Long-keeping soft and delicate cantonese red bean mooncake filling and preparation method and application thereof

Abstract

This invention discloses a long-lasting, soft and delicate Cantonese red bean mooncake filling, its preparation method, and its application, belonging to the field of food processing technology. The long-lasting, soft and delicate Cantonese red bean mooncake filling of this invention comprises the following components: red beans: 15%~35%; peanut oil pretreated with infrared radiation and degummed: 10%~25%; white sugar: 25%~45%; isomaltooligosaccharide: 2%~10%; water: 10%~30%. This invention fundamentally prevents starch retrogradation and hardening, allowing the red bean filling to maintain its soft and delicate texture for a long time. Simultaneously, this formula constructs a stable moisture-releasing structure, which can smoothly transport internal moisture to the crust, completely solving the problems of shrinkage, cracking, and shelling in traditional fillings later on. The pretreated peanut oil retains natural antioxidant components and has an extremely high oil retention rate, firmly locking in the oil and preventing leakage, effectively overcoming the problems of easy oil leakage and oxidation rancidity in high-oil fillings, significantly extending the product's shelf life.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a long-lasting, soft and delicate filling for Cantonese-style red bean mooncakes, its preparation method, and its application. Background Technology

[0002] As a traditional Chinese baked good, the overall quality of Cantonese-style mooncakes highly depends on the physicochemical properties and texture of the filling. Red bean paste filling holds a significant market share due to its unique flavor, but the starch content of its main ingredient, red beans, is as high as 55%–60%. During the gelatinization process, starch granules absorb water and swell, breaking intermolecular hydrogen bonds. However, during subsequent cooling and storage, the amylose and amylopectin molecules readily rearrange and associate, forming a double helix structure and transforming from a disordered state to an ordered crystalline state, thus inducing starch retrogradation. This microstructural restructuring manifests macroscopically as a significant increase in filling hardness, a rough and dry texture, and a substantial decrease in water-holding capacity, severely limiting the product's shelf life and overall acceptability.

[0003] To address the aforementioned starch retrogradation problem, existing technologies (such as CN 117337942 A) typically rely on the physical modification of starch by adding exogenous modified starches (such as acetylated distarch phosphate) and food colloids. However, such exogenous interventions have significant technical limitations: the introduction of chemically modified starches and colloids not only increases the complexity of the formulation system, which is inconsistent with the modern trend of "natural and additive-free" clean labels in baked goods, but also, large molecular colloids are prone to causing uncontrollable hydration competition in complex matrices, thus increasing the risk of imbalanced moisture distribution within the filling and subsequent drying and cracking. Simply relying on the mechanical modification of the exogenous carbohydrate backbone is insufficient to fundamentally block the recrystallization thermodynamic process of the starch double helix structure.

[0004] Besides adding modified starch, traditional processes often rely on high-sugar, high-oil formulations to slow down aging. Peanut oil, a key component of red bean paste, is typically refined using high-temperature pretreatment. This process not only destroys a large number of natural trace active compounds (such as polyphenols and vitamin E), but also results in some refined oils having high acid values ​​and high levels of free fatty acids. While free fatty acids can form single-helix complexes with amylose to some extent, conventionally refined oils are highly susceptible to hydrolysis of free fatty acids and free radical chain oxidation of unsaturated fatty acids during storage. This not only causes the acid value and peroxide value of the filling to rapidly exceed limits during shelf life, but also disrupts the stability of the water-oil emulsion system, leading to oil separation ("oil leakage") and severely impacting the overall acceptability of the product.

[0005] Furthermore, the unique processing techniques of Cantonese-style mooncakes necessitate a "softening" stage after baking. This involves the slow migration of moisture from the filling towards the crust, driven by a moisture gradient, softening the initially dry and hard crust. Traditional red bean fillings often use high concentrations of sucrose as a sweetener. While sucrose provides sweetness, its water-retention capacity is limited. During the later stages of storage, starch aging forces moisture out of the network structure, and conventional oils cannot form a dense physical water-blocking barrier, leading to disordered moisture loss to the outer layers. This not only fails to maintain an ideal dynamic moisture balance between the crust and filling but also accelerates the overall shrinkage and aging of the mooncake. Therefore, the baking industry urgently needs a filling matrix that can inhibit starch recrystallization at the molecular level, improve the water-oil binding stability of the system, and possess excellent antioxidant properties. Summary of the Invention

[0006] To address the technical problem of increased hardness in existing Cantonese red bean fillings during storage due to starch retrogradation, current technologies (CN 117337942 A) typically rely on the addition of exogenous modified starches (such as acetylated distarch phosphate) and food colloids. This approach not only increases the complexity of the formula, contradicting the modern trend of "additive-free, clean label" baked goods, but also carries the risk of uneven hydration leading to filling cracking. Furthermore, commercially available refined peanut oil loses its natural active components due to high-temperature decolorization, making it difficult to form a stable three-dimensional emulsified network with natural starch and sugars in the absence of exogenous emulsifiers. This formula deficiency results in a lack of dynamic equilibrium in the water activity between the crust and filling of Cantonese mooncakes after baking, manifesting as slow crust softening, subsequent filling shrinkage, decreased oil retention, and easy oxidation and rancidity of the oil during long-term storage.

[0007] This invention provides the following technical solution: This invention provides a Cantonese red bean mooncake filling that maintains its softness and smoothness for a long time, comprising the following components by mass fraction: Red beans: 15%~35%, peanut oil pretreated with infrared radiation and degummed: 10%~25%, white sugar: 25%~45%, isomaltooligosaccharide: 2%~10%; water: 10%~30%.

[0008] In one embodiment, the Cantonese red bean mooncake filling comprises, by mass fraction, the following components: Red beans: 20%~28%, peanut oil pretreated with infrared radiation and degummed: 12%~20%, white sugar: 30%~40%, isomaltooligosaccharide: 4%~8%, water: 15%~23%.

[0009] In one embodiment, the Cantonese red bean mooncake filling comprises, by mass fraction, the following components: 24% red beans, 16% peanut oil pretreated and degummed by infrared radiation, 35% white sugar, 6% isomaltooligosaccharide, and 19% water.

[0010] In one embodiment, the preparation of the infrared radiation pretreated and degummed peanut oil includes the following: S1 Pretreatment stage: The high oleic peanut raw material is spread in a single layer in a carrier and placed in an infrared radiation device for infrared pretreatment. After that, it is naturally cooled to room temperature and the red skin of the peanut is removed to obtain the processed peanut kernels. S2 Pressing and coarse separation stage: The peanut kernels obtained in S1 are pressed and extracted using hydraulic pressing equipment, centrifuged, and solid impurities and suspended matter are separated to obtain low-temperature pretreated high-oleic peanut oil. S3 Hydration and Degumming Stage: The low-temperature pretreated high-oleic peanut oil obtained in S2 is subjected to hydration and degumming to obtain peanut oil that has been pretreated and degummed by infrared radiation.

[0011] In one embodiment, the infrared pretreatment in step S1 is performed at a temperature of 110-130 °C for 30-60 min, with an infrared wavelength of 0.75-4 μm.

[0012] In one embodiment, the centrifugation parameters in step S2 are 5000~8000 r / min and the time is 5~10 min.

[0013] In one embodiment, the pressing pressure in step S2 is strictly controlled within the range of 40~50 MPa, and the pressing time is 30 min.

[0014] In one embodiment, the hydration degumming in step S3 specifically involves adding sodium citrate solution to low-temperature pretreated high-oleic peanut oil, then stirring in a water bath until obvious white flocculent aggregates are generated. The system is then moved to room temperature and allowed to settle for 1-2 hours. The underlying gum flocculents are then completely removed by centrifugation to obtain peanut oil that has been pretreated and degummed by infrared radiation.

[0015] In one embodiment, the water bath temperature is 80~90°C.

[0016] In one embodiment, the sodium citrate solution has a mass fraction of 5% to 8%.

[0017] In one embodiment, the isomaltooligosaccharide is either an IMO-50 syrup or an IMO-50 solid powder.

[0018] The present invention also provides a method for preparing the above-mentioned Cantonese red bean mooncake filling, comprising the following steps: (1) Select red bean raw materials, clean them, and soak them in water; (2) Cook the soaked red beans with water at a temperature of 100-110 °C for 45-65 minutes. After cooking, stir the red beans while they are still hot until they are smooth and free of granules. Then, while stirring at a low speed at 100-110 °C, add the peanut oil that has been pretreated by infrared radiation and degummed, the isomaltooligosaccharide and the white sugar in sequence and mix well. (3) Transfer the well-mixed red bean paste to a wok and stir-fry until the moisture content of the filling reaches 18%~25%. After cooling, seal and package for later use.

[0019] In one embodiment, the material-to-liquid ratio for soaking in step (1) is 1:2 to 1:4 (g:mL), and the soaking is carried out at a constant temperature of 15 to 25 °C for 12 to 18 hours.

[0020] In one embodiment, the soaking conditions in step (1) are constant temperature soaking at 20 °C for 15 hours.

[0021] In one embodiment, the cooking temperature in step (2) is 105°C and the cooking time is 55 min.

[0022] In one embodiment, the frying endpoint in step (3) is controlled to have a moisture content of 19% to 23% in the filling.

[0023] The present invention also provides a Cantonese red bean mooncake containing the above-mentioned filling, wherein the crust formula comprises, by weight parts: 35-55 parts of peanut oil pretreated with infrared radiation and degummed, 80-120 parts of invert sugar syrup, 140-180 parts of wheat flour, and 3-7 parts of lye water.

[0024] In one embodiment, the Cantonese red bean mooncake containing the above-mentioned filling has a crust recipe comprising, by weight, 45 parts of peanut oil pretreated with infrared radiation and degummed, 100 parts of invert sugar syrup, 160 parts of wheat flour, and 5 parts of lye water.

[0025] In one embodiment, the wheat flour is medium-low gluten wheat flour.

[0026] The present invention also provides a method for preparing a Cantonese red bean mooncake containing the above-mentioned filling, the method comprising: Mix the above-mentioned dough together to form a dough, add a measured amount of filling, press into a mold, and bake to obtain the final product.

[0027] In one embodiment, the skin-to-filling mass ratio is 2:8.

[0028] In one embodiment, the baking temperature is: 200~210°C for the top heat and 180~190°C for the bottom heat for 20~30 minutes.

[0029] Beneficial effects: Compared with existing technologies, it has the following advantages: (1) This invention completely eliminates chemically modified starch and edible colloids. Based on the synergistic effect of special peanut oil and isomaltooligosaccharide, a natural anti-aging barrier is formed, which prevents starch from retrograding and hardening, and keeps the red bean paste soft and delicate for a long time. Its anti-aging effect is better than that of additives, and it achieves true natural and additive-free results, which fully meet the "clean label" requirements of modern health foods. (2) This invention utilizes a specific ratio of oil and oligosaccharides to construct a stable water-oil emulsion matrix, which can steadily and continuously transport internal moisture to the dry and hard crust after baking. This not only allows the finished mooncakes to quickly "soften" on the 5th day, but also ensures that the crust and filling adhere tightly, completely solving the production problems of traditional red bean fillings that are prone to drying, cracking, and peeling in the later stages; (3) The pretreated peanut oil of this invention is protected from high-temperature refining damage and retains rich natural antioxidant components such as polyphenols. While giving the filling a smooth texture, it is tightly cross-linked with the matrix, with an oil retention rate of over 99.5%, firmly locking in the oil and preventing it from overflowing. Under high-temperature extreme testing, the acid value and peroxide value of the finished product are far lower than the national standard, completely solving the industry problems of easy oil separation and easy deterioration. Attached Figure Description

[0030] Figure 1 This is a graph showing the changes in the moisture content of the crust of Cantonese-style mooncakes during storage. Figure 2 This is a graph showing the changes in acid value during the storage of Cantonese-style mooncakes; Figure 3 This is a graph showing the changes in peroxide value during the storage of Cantonese-style mooncakes. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The specific embodiments described below further illustrate the present invention.

[0032] The testing method involved in this invention: (1) Determination of texture and hardness The hardness characteristics of red bean filling and finished mooncakes were tested using a TA.XTPlus texture analyzer (SMS, UK). The filling was formed into a cube with a side length of 3.5 cm. The testing conditions were: single compression, cylindrical probe P / 25, pre-test velocity 2 mm / s, test velocity 1 mm / s, post-test velocity 1 mm / s, compression deformation 50%, and trigger force 10 g. Hardness was measured on day 1 and day 14 of storage, and the measurements were repeated 5 times.

[0033] (2) Determination of oil holding capacity Weigh approximately 35 g of red bean filling, shape it into a cube, and place it on four layers of filter paper with a known dry weight (W1). Measure the total weight of the filter paper and filling (W2). After 24 hours, remove the filling, place the filter paper in a 60 °C oven to constant weight, and weigh it again (W3). .

[0034] (3) Color measurement The color of the samples was measured using an SC-10 colorimeter (Shenzhen Sanenshi Technology Co., Ltd.). The samples were packaged in transparent self-sealing bags. The color of the samples was represented by L*, a*, and b*. Three points were selected for measurement, and the measurement was repeated 5 times.

[0035] (4) Relative crystallinity (XRD) determination The filling sample stored for 14 days was freeze-dried and ground through a 100-mesh sieve. X-ray diffraction patterns were obtained using an X-ray diffractometer (scanning area 5°~45°, scanning speed 0.1° / s), and the relative crystallinity (RC) was calculated by comparing the areas of the crystalline and amorphous regions to characterize the degree of starch retrogradation.

[0036] (5) Sensory evaluation of mooncakes Fuzzy mathematics was used for the sensory evaluation of commercially available Cantonese-style mooncakes. Referring to the sensory characteristics specified in GB / T 19855-2015 "Mooncakes," four evaluation levels were determined for Cantonese-style mooncakes, as shown in Tables 1 and 2. All samples were cut into uniformly sized small pieces and placed in randomly numbered dishes. An uncut sample was placed to one side for observation of shape and color. The sensory evaluation panel consisted of 10 reviewers (5 men and 5 women) with food science backgrounds. Prior to the formal testing, the reviewers received multiple training sessions to ensure the accuracy of the evaluation results.

[0037] In the following embodiments, traditional sensory evaluation methods are used to evaluate Cantonese mooncakes, and the evaluation criteria are referenced in Table 1.

[0038] Table 1. Fuzzy Mathematical Evaluation Criteria for Cantonese Mooncakes

[0039] In the following embodiments, fuzzy mathematical sensory evaluations were performed on the shape, texture, color, taste and mouthfeel of Cantonese mooncakes, with the evaluation criteria referring to Table 2.

[0040] Table 2 Sensory Evaluation Standards for Cantonese Mooncakes

[0041] Shape, texture, color, flavor, and mouthfeel are four important factors affecting Cantonese-style mooncakes, forming a factor set E = (E1, E2, E3, E4). The four-level rating system (Excellent, Good, Average, Poor) constitutes the evaluation set V = (V1, V2, V3, V4).

[0042] Thirty evaluators with food science backgrounds were invited to score the importance of four factors affecting the quality of Cantonese-style mooncakes. The results were then averaged and normalized to obtain the weight set of the four factors. The factor weight set W = (W1, W2, W3, W4) = (0.20, 0.14, 0.24, 0.42), with taste and texture having the largest weight and texture the smallest.

[0043] The sources of raw materials involved in the embodiments and comparative examples of this invention are as follows: Preparation of peanut oil pretreated and degummed by infrared radiation (RO peanut oil): High-oleic peanuts were spread in a single layer in a carrier and placed in an infrared radiation device. The infrared wavelength was set to 0.75~4 μm (medium-short wave). The pretreatment temperature was precisely controlled at 120℃ for 60 min. The peanuts were allowed to cool naturally to room temperature and the red skin was removed. Subsequently, the peanuts were pressed under 45 MPa pressure for 30 min using a hydraulic press, and the crude oil was collected. The crude oil was then centrifuged at 6000 r / min for 10 min to separate solid impurities. The crude oil was placed in a 90℃ water bath, and 5% citric acid solution was added at 5% of the crude oil mass. The mixture was first stirred rapidly at 300 r / min for 20 min, and then stirred slowly at 60 r / min until a white flocculent substance was formed. After standing at room temperature for 2 h, the bottom layer of gum was removed by centrifugation to obtain the final product.

[0044] Example 1 A long-lasting, soft and delicate filling for Cantonese red bean mooncakes, the formula of which consists of the following components by weight percentage: 24% red beans, 16% peanut oil pretreated with infrared radiation and degummed, 35% white sugar, 6% isomaltooligosaccharide (IMO, purity ≥90%, Henan Wanbang Industrial Co., Ltd.), and the remainder is water 19% (final water content of the formula).

[0045] Filling preparation method: Accurately weigh 100.00 g of plump, impurity-free fresh red beans, wash them with purified water to remove surface dust, drain them, add sufficient pre-soaking water at a material-to-liquid ratio of 1:3 (g / mL), and soak them continuously in a 20 °C constant temperature incubator for 15 h. After soaking, filter out the excess soaking water and drain the red beans thoroughly. After soaking and draining, transfer the red beans to a jacketed steam reactor (or high-pressure cooker), add 150g of water, seal, and start the heating program. Accurately raise and maintain the internal temperature of the system to 105°C, and cook under low pressure for 55 minutes. After cooking, while still hot (with the core temperature of the system maintained above 85°C), start a high-shear homogenizer (8000 r / min, for 3-5 minutes) to blend the red bean slurry into a smooth paste without any lumps. Then, stabilize the reactor temperature at 105°C and start low-speed physical stirring (60 r / min). Under continuous shear, add 66.67 g of infrared radiation pretreated and degummed peanut oil, 25.00 g of isomaltooligosaccharide (IMO), and 145.83 g of white sugar in sequence at a uniform rate. The well-mixed red bean paste is transferred to a non-stick frying pan and continuously stir-fried at medium to high temperature to accelerate the evaporation of free water in the system. During the stir-frying process, a rapid moisture analyzer is used to continuously sample and monitor the process. When the total moisture content of the filling drops to 19%, heating is stopped immediately and the filling is removed from the pan. After the filling has cooled naturally to room temperature in a clean environment, it is vacuum degassed and sealed in a high-barrier composite aluminum foil packaging bag.

[0046] Mooncake Production: The filling prepared using the above method is used to wrap Cantonese red bean mooncakes (the crust-to-filling ratio is set at 2:8). The crust recipe by weight is as follows: 45.0 g of peanut oil pretreated with infrared radiation and degummed, 100.0 g of invert sugar syrup (Shanghai Fengwei Industrial Co., Ltd.), 160.0 g of medium-low gluten wheat flour, and 5.0 g of alkaline water. After the dough is prepared and allowed to rest, the filling is quantitatively wrapped, molded, and baked at 210°C (top heat) / 190°C (bottom heat) for 20 minutes. After cooling to room temperature, the mooncakes are sealed and packaged.

[0047] Example 2 The only difference from Example 1 is that the filling formula is adjusted by weight percentage as follows: 20% red beans, 20% RO peanut oil, 30% white sugar, 8% IMO, and the remainder is 22% water. All other parameters and conditions are the same as in Example 1.

[0048] Example 3 The only difference from Example 1 is that the filling formula is adjusted by weight percentage as follows: red beans 28%, RO peanut oil 12%, white sugar 40%, IMO 4%, and the remainder is water 16%; all other parameters and conditions are the same as in Example 1.

[0049] Comparative Example 1: Traditional commercially available formula (IMO-free, traditional peanut oil) The difference from Example 1 is that the filling formula, by weight percentage, is: 24% red beans, 16% commercially available high-temperature refined peanut oil (PO), 41% pure white sugar (which replaces the IMO portion in the formula), and the remainder is water 19%; all other parameters and conditions are the same as in Example 1.

[0050] Comparative Example 2 (IMO only, traditional peanut oil) The difference from Example 1 is that the filling formula, by weight percentage, is: 24% red beans, 16% commercially available high-temperature refined peanut oil (PO), 35% white sugar, 6% IMO, and the remainder is water 19%; other parameters and conditions are the same as in Example 1.

[0051] Comparative Example 3: Patent CN 117337942 A, containing modified starch and colloid. The difference from Example 1 is that the filling formula, by weight percentage, is: 22% red beans, 16% commercially available high-temperature refined peanut oil (PO), 35% white sugar, 6% IMO, 1.9% acetylated distarch phosphate, 0.1% konjac gum, and the remainder is water 19%; other parameters and conditions are the same as in Example 1.

[0052] Comparative Example 4: Traditional peanut oil + phenolic compounds + IMO The difference from Example 1 is that the filling formula, by weight percentage, is: 24% red beans, 16% compound modified peanut oil, 35% white sugar, 6% isomaltooligosaccharide (IMO), and the remainder is water; all other parameters and conditions are the same as in Example 1. In the preparation of compound modified peanut oil: the content of the main phenolic compounds in the RO peanut oil used in Example 1 was tested to be 486 mg / kg. In order to eliminate the interference of the difference in active substance concentration, commercially available vitamin E (the main phenolic compound in peanut oil) was artificially added to conventional peanut oil (PO) to precisely make up for the difference (i.e., an additional 156 mg of vitamin E was added to each kilogram of PO oil) so that its total concentration of active substances was consistent with that of RO peanut oil.

[0053] Results Analysis 1. The physicochemical and anti-aging indicators of the red bean fillings prepared in the examples and comparative examples were determined, and the results are shown in Table 3. Table 3. Results of determination of physicochemical and anti-aging indicators of red bean paste

[0054] Analysis of the data in Table 3 shows that the microscopic properties of each sample differed significantly during storage. Starch retrogradation is essentially a process in which gelatinized amylose and amylopectin molecules regroup, rearrange themselves through hydrogen bonds, and recrystallize. Macroscopically, this is manifested as an increase in the relative crystallinity (RC) and a significant rise in hardness.

[0055] Example 1 employed a specific mass percentage composition to construct the system (24% red beans, 16% infrared-treated and degummed peanut oil, and 6% isomaltooligosaccharide). After 14 days of storage, the hardness of Example 1 increased only from the initial 410.5 g to 565.6 g, with a hardness increase rate controlled at 37.80%, and the relative crystallinity was as low as 18.41%, demonstrating excellent thermodynamic inhibition of crystallization. The core mechanism lies in the fact that, under the specific concentration and hydration conditions set in the formulation, the peanut oil prepared by infrared low-temperature pretreatment is rich in fat-soluble active adjuncts such as polyphenols, as well as trace amounts of polar adjuncts such as phospholipids. Under mechanical homogeneous shearing, these natural amphiphilic adjuncts act as excellent surfactants, precisely mediating the insertion of lipid molecules into the hydrophobic cavities of red bean amylose, thereby assembling at the microscopic level into a highly sterically hindered V-shaped single-helix complex, completely blocking the recrystallization of the starch double helix from a thermodynamic perspective.

[0056] Compared to Comparative Example 1, which uses commercially available peanut oil that has undergone conventional high-temperature pretreatment but has not added isomaltooligosaccharide (IMO), its hardness surged to 1345.4 g after 14 days of storage (hardness increase rate of 138.00%), with a relative crystallinity as high as 26.25%. This is because conventional PO oils lack compatibility mediators of active adjuncts and cannot form a stable physical barrier phase with the natural native starch matrix, leading to spontaneous and rapid recrystallization of starch molecular chains.

[0057] Comparative Example 2, by introducing a single functional oligosaccharide (6% IMO), showed a decrease in the increase in hardness (88.90%). However, due to the lack of interfacial encapsulation and crystal network connectivity regulation by the specially processed peanut oil, the steric hindrance of the free amylose was insufficient, resulting in significantly lower anti-aging efficacy compared to Example 1. This indicates a significant molecular-level synergistic effect between the peanut oil treated by the specific process in this invention and the functional oligosaccharide; both are indispensable.

[0058] To further elucidate the mechanism of action of Example 1, commercially available vitamin E (the main phenolic compound in peanut oil) was artificially added to Comparative Example 4 for verification. The results showed that although Comparative Example 4, through the exogenous addition of phenolic compounds, provided limited hydrogen bonding cross-linking to some extent, resulting in a lower increase in hardness (65.20%) and crystallinity (22.18%) compared to Comparative Example 2 without polyphenols, its overall anti-aging efficacy was still significantly lower than that of Example 1. This indicates that simply adding exogenous phenolic compounds cannot reproduce the modification effect of the present invention. The reason is that the commercially available phenolic compound (vitamin E) introduced exogenously in Comparative Example 4 differs from the endogenous (in vivo) phenolic compound retained through a specific low-temperature infrared radiation process in Example 1 in terms of stereoisomer structure and multi-component natural composition distribution. This leads to poorer spatial adaptability between molecules, making it impossible to effectively trigger the molecular-liquid oil synergistic mechanism with the natural starch and oligosaccharides of red beans, thus hindering spontaneous assembly into a highly sterically hindered V-shaped single-helix complex network.

[0059] Furthermore, Example 1 exhibits an oil retention rate as high as 99.65%, significantly superior to the comparative examples. This is because the specially formulated oil, oligosaccharides, and gelatinized starch of this invention, under a specific dose-response relationship, construct an emulsified network matrix with a highly uniform spatial distribution and stable phase. This matrix firmly locks in the oil molecules, protecting unsaturated fatty acids from free radical chain oxidation, fundamentally solving the problem of free oil separation in high-oil-content fillings during the later stages of storage. The data fully demonstrate that the optimal formulation and preparation process established by this invention, with its "additive-free" natural interaction mechanism, successfully surpasses and replaces traditional chemical modification schemes.

[0060] 2. The fuzzy mathematical evaluation model was used to evaluate the overall quality of the finished Cantonese mooncakes after packaging. The results are shown in Table 4. Table 4. Fuzzy Mathematical Sensory Comprehensive Score of Finished Cantonese Mooncakes

[0061] As shown in Table 4, the finished mooncakes prepared in Example 1 had the highest percentage of excellent products (48.50%), achieving a fuzzy mathematics comprehensive score of 89.54, ranking first in overall quality and texture. Although Examples 2 and 3 also fell within the parameter range defined by this invention, their water-oil phase balance was slightly adjusted due to deviations in the specific ratios, resulting in a slight decrease in their comprehensive scores.

[0062] Comparative Example 3 replicated the existing physical adjustment scheme that relies on the exogenous addition of chemically modified starch (acetylated distarch phosphate) and macromolecular food colloids (konjac gum). Although it controlled the increase in filling hardness to a low level (47.20%) through the strong water absorption of exogenous hydrophilic colloids, the overall sensory score of its mooncake was only 76.90 points, which was inferior to that of Example 1 of this invention. At the same time, the sensory score of Comparative Example 4 (PO + exogenous polyphenols + IMO) (75.80 points) was also significantly lower than that of Example 1. This confirms that the addition of exogenous polyphenols alone cannot improve the high-temperature emulsification stability of the filling, and it is difficult to form a continuous and stable moisture release interface after baking.

[0063] Based on the analysis of the hydration kinetics theory of polymer multiphase systems, the reason lies in the fact that the exogenously introduced macromolecular food colloids and chemically modified starch have extremely high hydrophilicity and affinity, resulting in strong local water competition in the complex high-sugar and high-oil filling system. This uncontrollable water competition disrupts the original natural matrix network, leading to highly uneven local distribution of moisture at the microscopic level. During baking and subsequent storage, this not only causes the filling to exhibit an unnatural, dense gel texture (macroscopically manifested as a severe stickiness and coarse particle residue), but more importantly, this highly hydrophilic network tightly binds the moisture inside the filling, greatly hindering the normal moisture gradient penetration and migration from the filling towards the crust. Because moisture cannot migrate to the outer crust in an orderly and stable manner, the unique "softening" process of Cantonese mooncakes is hindered. Figure 1 The finished pastry crust remained dry and hard for a long time, accompanied by significant separation of the crust and filling, as well as shrinkage and peeling.

[0064] In addition, the softening characteristics and storage stability of mooncakes were investigated. Figure 1It can be seen that the moisture content of the Cantonese mooncake crust gradually increases with storage time. The moisture content of Example 1 stabilizes on the 5th day of storage, while that of Comparative Example 1 stabilizes on the 7th day. This indicates that Example 1 can promote the softening of the Cantonese mooncake. This is because the RO has a high phospholipid content, and phospholipids can act as emulsifiers in the crust system, thereby promoting moisture diffusion, reducing moisture loss during baking, and increasing the final moisture content. The figure also shows that the moisture content of both types of Cantonese mooncake crusts increases rapidly in the first 3 days, then the rate of increase slows down. This is because immediately after baking, the moisture evaporation of the crust creates a large water activity gradient between the crust and the filling, resulting in rapid moisture migration. As time progresses, the moisture difference between the crust and the filling gradually decreases, and the rate of moisture migration slows down. Furthermore, under the same storage time, the moisture content of the Cantonese mooncake crust in Example 1 was higher than that in Comparative Example 1. This is because the red bean filling in the Comparative Example used IMO to replace part of the white sugar. Since IMO can bind with water molecules through hydrogen bonds, it can improve the water-holding capacity of the filling. Therefore, the filling in Example 1 had a higher moisture content. During the softening process, the effect of the moisture gradient was greater than the interaction force between IMO and water molecules, so more moisture could migrate to the crust.

[0065] Therefore, Example 1 of this invention completely abandons the mechanical compounding of exogenous modified starch and food colloids, relying on the ternary synergistic mechanism of "16% pretreated peanut oil + 6% isomaltooligosaccharide + 24% red bean natural starch". IMO moderately anchors water molecules through hydrogen bonds via abundant active hydroxyl groups (reducing the free relaxation fluidity of water molecules), while the dense physical water-blocking interface formed by pretreated peanut oil reshapes the water activity gradient between the "skin-filling" multiphase system. In the early stage of storage, this system can drive internal water to penetrate to the outer crust at a stable kinetic rate, enabling the mooncake to quickly and efficiently complete the softening process on the 5th day of storage, and maintain a tight fit between the crust and filling, and a soft and melt-in-your-mouth texture for a long time.

[0066] Acid value is an important indicator reflecting the degree of rancidity of oils and fats. National standards stipulate that the acid value of baked goods should be ≤5 mg / g. Generally, mooncakes with an acid value >3 mg / g are considered unsuitable for consumption. Peroxide value indicates the degree of oxidation of oils and fatty acids; a higher value indicates a greater degree of oxidation. National standards stipulate that the peroxide value of baked goods should be ≤0.25 g / 100 g. Figure 2 and Figure 3The figure shows the changes in acid value and peroxide value of two types of Cantonese mooncakes during storage. As can be seen from the figure, the acid value and peroxide value of both samples increased significantly over time, and the acid value and peroxide value of the Cantonese mooncake prepared with the formula of Comparative Example 1 were consistently higher than those prepared with the formula of Example 1. The difference in acid value between the two samples was small in the first 5 weeks, after which the acid value of the Cantonese mooncake prepared with the formula of Comparative Example 1 increased rapidly. By the 8th week of storage, the acid value exceeded 3 mg / g, indicating low edible quality. By the 10th week of storage, the acid value of the sample approached 5 mg / g, rendering it inedible. The increase in acid value during the storage of Cantonese mooncakes was due to the production of free fatty acids from oil hydrolysis. The Cantonese mooncake prepared with the formula of Example 1 had an acid value of 2.61 mg / g by the 10th week of storage, significantly lower than that of the formula of Comparative Example 1, and still retained edible value. Regarding peroxide value, in the early stages of oil oxidation, free radicals formed react with unsaturated fatty acids, producing less H2O2 and resulting in a slower oxidation rate. Once free radicals form, the oxidation rate of oils increases exponentially. Simultaneously, the accumulation of small-molecule polar substances and impurities in the oil during the initial reaction further promotes subsequent oxidation reactions. Figure 3 It can be seen that the peroxide value of the sample prepared with the formulation of Comparative Example 1 increased rapidly in the 8th week, and the peroxide value at the 10th week of storage was 0.053 g / 100 g higher than that of the sample prepared with the formulation of Example 1. However, the peroxide values ​​of both samples at the 10th week of storage were within the national standard range. The reason why the peroxide value of the sample prepared with the formulation of Example 1 remained low may be because the peanut oil, after low-temperature infrared pretreatment, retained a large number of trace active ingredients, such as vitamin E and polyphenols. These substances have natural antioxidant functions, thus slowing down the oxidation process of the product to a certain extent and improving the edible quality of Cantonese mooncakes.

[0067] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A long-lasting, soft and delicate filling for Cantonese-style red bean mooncakes, characterized in that, By mass fraction, it includes the following components: Red beans: 15%~35%, peanut oil pretreated with infrared radiation and degummed: 10%~25%, white sugar: 25%~45%, isomaltooligosaccharide: 2%~10%; water: 10%~30%.

2. The Cantonese-style red bean mooncake filling according to claim 1, characterized in that, By mass fraction, it includes the following components: red beans: 20%~28%, peanut oil pretreated with infrared radiation and degummed: 12%~20%, white sugar: 30%~40%, isomaltooligosaccharide: 4%~8%, and water: 15%~23%.

3. The Cantonese-style red bean mooncake filling according to claim 1, characterized in that, The filling for the Cantonese-style red bean mooncake, by mass fraction, comprises the following components: 24% red beans, 16% peanut oil pretreated with infrared radiation and degummed, 35% white sugar, 6% isomaltooligosaccharide, and 19% water.

4. The Cantonese-style red bean mooncake filling according to any one of claims 1 to 3, characterized in that, The preparation of the peanut oil pretreated and degummed by infrared radiation includes the following steps: S1 Pretreatment stage: The high oleic peanut raw material is spread in a single layer in a carrier and placed in an infrared radiation device for infrared pretreatment. After that, it is naturally cooled to room temperature and the red skin of the peanut is removed to obtain the processed peanut kernels. S2 Pressing and coarse separation stage: The peanut kernels obtained in S1 are pressed and extracted using hydraulic pressing equipment, centrifuged, and solid impurities and suspended matter are separated to obtain low-temperature pretreated high-oleic peanut oil. S3 Hydration and Degumming Stage: The low-temperature pretreated high-oleic peanut oil obtained in S2 is subjected to hydration and degumming to obtain peanut oil that has been pretreated and degummed by infrared radiation.

5. The Cantonese-style red bean mooncake filling according to any one of claims 1 to 3, characterized in that, The isomaltooligosaccharide is either IMO-50 syrup or IMO-50 solid powder.

6. A method for preparing the filling for Cantonese-style red bean mooncakes according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Select red bean raw materials, clean them, and soak them in water; (2) Cook the soaked red beans with water at a temperature of 100-110 °C for 45-65 minutes. After cooking, stir the red beans while they are still hot until they are smooth and free of granules. Then, while stirring at a low speed at 100-110 °C, add the peanut oil that has been pretreated by infrared radiation and degummed, the isomaltooligosaccharide and the white sugar in sequence and mix well. (3) Transfer the well-mixed red bean paste to a wok and stir-fry until the moisture content of the filling reaches 18%~25%. After cooling, seal and package for later use.

7. The method according to claim 6, characterized in that, The final cooking point in step (3) is when the moisture content of the filling reaches 19% to 23%.

8. A Cantonese red bean mooncake comprising the Cantonese red bean mooncake filling according to any one of claims 1 to 5, characterized in that, The crust recipe, by weight, includes: 35-55 parts of peanut oil pretreated with infrared radiation and degummed, 80-120 parts of invert sugar syrup, 140-180 parts of wheat flour, and 3-7 parts of lye water.

9. The Cantonese-style red bean mooncake according to claim 8, characterized in that, The crust recipe, by weight, includes: 45 parts of peanut oil pretreated with infrared radiation and degummed, 100 parts of invert sugar syrup, 160 parts of wheat flour, and 5 parts of lye water.

10. A method for preparing a Cantonese red bean mooncake containing the Cantonese red bean mooncake filling according to any one of claims 1 to 5, characterized in that, The method is as follows: mix the dough ingredients of the Cantonese red bean mooncake as described in claim 8 or 9 together to form a dough, wrap the filling in a fixed amount, press it into a mold, and bake it to obtain the mooncake.

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