occur earliest, but the acidity and pH value were also the highest at the storage endpoint. The shelf life calculated at room temperature was also the shortest among all groups. This fully verifies that the HPMC coating structure has the dual core functions of high temperature protection and room temperature controllable slow release.

[0069] Comparative Example 3, without added starch acetate, lost its anchoring structure relying on the intermolecular hydrogen bonds formed between starch acetyl groups and acetic acid carboxyl groups. Acetic acid, as the core antibacterial component inhibiting molds and yeasts, easily volatilized and migrated during steaming and processing after losing hydrogen bond binding. Therefore, the acetic acid retention rate in this group was the lowest among the three comparative examples. Since starch acetate mainly acts on the acetic acid component and does not directly affect the activity of non-acetic acid antibacterial components and the outer barrier of microspheres, the decrease in the retention rate of non-acetic acid antibacterial components in this group was significantly weaker than that in Comparative Example 2, and the acetic acid release rate was significantly accelerated in the in vitro release test. In the food preservation test, the large loss of acetic acid led to a significant weakening of the system's inhibitory ability against molds and yeasts. Even if the non-acetic acid antibacterial components still retained a certain activity and could effectively inhibit bacterial growth, they could not completely prevent food spoilage. This indicates that the hydrogen bond anchoring effect of starch acetate is an important foundation for ensuring the stable retention of acetic acid components and achieving broad-spectrum and long-lasting antibacterial effects in products.

[0070] Comparative Examples 1-3, lacking the hydrophobic barrier structure constructed by hydrogenated palm oil, the temperature-responsive coating structure formed by HPMC, and the acetic acid hydrogen bond anchoring structure achieved by acetate starch, resulted in a decrease in acetic acid retention and a significant loss of the activity of non-acetic acid antibacterial components under high-temperature steaming conditions. During room temperature storage, the acetic acid release rate accelerated and even a burst release phenomenon occurred. When applied to steamed buns, the samples showed earlier mold growth, increased acidity during storage, and a significantly shortened shelf life at room temperature. All of these factors resulted in varying degrees of deterioration in high-temperature processing stability, controllable slow-release performance at room temperature, and long-term food preservation performance.

[0071] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0072] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for preparing a food preservative complex based on baking powder, characterized in that, Includes the following steps: S1. Mix whey baking powder, sucrose baking powder and deionized water, and then ball mill and sieve to obtain a baking powder suspension; S2. After sterilizing and cooling the baking powder suspension, add sodium octenyl succinate starch, microcrystalline cellulose, trehalose and Tween 80 in sequence and mix. Add starch acetate and hydrogenated palm oil powder, disperse, add vinegar powder, adjust pH and obtain a mixture. S3. The mixture is heated and kept at the temperature to obtain a pregel solution, which is then spray-dried and sieved to obtain microspheres; S4. Mix calcium lactate with deionized water to obtain an aqueous solution of calcium lactate; mix hydroxypropyl methylcellulose, polyethylene glycol 400 and deionized water to obtain a coating solution; crosslink microspheres through fluidized bed crosslinking of calcium lactate aqueous solution, atomize and spray the coating solution, and fluidize to obtain coated microspheres; add fumed silica and mix to obtain a food preservative complex based on baking powder.

2. The method for preparing a food preservative complex based on baking powder according to claim 1, characterized in that, In S1, the mass-to-volume ratio of whey yeast, sucrose yeast, and deionized water is (19-21) g: (9.5-10.5) g: 100 mL.

3. The method for preparing a food preservative complex based on baking powder according to claim 1, characterized in that, In S1, the ball milling conditions are as follows: the first-stage ball milling speed is set to 1700-1900 r / min and the first-stage ball milling time is set to 35-45 min; the second-stage ball milling speed is set to 2100-2300 r / min and the second-stage ball milling time is set to 55-65 min.

4. The method for preparing a food preservative complex based on baking powder according to claim 1, characterized in that, In S2, the mass ratio of the baking powder suspension, sodium octenyl succinate starch, microcrystalline cellulose, trehalose, Tween 80, starch acetate, hydrogenated palm oil powder and vinegar powder is (118-131): (4.8-5.2): (1.9-2.1): (0.9-1.1): (0.45-0.55): (14.5-15.5): (2.9-3.1): (8.5-9.5).

5. The method for preparing a food preservative complex based on baking powder according to claim 1, characterized in that, In step S2, the sterilization step is as follows: heating in a water bath to 58-62℃ and holding for 28-32 minutes; the target cooling temperature is 38-42℃; the pH adjustment step is as follows: adding a 10wt% dilute acetic acid solution at a rate of 0.3-0.5mL / min to adjust the pH of the system to 4.1-4.

3.

6. The method for preparing a food preservative complex based on baking powder according to claim 1, characterized in that, In step S3, the target heating temperature is 63-67℃; the holding time is 4-6 min; the spray drying steps are as follows: setting the inlet air temperature to 83-87℃, the outlet air temperature to 43-47℃, the atomizing disc rotation speed to 24000-26000 r / min, the feed rate to 16-20 mL / min, and using compressed air to pulse-purge the tower wall every 4-6 min at a pressure of 0.18-0.22 MPa.

7. The method for preparing a food preservative complex based on baking powder according to claim 1, characterized in that, In step S3, the particle size of the microspheres is 20μm-30μm.

8. The method for preparing a food preservative complex based on baking powder according to claim 1, characterized in that, In step S4, the mass-to-volume ratio of calcium lactate to deionized water is (0.14-0.16) g: 3 mL; the mass-to-volume ratio of hydroxypropyl methylcellulose, polyethylene glycol 400, fumed silica, and deionized water is (0.95-1.05) g: (0.09-0.11) g: (0.28-0.32) g: 8.9 mL.

9. The method for preparing a food preservative complex based on baking powder according to claim 1, characterized in that, In step S4, the fluidized crosslinking conditions are: spray rate 2.8-3.2 mL / min, inlet air temperature 38-42℃, bed height 1.1-1.3 m, airflow velocity 1.7-1.9 m / s, and time 18-22 min; the atomized spraying conditions are: spray rate 1.3-1.7 mL / min, inlet air temperature 43-47℃, and time 13-17 min.

10. A food preservative complex based on baking powder obtained by the preparation method according to any one of claims 1-9.

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