Method for preparing a fiber-reinforced low-fat chocolate and fiber-reinforced low-fat chocolate

Abstract

The application provides a method for preparing fiber-reinforced low-fat chocolate and fiber-reinforced low-fat chocolate, and relates to the technical field of food processing, and comprises the following steps: whey protein gel network construction, raw material pretreatment, mixture temperature adjustment, mold vibration, cooling and demolding and the like. The chocolate prepared by the method has excellent sensory quality and nutritional value, the fat content is significantly reduced, the dietary fiber content is significantly increased, the texture is fine, and the thermal stability is good, and the problems of high heat and high fat of traditional chocolate are solved, and a feasible technical scheme is provided for development of a new type of nutritional and healthy chocolate product.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a method for preparing fiber-fortified low-fat chocolate and the fiber-fortified low-fat chocolate itself. Background Technology

[0002] Chocolate is a globally popular food with a continuously growing market. However, traditional chocolate is high in cocoa butter and rich in saturated fatty acids. Excessive consumption can easily lead to health problems such as obesity, high cholesterol, and cardiovascular disease, which contradicts the increasingly health-conscious eating habits of modern consumers.

[0003] With increasing health awareness, market demand for chocolate is gradually shifting towards functional and health-oriented products. However, simply reducing fat content often leads to a decline in chocolate's taste and processing performance, especially affecting its unique melting characteristics and storage stability. Therefore, developing chocolate products that maintain good sensory quality while also possessing health benefits has become an important research direction for the industry.

[0004] The use of fat analogs to replace fat in food has a long history. As early as the 1960s, with the rise of healthy eating concepts, the food industry began exploring fat substitution solutions. Initially, protein and carbohydrate-based raw materials, such as whey protein and starch, were mainly used, but these were limited by thermal stability and taste reproduction. In the 1980s, synthetic fat substitutes, represented by Olestra, emerged. Although used in snacks, they were controversial due to potential digestive side effects. Subsequently, natural or modified ingredients such as micronized proteins, colloids, and dietary fiber gradually became mainstream, especially in low-fat sauces, ice cream, and baked goods. In the 21st century, compounding technology and the trend towards clean labeling have further propelled the development of fat analogs towards functionalization and naturalization. However, in systems like chocolate, which are high in fat and have high sensory requirements, fat substitution still faces significant challenges: cocoa butter not only gives the product a smooth texture but also directly affects crystal structure formation, flavor release, and the thermodynamic stability of the final product.

[0005] While adding dietary fiber can enhance the health value of a product, it typically increases viscosity and decreases fluidity, further impacting the processing performance and final texture of the chocolate. In particular, controlling the glass transition temperature is crucial; improper handling can easily lead to textural degradation, fat migration, or blooming during storage. Current technology has not systematically solved the problem of maintaining a smooth texture, crispness, and suitable glass transition behavior in chocolate while reducing fat and adding fiber, and it also struggles to avoid flavor loss or off-flavors.

[0006] Therefore, in the process of improving health, how to reduce fat and increase fiber while maintaining or even increasing the glass transition temperature of chocolate through raw material synergy and process optimization, so as to ensure the texture stability and flavor retention of the product during storage, has become a key breakthrough for the technological upgrading of the current chocolate industry. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing fiber-fortified low-fat chocolate and the fiber-fortified low-fat chocolate, in order to solve the problem that the existing technology cannot maintain the delicate texture, crispness and suitable glass transition behavior of chocolate while reducing fat and adding fiber, resulting in flavor loss or off-flavors.

[0008] To achieve the above objectives, this application provides a method for preparing fiber-fortified low-fat chocolate, the method comprising:

[0009] Step 1: According to the weight parts, 20-30 parts whey protein powder, 3-5 parts locust bean gum, 2-5 parts konjac gum, 1-3 parts carrageenan powder are used as the main gelling matrix, 3-5 parts egg yolk powder are used as natural emulsifier and flavor enhancer, and 20-30 parts water are mixed to form a precise dispersion system.

[0010] After mixing and stirring for 10-30 min, the mixture is micronized to controllably disintegrate and reassemble the protein aggregates, forming a gel network structure with an average particle diameter of less than 10 μm, thereby obtaining a dense whey protein-based fat mimic.

[0011] Step two: Place 12-15 parts of cocoa butter, 5-10 parts of the whey protein-based fat mimicry prepared in step one, and 5-10 parts of wheat bran soluble dietary fiber powder in a water bath and heat to melt, forming a homogeneous oil-phase composite matrix; wherein,

[0012] Add 30-40 parts of cocoa liquor and stir continuously to form chocolate base;

[0013] Add 10.5-13.5 parts of powdered sugar, 1-3 parts of skim milk powder, 0.1-0.3 parts of soybean lecithin, 0.1-0.3 parts of whey powder, 0.1-0.3 parts of polyglycerol fatty acid ester, and 0.1-0.3 parts of conjugated linoleic acid glyceride, and continue stirring until a homogeneous and stable mixture is formed;

[0014] Specifically, cocoa butter, fat analogues, and wheat bran soluble dietary fiber are heated and melted in a water bath at 50-60℃ to form a homogeneous oil-phase composite matrix; cocoa liquor is added and continuously stirred to form a stable and homogeneous chocolate base; powdered sugar is added in small amounts multiple times, and after being mixed evenly, skim milk powder, soy lecithin, whey powder, polyglycerol fatty acid esters, and conjugated linoleic acid glycerides are added, and the mixture is continuously stirred until a homogeneous and stable blend system is formed;

[0015] Polyglycerol fatty acid esters and conjugated linoleic acid glycerides synergistically emulsify and promote fiber dispersion, while soybean lecithin and whey powder work together to stabilize the solid-liquid interface and prevent particle aggregation.

[0016] Step 3: The mixture obtained in Step 2 is subjected to temperature control using a segmented temperature control method. Specifically:

[0017] Heat the mixture to 50-60℃ and hold for 5-10 minutes to allow the crystals to completely melt.

[0018] Place it in an ice-water bath to cool and stir continuously. After cooling to 30-40℃, remove it to induce the formation of various metastable crystal forms.

[0019] Continue stirring until the temperature drops to 27-33℃ to promote the transformation of the metastable crystal form to the stable β-type;

[0020] Cool again to around 20-27℃ to enhance crystallization;

[0021] Finally, heat the mixture to 30-40℃ to melt the unstable crystal form, retain and stabilize the β-type crystal, and obtain a tempered chocolate paste with suitable fluidity and crystal structure.

[0022] Continuous stirring is required during each of the above temperature control stages to ensure uniform temperature.

[0023] Step 4: Pour the tempered chocolate mixture from Step 3 into a thermostatic mold, shake to remove air bubbles, and let it stand to cool to room temperature for 20-50 minutes.

[0024] Step 5: Place the chocolate mixture in a refrigerator and refrigerate until it solidifies and sets. Once solidified, unmold the mixture to obtain the finished product. Preferably, the refrigerator temperature is 0-4℃ and the refrigeration time is 5-15 minutes to ensure that the chocolate is completely solidified and set.

[0025] Furthermore, in step one above, preferably, 20 parts whey protein powder, 3 parts locust bean gum, 2 parts konjac gum, 1 part carrageenan powder, 3 parts egg yolk powder, and 20 parts water are compounded into a precisely dispersed mixture system.

[0026] Furthermore, in step one above, preferably, 30 parts whey protein powder, 5 parts locust bean gum, 5 parts konjac gum, 3 parts carrageenan powder, 5 parts egg yolk powder and 30 parts water are compounded into a precisely dispersed mixture system.

[0027] Furthermore, in step one above, preferably, 25 parts whey protein powder, 4 parts locust bean gum, 3.5 parts konjac gum, 2 parts carrageenan powder, 4 parts egg yolk powder and 25 parts water are compounded into a precisely dispersed mixture system.

[0028] Furthermore, in step two above, preferably, 12 parts of cocoa butter, 5 parts of whey protein-based fat analog prepared in step one, and 5 parts of wheat bran soluble dietary fiber powder are placed in a water bath and heated to melt, forming a uniform oil phase composite matrix.

[0029] Add 30 parts of cocoa liquor and stir continuously to form chocolate base;

[0030] Add 10.5 parts of powdered sugar, 1 part of skim milk powder, 0.1 parts of soy lecithin, 0.1 parts of whey powder, 0.1 parts of polyglycerol fatty acid ester and 0.1 parts of conjugated linoleic acid glyceride, and continue stirring until a homogeneous and stable mixture is formed.

[0031] Furthermore, in step two above, preferably, 15 parts of cocoa butter, 10 parts of whey protein-based fat analog prepared in step one, and 10 parts of wheat bran soluble dietary fiber powder are placed in a water bath and heated to melt, forming a uniform oil phase composite matrix.

[0032] Add 40 parts of cocoa liquor and stir continuously to form chocolate base;

[0033] Add 13.5 parts powdered sugar, 3 parts skim milk powder, 0.3 parts soy lecithin, 0.3 parts whey powder, 0.3 parts polyglycerol fatty acid ester and 0.3 parts conjugated linoleic acid glyceride, and continue stirring until a homogeneous and stable mixture is formed.

[0034] Furthermore, in step two above, preferably, 13 parts of cocoa butter, 8 parts of whey protein-based fat analog prepared in step one, and 8 parts of wheat bran soluble dietary fiber powder are placed in a water bath and heated to melt, forming a uniform oil phase composite matrix.

[0035] Add 35 parts of cocoa liquor and stir continuously to form chocolate syrup;

[0036] Add 12 parts powdered sugar, 2 parts skim milk powder, 0.2 parts soy lecithin, 0.2 parts whey powder, 0.2 parts polyglycerol fatty acid ester, and 0.2 parts conjugated linoleic acid glyceride, and continue stirring until a homogeneous and stable mixture is formed.

[0037] Furthermore, in step one, whey protein powder, locust bean gum, konjac gum and carrageenan powder are mixed as a gel matrix; a high-speed shearing machine is used at a speed of 6000-13000 r / min for a shearing time of 2-5 min to form a gel network structure with an average particle diameter of less than 10 μm.

[0038] Furthermore, in step two, the water bath heating temperature is controlled at 50-60℃ to ensure that cocoa butter, fat analogues, and wheat bran soluble dietary fiber are fully dissolved and do not deteriorate.

[0039] Furthermore, in step two, 0.3-0.5 parts of food flavoring and fragrance are added.

[0040] Furthermore, in step two, 0.3-0.5 parts of food flavoring and fragrance are added.

[0041] This solution provides a fiber-fortified low-fat chocolate, which is prepared using the method described above.

[0042] The method for preparing fiber-fortified low-fat chocolate provided in this application has the following technical advantages compared to existing technologies:

[0043] 1. By using whey protein-based fat mimics to partially replace cocoa butter in existing chocolate products, and combining the synergistic effect of wheat bran soluble dietary fiber, through multiple specific temperature-regulating processes, the stable β-crystal form of lipids is preserved while the non-fat matrix remains in a glassy state. This successfully produces high-quality, high-fiber, low-fat chocolate with significantly reduced fat content and significantly increased dietary fiber content, meeting the needs of modern healthy eating.

[0044] 2. Whey protein-based fat mimics are micronized through compound colloids to form a fine and uniform gel network, resulting in a dense whey protein-based fat mimic. This mimic can accurately simulate the sensory and functional properties of fat. It is low in fat and high in protein, with a natural and safe formula, broad compatibility, controllable and easily industrialized process, and synergistic effects of its components, providing a high-quality solution for low-fat foods.

[0045] 3. The chocolate prepared by this method has good thermal stability. The glass transition temperature and enthalpy value are suitable, as determined by differential scanning calorimetry. During storage, it is not prone to phenomena such as oil precipitation, surface blooming, or quality deterioration. Attached Figure Description

[0046] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0047] Figure 1 It is a data chart comparing the texture quality;

[0048] Figure 2 This is a picture of a chocolate product illustrating a method for preparing fiber-fortified low-fat chocolate. Detailed Implementation

[0049] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0050] Example 1

[0051] A method for preparing fiber-fortified low-fat chocolate, comprising:

[0052] Step 1: Accurately weigh 20g whey protein powder, 3g locust bean gum, 2g konjac gum, and 1g carrageenan powder as the main gelling matrix. Weigh 3g egg yolk powder as a natural emulsifier and flavor enhancer. Measure 25g water and mix to form a precise dispersion system. After mixing with a magnetic stirrer for 10 minutes, use a high-speed shear machine at 8000 r / min to micronize the dispersion system for 2.5 minutes to obtain an emulsion with an average particle diameter of 8μm, which is the whey protein-based fat mimicry. Seal and refrigerate for later use.

[0053] Step 2: Weigh the raw materials according to the following proportions: 40g cocoa liquor, 15g cocoa butter, 4g fat analog prepared in Step 1, 5g wheat bran soluble dietary fiber powder, 13g sugar powder, 2g skim milk powder, 0.3g soy lecithin, 0.3g whey powder, 0.3g polyglycerol fatty acid ester, 0.3g conjugated linoleic acid glyceride, and 0.4g food flavoring.

[0054] Cocoa butter, fat analogue, and wheat bran soluble dietary fiber were placed in a 50°C constant temperature water bath and heated for 15 minutes until completely melted. Cocoa liquor was then added, and the mixture was stirred continuously for 10 minutes to obtain a homogeneous cocoa liquor. Powdered sugar was added in small amounts multiple times, stirring for 5 minutes after each addition, until the sugar was completely dissolved. Subsequently, skim milk powder, soy lecithin, whey powder, polyglycerol fatty acid esters, conjugated linoleic acid glycerides, and food flavorings were slowly added and stirred continuously for 8 minutes to form a homogeneous and stable mixture. Polyglycerol fatty acid esters and conjugated linoleic acid glycerides synergistically emulsified the mixture, promoting fiber dispersion. Soy lecithin and whey powder together stabilized the solid-liquid interface, preventing particle aggregation. Fat analogue and dietary fiber worked synergistically to help stabilize the dispersion of solid particles and improve the textural homogeneity of the system.

[0055] Step 3: Pour the mixture into a temperature control machine and use a segmented temperature control method for temperature adjustment. Heat to 50°C and hold for 5 minutes to completely melt the crystals. Then place it in an ice-water bath and cool while stirring until the temperature drops to 30°C, inducing the formation of various metastable crystal forms. Remove and continue stirring for 10 minutes until the temperature drops to 27°C, promoting the transformation of the metastable crystal forms into the stable β-type. Cool again in an ice-water bath for 3 minutes until the temperature drops to 25°C, strengthening crystallization. Finally, reheat to 30°C to complete the temperature adjustment and obtain a temperature-controlled chocolate paste with suitable fluidity and crystalline structure.

[0056] Step 4: Pour the tempered chocolate mixture into a silicone mold that has been preheated to 30°C. Place the mold on a vibrating table and vibrate for 30-50 seconds to remove air from the mixture.

[0057] Step 5: Place the molded chocolate at room temperature for 25 minutes until the temperature drops to 25°C; then place it in a refrigerator at 4°C for 5 minutes until the chocolate is completely solidified; remove the mold and gently unmold to obtain the finished product of fat analogue-fortified and dietary fiber-enhanced chocolate.

[0058] Example 2

[0059] A method for preparing fiber-fortified low-fat chocolate, comprising:

[0060] Step 1: Accurately weigh 21g whey protein powder, 5g locust bean gum, 2g konjac gum, and 1g carrageenan powder as the main gelling matrix. Weigh 3g egg yolk powder as a natural emulsifier and flavor enhancer. Measure 28g water and mix to form a precise dispersion system. After mixing and stirring for 15 minutes, shear the mixture for 2 minutes at 8000r / min using a high-speed shearing machine to obtain an emulsion with an average particle diameter of 9μm, which is the whey protein-based fat mimicry. Seal and refrigerate for later use.

[0061] Step 2: Weigh the raw materials: 35g cocoa liquor, 16g cocoa butter, 3g fat analog prepared in Step 1, 5g wheat bran soluble dietary fiber powder, 13g sugar powder, 2g skim milk powder, 0.3g soy lecithin, 0.3g whey powder, 0.3g polyglycerol fatty acid ester, 0.3g conjugated linoleic acid glyceride, and 0.4g food flavoring.

[0062] Cocoa butter, fat analogue, and wheat bran soluble dietary fiber were heated in a 58°C water bath for 10 minutes until melted. Cocoa liquor was added and stirred for 12 minutes to obtain cocoa liquor. Sugar powder was added in batches and stirred. Skim milk powder was added and stirred for 10 minutes to form a homogeneous mixture.

[0063] Cocoa butter, fat analogue, and wheat bran soluble dietary fiber were placed in a 58°C constant temperature water bath and heated for 10 minutes until completely melted. Cocoa liquor was then added, and the mixture was stirred continuously for 12 minutes to obtain a homogeneous cocoa liquor. Powdered sugar was added in small amounts several times, stirring for 5 minutes after each addition, until the powdered sugar was completely dissolved. Subsequently, skim milk powder, soy lecithin, whey powder, polyglycerol fatty acid esters, conjugated linoleic acid glycerides, and food flavorings were slowly added, and the mixture was stirred continuously for 10 minutes to form a homogeneous and stable mixture.

[0064] Step 3: Pour the mixture into a temperature control machine and use a segmented temperature control method for temperature adjustment. Heat to 50°C and hold for 6 minutes to completely melt the crystals. Then place it in an ice-water bath and cool while stirring until the temperature drops to 33°C, inducing the formation of various metastable crystal forms. Remove and continue stirring for 10 minutes until the temperature drops to 28°C, promoting the transformation of the metastable crystal forms into the stable β-type. Cool again in an ice-water bath for 3 minutes until the temperature drops to 25°C, strengthening crystallization. Finally, reheat to 30°C to complete the temperature adjustment and obtain a temperature-controlled chocolate paste with suitable fluidity and crystalline structure.

[0065] Step 4: Pour the tempered chocolate mixture into a silicone mold that has been preheated to 30°C. Place the mold on a vibrating table and vibrate for 40 seconds to remove air from the mixture.

[0066] Step 5: Place the molded chocolate at room temperature for 35 minutes until the temperature drops to 25°C; then place it in a refrigerator at 4°C for 10 minutes until the chocolate is completely solidified; remove the mold and gently unmold to obtain the finished product of fat analogue-fortified and dietary fiber-enhanced chocolate.

[0067] Please refer to the actual product of the fiber-fortified low-fat chocolate prepared using the method described in this embodiment. Figure 2 .

[0068] Comparative Example 1 (Traditional Full-Fat Chocolate)

[0069] The difference from Example 1 is that whey protein-based fat analogues and wheat bran soluble dietary fiber are not added; only conventional chocolate formulas and processes are used, while the other steps are the same as in Example 1.

[0070] Comparative Example 2 (Fat analogues added only, no dietary fiber added)

[0071] The difference from Example 1 is that no wheat bran soluble dietary fiber is added, while other raw materials and processes remain unchanged. The wheat bran soluble dietary fiber in the formula is replaced with an equal amount of cocoa butter, and the other steps are the same as in Example 1.

[0072] Comparative Example 3 (Dietary fiber only, no fat analogues added)

[0073] The difference from Example 1 is that the whey protein-based fat analog is removed, while other ingredients and processes remain unchanged. The fat analog portion in the formulation is replaced with an equal amount of cocoa butter, and the other steps are the same as in Example 1.

[0074] Comparative Example 4

[0075] The difference from Example 1 is that the high-speed shearing speed in the whey protein gel network construction process was adjusted to 4000 r / min and the shearing time was shortened to 60 s. Other formulations and steps are the same as in Example 1.

[0076] Comparative Example 5 (different types of substitute colloids)

[0077] The difference from Example 1 is that in step one, locust bean gum, konjac gum, and carrageenan are replaced with equal amounts of xanthan gum, guar gum, and guar gum, while the other steps are the same as in Example 1.

[0078] I. Composition Analysis and Sensory Evaluation

[0079] Soluble dietary fiber content was determined according to AACC 32-07.01; fat content was determined according to GB 5009.6-2016; and protein content was determined according to GB 5009.5-2025. Sensory evaluation was conducted according to GB / T 10220-2012, with a trained sensory evaluation team comprehensively evaluating the product's appearance, color, aroma, taste, and overall acceptability.

[0080] Table 1 Comparison of Nutritional Components and Sensory Scores

[0081] sample Soluble dietary fiber (%) Fat(%) protein(%) Sensory rating Example 1 8.98 25.1 7.51 99.4 Example 2 8.36 26.8 7.33 98.7 Comparative Example 1 0.35 43.8 1.63 85.6 Comparative Example 2 0.35 33.6 7.38 89.5 Comparative Example 3 8.57 42.5 1.65 88.3 Comparative Example 4 8.03 27.3 7.50 91.2 Comparative Example 5 8.56 26.5 7.52 92.3

[0082] Comparative examples and comparative examples show that the products prepared using this method significantly reduce fat and increase dietary fiber and protein content while maintaining excellent sensory quality. The dietary fiber content of Examples 1 and 2 is 8.36% and 8.98%, respectively, significantly higher than the 0.35% of Comparative Examples 1 and 2; the fat content of Examples 1 and 2 is 25.1% and 26.8%, significantly lower than the 33.6%-43.8% of Comparative Examples 1-3; the protein content of Examples 1 and 2 is 7.51% and 7.33%, significantly higher than the 1.63% and 1.65% of Comparative Examples 1 and 3. The sensory scores of Examples 1 and 2 (99.4 and 98.7) are significantly higher than and significantly lower than the 85.6-92.3 of Comparative Examples 1-5. This indicates that the synergistic effect of fat mimics and soluble dietary fiber can significantly improve the nutritional and sensory quality of the chocolate system.

[0083] II. Texture Analysis

[0084] Texture profile analysis (TPA) was performed using a texture analyzer, and the tested parameters were hardness, elasticity, adhesiveness, and chewiness. An SMA P / 2 probe was used, with a testing rate of 1 mm / s before and after the test. Samples were prepared as cuboids 3.5 cm long, 3 cm wide, and 2.5 cm high, with a data frequency of 10 Hz and a contact trigger point load of 5 g. Each sample was measured three times, and the average value was taken.

[0085] Figure 1 shows the comparative data on texture quality (different letters above different columns of the same type indicate significant differences). By comparing the examples and comparative examples, it can be seen that the product of this scheme significantly improves texture quality while significantly reducing fat and increasing dietary fiber and protein content. The hardness of Examples 1 and 2 is 2505g and 2755g, respectively, far lower than the 3388g of the full-fat chocolate in Comparative Example 1; the adhesiveness of Examples 1 and 2 is 815 and 806, respectively, with no significant difference from Comparative Examples 1-5; the chewiness of Examples 1 and 2 is 691g and 632g, respectively, far higher than Comparative Examples 1-4. This indicates that the synergistic effect of fat analogues and soluble dietary fiber can significantly improve the nutritional quality of the chocolate system without affecting texture characteristics.

[0086] III. Determination of Enthalpy and Glass Transition Temperature

[0087] The enthalpy of melting (ΔH) was determined using differential scanning calorimetry (DSC). 3-4 mg of chocolate sample was accurately weighed and placed in a sealed aluminum pan, pressed into a tablet, and then measured. Nitrogen flow rate was 50 mL / min, the measurement temperature range was 20℃-70℃, and the heating rate was 10℃ / min. ΔH was obtained by integrating the melting peak area of ​​the melting curve using the DSC instrument's built-in software.

[0088] The glass transition temperature (Tg) was determined using differential scanning calorimetry (DSC). 3-4 mg of chocolate sample was accurately weighed and placed in a sealed aluminum pan, compressed into a tablet, and then measured. The sample measurement procedure was as follows: the sample was cooled from 25°C to -80°C at a rate of -20°C / min and held for 5 min; then heated to 14°C (Tm annealing temperature) at a rate of 20°C / min and held for 5 min; then cooled to -80°C. Finally, the temperature was increased to 100°C at a rate of 20°C / min, and the Tg of the sample was analyzed based on the second heating curve.

[0089] Table 2. Results of enthalpy and glass transition temperature

[0090] sample Enthalpy of fusion ΔH (J / g) Glass transition temperature Tg (ºC) Example 1 52.8 21.3 Example 1 43.6 20.8 Comparative Example 1 29.3 3.44 Comparative Example 2 33.5 5.36 Comparative Example 3 30.1 4.52 Comparative Example 4 40.0 16.1 Comparative Example 5 41.3 16.6

[0091] Comparative examples and comparative examples show that the product prepared by this method comprehensively surpasses existing technologies in key indicators of thermodynamics and storage stability, while solving the industry problem of balancing the taste and storage stability of high-fiber chocolate. The melting enthalpy ΔH of Examples 1 and 2 are 52.8 J / g and 43.6 J / g, respectively, which are significantly higher than the 29.3-41.3 J / g of the comparative examples, indicating that they have higher thermodynamic stability.

[0092] The glass transition temperatures (Tg) of Examples 1 and 2 are above 20°C, while those of the comparative examples are below 17°C. This allows them to remain in a stable glassy state at room temperature, effectively inhibiting fat migration and blooming, maintaining texture and flavor, and achieving excellent shelf-life stability.

[0093] The above data shows that the embodiment, through unique ingredient and process design, successfully constructed a synergistic system of high melting enthalpy and high Tg, with a predicted shelf life of over 18 months. This means that the product not only tastes close to traditional high-quality chocolate, but also overcomes the long-standing bottleneck of high-fiber chocolate being "prone to blooming and difficult to preserve," giving it stronger product competitiveness.

[0094] IV. β-Crystal Form Content Test

[0095] The chocolate sample was ground into a fine powder, passed through an 80-mesh sieve, and evenly spread in the sample cell. The X-ray diffractometer was set to a scanning range of 5°-85°, a scanning speed of 8° / min, and a step size of 0.02°. The diffraction pattern was scanned and recorded, and the characteristic peaks of the β-crystal form and other crystal forms were identified. The area of ​​each characteristic peak was integrated using the spectral analysis software. The β-crystal form content was calculated as: β-crystal form content = total area of ​​β-crystal form characteristic peaks / total area of ​​all crystal form characteristic peaks × 100%.

[0096] Table 3. Test data on β-crystal content

[0097] sample β-crystal content (%) Example 1 93.6 Example 1 92.8 Comparative Example 1 69.3 Comparative Example 2 73.5 Comparative Example 3 70.1 Comparative Example 4 80.0 Comparative Example 5 87.3

[0098] Data shows that the β-crystal content of this product (Examples 1 and 2) is as high as 93.2% and 92.8%, respectively, significantly better than the 69.3%-87.3% of the comparative examples. This directly translates into better taste and melting characteristics, and gives the product excellent anti-frosting properties. This result confirms from a crystallographic perspective that this solution successfully overcomes the interference of the low-fat, high-fiber system on crystallization, achieving precise control over the fat crystal structure, thus achieving a leading position in macroscopic performance and providing a reliable solution for producing high-quality, long-shelf-life high-fiber chocolate.

[0099] V. Oxidative Acid Value Test

[0100] According to GB 5009.229-2025, grind the chocolate sample into a fine powder, weigh 5g of the chocolate sample into an Erlenmeyer flask, add 100mL of petroleum ether, and shake to dissolve; add 3 drops of phenolphthalein indicator, and titrate with 0.1mol / L sodium hydroxide standard solution until the solution turns pink and does not fade for 15s, and record the volume of standard solution consumed (V, mL); at the same time, perform a blank control and record the volume of standard solution consumed in the blank control (V0, mL).

[0101] The formula for calculating the oxidation acid value is:

[0102] ;

[0103] Where c is the concentration of the sodium hydroxide standard solution (mol / L) and m is the sample mass (g).

[0104] Table 4 Oxidative Acid Value Test

[0105] sample β-crystal content (%) Example 1 0.28 Example 1 0.36 Comparative Example 1 0.93 Comparative Example 2 0.73 Comparative Example 3 0.80 Comparative Example 4 0.61 Comparative Example 5 0.63

[0106] The data above show that the oxidative acid value of Examples 1 and 2 is extremely low (0.28-0.36 mg NaOH / g), significantly better than the 0.61-0.93 mg NaOH / g of all comparative examples. This demonstrates that the technology is highly effective in inhibiting oxidative rancidity of oils and fats, and, together with the previously revealed high β-crystal content, ensures excellent product stability and long shelf life from both chemical and physical perspectives.

[0107] In summary, the preparation method provided in this scheme, based on the synergistic effect of whey protein-based fat mimics and wheat bran soluble dietary fiber, partially replaces traditional cocoa butter. By optimizing key process parameters such as rotation speed, shear time, and the amount of dietary fiber and fat mimics added, and through steps including raw material pretreatment, mixing, temperature adjustment, molding, and cooling, a high-fiber, low-fat chocolate product is prepared. The optimized process parameters are: rotation speed 6000-13000 r / min, shear time 120s-300s, soluble dietary fiber addition 5%-15%, and fat mimic addition 5%-20%. Accelerated shelf-life testing shows that this product has a predicted shelf life of over 18 months at 25℃, which is superior to similar commercially available products (typically 12 months).

[0108] The chocolate prepared by this method has both excellent sensory quality and nutritional value, with significantly reduced fat content, significantly increased dietary fiber content, delicate texture, and good thermal stability. It solves the problem of high calories and high fat in traditional chocolate and provides a feasible technical solution for the development of new nutritious and healthy chocolate products.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing fiber-fortified low-fat chocolate, characterized in that, include: Step 1: According to the weight parts, combine 20-30 parts whey protein powder, 3-5 parts locust bean gum, 2-5 parts konjac gum, 1-3 parts carrageenan powder, 3-5 parts egg yolk powder and 20-30 parts water to form a precise dispersion system. After mixing and stirring for 10-30 min, the mixture is micronized to form a gel network structure with an average particle diameter of less than 10 μm, thereby obtaining a dense whey protein-based fat mimic. Step 2: Place 12-15 parts of cocoa butter, 5-10 parts of whey protein-based fat analog prepared in Step 1, and 5-10 parts of wheat bran soluble dietary fiber powder in a water bath and heat to melt them to form a uniform oil phase composite matrix. Add 30-40 parts of cocoa liquor and stir continuously to form chocolate base; Add 10.5-13.5 parts of powdered sugar, 1-3 parts of skim milk powder, 0.1-0.3 parts of soybean lecithin, 0.1-0.3 parts of whey powder, 0.1-0.3 parts of polyglycerol fatty acid ester, and 0.1-0.3 parts of conjugated linoleic acid glyceride, and continue stirring until a homogeneous and stable mixture is formed; Step 3: Heat the mixture obtained in Step 2 to 50-60℃ and hold for 5-10 minutes to allow the crystals of the mixture to completely melt. Place it in an ice-water bath to cool and stir continuously. After cooling to 30-40℃, remove it to induce the formation of various metastable crystal forms. Continue stirring until the temperature drops to 27-33℃ to promote the transformation of the metastable crystal form to the stable β-type; Cool again to around 20-27℃ to enhance crystallization; Finally, heat the mixture to 30-40℃ to melt the unstable crystal form, retain and stabilize the β-type crystal, and obtain a tempered chocolate paste with suitable fluidity and crystal structure. Step 4: Pour the tempered chocolate mixture from Step 3 into a thermostatic mold, shake to remove air bubbles, and let it stand to cool to room temperature. Step 5: Place the chocolate mixture in the refrigerator and refrigerate until it solidifies and sets. Remove it from the mold to obtain the finished product.

2. The method according to claim 1, characterized in that, In step one, 20 parts whey protein powder, 3 parts locust bean gum, 2 parts konjac gum, 1 part carrageenan powder, 3 parts egg yolk powder, and 20 parts water are mixed into a precisely dispersed mixture system.

3. The method according to claim 1, characterized in that, In step one, 30 parts whey protein powder, 5 parts locust bean gum, 5 parts konjac gum, 3 parts carrageenan powder, 5 parts egg yolk powder, and 30 parts water are mixed into a precisely dispersed mixture system.

4. The method according to claim 1, characterized in that, In step one, 25 parts whey protein powder, 4 parts locust bean gum, 3.5 parts konjac gum, 2 parts carrageenan powder, 4 parts egg yolk powder, and 25 parts water are mixed into a precise dispersion system.

5. The method according to claim 1, characterized in that, In step two, 12 parts of cocoa butter, 5 parts of whey protein-based fat analog prepared in step one, and 5 parts of wheat bran soluble dietary fiber powder are placed in a water bath and heated to melt, forming a uniform oil phase composite matrix. Add 30 parts of cocoa liquor and stir continuously to form chocolate base; Add 10.5 parts of powdered sugar, 1 part of skim milk powder, 0.1 parts of soy lecithin, 0.1 parts of whey powder, 0.1 parts of polyglycerol fatty acid ester and 0.1 parts of conjugated linoleic acid glyceride, and continue stirring until a homogeneous and stable mixture is formed.

6. The method according to claim 1, characterized in that, In step two, 15 parts of cocoa butter, 10 parts of whey protein-based fat analog prepared in step one, and 10 parts of wheat bran soluble dietary fiber powder are placed in a water bath and heated to melt, forming a uniform oil phase composite matrix. Add 40 parts of cocoa liquor and stir continuously to form chocolate base; Add 13.5 parts powdered sugar, 3 parts skim milk powder, 0.3 parts soy lecithin, 0.3 parts whey powder, 0.3 parts polyglycerol fatty acid ester and 0.3 parts conjugated linoleic acid glyceride, and continue stirring until a homogeneous and stable mixture is formed.

7. The method according to claim 1, characterized in that, In step two, 13 parts of cocoa butter, 8 parts of whey protein-based fat analog prepared in step one, and 8 parts of wheat bran soluble dietary fiber powder are placed in a water bath and heated to melt, forming a uniform oil phase composite matrix. Add 35 parts of cocoa liquor and stir continuously to form chocolate syrup; Add 12 parts powdered sugar, 2 parts skim milk powder, 0.2 parts soy lecithin, 0.2 parts whey powder, 0.2 parts polyglycerol fatty acid ester, and 0.2 parts conjugated linoleic acid glyceride, and continue stirring until a homogeneous and stable mixture is formed.

8. The method according to claim 1, characterized in that, In step one, whey protein powder, locust bean gum, konjac gum and carrageenan powder are mixed as a gel matrix; a high-speed shearing machine is used at a speed of 6000-13000 r / min for 2-5 min to form a gel network structure with an average particle diameter of less than 10 μm.

9. The method according to claim 1, characterized in that, In step two, 0.3-0.5 parts of food flavoring and fragrance are also added.

10. A fiber-fortified low-fat chocolate, prepared by the method described in any one of claims 1-9.

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