Low-temperature stable chocolate and preparation method thereof

Abstract

The invention discloses low-temperature stable chocolate and a preparation method thereof, and belongs to the technical field of food. The preparation method of the low-temperature stable chocolate comprises the following steps: heating and dissolving cocoa butter, cocoa mass, psicose, milk, soybean lecithin and palm kernel edible oil, and fully and uniformly mixing to obtain chocolate slurry; sequentially carrying out cooling ultrasonic treatment, temperature-regulating ultrasonic treatment, defoaming and forming to obtain the low-temperature stable chocolate. According to the process, a stable system with uniform crystals and a compact structure is finally constructed, so that the chocolate can keep smooth appearance, smooth taste, no frosting and no sand return for a long time under low-temperature storage.

Description

Technical Field

[0001] This invention belongs to the field of food technology, specifically relating to a low-temperature stable chocolate and its preparation method. Background Technology

[0002] Chocolate is renowned for its rich, smooth texture and melt-in-your-mouth quality, enjoying a large global consumer market. In recent years, with similar brightness, aroma, flavor, and color, mid-to-high-end chocolates have become increasingly popular due to their unique taste and health benefits. Low-calorie options are also a major trend in the chocolate industry, as low-calorie sweeteners can partially replace sucrose to reduce the calorie content of chocolate. Meanwhile, emerging markets are being continuously developed. These markets, mostly located in tropical or subtropical regions with large temperature fluctuations and insufficient cold chain logistics, present another quality challenge for the chocolate industry. Blooming, characterized by white spots on the surface of chocolate, affects its luster and taste, leading to appearance and texture defects. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a method for preparing low-temperature stable chocolate, which solves the problem of blooming of chocolate in low-temperature environments, can adapt to complex low-temperature storage environments, and enables it to maintain its high-quality sensory and texture for a long time under low-temperature storage conditions.

[0004] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing low-temperature stable chocolate, characterized by comprising the following steps: Cocoa butter, cocoa liquor, allulose, milk, phospholipids, and edible oil are heated and dissolved, and then thoroughly mixed to obtain a chocolate syrup. The syrup is then subjected to cooling sonication, temperature-regulating sonication, defoaming, and molding to obtain low-temperature stable chocolate. The temperature-controlled ultrasound is specifically performed as follows: the chocolate syrup is first cooled to 18-23℃ at a rate of 1.5-2.5℃ / min and held at that temperature for 6-10 minutes. Then, it is heated to 23-28℃ at a rate of 0.3-1℃ / min and held for 13-18 minutes. After that, it is heated to 25-30℃ at a rate of 0.1-0.5℃ / min and held for 2-12 minutes, while simultaneously being ultrasonicated at 18-25kHz for 3-7 minutes.

[0005] Preferably, the weight ratio of the cocoa liquor, cocoa butter, allulose, milk, phospholipids, and edible oil is (30-55):(15-35):(13-20):(1-3):(0.1-0.5):(6-10).

[0006] This invention adds allulose to the chocolate raw material. Allulose has a low crystallinity and can participate in building a more stable crystal structure. Cocoa butter ideally crystallizes in the β-V form, and allulose can act as a crystal nucleus template to promote the formation of the ideal crystal form, improve crystal stability, reduce the conversion to coarse crystals during storage, and prevent blooming in chocolate. It can also reduce the formation of hard crystals in chocolate, ensuring a smooth texture. Furthermore, allulose can improve the thermodynamic stability of the amorphous regions of chocolate, reduce molecular migration at low temperatures, and thus reduce graininess in low-temperature environments. Allulose has good water retention and viscosity stability, while emulsifiers can enhance fluidity. The two work synergistically to enhance the uniformity of the chocolate paste, improve fluidity and extensibility, and prevent oil-water separation, thereby avoiding blooming during storage.

[0007] Preferably, the phospholipid is one or more of soybean lecithin, lecithin, sucrose fatty acid ester, and mono- and diglyceride fatty acid ester.

[0008] Preferably, the edible oil is one or more of palm oil, coconut oil, and olive oil.

[0009] Preferably, the heating and dissolving temperature is 45-55°C. The dissolution of allulose at this stage helps maintain the homogeneity of the slurry due to its water retention and viscosity stability, and works synergistically with the emulsifier to prevent oil-water separation, thus providing conditions for building a stable system.

[0010] Preferably, the temperature of the cooling ultrasound is 28-35℃. Cooling to 28-35℃ is close to the crystallization initiation temperature of cocoa butter, promoting the initial nucleation of cocoa butter crystals and preparing for temperature regulation. The cavitation effect generated by ultrasound can break up particle clusters, resulting in a more uniform distribution of allulose, cocoa butter, and other components. Allulose acts as a crystal nucleus template, and ultrasound can accelerate its interaction with cocoa butter, guiding the formation of the ideal crystal form while reducing the formation of hard crystals. Ultrasonic treatment can improve the homogeneity of the slurry, avoid local component segregation, and thus reduce the risk of blooming during storage.

[0011] Preferably, the cooling ultrasound has an ultrasonic frequency of 40 kHz and a duration of 20 min.

[0012] This invention regulates the crystallization behavior of cocoa butter through precise temperature control combined with low-power ultrasound. First, the temperature is lowered to 18-23°C at a rate of 1.5-2.5°C / min and held for 6-10 minutes to promote extensive nucleation of cocoa butter, forming small crystal nascent forms. During this isothermal stage, the crystals begin to grow, but they are mostly metastable at this stage and require further processing for transformation. Then, the temperature is increased to 23-28°C at a rate of 0.3-1°C / min and maintained for 13-18 minutes to melt unstable crystals (such as low-melting-point crystal forms), retaining the more thermodynamically stable crystals. Allulose acts as a template, preferentially guiding the formation of β-V crystal forms and inhibiting the formation of large crystals. Simultaneously, low-power ultrasound breaks up the crystal aggregates, ensuring small and uniform crystal sizes and forming a dense and stable network structure. This shortens the traditional tempering time, improves system stability, and enhances the smoothness of the chocolate.

[0013] Throughout the temperature regulation process, allulose reduces the molecular migration rate in the amorphous region, enhances thermodynamic stability, and reduces crystal transformation at low temperatures, thereby preventing frosting.

[0014] Preferably, the molding process involves allowing the material to stand at 4°C until it hardens.

[0015] The present invention also provides a low-temperature stable chocolate, which is prepared by the above-described preparation method.

[0016] It contains at least the following beneficial technical effects: This invention, through the synergistic design of functional ingredients and processes, enables chocolate to adapt to complex low-temperature storage environments, fundamentally solving problems such as blooming (white spots on the surface), graininess leading to loss of appearance and reduced taste.

[0017] Allulose, on the one hand, guides cocoa butter to form and stabilize small, ideal crystals, thus preventing blooming; on the other hand, it reduces molecular migration at low temperatures, effectively preventing crystallization.

[0018] By employing an ultrasound-assisted precision temperature control process, the chocolate crystallization process is homogenized and precisely regulated. This process works synergistically with the effects of allulose to ultimately create a stable system with uniform crystals and a dense structure. This allows the chocolate to maintain a smooth appearance and a smooth texture for a long time under low-temperature storage conditions, ensuring consistently high-quality sensory and textural qualities. Detailed Implementation

[0019] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0020] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0021] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0022] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0023] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0024] Unless otherwise specified, "room temperature" and "normal temperature" in this invention refer to 25±2℃.

[0025] Unless otherwise specified, all raw materials or instruments used in the following embodiments of the present invention are commercially available.

[0026] Example 1 This embodiment prepares a low-temperature stable chocolate, which is made from the following raw materials in parts by weight: 40 parts cocoa liquor, 20 parts cocoa butter, 15 parts allulose, 2 parts milk, 0.3 parts soy lecithin, and 8 parts palm kernel oil.

[0027] The method for preparing the chocolate includes the following steps: ① Dissolve cocoa butter, cocoa liquor, allulose, milk, soy lecithin, and palm kernel oil at 50°C and mix thoroughly to obtain chocolate syrup.

[0028] ② Cooling and ultrasonic treatment: Cool the chocolate liquid to 30℃ and treat it with ultrasonic treatment at 40kHz for 20 minutes.

[0029] ③Temperature-controlled ultrasound: First, cool the chocolate mixture to 20℃ at 2℃ / min and hold for 8 minutes. Then, raise it to 25℃ at 0.5℃ / min and hold for 15 minutes. Next, raise it to 28℃ at 0.3℃ / min and hold for 10 minutes. Simultaneously, use 20kHz low-power ultrasound for 5 minutes to break up the agglomerates.

[0030] ④ Pour the temperature-adjusted slurry into the mold, tap gently to remove air bubbles, let it stand at 4℃ until hardened, and store at low temperature.

[0031] Example 2 This embodiment prepares a low-temperature stable chocolate, which is made from the following ingredients in parts by weight: 30 parts cocoa liquor, 15 parts cocoa butter, 13 parts allulose, 1 part milk, 0.1 parts soy lecithin, and 6 parts palm kernel oil.

[0032] The preparation method in this embodiment is the same as in Embodiment 1.

[0033] Example 3 This embodiment prepares a low-temperature stable chocolate, which is made from the following ingredients in parts by weight: 55 parts cocoa liquor, 35 parts cocoa butter, 20 parts allulose, 3 parts milk, 0.5 parts soy lecithin, and 10 parts palm kernel oil.

[0034] The preparation method in this embodiment is the same as in Embodiment 1.

[0035] Example 4 This embodiment provides a low-temperature stable chocolate, which uses the same raw materials as that in Example 1, but differs in the preparation method, specifically including the following steps: ① Dissolve cocoa butter, cocoa liquor, allulose, milk, soy lecithin, and palm kernel oil at 45°C and mix thoroughly to obtain chocolate syrup.

[0036] ② Cooling and ultrasonic treatment: Cool the chocolate liquid to 28℃ and treat it with ultrasonic treatment at 40kHz for 20 minutes.

[0037] ③Temperature-controlled ultrasound: First, cool the chocolate mixture to 18℃ at 2.5℃ / min and hold for 10 minutes. Then, increase the temperature to 23℃ at 1℃ / min and hold for 18 minutes. Next, increase the temperature to 25℃ at 0.5℃ / min and hold for 12 minutes. Simultaneously, use 18kHz low-power ultrasound for 7 minutes to break up the polycrystalline material.

[0038] ④ Pour the temperature-adjusted slurry into the mold, tap gently to remove air bubbles, let it stand at 4℃ until hardened, and store at low temperature.

[0039] Example 5 This embodiment provides a low-temperature stable chocolate, which uses the same raw materials as that in Example 1, but differs in the preparation method, specifically including the following steps: ① Dissolve cocoa butter, cocoa liquor, allulose, milk, soy lecithin, and palm kernel oil at 55°C and mix thoroughly to obtain chocolate syrup.

[0040] ② Cooling and ultrasonic treatment: Cool the chocolate liquid to 35℃ and treat it with ultrasonic treatment at 40kHz for 20 minutes.

[0041] ③Temperature-controlled ultrasound: The chocolate mixture is first cooled to 23℃ at 1.5℃ / min and held at that temperature for 6 minutes. Then, it is heated to 28℃ at 0.3℃ / min and held for 13 minutes. After that, it is heated to 30℃ at 0.1℃ / min and held for 8 minutes. At the same time, it is subjected to low-power ultrasound at 25kHz for 3 minutes to break up the polycrystalline material.

[0042] ④ Pour the temperature-adjusted slurry into the mold, tap gently to remove air bubbles, let it stand at 4℃ until hardened, and store at low temperature.

[0043] Comparative Example 1 The preparation method of this comparative example is the same as that of Example 1, except that allulose is replaced with white sugar.

[0044] Comparative Example 2 The preparation method of this comparative example is the same as that of Example 1, except that allulose is 22 parts.

[0045] Comparative Example 3 The preparation method of this comparative example is the same as that of Example 1, except that: 10 parts of allulose are used.

[0046] Comparative Example 4 The preparation method of this comparative example is the same as that of Example 1, except that soybean lecithin is replaced with polyglycerol fatty acid ester.

[0047] Comparative Example 5 The preparation method of this comparative example is the same as that of Example 1, except that the method of step ② is different, as follows: the temperature of the above slurry is controlled at 50°C and finely ground for 1 hour.

[0048] Comparative Example 6 The preparation method of this comparative example is the same as that of Example 1, except that the temperature adjustment method in step ③ is different, as follows: the chocolate syrup is first cooled to 20°C at 2°C / min and kept at that temperature for 8 min, then heated to 25°C at 0.5°C / min and kept at that temperature for 15 min, and then heated to 28°C at 0.3°C / min and kept at that temperature for 10 min; no ultrasonic treatment is performed.

[0049] Comparative Example 7 The preparation method of this comparative example is the same as that of Example 1, except that the temperature adjustment method in step ③ is different, as follows: the chocolate paste is first cooled to 26°C at 1.2°C / min and kept at that temperature for 4 min, then heated to 30°C at 0.2°C / min and kept at that temperature for 10 min, and then heated to 35°C at 0.1°C / min and kept at that temperature for 5 min; at the same time, it is sonicated at 30 kHz low power for 2 min.

[0050] Experimental Example 1 The main sensory evaluation items were texture, color, flavor, mouthfeel, and storage characteristics. The sensory evaluation criteria are shown in Table 1. A total of 20 people participated in the experiment. The highest score for each sensory evaluation item was 10 points, and the lowest was 0 points. The total score was calculated, and the average score was taken. A higher average score indicates a better result for the chocolate oat bar. The evaluation results are shown in Table 2.

[0051] Table 1 Sensory Evaluation Criteria

[0052] Table 2 Sensory evaluation results

[0053] Analysis of Table 2 above shows that, in terms of texture, color, flavor, mouthfeel, and viscosity, Examples 1-3 using allulose are superior to Comparative Example 1 using granulated sugar. Example 1 using soybean lecithin is superior to Comparative Example 4 using polyglycerol fatty acid esters; Example 1 using low-temperature ultrasonic solubilization is superior to Comparative Example 5 using high-temperature milling; and Example 1 using ultrasonic homogenization is superior to Comparative Example 6 without ultrasonic homogenization. When the weight ratio of cocoa butter to allulose is between 1.1:1 and 1.75:1 (Examples 1, 2, and 3), the overall chocolate performance is better than Comparative Examples 2 and 3, with the best overall performance at a cocoa butter to allulose ratio of 1.33:1. Compared to Example 1, Comparative Example 7 had improperly set preparation process parameters, resulting in a lower sensory evaluation of the chocolate.

[0054] Experimental Example 2 Hardness testing method: Cut the chocolate into uniform small pieces (2cm×2cm×1cm) to ensure consistent thickness and size. Use a cone probe with a constant compression speed (1mm / s) and compression depth (0.6cm). Chocolate with a hardness between 400-600gf is considered moderately firm; excessively high hardness indicates a hard chocolate, while insufficient hardness indicates a sticky and soft chocolate. All data are from three replicate experiments, and the data in the table are the mean ± standard deviation. A texture analyzer was used to test the hardness of each example and comparative example; the results are shown in Table 3.

[0055] Table 3 Hardness test results

[0056] Analysis of Table 3 above shows that, in terms of hardness, Examples 1-3 using allulose are superior to Comparative Example 1 using granulated sugar. Example 1 using soybean lecithin is superior to Comparative Example 4 using polyglycerol fatty acid esters; Example 1 using low-temperature ultrasonic solubilization is superior to Comparative Example 5 (too hard) using high-temperature milling; and Example 1 using ultrasonic homogenization is superior to Comparative Example 6 (too soft) without ultrasonic homogenization. When the weight ratio of cocoa butter to allulose is between 1.1:1 and 1.75:1 (Examples 1, 2, and 3), the overall chocolate performance is better than Comparative Examples 2 and 3, with the best overall performance at a cocoa butter to allulose ratio of 1.33:1. Compared to Example 1, Comparative Example 7 had improperly set preparation process parameters, resulting in a decrease in chocolate hardness.

[0057] Experimental Example 3 Whiteness testing: Chocolate was stored at 18℃ and 25℃, and the whiteness index was measured using a colorimeter after 0 days, 10 days, and 20 days of storage. A higher whiteness index indicates more severe blooming. All data were obtained from three replicate experiments, and the data in Table 4 are the mean ± standard deviation.

[0058] Table 4 Whiteness Index Detection Results

[0059] Analysis of Table 4 shows that, when stored at 18℃ and 25℃, the stability at 18℃ is better. Compared with Comparative Example 1 using sucrose, Examples 1-3 using allulose have better low-temperature stability. Example 1 using soybean lecithin is superior to Comparative Example 4 using polyglycerol fatty acid esters; Example 1 using low-temperature ultrasonic solubilization is superior to Comparative Example 5 using high-temperature milling; and Example 1 using ultrasonic homogenization is superior to Comparative Example 6 without ultrasonic homogenization. When the weight ratio of cocoa butter to allulose is between 1.1:1 and 1.75:1 (Examples 1, 2, and 3), the overall chocolate performance is better than Comparative Examples 2 and 3, with the best overall performance at a cocoa butter to allulose ratio of 1.33:1. Compared to Example 1, Comparative Example 7 had improperly set preparation process parameters, resulting in reduced storage stability of the chocolate.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing low-temperature stable chocolate, characterized in that, Includes the following steps: Cocoa butter, cocoa liquor, allulose, milk, phospholipids, and edible oil are heated and dissolved, and then thoroughly mixed to obtain a chocolate syrup. The syrup is then subjected to cooling sonication, temperature-regulating sonication, defoaming, and molding to obtain low-temperature stable chocolate. The temperature-controlled ultrasound is specifically performed as follows: the chocolate syrup is first cooled to 18-23℃ at a rate of 1.5-2.5℃ / min and held at that temperature for 6-10 minutes. Then, it is heated to 23-28℃ at a rate of 0.3-1℃ / min and held for 13-18 minutes. After that, it is heated to 25-30℃ at a rate of 0.1-0.5℃ / min and held for 2-12 minutes, while simultaneously being ultrasonicated at 18-25kHz for 3-7 minutes.

2. The preparation method according to claim 1, characterized in that, The weight ratio of the cocoa liquor, cocoa butter, allulose, milk, phospholipids, and edible oil is (30-55):(15-35):(13-20):(1-3):(0.1-0.5):(6-10).

3. The preparation method according to claim 2, characterized in that, The phospholipid is one or more of soybean lecithin, lecithin, sucrose fatty acid ester, and mono- and diglyceride fatty acid esters.

4. The preparation method according to claim 2, characterized in that, The edible oil is one or more of palm oil, coconut oil, and olive oil.

5. The preparation method according to claim 1, characterized in that, The heating and melting temperature is 45-55℃.

6. The preparation method according to claim 1, characterized in that, The temperature of the cooling ultrasound is 28-35℃.

7. The preparation method according to claim 4, characterized in that, The cooling ultrasound has a frequency of 40 kHz and a duration of 20 min.

8. The preparation method according to claim 1, characterized in that, The molding process involves allowing the material to stand at 4°C until it hardens.

9. A low-temperature stable chocolate, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

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