A method for producing low-sugar high-dietary fiber apple chips

Abstract

The application discloses a production method of low-sugar high-dietary-fiber apple crisp chips and belongs to the technical field of food processing. The method uses apple residues, a by-product after apple juice extraction, as raw materials and sequentially performs the following processes: air drying, ultrafine grinding, water adding and shaping, and drying to prepare the apple crisp chips. In the method, most of soluble sugar is separated from the fruit juice in the juice extraction process, so that the natural low-sugar characteristic of the product is realized. Meanwhile, the fiber particle size is refined through the ultrafine grinding, the rough taste of the dietary fiber is improved, and the drying technology is combined to make the product have good crispness without adding grease.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a method for producing low-sugar, high-diet apple chips. Background Technology

[0002] Apple crisps are a type of snack food made from fresh apples through processes such as drying or frying. Because they retain the flavor, color, and nutrients of apples well, and are crispy and easy to carry, they have gained a significant position in the fruit and vegetable crisp market in recent years. With increasing consumer health awareness, the demand for functional snack foods that are low in sugar, high in dietary fiber, and low in calories continues to grow, especially for people with diabetes, obesity, and those trying to control their blood sugar. The market is placing higher demands on apple crisp products that combine low sugar and high dietary fiber.

[0003] Currently, common processing methods for apple chips include vacuum frying, hot air drying, microwave drying, and vacuum freeze-drying. However, existing apple chip products generally suffer from the following problems: First, apples naturally contain high levels of fructose, glucose, and sucrose. After dehydration and concentration, the total sugar content in the chips usually increases significantly, resulting in a high glycemic index, making it difficult to meet the needs of people on a sugar-controlled diet. Second, traditional apple chips are mainly dried by slicing whole apples, resulting in relatively limited dietary fiber content. They mainly rely on the insoluble fiber inherent in the fruit pulp, while soluble dietary fiber is easily lost during processing. Third, while vacuum frying can improve the texture, it introduces more oil, increasing the product's fat content. Non-frying drying processes often result in chips that are hard, have poor chewiness, or suffer from severe browning. Currently, no existing technology has been found that can systematically achieve low-sugar, high-fiber apple chip products with good sensory quality.

[0004] To address the aforementioned problems, this invention provides a method for producing low-sugar, high-fiber apple chips using apple pomace, a byproduct of apple juicing, as raw material. Apple pomace is a large-scale byproduct generated during fruit juice processing, rich in natural dietary fiber. Furthermore, during the juicing process, most of the soluble sugars are removed with the juice, resulting in a significantly lower total sugar content compared to the original fruit. Using apple pomace as raw material to prepare chips not only achieves high-value utilization of the byproduct, reducing resource waste and environmental pollution, but also naturally achieves the dual goals of low sugar and high dietary fiber without relying on exogenous sugar removal processes, demonstrating promising industrial application prospects. Summary of the Invention

[0005] In view of the above-mentioned prior art, the purpose of this invention is to provide a method for producing low-sugar, high-fiber apple chips. This invention uses apple pomace, a byproduct of apple juicing, as raw material, and prepares the product through a series of processes including forced-air drying, ultra-fine grinding, water addition and molding, and further drying. The juicing process separates most of the soluble sugars with the juice, achieving the product's naturally low-sugar characteristics. Simultaneously, ultra-fine grinding refines the fiber particle size, improving the rough texture of the dietary fiber, and combined with drying technology, the product maintains good crispness without the addition of oil.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides a method for producing low-sugar, high-diet apple chips, comprising the following steps: (1) Crushing and juicing: Wash fresh apples, crush them, juice them, and separate the apple pulp; (2) Blow-air drying: The apple pomace is dried by blow-air drying to obtain dried apple pomace; (3) Ultrafine grinding: The dried apple pomace is ultrafine ground to obtain apple pomace ultrafine powder; (4) Add water to form a mold: Add pure water to the apple pomace ultrafine powder, stir evenly to form a slurry, and spread the slurry evenly into the mold; (5) Slurry drying: The shaped material is subjected to vacuum freeze-drying or puffing drying to obtain apple chips. See the process flow below. Figure 1 .

[0007] Crushing and Juicing: Fresh apples are washed and cleaned, then crushed and juiced using a crusher and screw press to separate apple juice and apple pomace. Any apple variety can be used, such as Fuji, Gala, Golden Delicious, and Guoguang, which are commonly used for fresh consumption or processing. The resulting apple pomace has a total sugar content that is more than 60% lower than the original fruit, and a total dietary fiber content that is 2 to 3 times higher.

[0008] Furthermore, in step (2), the apple pomace is dried by blowing air at 55-65℃, and the moisture content of the final dried apple pomace is 5-15%.

[0009] Blow-air drying: Place the apple pomace obtained in step (1) in a blow-air drying oven or belt dryer, and dry at a temperature of 50-80°C, preferably 55-65°C, until the moisture content is 5%-15%, preferably 8%-10%. This step can effectively extend the storage time of apple pomace and provide materials with suitable moisture content for subsequent ultrafine grinding.

[0010] Furthermore, in step (3), the particle size of the pulverized apple pomace ultrafine powder is 100-500 mesh.

[0011] Ultrafine grinding: The dried apple pomace is ultrafine ground. Grinding equipment can include an air jet mill, a vibratory mill, or a planetary ball mill. The particle size is controlled between 100 and 500 mesh, preferably 150 to 300 mesh. Ultrafine grinding can significantly reduce the particle size of fiber particles, improve the roughness and gritty feeling of dietary fiber in the mouth, and is beneficial for subsequent shaping and improving taste quality.

[0012] Furthermore, in step (4), the mass ratio of apple pomace ultrafine powder to purified water is 1:(1-4); the thickness of the slurry after being poured into the mold is 1-8mm.

[0013] Water addition and molding: Add 1 to 4 times the weight of water, preferably 1.5 to 2.5 times the weight of water, to the ultrafine apple pomace powder obtained in step (3), and stir thoroughly to form a uniform slurry. Spread the slurry evenly into the mold or molding frame on the conveyor belt, with a molding thickness of 1 to 8 mm, preferably 2 to 5 mm. The molding shape can be round, square, heart-shaped, or irregular, depending on the product requirements.

[0014] In this step, exogenous dietary fiber may be selectively added at a rate of 5% to 25% of the dry weight of the apple pomace ultrafine powder. The exogenous dietary fiber is selected from one or more of resistant dextrin, polydextrose, inulin, oat fiber, and wheat fiber to further increase the total dietary fiber content of the product to more than 20%.

[0015] Furthermore, in step (5), during vacuum freeze drying, apple chips are obtained through pre-freezing, primary drying, and secondary drying; During pre-freezing, place the shaped material at -25 to -45°C for 2 to 6 hours; During the first drying process, under an absolute pressure of 10 to 100 Pa, the shelf temperature is raised to -10 to 0°C at a heating rate of 5 to 15°C / hour, and the drying process lasts for 8 to 12 hours. During the second drying process, the temperature is further increased to 25–50°C, and the drying time is 4–10 hours to obtain apple crisps.

[0016] Furthermore, in step (5), during puffing and drying: The shaped material is placed in an extruder, heated to 80-130℃, and pressurized to 0.2-0.6MPa for 1-8 minutes. The pressure relief valve is opened instantly, and the pressure drops to atmospheric pressure within 0.1-1 seconds, causing the material to flash-expand. The expanded material is then removed and placed in a hot air drying oven at 60-85℃ for 10-40 minutes for auxiliary drying to obtain apple chips.

[0017] Drying: The shaped material shall be dried using any of the following methods: Method 1: Vacuum freeze drying The shaped material is placed in a vacuum freeze-drying apparatus. The pre-freezing temperature is -25 to -45°C, preferably -30 to -40°C, and the freezing time is 2 to 6 hours to ensure complete solidification. In the first drying stage (sublimation drying), the vacuum degree is controlled at 10 to 100 Pa, preferably 20 to 50 Pa, and the shelf temperature is increased from the pre-freezing temperature to -10 to 0°C at a rate of 5 to 15°C / hour, with a drying time of 8 to 16 hours. In the second drying stage (desorption drying), the shelf temperature continues to rise to 25 to 50°C, and the drying time is 4 to 10 hours. The final product has a moisture content ≤6%, preferably ≤5%.

[0018] Method 2: Extrusion Drying The shaped material is placed in a variable-temperature, differential-pressure puffing device. The puffing chamber temperature is set to 80–130℃, preferably 90–120℃; the puffing pressure is 0.2–0.6 MPa, preferably 0.3–0.5 MPa; and the holding time is 1–8 minutes, preferably 2–5 minutes. After the holding time is reached, the pressure relief valve is instantly opened to atmospheric pressure, with a pressure drop time ≤1 second. The puffing force generated by the rapid vaporization of moisture causes the material to form a loose, porous structure. After puffing, auxiliary hot air drying is used at a temperature of 60–85℃ for 10–40 minutes to ensure that the final moisture content of the product is ≤7%, preferably ≤6%.

[0019] Cooling and Packaging: Cool the dried chips to room temperature, sort and package them according to product specifications, preferably using nitrogen-filled or aluminum foil sealed packaging to maintain the crisp texture and extend shelf life.

[0020] A second aspect of the present invention provides low-sugar, high-diet apple chips prepared by any of the production methods described in any one of the inventions.

[0021] The apple crisps produced by this invention have a total sugar content of ≤5g / 100g and a total dietary fiber content of ≥15g / 100g. No free sugar or oil is added. The product has a natural light yellow to pale yellow-brown color, a crispy texture, and no obvious rough fiber feel.

[0022] The beneficial effects of this invention are: 1. Naturally low in sugar, no sugar removal process required: Made directly from apple pomace, a byproduct of apple juicing. During the juicing process, most of the soluble fructose, glucose, and sucrose are separated with the juice. The total sugar content of the apple pomace is reduced by more than 60% compared to the original fruit. The resulting crisps have a total sugar content of less than 5g / 100g, naturally meeting the requirements for low-sugar foods, without the need for additional sugar removal processes or the addition of sugar substitutes.

[0023] 2. High dietary fiber and high-value utilization of by-products: Apple pomace is rich in insoluble and soluble dietary fiber, with a total dietary fiber content 2 to 3 times that of the original fruit. Through ultra-fine grinding and compounding with exogenous fiber, the total dietary fiber content of the product can reach 15% to 30%. At the same time, it realizes the resource utilization of by-products of juice processing, reduces environmental pollution, and lowers raw material costs.

[0024] 3. Dual drying process options to meet different production needs: This invention provides two process paths: vacuum freeze-drying and puffing drying. Vacuum freeze-drying can retain the natural color, flavor, and fibrous skeleton structure of apple pomace to the maximum extent, resulting in products with good rehydration properties and regular shape; puffing drying has the advantages of short drying time, low energy consumption, and small equipment investment, making it suitable for large-scale continuous production.

[0025] 4. No added sugar or oil, pure and healthy: No added white sugar, syrup, oil or food additives (except acidity regulators) are added throughout the entire process. The product ingredients are clean, which meets the "clean label" consumer trend and is suitable for long-term consumption by diabetic patients, people who are trying to lose weight and people who need high dietary fiber.

[0026] 5. Crispy texture and excellent sensory quality: The fiber particle size is refined to 100-300 mesh through ultra-fine grinding, which effectively improves the roughness and gritty feel of the fiber; combined with the porous skeleton of freeze-drying or the honeycomb structure formed by puffing flash evaporation, the crisps are crispy and do not hurt your teeth, and there is no greasy feeling of fried products. Attached Figure Description

[0027] Figure 1 This is a flowchart of the production process of the present invention.

[0028] Figure 2 This represents the total sugar content of the apple chips.

[0029] Figure 3 This represents the total dietary fiber content of the apple crisps. Detailed Implementation

[0030] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0031] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0032] The test materials used in the embodiments of the present invention, unless otherwise specified, are all conventional test materials in the art and can be purchased through commercial channels.

[0033] Example 1: Preparation of apple chips using vacuum freeze-drying process A method for producing low-sugar, high-fiber apple crisps, comprising the following steps: (1) Crushing and juicing: Fresh Fuji apples were washed, crushed, and juiced. Apple pulp was separated and its total sugar content was determined to be 8.2g / 100g (wet basis) and its total dietary fiber content was 12.6g / 100g (wet basis). (2) Drying by blowing air: Place the apple pomace in a drying oven and dry it at 60°C until the moisture content is 10% to obtain dried apple pomace; (3) Ultrafine grinding: The dried apple pomace is ground to 200 mesh using an ultrafine grinder to obtain apple pomace ultrafine powder; (4) Add water to form a slurry: Add twice the weight of pure water to the apple pomace ultrafine powder, stir evenly to form a slurry, and spread the slurry evenly into a square mold with a thickness of 3mm. (5) Vacuum freeze drying: Pre-freezing: Place the shaped material at -35℃ and freeze for 3 hours; One-time drying: Under an absolute pressure of 30 Pa, the shelf temperature is raised from -35℃ to -10℃ at a heating rate of 10℃ / hour, and dried for 10 hours; Secondary drying: Continue heating to 35℃ and dry for 6 hours to obtain apple chips. Store in a nitrogen-filled, light-proof, and airtight container.

[0034] Example 2: Preparation of apple chips using a puffing and drying process A method for producing low-sugar, high-fiber apple crisps, comprising the following steps: (1) Crushing and juicing: Fresh Fuji apples were washed, crushed, and juiced. Apple pulp was separated and its total sugar content was determined to be 8.2g / 100g (wet basis) and its total dietary fiber content was 12.6g / 100g (wet basis). (2) Drying by blowing air: Place the apple pomace in a drying oven and dry it at 55°C until the moisture content is 8% to obtain dried apple pomace; (3) Ultrafine grinding: The dried apple pomace is ground to 150 mesh using an ultrafine grinder to obtain apple pomace ultrafine powder; (4) Add water to form a slurry: Add 1.5 times the weight of water to the apple pomace ultrafine powder, stir evenly to form a slurry, and spread the slurry evenly into a round mold with a thickness of 4mm; (5) Extrusion and drying: The shaped material is placed into the extruder cavity, heated to 100℃, pressurized to 0.3MPa, and maintained for 3 minutes; The pressure relief valve is opened instantly, and the pressure drops to atmospheric pressure within 0.5 seconds, causing the material to flash and expand. Remove the puffed material and place it in a 70℃ hot air drying oven for 15 minutes to obtain apple chips. Store the chips in a nitrogen-filled, light-proof, and airtight container.

[0035] Comparative Example The difference between this comparative example and Example 1 is that apple pomace is not used as raw material; instead, fresh apples are sliced ​​directly and then freeze-dried.

[0036] The specific steps are as follows: (1) Raw material processing: Take fresh Fuji apples, wash them, remove the cores, and cut them into uniform thin slices with a thickness of 3mm; (2) Pre-freezing: Place apple slices at -35℃ and freeze for 3 hours; (3) Vacuum freeze drying: Under an absolute pressure of 30 Pa, the shelf temperature is raised from -35 °C to -10 °C at a heating rate of 10 °C / hour and dried for 10 hours; the temperature is raised to 35 °C for a second drying and dried for 6 hours to obtain apple chips, which are then sealed and stored in a nitrogen-filled, light-proof container.

[0037] Test case The apple chips obtained in Examples 1-2 and the comparative examples were subjected to physicochemical index testing and sensory evaluation.

[0038] 1. Physicochemical index testing The testing indicators are total sugar, total dietary fiber, and water content, and the standards used are as follows: The total sugar content was determined according to the acid hydrolysis-Rhine-Enon method in "GB 5009.8-2023 National Food Safety Standard for the Determination of Fructose, Glucose, Sucrose, Maltose and Lactose in Food".

[0039] The determination of total dietary fiber content was carried out in accordance with "GB 5009.88-2023 National Food Safety Standard - Determination of Dietary Fiber in Food".

[0040] Moisture content determination shall be performed in accordance with “GB 5009.3-2016 National Food Safety Standard - Determination of Moisture in Food”.

[0041] The test results are shown in Table 1.

[0042] Table 1. Physicochemical Indicators Detection According to Table 1 and Figure 2 As a result, in terms of total sugar, this invention directly uses apple pomace, a byproduct of apple juicing, as raw material. During the juicing process, most of the soluble fructose, glucose, and sucrose are separated with the juice. The total sugar content of the apple pomace is reduced by more than 60% compared with the original fruit. The total sugar content of the resulting crisps is less than 5g / 100g, naturally meeting the requirements for low-sugar foods. No additional sugar removal process or addition of sugar substitutes is required, which is superior to the comparative example.

[0043] According to Table 1 and Figure 3 As a result, in terms of total dietary fiber, apple pomace itself is rich in both insoluble and soluble dietary fiber, with a total dietary fiber content 2 to 3 times that of the original fruit. After ultra-fine grinding and compounding with exogenous fiber, the total dietary fiber content of the product can reach 15% to 30%. At the same time, it realizes the resource utilization of by-products of juice processing, reduces environmental pollution, and lowers raw material costs, which is superior to the comparative ratio.

[0044] 2. Sensory evaluation Currently, there are no specific standards for apple chips. Instead, the general national standards for sensory analysis of food are followed, as shown in Table 2.

[0045] Table 2 Sensory Evaluation Criteria The scoring details are shown in Table 3.

[0046] Table 3 Scoring Details The sensory evaluation results are shown in Table 4.

[0047] Table 4 Sensory Evaluation Results According to the results in Table 4, the present invention refines the fiber particle size to 100-300 mesh through ultra-fine grinding, which effectively improves the roughness and gritty feel of the fiber; combined with the porous skeleton of freeze-drying or the honeycomb structure formed by puffing flash evaporation, the crisps are crispy and not hard to chew, and do not have the greasy feeling of fried products, which is superior to the comparative example.

[0048] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for producing low-sugar, high-fiber apple crisps, characterized in that, Includes the following steps: (1) Crushing and juicing: Wash fresh apples, crush them, juice them, and separate the apple pulp; (2) Blow-air drying: The apple pomace is dried by blow-air drying to obtain dried apple pomace; (3) Ultrafine grinding: The dried apple pomace is ultrafine ground to obtain apple pomace ultrafine powder; (4) Add water to form a mold: Add pure water to the apple pomace ultrafine powder, stir evenly to form a slurry, and spread the slurry evenly into the mold; (5) Slurry drying: The shaped material is subjected to vacuum freeze drying or puffing drying to obtain apple chips.

2. The method for producing low-sugar, high-diet apple crisps according to claim 1, characterized in that, In step (2), the apple pomace is dried by blowing air at 55-65℃, and the moisture content of the final dried apple pomace is 5-15%.

3. The method for producing low-sugar, high-fiber apple crisps according to claim 1, characterized in that, In step (3), the particle size of the crushed apple pomace ultrafine powder is 100-500 mesh.

4. The method for producing low-sugar, high-diet apple crisps according to claim 1, characterized in that, In step (4), the mass ratio of apple pomace ultrafine powder to purified water is 1:(1-4); the thickness of the slurry after being poured into the mold is 1-8mm.

5. The method for producing low-sugar, high-diet apple crisps according to claim 1, characterized in that, In step (5), during vacuum freeze drying, apple chips are obtained through pre-freezing, primary drying, and secondary drying. During pre-freezing, place the shaped material at -25 to -45°C for 2 to 6 hours; During the first drying process, under an absolute pressure of 10 to 100 Pa, the shelf temperature is raised to -10 to 0°C at a heating rate of 5 to 15°C / hour, and the drying process lasts for 8 to 12 hours. During the second drying process, the temperature is further increased to 25–50°C, and the drying time is 4–10 hours to obtain apple crisps.

6. The method for producing low-sugar, high-fiber apple crisps according to claim 1, characterized in that, In step (5), during puffing and drying: The shaped material is placed in an extruder, heated to 80-130℃, and pressurized to 0.2-0.6MPa for 1-8 minutes. The pressure relief valve is opened instantly, and the pressure drops to atmospheric pressure within 0.1-1 seconds, causing the material to flash-expand. The expanded material is then removed and placed in a hot air drying oven at 60-85℃ for 10-40 minutes for auxiliary drying to obtain apple chips.

7. Low-sugar, high-diet apple chips prepared by the production method according to any one of claims 1-6.

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