Fermentation agent for fermented apple chips and fermentation method

Abstract

The application discloses a kind of fermenting apple crisp piece with fermentation inoculant and fermentation method, it is related to the technical field of fermenting apple crisp piece preparation, fermentation inoculant is made by the proportion of 1:2:2 by cell number and is mixed into Lactobacillus plantarum LNJ-002, Leuconostoc pseudomesenteroides and lemon Leuconostoc;Among them, the preservation number of Lactobacillus plantarum LNJ-002 is CGMCC No.20610;The preservation number of Leuconostoc pseudomesenteroides is CGMCC No.29506;Preparation process includes: first, apple is sliced, color protection, and apple slice is obtained;The obtained apple slice is inoculated with the fermentation inoculant, and erythritol, fructose syrup is added, soaked with water, and fermented;Microwave-intermittent-pressure-difference flash drying is used to prepare apple crisp piece.The specific fermentation inoculant is selected in the application, can effectively avoid bacterial contamination, and can produce a large amount of flavor substances, improve the taste of fermented apple crisp piece, at the same time, fructose syrup and erythritol are added in the fermentation process, which provides a nutrient environment for the growth and reproduction of fermentation strains, and improves the fermentation speed.

Description

Technical Field

[0001] This invention relates to the field of fermented apple chip preparation technology, and more specifically to a fermentation agent and fermentation method for fermented apple chips. Background Technology

[0002] Apple cultivation is widespread and yields are high. However, improper harvesting time can easily lead to browning of the fruit, shortening its shelf life. Currently, apples are mainly sold through wholesale, picking, and retail of fresh fruit, primarily by fruit farmers themselves, resulting in overcapacity. Therefore, developing intensive processing of apples to increase added value is of great significance for extending product shelf life and boosting local economic development.

[0003] Dried apple products are a relatively traditional type of apple processed product. Their biggest advantage is their low moisture content and water activity, making them easy to preserve and extending their shelf life. They also have a higher proportion of dietary fiber, are convenient to carry, and are suitable for special groups such as the elderly and children. Furthermore, fermentation is a processing technique that typically utilizes the metabolism and transformation of probiotics to produce specific metabolites and enzymes, thereby altering the nutritional composition, taste, and flavor of fruits and vegetables. As people gradually develop a consumer focus on nutritious and healthy foods, fermented foods are becoming increasingly popular.

[0004] Therefore, how to provide a fermentation agent for fermented apple chips and how to prepare fermented apple chips are problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a fermentation agent and fermentation method for fermenting apple chips.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A fermentation agent for fermenting apple chips, wherein the fermentation agent is prepared by mixing Lactobacillus plantarum LNJ-002, ethanol-resistant Pediococcus, and Leuconostoc mesenteroides in a cell count (CFU / mL) ratio of 1:2:2; wherein, Lactobacillus plantarum LNJ-002 has the preservation number CGMCC No.20610 and is classified as Lactobacillus plantarum subsp. plantarum; and ethanol-resistant Pediococcus has the preservation number CGMCC No.29506 and is classified as Pediococcus ethanolidurans.

[0008] The technical effects achieved by the above solutions are as follows: Lactobacillus plantarum has stable fermentation effect, is resistant to low temperatures, maintains the acidity of the fermentation environment, and avoids contamination by other microorganisms; Pediococcus ethanol-resistant can regulate the intestinal flora, competitively inhibit the growth of pathogenic microorganisms, maintain the balance of intestinal flora, activate the activity of acidic proteases, prevent the production of harmful substances, and enhance the body's immune function; Leuconostoc mesenteroides (commercially available) has strong acid production capacity, rapid metabolism, and produces a large number of flavor substances and flavor precursors, which can give fermented apples a better flavor.

[0009] As having the same inventive concept as the above-mentioned technical solution, this invention also claims protection for a method for preparing fermented apple chips, wherein fermentation is carried out using the aforementioned fermentation agent, and the specific process includes:

[0010] 1) First, slice the apple and preserve its color to obtain apple slices;

[0011] 2) The fermentation agent was added to the obtained apple slices, along with erythritol and fructose syrup. The slices were then soaked in water and fermented. Apple crisps were prepared by microwave-intermittent-pressure difference flash drying.

[0012] The effects of adding high-fructose corn syrup are: high-fructose corn syrup has a high sweetness, which can effectively reduce the acidity of fermented mashed apples; high-fructose corn syrup has high solubility, which can inhibit mold and other miscellaneous bacteria while providing a nutrient environment for the growth and reproduction of effective fermentation strains, thereby increasing the fermentation speed.

[0013] The benefits of adding erythritol are as follows: Erythritol is a functional sweetener with a mild flavor and a cooling sensation after consumption, providing consumers with a pleasant experience. Furthermore, erythritol has a low calorie content, does not cause blood sugar fluctuations, and can promote the proliferation of bifidobacteria in the gut while inhibiting the growth of pathogenic bacteria.

[0014] The synergistic effect of the two sweeteners is excellent, improving the taste of the product and reducing the sourness and bitterness.

[0015] In the above technical solution, in step 1), the slicing is to cut the apple into thin slices with a thickness of 0.5-1cm.

[0016] The technical effect achieved by the above technical solution is that when apples are cut into slices of this thickness, the dried fermented apple chips have a good shape, no breakage, and a good taste.

[0017] In the above technical solution, in step 1), the color protection is achieved by soaking apple slices in an aqueous solution containing 0.5-2 mg / g trehalose, 0.5-1 mg / g sodium isoascorbate and 10-20 mg / g NaCl at 25-30°C for 30-60 minutes.

[0018] The technical effect achieved by the above technical solution is that after color protection treatment, the fermented apple crisps have a bright color and a high sensory score.

[0019] In the above technical solution, in step 2), the amount of erythritol added is 1-10% of the weight of the apple slices, and the amount of fructose syrup added is 10-20% of the weight of the apple slices.

[0020] In the above technical solution, in step 2), the amount of water added should be such that the apple slices are below the liquid surface; and during the fermentation process, the apple slices should always be kept below the liquid surface.

[0021] In the above technical solution, in step 2), the amount of fermentation agent added is 1-2% of the mass of apple slices, and the fermentation is carried out at a temperature of 18-20℃ in a dark and sealed environment for 7-14 days.

[0022] The technical effects achieved by the above solutions are: fermentation at a temperature of 18-20℃ and in a dark, sealed environment for 7-14 days allows for more complete fermentation and avoids excessive oxidation of antioxidants in the apple slices.

[0023] In the above technical solution, in step 2), the microwave-intermittent-pressure difference flash drying is as follows: microwave power 1600-2000kW, vacuum degree 15-20kPa, drying to a moisture content of 10-30%, intermittent drying at 40-45% relative humidity for 12-24 hours or without interruption, followed by pressure difference flash drying at a flash temperature of 90-100℃ for 10-20 minutes, reducing the flash pressure to 4kPa, evacuation temperature of 40-60℃, and evacuation for 2-4 hours.

[0024] The technical effects achieved by the above technical solution are: under this combined drying method, the moisture removal is more uniform, the fermented apple crisps have a better taste and higher sensory scores, and compared with the hot air drying in the existing technology, the total phenol and total flavonoid content can be significantly increased.

[0025] In summary, the specific fermentation agent used in this invention can effectively avoid contamination by other microorganisms and produce a large number of flavor substances, improving the taste of fermented apple chips. At the same time, the addition of fructose syrup and erythritol during the fermentation process provides a nutrient environment for the growth and reproduction of the fermentation strains, thereby increasing the fermentation speed. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The *Lactobacillus plantarum* LNJ-002 used in the following examples is classified as *Lactobacillus plantarum* subsp. *plantarum*, with accession number CGMCC No. 20610. This strain is deposited at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, on September 8, 2020. This strain was isolated from the fermentation broth of low-temperature fermented sauerkraut from Northeast China and obtained through continuous low-temperature acclimatization. The ethanol-resistant *Pediococcus ethanolidurans* is classified as *Pediococcus ethanolidurans*, with accession number CGMCC. No. 29506, the depository of this strain is China General Microbiological Culture Collection Center, address: No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, deposit date: January 2, 2024. This strain was isolated from the fermentation broth of Northeast sauerkraut and obtained by continuous irradiation mutagenesis and screening for stable growth characteristics; Leuconostoc mesenteroides BNCC194779 is produced by Shangcheng Beina Chuanglian Biotechnology Co., Ltd.

[0028] The Lactobacillus plantarum 5R3, Pediococcus lactis 10R6D, and Leuconostoc tartrate XJ1R12 used in the comparative examples were all produced by Sichuan Yidongyuan Biotechnology Co., Ltd.

[0029] Example 1

[0030] Fermented apple crisps and their preparation method include the following steps:

[0031] Apples were washed, peeled, cored, and sliced ​​into 1cm thin slices. They were then soaked in an aqueous solution containing 20mg / g NaCl at 30℃ for 30 minutes. After color preservation, a starter culture prepared by mixing *Lactobacillus plantarum*, *Pediococcus ethanol-resistant*, and *Leuconostoc tumefaciens* in a 1:1:1 ratio was inoculated at a rate of 1%. Erythritol (10% by weight of apples) and fructose syrup (15% by weight of apples) were added, along with purified water to cover the apple slices. The mixture was then fermented at 20℃ in a dark, sealed container for 12 days. The fermented apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 2000kW and 15kPa until the moisture content reached 20%. After 18 hours of intermittent drying at 40% relative humidity, a pressure difference flash drying process was performed at 95℃ for 20 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 50℃ for 2 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0032] Example 2

[0033] Fermented apple crisps and their preparation method include the following steps:

[0034] Apples were washed, peeled, cored, and sliced ​​into 0.5cm thin slices. They were then soaked for 60 minutes at 25°C in an aqueous solution containing 1 mg / g trehalose and 15 mg / g NaCl. After color preservation, a starter culture prepared by mixing *Lactobacillus plantarum*, *Pediococcus ethanol-resistant*, and *Leuconostoc tumefaciens* in a 2:1:1 ratio was added at a concentration of 1%. Erythritol (10% of apple weight) and fructose syrup (10% of apple weight) were added, along with purified water to cover the apple slices. The mixture was then fermented at 18°C ​​in a dark, sealed container for 7 days. The fermented apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1600kW and 15kPa until the moisture content reached 25%. After 24 hours of intermittent drying at 45% relative humidity, pressure difference flash drying was performed at 100°C for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 60°C for 4 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0035] Example 3

[0036] Fermented apple crisps and their preparation method include the following steps:

[0037] Apples were washed, peeled, cored, and sliced ​​into 0.8cm thin slices. They were then soaked for 50 minutes at 25°C in an aqueous solution containing 1 mg / g sodium isoascorbate and 15 mg / g NaCl. After color preservation, a starter culture prepared by mixing *Lactobacillus plantarum*, *Pediococcus ethanol-resistant*, and *Leuconostoc tumefaciens* in a 1:1:2 ratio was added at a concentration of 1.5%. Erythritol (5% by weight of apples) and fructose syrup (15% by weight of apples) were added, along with purified water to cover the apple slices. The mixture was then fermented at 20°C in a dark, sealed container for 10 days. The fermented apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1800kW and 16kPa until the moisture content reached 30%. After 12 hours of intermittent drying at 40% relative humidity, pressure differential flash drying was performed at 95°C for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 40°C for 4 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0038] Example 4

[0039] Fermented apple crisps and their preparation method include the following steps:

[0040] Apples were washed, peeled, cored, and sliced ​​into 1cm thin slices. They were then soaked for 40 minutes at 30℃ in an aqueous solution containing 0.5mg / g trehalose, 0.5mg / g sodium isoascorbate, and 20mg / g NaCl. After color preservation, a starter culture prepared by mixing *Lactobacillus plantarum*, *Pediococcus ethanol-resistant*, and *Leuconostoc tartrate* in a 1:2:1 ratio was inoculated at a rate of 2%. Erythritol (5% by weight of apples) and fructose syrup (20% by weight of apples) were added, along with purified water to cover the apple slices. The mixture was then fermented at 18℃ in a dark, sealed container for 12 days. The fermented apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 2000kW and 20kPa until the moisture content reached 15%. After 18 hours of intermittent drying at 43% relative humidity, a pressure difference flash drying process was performed at 90℃ for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 50℃ for 3 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0041] Example 5

[0042] Fermented apple crisps and their preparation method include the following steps:

[0043] Apples were washed, peeled, cored, and sliced ​​into 0.8cm thin slices. They were then soaked for 30 minutes at 30℃ in an aqueous solution containing 2mg / g trehalose, 1mg / g sodium isoascorbate, and 10mg / g NaCl. After color preservation, a starter culture prepared by mixing *Lactobacillus plantarum*, *Pediococcus ethanol-resistant*, and *Leuconostoc tumefaciens* in a 1:2:2 ratio was inoculated at a rate of 2%. Erythritol (10% by weight of apples) and fructose syrup (20% by weight of apples) were added, along with purified water to cover the apple slices. The mixture was then fermented at 20℃ in a dark, sealed container for 14 days. The fermented apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1800kW and 15kPa until the moisture content reached 10%. After 24 hours of intermittent drying at 45% relative humidity, pressure difference flash drying was performed at 95℃ for 10 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 60℃ for 2 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0044] Comparative Example 1

[0045] Fermented apple crisps and their preparation method include the following steps:

[0046] Apples were washed, peeled, cored, and cut into 0.5cm thin slices. 0.5% *Lactobacillus plantarum* LNJ-002 (CGMCC No. 20610) was inoculated into the slices, along with 10% erythritol and 20% fructose syrup (by weight of the apples). Purified water was added to cover the apple slices. The mixture was then fermented at 20°C in a dark, sealed container for 14 days. After fermentation, the apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1800kW and 20kPa until the moisture content reached 20%. After 12 hours of intermittent drying at 40% relative humidity, a pressure difference flash drying process was performed at 95°C for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 60°C for 2 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0047] Comparative Example 2

[0048] Fermented apple crisps and their preparation method include the following steps:

[0049] Apples were washed, peeled, cored, and cut into 0.5cm thin slices. A starter culture prepared by mixing *Lactobacillus plantarum* 5R3, *Pediococcus lactis* 10R6D, and *Leuconostoc mesenteroides* XJ1R12 in a 1:2:2 ratio was added at a concentration of 2%. Erythritol (10% of apple weight) and fructose syrup (20% of apple weight) were added, along with purified water to cover the apple slices. The mixture was fermented at 20°C in a dark, sealed container for 14 days. After fermentation, the apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1800kW and 20kPa until the moisture content reached 20%. After 12 hours of intermittent drying at 40% relative humidity, a pressure difference flash drying process was performed at 95°C for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 60°C for 2 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0050] Comparative Example 3

[0051] Fermented apple crisps and their preparation method include the following steps:

[0052] Apples were washed, peeled, cored, and cut into 0.5cm thin slices. A starter culture prepared by mixing *Lactobacillus plantarum* 5R3, ethanol-resistant *Pediococcus ethanolans* (CGMCC No. 29506), and *Leuconostoc mesenteroides* BNCC194779 in a 1:2:2 ratio (2% inoculation amount) was added. Erythritol (10% by weight of apples) and fructose syrup (20% by weight of apples) were added, along with purified water to cover the apple slices. The mixture was fermented at 20°C in a dark, sealed container for 14 days. After fermentation, the apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1800kW and 20kPa until the moisture content reached 20%. After 12 hours of intermittent drying at 40% relative humidity, a pressure difference flash drying process was performed at 95°C for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 60°C for 2 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0053] Comparative Example 4

[0054] Fermented apple crisps and their preparation method include the following steps:

[0055] Apples were washed, peeled, cored, and cut into 0.5cm thin slices. A starter culture prepared by mixing *Lactobacillus plantarum* LNJ-002 (CGMCC No. 20610), *Pediococcus lactis* 10R6D, and *Leuconostoc mesenteroides* BNCC194779 in a 1:2:2 ratio was inoculated at 2% of the apple's weight. Erythritol (10% by weight of apple) and fructose syrup (20% by weight of apple) were added, along with purified water to cover the apple slices. The mixture was fermented at 20°C in a dark, sealed container for 14 days. After fermentation, the apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1800kW and 20kPa until the moisture content reached 20%. After 12 hours of intermittent drying at 40% relative humidity, a pressure difference flash drying process was performed at 95°C for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 60°C for 2 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0056] Comparative Example 5

[0057] Fermented apple crisps and their preparation method include the following steps:

[0058] Apples were washed, peeled, cored, and cut into 0.5cm thin slices. A starter culture was inoculated at 2% of the apple slices, consisting of *Lactobacillus plantarum* LNJ-002 (CGMCC No. 20610), ethanol-resistant *Pediococcus ethanolifer* (CGMCC No. 29506), and *Leuconostoc mesenteroides* XJ1R12 in a 1:2:2 ratio. Erythritol (10% by weight of apples) and fructose syrup (20% by weight of apples) were added, along with purified water to cover the apple slices. The mixture was fermented at 20°C in a dark, sealed container for 14 days. After fermentation, the apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1800kW and 20kPa until the moisture content reached 20%. After 12 hours of intermittent drying at 40% relative humidity, a pressure differential flash drying process was performed at 95°C for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 60°C for 2 hours. The resulting product was then removed and cooled to obtain fermented apple crisps.

[0059] Comparative Example 6

[0060] Fermented apple crisps and their preparation method include the following steps:

[0061] Apples were washed, peeled, cored, and cut into 0.5cm thin slices. A fermentation agent prepared by mixing *Lactobacillus plantarum*, ethanol-resistant *Pediococcus ethanolans*, and *Leuconostoc tumefaciens* in a 1:2:2 ratio was inoculated at 2% of the total volume. Purified water was added to cover the apple slices. The mixture was fermented at 20°C in a dark, sealed container for 14 days. After fermentation, the apple slices were removed, the fermentation liquid drained, and then microwaved under vacuum at 1800kW and 20kPa until the moisture content reached 20%. After a 12-hour interval at 40% relative humidity, a pressure differential flash drying process was performed at 95°C for 15 minutes, followed by a final flash pressure reduction to 4kPa and a vacuum temperature of 60°C for 2 hours. The apple slices were then removed and cooled to obtain the fermented apple crisp product.

[0062] Comparative Example 7

[0063] Fermented apple crisps and their preparation method include the following steps:

[0064] Apples are washed, peeled, cored, and cut into 0.5cm thin slices. A starter culture prepared by mixing *Lactobacillus plantarum*, *Pediococcus ethanol-resistant*, and *Leuconostoc tumefaciens* in a 1:2:2 ratio is inoculated at 2% of the apple's volume. Erythritol (10% by weight of apple) and fructose syrup (20% by weight of apple) are added, along with purified water to cover the apple slices. The mixture is then fermented at 20°C in a dark, sealed container for 14 days. After fermentation, the apple slices are removed, the fermentation liquid is drained, and the slices are dried in hot air at 70°C for 8 hours. Finally, they are cooled to obtain fermented apple crisps.

[0065] Experiments were conducted using the products of Examples 1-5 and Comparative Examples 1 to 7, and the results are shown in Tables 1 to 3.

[0066] Table 1. Color and Nutritional Components of Apple Chips

[0067]

[0068] As shown in Table 1, this invention can effectively improve the brightness of fermented apple chips while greatly preserving nutrients. Compared to adding a small amount of single lactic acid bacteria, this invention can reduce nutrient loss; compared to not adding fructose syrup and erythritol, this invention can effectively improve product color; compared to ordinary hot air drying, this invention can effectively reduce the loss of total phenols and total flavonoids, while improving product brightness and enhancing sensory quality.

[0069] Table 2 Sensory Evaluation Criteria

[0070]

[0071]

[0072] Table 3 Sensory scores and crispness of fermented apple crisp products

[0073]

[0074] As shown in Table 3, the fermented apple chips of this invention have a good appearance, a pleasant sweet and sour taste, and a crisp texture, making them very popular.

[0075] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing fermented apple chips, characterized in that, The specific process includes: 1) First, slice the apple and preserve its color to obtain apple slices; 2) Inoculate the obtained apple slices with fermentation agent, add erythritol and fructose syrup, soak in water, and ferment; prepare apple crisps by microwave-intermittent-pressure difference flash drying. The fermentation agent is composed of *Lactobacillus plantarum* subsp. *plantarum* (… Lactobacillus plantarum subsp.plantarum LNJ-002, ethanol-resistant Pediococcus ( Pediococcus ethanolidurans The mixture of *Lactobacillus plantarum* and *Leuconostoc mesenteroides* was prepared in a ratio of 1:2:2; wherein, the *Lactobacillus plantarum* subsp. *plantarum* LNJ-002 has the preservation number CGMCC No.20610, and the ethanol-resistant *Pediococcus spp.* has the preservation number CGMCC No.29506. In step 1), the color protection involves soaking apple slices at 25-30°C in an aqueous solution containing 0.5-2 mg / g trehalose, 0.5-1 mg / g sodium isoascorbate, and 10-20 mg / g NaCl for 30-60 minutes. In step 2), the microwave-intermittent-pressure difference flash drying is as follows: microwave power 1600-2000kW, vacuum degree 15-20kPa, drying to a moisture content of 10-30%, intermittent drying at 40-45% relative humidity for 12-24 hours or without interruption, followed by pressure difference flash drying at a flash temperature of 90-100℃ for 10-20 minutes, reducing the flash pressure to 4kPa, evacuation temperature of 40-60℃, and evacuation for 2-4 hours.

2. The method for preparing fermented apple chips according to claim 1, characterized in that, In step 1), the slicing is to cut the apple into thin slices with a thickness of 0.5-1cm.

3. The method for preparing fermented apple chips according to claim 1, characterized in that, In step 2), the amount of erythritol added is 1-10% of the weight of the apple slices, and the amount of fructose syrup added is 10-20% of the weight of the apple slices.

4. The method for preparing fermented apple chips according to claim 1, characterized in that, In step 2), the amount of water added is such that the apple slices are below the liquid surface; and during the fermentation process, the apple slices are always kept below the liquid surface.

5. The method for preparing fermented apple chips according to claim 1, characterized in that, In step 2), the amount of fermentation agent added is 1-2% of the weight of the apple slices, and the fermentation is carried out at a temperature of 18-20℃ in a dark and sealed environment for 7-14 days.

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