High-fiber crabapple sweetend roll and preparation method thereof

Abstract

The invention discloses a preparation method of high-fiber crabapple sweetend rolls, which comprises the following steps: step 1, cleaning crabapples, and separating pulp and kernels from one part of crabapples; step 2, mixing the kernels and the whole crabapples, and steaming in water until the crabapples are in a soft and glutinous state; step 3, adding water to submerge the raw materials, and boiling with water to obtain crude fruit pulp containing fruit seeds and seed shells; step 4, filtering the crude fruit pulp to remove fruit seeds, fruit stems and seed shells; uniformly mixing filter residues with water, standing to precipitate fruit seeds at the bottom, and removing the fruit seeds; step five, homogenizing and refining the filtered fruit pulp and the filter residue without the fruit seeds, and adding a compound enzyme for enzymolysis, the compound enzyme comprising laccase, lignin peroxidase and multifunctional peroxidase; step 6, adding a proper amount of sweetening agent, and boiling under a stirring condition until the fruit pulp is in a non-dripping thick paste state; and step seven, paving into a thin layer, rubbing down, and drying until a tough skin-like object is formed. The method has the beneficial effects of low production equipment investment in the production process and high crude fiber content of the produced sweetend roll.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing. More specifically, the present invention relates to a high-fiber Malus asiatica fruit roll and a preparation method thereof. Background Art

[0002] Malus asiatica is rich in resources in China. Malus asiatica has a unique flavor and is rich in various nutrients such as organic acids, minerals, vitamins, and dietary fiber, among which the contents of zinc, selenium, and iron are the highest. Compared with other fruits, the contents of antioxidant factors such as flavonoids, polysaccharides, and polyphenols in Malus asiatica are more prominent, and it has health care effects such as promoting digestion, reducing blood pressure, reducing blood lipids, softening blood vessels, antioxidation, and anti-cancer.

[0003] Due to the prominent problem of difficult storage of Malus asiatica, it is necessary to process Malus asiatica. At present, the main products of Malus asiatica processing include Malus asiatica dried fruits, Malus asiatica beverages, Malus asiatica jams, Malus asiatica preserves, etc. However, during the processing of Malus asiatica, by-products such as fruit cores and fruit residues are wasted seriously and not fully utilized. Fruit roll is a kind of candied fruit product with nutritious, appetizing, easy to carry, and suitable for all ages. At present, the commercially available fruit roll is mainly made of hawthorn as raw material, the products are relatively single, and a large amount of food additives are required. Summary of the Invention

[0004] An object of the present invention is to solve at least the above problems and provide at least the advantages described hereinafter.

[0005] To achieve these objects and other advantages in accordance with the present invention, there is provided a preparation method of a high-fiber Malus asiatica fruit roll, comprising the following steps:

[0006] Step 1, raw material treatment: washing Malus asiatica, and separating the pulp and the fruit core from a part of Malus asiatica;

[0007] Step 2, steaming in water: mixing the fruit core and the whole Malus asiatica according to a mass ratio of 1.5-2:1, and steaming in water until Malus asiatica becomes soft and glutinous;

[0008] Step 3, boiling in water: adding water to cover the raw materials steamed in step 2, and boiling in water for a period of time under stirring conditions to obtain a crude fruit pulp containing fruit seeds and seed coats;

[0009] Step 4, filtering: filtering the crude fruit pulp to remove fruit seeds, fruit stalks, and seed coats; mixing the filter residue with water and mixing evenly, standing still to make the fruit seeds precipitate at the bottom, and removing the fruit seeds;

[0010] Step 5, refining and enzymatic hydrolysis: homogenizing and refining the filtered fruit pulp and the filter residue after removing the fruit seeds, and then adding a compound enzyme for enzymatic hydrolysis, wherein the compound enzyme includes laccase, lignin peroxidase, and versatile peroxidase;

[0011] Step 6, Blending: Add an appropriate amount of sweetener to the enzymatically hydrolyzed mixed fruit pulp, and boil it under stirring conditions until the fruit pulp becomes a thick mud state that does not drip.

[0012] Step 7, Scraping and Drying: Spread the fruit pulp in a thick mud state into a thin layer, level it, and dry it until it becomes a tough leathery substance, thus obtaining the high-fiber sand fruit roll.

[0013] Preferably, the water-boiling time in Step 3 is 20 - 30 min.

[0014] Preferably, a 20-mesh filter sieve is used during filtration in Step 4, and the mass ratio of the filter residue to water is 1:10.

[0015] Preferably, the mass ratio of the complex enzyme to the total mass of the fruit pits and whole sand fruits in Step 2 is 0.01 - 0.05:100, the enzymatic hydrolysis temperature is 25 - 60 °C, the enzymatic hydrolysis time is 6 - 12 h, and the enzyme activities of laccase, lignin peroxidase, and multifunctional peroxidase are 679.28 U / g, 717.2 U / g, and 652.8 U / g respectively, with a mass ratio of 1:1:2.

[0016] Preferably, the sweetener in Step 6 is sucrose, and the addition amount is 10 - 15 wt% of the total mass of the fruit pits and whole sand fruits in Step 2. The boiling time in Step 6 is 30 - 60 min.

[0017] Preferably, in Step 5, high-pressure homogenization is used for refinement, and it is circulated 2 - 3 times under a pressure of 20 - 30 MPa. Each treatment interval is static for 5 - 10 minutes, and the particle size of the refined fruit pulp is ≤50 μm.

[0018] The enzymatic hydrolysis process is carried out in two stages: In the first stage, enzymatic hydrolysis is carried out at 35 - 40 °C for 2 - 3 hours, and in the second stage, the temperature is raised to 50 - 55 °C and enzymatic hydrolysis continues for 4 - 6 hours, and continuous stirring is carried out at 200 - 300 rpm during the enzymatic hydrolysis process.

[0019] Preferably, in Step 7, a food-grade oil paper is laid on the oven tray to carry the fruit pulp, a spatula is used to level the thin layer, the thickness of the thin layer is 2 - 3 mm, and the oven is used to dry the thin layer. The drying temperature is 40 - 60 °C, and the drying time is 7 - 10 h.

[0020] Preferably, it further includes Step 8. After the leathery substance in Step 7 is cooled, it is cut into strip-shaped fruit rolls, rolled into rolls and placed, and then packaged with cellophane.

[0021] Provide a high-fiber sand fruit roll, which is prepared by the above preparation method.

[0022] Preferably, the crude cellulose content of the high-fiber sand fruit roll is 9 - 15%.

[0023] The present invention has at least the following beneficial effects:

[0024] First, aiming at the high-value utilization of Beggerlice fruit kernels, the present application uses Beggerlice fruit kernels as the main raw material and produces high-fiber probiotic Beggerlice fruit pastilles through a series of processes such as steaming, boiling, pulping, refining, and blending.

[0025] Second, the fruit pastilles prepared in the present application contain no food additives, are sweet and sour to taste, have an attractive color, and retain the rich and unique flavor of Beggerlice. It not only has the effect of promoting digestion and appetizing of traditional fruit pastilles but also is a good prebiotic food for regulating the intestinal flora. Using the whole Beggerlice fruit to make fruit pastilles in the present application can not only achieve the high-value utilization of Beggerlice, improve the high added value of Beggerlice, prepare a fruit pastille with high cellulose content and no additives, but also has less investment in production equipment, a short production cycle, and high production efficiency in the production process.

[0026] Third, the crude fiber content of the Beggerlice fruit pastilles prepared in the present application reaches 12%, and the total phenol content reaches 30 - 40 mg / Kg; the fruit pastilles are moderately hard and soft, have a sweet and sour taste, and have a strong Beggerlice flavor; the fruit pastilles are golden yellow, different from other fruit pastilles. Most of the commercially available fruit pastilles are mainly made of hawthorn and the products are dark red-brown, enriching the colors of fruit pastilles.

[0027] Fourth, traditional fruit pastille processes mostly use single enzymatic hydrolysis or mechanical crushing, while the present invention refines the fiber to the micron level (≤50 μm) through high-pressure homogenization (circular treatment at 20 - 30 MPa), and breakthroughly combines two-stage dynamic enzymatic hydrolysis: the first stage is at low temperature (35 - 40 °C) to activate the degradation of phenolic substances by laccase, and the second stage is to increase the temperature (50 - 55 °C) to strengthen the directional deconstruction of the fiber skeleton by lignin peroxidase. Experiments show that this combination increases the dissolution rate of crude fiber by 23.5%, and the breaking points of fiber molecular chains are controllable, avoiding over-degradation.

[0028] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0029] Figure 1 A photograph of the Beggerlice raw material of the present invention;

[0030] Figure 2 A photograph of the Beggerlice fruit kernels of the present invention;

[0031] Figure 3 A photograph of the Beggerlice fruit pastilles of one of the embodiments of the present invention;

[0032] Figure 4 A photograph of the fruit pulp in the thick mud state of Example 3 of the present invention spread on greaseproof paper;

[0033] Figure 5 It is a photo of commercially purchased Malus asiatica fruit leather. Specific implementation manners

[0034] The following further elaborates on the present invention in conjunction with the attached drawings, so that those skilled in the art can implement it with reference to the text of the specification.

[0035] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation schemes are all conventional methods, and the reagents and materials, unless otherwise specified, can all be obtained through commercial channels.

[0036] <Example 1>

[0037] A preparation method of high-fiber Malus asiatica fruit leather includes the following steps:

[0038] Step 1. Raw material treatment: Wash the Malus asiatica fruits, and take a part of the Malus asiatica fruits to separate the pulp and the fruit core;

[0039] Step 2. Steam in water bath: Mix the fruit cores and the whole Malus asiatica fruits, with masses of 280 g and 140 g respectively, and steam them in water bath for 30 min until the Malus asiatica fruits become soft and glutinous;

[0040] Step 3. Boil in water: Add water to cover the raw materials steamed in Step 2, and boil them for 30 min under stirring conditions to obtain a crude fruit pulp containing fruit seeds and seed coats;

[0041] Step 4. Filter: Filter the crude fruit pulp through a 20-mesh sieve to remove the fruit seeds, fruit stalks and seed coats, mix the filter residue with water at a mass ratio of 1:10, let it stand still to make the fruit seeds precipitate at the bottom, and remove the fruit seeds;

[0042] Step 5. Refine and enzymolysis: Grind the filtered fruit pulp and the filter residue after removing the fruit seeds with a colloid mill for 1 min, then add a compound enzyme for enzymolysis. The mass ratio of the compound enzyme to the total mass of the fruit cores and the whole Malus asiatica fruits in Step 2 is 0.02:100, the enzymolysis temperature is 45 °C, the enzymolysis time is 6 h, the compound enzyme is laccase, lignin peroxidase and multifunctional peroxidase, and the enzyme activities are 679.28 U / g, 717.2 U / g and 652.8 U / g respectively, and the mass ratio is 1:1:2;

[0043] Step 6. Blending: Add 15 wt% of sucrose based on the total mass of the fruit cores and the whole Malus asiatica fruits in Step 2 to the enzymolyzed fruit pulp, and boil it for 30 min under stirring conditions until the fruit pulp becomes a thick mud state that does not drip;

[0044] Step 7. Scraping and drying: Lay food-grade oil paper on the oven tray, spread the fruit pulp in the state of thick mud on the oil paper, and spread it into a thin layer with a thickness of 2-3 mm, and smooth it. Dry it in an oven at 60 °C for 7 h until it becomes a tough skin-like substance. After the skin-like substance cools, cut it into strip-shaped fruit leather rolls, place them in rolls, and then pack them with cellophane to obtain the high-fiber crabapple fruit leather.

[0045] <Example 2>

[0046] A preparation method of high-fiber crabapple fruit leather, comprising the following steps:

[0047] Step 1. Raw material treatment: Wash the crabapples, and take a part of the crabapples to separate the pulp and the fruit core;

[0048] Step 2. Steaming in water: Mix the fruit cores and whole crabapples, with masses of 280 g and 140 g respectively, and steam them in water for 30 min until the crabapples are in a soft and glutinous state;

[0049] Step 3. Boiling in water: Add water to cover the raw materials steamed in Step 2, and boil them for 30 min under stirring conditions to obtain a crude fruit pulp containing fruit seeds and seed husks;

[0050] Step 4. Filtration: Use a 20-mesh sieve to filter the crude fruit pulp to remove fruit seeds, fruit stalks and seed husks. Mix the filter residue with water at a mass ratio of 1:10, let it stand still to make the fruit seeds precipitate at the bottom, and remove the fruit seeds;

[0051] Step 5. Refining and enzymatic hydrolysis: Grind the filtered fruit pulp and the filter residue after removing the fruit seeds with a colloid mill for 1 min, and then add a composite enzyme for enzymatic hydrolysis. The mass ratio of the composite enzyme to the total mass of the fruit cores and whole crabapples in Step 2 is 0.05:100. The enzymatic hydrolysis temperature is 25 °C, and the enzymatic hydrolysis time is 6 h. The composite enzyme is laccase, lignin peroxidase and multifunctional peroxidase, and the enzyme activities are 679.28 U / g, 717.2 U / g and 652.8 U / g respectively, and the mass ratio is 1:1:2;

[0052] Step 6. Blending: Add 15 wt% of sucrose to the enzymatically hydrolyzed fruit pulp, and boil it for 60 min under stirring conditions until the fruit pulp becomes a thick mud state that does not drip;

[0053] Step 7. Scraping and drying: Lay food-grade oil paper on the oven tray, spread the fruit pulp in the state of thick mud on the oil paper, and spread it into a thin layer with a thickness of 2-3 mm, and smooth it. Dry it in an oven at 40 °C for 9 h until it becomes a tough skin-like substance. After the skin-like substance cools, cut it into strip-shaped fruit leather rolls, place them in rolls, and then pack them with cellophane to obtain the high-fiber crabapple fruit leather.

[0054] <Example 3>

[0055] Preparation method of high-fiber Malus asiatica fruit roll, comprising the following steps:

[0056] Step 1, raw material treatment: Wash the Malus asiatica, and take a part of the Malus asiatica to separate the pulp and the fruit core;

[0057] Step 2, steaming in water: Mix the fruit core and the whole Malus asiatica, with masses of 280 g and 140 g respectively, and steam in water for 30 min until the Malus asiatica becomes soft and glutinous;

[0058] Step 3, boiling in water: Add water to cover the raw materials steamed in Step 2, and boil in water for 30 min under stirring conditions to obtain a crude pulp containing fruit seeds and seed husks;

[0059] Step 4, filtering: Filter the crude pulp through a 20-mesh sieve to remove the fruit seeds, fruit stalks and seed husks, mix the filter residue with water at a mass ratio of 1:10, mix well, let stand to precipitate the fruit seeds at the bottom, and remove the fruit seeds;

[0060] Step 5, refining and enzymatic hydrolysis: Grind the filtered pulp and the filter residue after removing the fruit seeds with a colloid mill for 1 min, then add a compound enzyme for enzymatic hydrolysis. The mass ratio of the compound enzyme to the total mass of the fruit core and the whole Malus asiatica in Step 2 is 0.04:100, the enzymatic hydrolysis temperature is 25 °C, the enzymatic hydrolysis time is 6 h, the compound enzyme is laccase, lignin peroxidase and multifunctional peroxidase, and the enzyme activities are 679.28 U / g, 717.2 U / g and 652.8 U / g respectively, and the mass ratio is 1:1:2;

[0061] Step 6, blending: Add 10 wt% of sucrose to the pulp after enzymatic hydrolysis, and boil for 30 min under stirring conditions until the pulp becomes a thick mud state that does not drip;

[0062] Step 7, scraping and drying: Lay food-grade oil paper on the oven tray, spread the pulp in the thick mud state on the oil paper, and spread it into a thin layer with a thickness of 2-3 mm, and smooth it. Dry it in an oven at 60 °C for 7 h until it becomes a tough skin-like substance. After the skin-like substance cools, cut it into strip-shaped fruit rolls, roll them into rolls and place them, and then package them with cellophane to obtain the high-fiber Malus asiatica fruit roll.

[0063] <Comparative Example 1>

[0064] Preparation method of Malus asiatica fruit roll, comprising the following steps:

[0065] Step 1, raw material treatment: Wash the Malus asiatica, and take a part of the Malus asiatica to separate the pulp and the fruit core;

[0066] Step 2, steaming in water: Mix the fruit core and the whole Malus asiatica, with masses of 280 g and 140 g respectively, and steam in water for 30 min until the Malus asiatica becomes soft and glutinous;

[0067] Step 3. Boiling in water: Add water to cover the raw materials steamed in Step 2, and boil for 30 min under stirring conditions to obtain a crude fruit pulp containing fruit seeds and seed husks;

[0068] Step 4. Filtration: Filter the crude fruit pulp through a 20-mesh sieve to remove fruit seeds, fruit stalks and seed husks. Mix the filter residue with water at a mass ratio of 1:10, let it stand still to allow the fruit seeds to precipitate at the bottom, and remove the fruit seeds;

[0069] Step 5. Refining and enzymatic hydrolysis: Grind the filtered fruit pulp and the filter residue after removing the fruit seeds with a colloid mill for 1 min, and let it stand still at 45 °C for 2 h;

[0070] Step 6. Blending: Add 15 wt% of sucrose to the fruit pulp after enzymatic hydrolysis, and boil for 60 min under stirring conditions until the fruit pulp becomes a thick mud state that does not drip;

[0071] Step 7. Scraping and drying: Lay food-grade oil paper on the oven tray, spread the fruit pulp in the thick mud state on the oil paper, and spread it into a thin layer with a thickness of 2-3 mm, and smooth it. Dry it in an oven at 40 °C for 9 h until it becomes a tough leathery substance. After the leathery substance cools, cut it into strip-shaped fruit leather rolls, roll them into rolls and place them, and then package them with glass paper to obtain the high-fiber sand fruit leather roll.

[0072] <Comparative Example 2>

[0073] A method for preparing sand fruit leather roll, comprising the following steps:

[0074] Step 1. Raw material treatment: Wash the sand fruit raw materials.

[0075] Step 2. Steaming in water: Remove the cores and seeds of the sand fruits, and steam them in water for 30 min until the sand fruits become soft and glutinous.

[0076] Step 3. Boiling in water: Add water to cover the raw materials steamed in Step 2, and boil for 30 min under stirring conditions to obtain a crude fruit pulp.

[0077] Step 4. Filtration: Filter the crude fruit pulp through a 20-mesh sieve to remove the fruit peels and impurities.

[0078] Step 5. Blending: Add 30 wt% of sucrose, a certain amount of potassium sorbate, sodium benzoate and carrageenan to the fruit pulp, and boil for 60 min under stirring conditions until the fruit pulp becomes a thick mud state that does not drip;

[0079] Step 7. Scraping and drying: Lay food-grade oil paper on the oven tray, spread the fruit pulp in the thick mud state on the oil paper, and spread it into a thin layer with a thickness of 2-3 mm, and smooth it. Dry it in an oven at 40 °C for 9 h until it becomes a tough leathery substance. After the leathery substance cools, cut it into strip-shaped fruit leather rolls, roll them into rolls and place them, and then package them with glass paper to obtain the high-fiber sand fruit leather roll.

[0080] <Sensory evaluation>

[0081] The sensory evaluation of the apple fruit pastes prepared by the methods of Examples 1 to 3 and Comparative Examples 1 and 2 was carried out. The sensory evaluation criteria and results are shown in Table 1.

[0082] Table 1 Sensory evaluation criteria and results

[0083]

[0084]

[0085] It can be seen from Table 1 that the apple fruit pastes prepared in Examples 1 to 3 and the comparative examples all had relatively high scores in the sensory evaluation.

[0086] <Nutritional component detection>

[0087] The components of the apple fruit pastes prepared by the methods of Examples 1 to 3 and the comparative examples and the commercially available products were detected, and the results are shown in the following table:

[0088] Table 2 Nutritional components

[0089]

[0090] It can be seen from the data in Table 2 that the crude fiber content of the apple fruit pastes prepared in Examples 1 to 3 was as high as over 12%, far exceeding that of Comparative Example 1 and the commercially available products; the polyphenol content was as high as over 33 mg / Kg, also significantly higher than that of Comparative Example 1 and the commercially available products.

[0091] Polyphenols are natural antioxidants and antibacterial agents. A high content can reduce product spoilage and deterioration, and can reduce or avoid the use of food additives such as preservatives (potassium sorbate, sodium benzoate). While improving the cellulose in the system by complex enzyme hydrolysis treatment, the pectin properties were also improved by sugar boiling at 15 wt%, enhancing the adhesiveness and film-forming properties, and reducing or avoiding the addition of gelling substances such as carrageenan. The green and clean label of the product was achieved.

[0092] <Result analysis>

[0093] 1. Principles of Examples 1 to 3: Using whole Malus asiatica Nakai fruits (including the fruit cores) as raw materials, the Malus asiatica Nakai fruits are softened by steaming in a water bath to break the cell structure, facilitating subsequent processing. Boiling in water further enables the components of the pulp and the fruit cores to be fully dissolved, forming a crude fruit pulp. The fruit seeds, fruit stalks, seed husks and other impurities are removed by filtration to ensure the taste of the product. Enzymatic hydrolysis is carried out using a composite enzyme (laccase, lignin peroxidase and multifunctional peroxidase) to degrade some macromolecular substances in the raw materials, increasing the availability of dietary fiber and enhancing the nutritional value and functional properties of the product. Sucrose is added to adjust the taste and then boiled to concentrate the fruit pulp and evaporate the water, forming an appropriate consistency. Finally, it is sliced and dried to form a tough skin-like substance from the fruit pulp, obtaining high-fiber Malus asiatica Nakai fruit leather.

[0094] 2. Principle of Comparative Example 1: The first four steps are the same as those in the examples, but in the refinement and enzymatic hydrolysis steps, it is only ground finely by a colloid mill and then left standing at 45 °C for 2 h, and no composite enzyme is added for enzymatic hydrolysis. This means that the macromolecular substances cannot be fully degraded, and the fiber content and quality characteristics of the product cannot be effectively improved. The formation of the fruit leather mainly depends on the components of the raw materials themselves and subsequent conventional processing.

[0095] 3. Principle of Comparative Example 2: The Malus asiatica Nakai fruits are processed after removing the cores and seeds, excluding the utilization of the fruit cores. Preservatives such as potassium sorbate and sodium benzoate and gelling substances such as carrageenan are added in the formulation step. By adding these food additives, the shelf life, texture and forming effect of the product are improved, which is different from the idea of using the inherent characteristics of the raw materials and composite enzyme treatment in the examples to enhance the product quality.

[0096] Examples 1 to 3 use the Malus asiatica Nakai fruit cores as one of the main raw materials to realize the high-value utilization of whole Malus asiatica Nakai fruits, changing the traditional single mode of using mainly hawthorn as the raw material for fruit leather, and making full use of the rich resources of Malus asiatica Nakai and the potential value of its fruit cores. The use of the composite enzyme enzymatic hydrolysis technology improves the crude fiber content and polyphenol content of the product, enhancing the nutritional value and antioxidant performance of the product. Without adding preservatives and additional gelling substances, the pectin characteristics are improved through enzymatic hydrolysis and reasonable sugar boiling process, achieving good texture and forming effect of the product, meeting the requirements of green clean label. The prepared fruit leather does not contain food additives, is sweet and sour, has an attractive color, retains the rich and unique flavor of Malus asiatica Nakai, not only has the effect of promoting digestion of traditional fruit leather, but also can regulate the intestinal flora, and the crude fiber content reaches 9-15%, the total phenol content reaches 30-40 mg / Kg, and the color is golden yellow, enriching the variety of fruit leather.

[0097] In Comparative Example 1, no composite enzyme enzymatic hydrolysis is used, lacking key technical means in improving the nutritional components and quality of the product, and the product is far lower than the examples in terms of crude fiber and polyphenol content.

[0098] Although the Malus asiatica fruit leather was also made in Comparative Example 2, it relied on removing the cores and seeds and did not utilize the fruit kernel resources. At the same time, a variety of food additives were added to ensure the product quality and forming, which was not in line with the direction of green and high-value utilization of raw materials.

[0099] In Examples 1 to 3, the raw material treatment and enzymatic hydrolysis were coordinated: the whole Malus asiatica fruit (including the fruit kernel) was treated and then subjected to complex enzyme hydrolysis. The components in the fruit kernel interacted with the pulp components during the enzymatic hydrolysis process, jointly improving the fiber content and polyphenol content of the product, and achieving the goal of high fiber and high nutrition.

[0100] The enzymatic hydrolysis and formulation were coordinated: the complex enzyme hydrolysis enhanced the system cellulose, changed the structure and properties of the raw materials, so that when adding an appropriate amount of sucrose for boiling during formulation, it could better improve the pectin characteristics, enhance the adhesiveness and film-forming characteristics, reduce or avoid the addition of additional gelling substances, and achieve good texture and forming effects of the product.

[0101] The overall coordination of each step: from raw material treatment, steaming in water, boiling in water, filtering, refining enzymatic hydrolysis, formulation to scraping and drying, each step was closely coordinated. For example, steaming in water and boiling in water created favorable conditions for filtering and enzymatic hydrolysis, filtering ensured the purity of the raw materials for subsequent enzymatic hydrolysis and formulation, and enzymatic hydrolysis and formulation laid the foundation for forming a fruit leather with good texture during the final scraping and drying. The synergistic effect of each step achieved the preparation of high-fiber Malus asiatica fruit leather.

[0102] In Comparative Example 1, complex enzyme hydrolysis was not carried out, resulting in a lack of a key synergistic mechanism for improving the product quality between steps such as raw material treatment, boiling in water, filtering and subsequent static treatment, and it was unable to effectively improve the nutritional components and quality characteristics of the product like the examples.

[0103] The way of adding food additives in Comparative Example 2 was different from the synergistic mode of improving the product quality through the inherent characteristics of raw materials and enzymatic hydrolysis in the examples. Substances such as added preservatives and carrageenan externally supplemented the preservation and texture characteristics of the product, rather than the mutual promotion of each technical feature and the joint improvement of the natural quality and high-value utilization effect of the product like the examples.

[0104] Furthermore, in Examples 1 to 3, in step five, homogenization and refinement were carried out by a high-pressure homogenizer under a pressure of 20 - 30 MPa for 2 - 3 cycles, with a static interval of 5 - 10 minutes between each treatment, and the particle size of the refined pulp was ≤50 μm; the enzymatic hydrolysis process was carried out in two stages: the first stage was enzymatic hydrolysis at 35 - 40 °C for 2 - 3 hours, and the second stage was to raise the temperature to 50 - 55 °C and continue enzymatic hydrolysis for 4 - 6 hours, and continuous stirring was carried out at 200 - 300 rpm during the enzymatic hydrolysis process.

[0105] Synergistic Homogenization and Dynamic Enzymolysis: Traditional hawthorn roll processes mostly use single enzymolysis or mechanical crushing. In this invention, through high-pressure homogenization (circular treatment at 20 - 30 MPa), the fibers are refined to the micron level (≤50 μm), and two-stage dynamic enzymolysis is innovatively combined: in the first stage, laccase is activated at low temperature (35 - 40 °C) to degrade phenolic substances, and in the second stage, the temperature is raised (50 - 55 °C) to strengthen the directional deconstruction of the fiber skeleton by lignin peroxidase. Experiments show that this combination increases the dissolution rate of crude fibers by 23.5%, and the breaking points of fiber molecular chains are controllable, avoiding over-degradation.

[0106] Synergistic Cooking of Fruit Kernels and Whole Fruits: In step two, the mass ratio of fruit kernels to whole fruits is limited to (1.5 - 2:1). The lignin in the fruit kernels and the pectin in the pulp of the whole fruit form a gel network during steaming in a water bath, and after subsequent homogenization, it becomes a fiber-reinforced phase. Comparative experiments show that at this ratio, the water-holding capacity of the fibers reaches 12.3 g / g, which is 67% higher than that of single-pulp treatment, endowing the final product with unique toughness and chewiness.

[0107] Targeted Removal of Anti-Nutritional Factors: The multi-functional peroxidase (mass fraction 50%) in the complex enzyme specifically decomposes the tannin-protein complex in Chinese flowering crabapples. Combined with the static precipitation process, the tannin residue in the final product is <0.2%, which is 90% lower than that of the traditional acid leaching method, and fiber loss is avoided. This technological breakthrough solves the industry problem of high astringency in high-fiber Chinese flowering crabapple products.

[0108] Observed by scanning electron microscopy, the fibers of the final product show a three-dimensional porous network structure, with a specific surface area of 15.7 m 2 / g, and the adsorption capacity for intestinal probiotics (such as Bifidobacterium) is increased by 4.8 times. In vitro simulated digestion experiments confirm that the slow-release fibers produce 12.4 mmol / g of short-chain fatty acids after 48 h of fermentation in the colon, which is significantly better than that of conventional hawthorn rolls (4.2 mmol / g). The experimental process is as follows:

[0109] 1. Fiber Structure Characterization (Observation by Scanning Electron Microscopy)

[0110] Sample Preparation:

[0111] Take 1 g of the finished product of high-fiber Chinese flowering crabapple hawthorn roll, and obtain a fresh cross-section after cryo-fracturing in liquid nitrogen;

[0112] Place it in a 2.5% glutaraldehyde solution for fixation for 24 h, and dehydrate it with gradient ethanol (30%, 50%, 70%, 90%, 100%), with each treatment lasting for 15 min;

[0113] After drying with a critical point dryer (Hitachi HCP-2), sputter a 5-nm-thick gold film (ion sputtering instrument: JEOL JFC-1600).

[0114] Observation Conditions:

[0115] Scanning electron microscope model: Zeiss Sigma 300;

[0116] Accelerating voltage: 5 kV, working distance 8 mm, secondary electron imaging mode;

[0117] Select 5 different fields of view (×5000 magnification) for photographing, and analyze the pore size distribution and porosity using ImageJ software.

[0118] 2. Specific surface area measurement (BET method)

[0119] Sample treatment:

[0120] Crush the rolled fruit leather and sieve it through a 100-mesh sieve. Take 0.5 g of the sample and degas it in a vacuum drying oven at 120 °C for 6 h;

[0121] Test parameters:

[0122] Instrument: Micromeritics ASAP 2460 physical adsorption analyzer;

[0123] Adsorbed gas: high-purity nitrogen (77 K), relative pressure range (P / P 0 ) 0.05 - 0.30;

[0124] Calculate the specific surface area using the BET equation and analyze the pore size distribution using the DFT model.

[0125] 3. Probiotic adsorption capacity experiment (taking Bifidobacterium as an example)

[0126] Strains and cultivation:

[0127] Strain: Bifidobacterium infantis (Bifidobacterium infantis ATCC 15697);

[0128] Culture medium: MRS liquid medium (containing 0.05% L-cysteine), anaerobically culture at 37 °C for 24 h (anaerobic jar: 10% H 2 、10% CO 2 、80% N 2 ).

[0129] Adsorption test:

[0130] Take 0.1 g of rolled fruit leather fragments (1 × 1 cm) and mix them with 10 mL of bacterial suspension (OD 600 = 1.0);

[0131] After static incubation at 37 °C for 2 h, centrifuge (3000 rpm, 5 min) to collect the supernatant;

[0132] Determine the difference in the number of viable bacteria before and after adsorption by the plate counting method, and calculate the adsorption rate:

[0133] Adsorption capacity (CFU / g) = (Initial bacterial count - Free bacterial count) / Sample mass

[0134] 4. In vitro simulated digestion and colonic fermentation

[0135] a. Oral-stomach-small intestine stage:

[0136] Oral digestion: 2 g sample + 3 mL simulated saliva (containing 75 U / mL α-amylase), oscillate at 37 °C (100 rpm) for 2 min;

[0137] Stomach digestion: Adjust the pH to 2.0, add pepsin (2000 U / mL), oscillate at 37 °C for 2 h;

[0138] Small intestine digestion: Adjust the pH to 6.8, add pancreatin (100 U / mL trypsin, 50 U / mL chymotrypsin), oscillate at 37 °C for 4 h.

[0139] b. Colonic fermentation:

[0140] Inoculum preparation: Mix healthy human fecal samples (n = 5), dilute in anaerobic phosphate buffer (1:10 w / v), and filter to remove large particles;

[0141] Fermentation system: 5 mL digestion residue + 45 mL basal medium (containing 1% peptone, 0.5% yeast extract) + 10% inoculum;

[0142] Ferment anaerobically at 37 °C for 48 h, monitor the pH every hour and record the gas production.

[0143] c. Short-chain fatty acid (SCFA) determination:

[0144] Take 1 mL of the fermentation broth, add 0.2 mL of 25% metaphosphoric acid and mix well, centrifuge (12000 rpm, 10 min);

[0145] Filter the supernatant through a 0.22 μm filter membrane and analyze by GC-MS (Agilent 7890B / 5977A);

[0146] Chromatographic conditions: HP-INNOWAX capillary column (30 m × 0.25 mm × 0.25 μm), carrier gas is helium (1 mL / min), programmed temperature rise (80 °C → 220 °C, 5 °C / min).

[0147] 5. Data comparison (conventional guodanpi control group)

[0148] Control group preparation: Traditional process (without pit addition, without enzymatic hydrolysis, and without fiber homogenization);

[0149] Parallel experiments: All of the above tests were repeated three times under the same conditions, and t-tests were performed using SPSS 26.0 (a significant difference was defined as p < 0.05).

[0150] Examples of key results:

[0151] Examples of the results in Table 3

[0152]

[0153] The present invention significantly improves the bioavailability of the fiber structure through fiber refinement and directional enzymatic hydrolysis, providing quantifiable technical support for the development of functional leisure foods.

[0154] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated and described examples here.

Claims

1. A method for preparing high-fiber crab apple peel, characterized in that: The following steps are involved: Step 1: Raw material processing: Wash the crab apples, take a portion of the crab apples and separate the pulp and core; Step 2: Steaming: Mix the core and the whole sand apple in a mass ratio of 1.5 to 2:1, and steam the sand apple until it becomes soft and glutinous; Step 3, boiling: add water to cover the raw materials steamed in step 2, boil them for a period of time under stirring conditions, and obtain a coarse pulp containing fruit seeds and seed shells; Step 4: Filter: Filter the coarse pulp to remove the seeds, stalks and seed shells; mix the filter residue with water, let it stand to allow the seeds to settle at the bottom, and remove the seeds; Step 5, refinement and enzymolysis: homogenize and refine the filtered pulp and the filter residue after removing the seeds, and then add a composite enzyme for enzymolysis, wherein the composite enzyme includes laccase, lignin peroxidase and multifunctional peroxidase; Step 6: blending: add an appropriate amount of sweetener to the mixed fruit pulp after enzymatic hydrolysis, and cook under stirring until the fruit pulp is in a thick mud state without dripping; Step 7, scraping and drying: the thick muddy fruit pulp is spread into a thin layer, and is smoothed, and dried until it becomes a tough skin-like substance, thus obtaining the high-fiber crab apple fruit leather.

2. The method for preparing the high-fiber crab apple peel according to claim 1, characterized in that: The boiling time in step 3 is 20 to 30 minutes.

3. The method for preparing the high-fiber crab apple peel according to claim 1, characterized in that: In step 4, a 20-mesh filter screen is used for filtering, and the mass ratio of filter residue to water is 1:

10.

4. The method for preparing the high-fiber crab apple peel according to claim 1, characterized in that: The mass ratio of the complex enzyme in step five to the total mass of the fruit core and the whole sand apple in step two is 0.01-0.05:100, the enzymatic hydrolysis temperature is 25-60°C, the enzymatic hydrolysis time is 6-12h, and the enzyme activities of laccase, lignin peroxidase and multifunctional peroxidase are 679.28U / g, 717.2U / g and 652.8U / g respectively, with a mass ratio of 1:1:

2.

5. The method for preparing the high-fiber crab apple peel according to claim 1, characterized in that: The sweetener in step six is ​​sucrose, and the added amount is 10-15wt% of the total mass of the fruit core and the whole crab apple in step two; the boiling time in step six is ​​30-60min.

6. The method for preparing the high-fiber crab apple peel according to claim 1, characterized in that: In step 5, the homogenization and refinement is carried out by using a high-pressure homogenizer at a pressure of 20-30 MPa for 2-3 cycles, and each treatment is allowed to stand for 5-10 minutes. After refinement, the pulp particle size is ≤50 μm; The enzymatic hydrolysis process is carried out in two stages: the first stage is enzymatic hydrolysis at 35-40°C for 2-3 hours, and the second stage is heated to 50-55°C and continued to enzymatic hydrolysis for 4-6 hours, and the enzymatic hydrolysis is continuously stirred at 200-300 rpm during the enzymatic hydrolysis.

7. The method for preparing high-fiber crab apple peel according to claim 1, characterized in that: In step seven, food-grade oil paper is laid on the oven tray to carry the fruit pulp, a thin layer is smoothed with a scraper, the thickness of the thin layer is 2 to 3 mm, and the thin layer is dried in an oven at a drying temperature of 40 to 60° C. for 7 to 10 hours.

8. The method for preparing the high-fiber crab apple peel according to claim 1, characterized in that: The method further comprises the step eight of cutting the peel of the step seven into strips after the peel is cooled, rolling the strips into a roll, and then wrapping the strips with cellophane.

9. High-fiber crab apple peel, characterized in that: The high-fiber crab apple peel is prepared by the preparation method described in any one of claims 1 to 8.

10. The high-fiber crab apple peel according to claim 9, characterized in that: The crude cellulose content of the high-fiber crab apple peel is 9-15%.

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