Preparation method of bio-dried probiotic dried longan fruits

Abstract

The invention discloses a preparation method of bio-dried probiotic dried longan fruits. The method comprises the following steps: selecting, cleaning, performing surface sterilization, drying, shelling, preparing a bacillus natto suspension, inoculating bacillus natto, performing low-temperature fermentation, draining, preparing chickpea homogenate, wrapping, performing low-temperature fermentation, drying and the like. According to the invention, innovative means of bacillus natto fermentation, low-temperature fermentation, activation of bacillus natto by using longan juice, preparation of the wrapping liquid by using the fermented raw pulp, addition of chickpea prebiotics and the like are adopted, so that the dried longan fruits which are safe to eat, rich in health-care function, excellent in processing technology, good in nutrient component maintenance, unique in flavor and novel in product form are provided for consumers. Compared with the prior art, the product quality is guaranteed, the market competitiveness is improved, a novel food integrating health, deliciousness and characteristics is provided for consumers, the requirements of the consumers for high-quality healthy food are met, and important innovation value and application prospects are achieved in the food field.

Description

Technical Field

[0001] The invention relates to the technical field of food, and in particular to a method for preparing bio-dried beneficial longan dried fruit. Background Art

[0002] Longan is a tropical fruit that is deeply loved by the public. It is widely planted in southern my country and has rich nutritional value, such as containing a variety of vitamins, minerals and amino acids. At present, there are various processing methods for longan, among which dried longan fruit is an important form of processed products. The main methods for preparing dried longan fruit on the market are sun drying, oven drying and microwave vacuum drying. However, these traditional and existing preparation methods have some obvious problems, which limit the further improvement of the quality of dried longan fruit and the development of the industry.

[0003] Color change: During the drying process, if the temperature is too high or the drying time is too long, the longan is prone to browning, resulting in poor color and affecting the appearance quality of the product. In the traditional sun drying method, if there is continuous rainy weather, the longan cannot be dried in time and is prone to mold and browning. Different drying methods have different effects on the color of longan. In the hot air drying method, due to the poor uniformity of the hot air, it is easy to cause the local temperature of the longan to be too high, resulting in browning.

[0004] Loss of nutrients: The high temperature during the drying process will cause the loss of nutrients such as vitamin C and vitamin B in longan, and will also destroy the antioxidant substances in longan, such as polyphenol compounds, thereby reducing the nutritional value and health benefits of dried longan. Especially in the case of high temperature drying and long drying time, the loss of nutrients is more obvious.

[0005] Uneven drying: Whether it is the sun drying method or the oven drying method, uneven drying is prone to occur. During the sun drying process, due to the different angles and intensities of sunlight and the different placement positions, some longans will be over-dried while others will not be completely dried. When using an oven to dry, if the hot air circulation of the equipment is uneven or the longans are placed too densely, uneven drying will also occur.

[0006] Microbial contamination: Some traditional drying methods, such as sun drying, cannot ensure the sanitary conditions of the drying environment, which can easily breed mold or be contaminated by dust, insects, etc., thus affecting the quality of the product.

[0007] Energy consumption and cost: Some new drying methods, such as microwave vacuum drying and heat pump drying, have high drying efficiency and better product quality than traditional methods, but the investment cost of equipment is high and the energy consumption is relatively large, which increases the production cost of dried longan fruit. In large-scale production, how to reduce energy consumption and cost in the drying process is an important issue that needs to be solved.

[0008] In view of the above problems, developing a new method for preparing high-quality dried longan fruit is of vital practical significance. Summary of the invention

[0009] The purpose of the present invention is to develop a preparation method of bio-dried probiotic longan dried fruit, enrich the types of longan dried fruit products, and improve the nutrient content and antioxidant capacity through natto bacteria fermentation, and add chickpea prebiotics to enrich the health care function of the product and change the single product form.

[0010] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0011] A method for preparing bio-dried beneficial longan dried fruit comprises the following steps:

[0012] (1) Selection and cleaning: Select fresh longan fruits with moderate maturity, no pests or diseases, and intact skin, wash them with clean water until there are no obvious stains, and then perform ultrasonic cleaning;

[0013] (2) Surface sterilization and drying: The fresh longan fruit in step (1) is surface sterilized and then dried with air at room temperature;

[0014] (3) Shelling: Shelling the fresh longan fruit in step (2) and placing it in a sterile container;

[0015] (4) Preparation of Bacillus natto suspension: adding Bacillus natto seeds to a seed liquid culture medium to obtain a Bacillus natto seed liquid;

[0016] (5) Inoculating Bacillus natto: inoculating the Bacillus natto seed solution obtained in step (4) onto the shelled longan flesh;

[0017] (6) low temperature fermentation: subjecting the mixture of longan pulp and Bacillus natto obtained in step (5) to low temperature fermentation culture;

[0018] (7) Draining: Drain the longan pulp in step (6);

[0019] (8) preparing chickpea homogenate: adding sterile water, chickpea flour and α-amylase to the remaining mixed solution after draining in step (7), and homogenizing into a slurry;

[0020] (9) wrapping: adding the longan pulp obtained in step (7) to the chickpea homogenate prepared in step (8) and wrapping evenly;

[0021] (10) Low-temperature fermentation and drying: The longan pulp obtained in step (9) with the chickpea slurry uniformly coated on the surface is subjected to low-temperature fermentation to obtain probiotic longan dried fruit.

[0022] In step (1), the ultrasonic cleaning is carried out at an ultrasonic frequency of 40 kHz for 10 minutes.

[0023] In step (2), the surface sterilization is performed by soaking the fresh longan fruit in 75% ethanol for 1 minute.

[0024] In step (4), the formula of the seed liquid culture medium is: 2% glucose, 1% yeast powder, and the solvent is purified water.

[0025] In step (6), the low-temperature fermentation is carried out at 35° C. for 12 hours.

[0026] In step (8), the chickpea flour and α-amylase are added in a ratio of: 100 parts of chickpea flour and 1 part of α-amylase to every 90 parts of liquid.

[0027] In step (8), the amount of sterile water added is adjusted according to the amount of mixed liquid produced in step (7).

[0028] In step (10), the low-temperature fermentation is carried out at 40° C. for 24 hours.

[0029] The present invention also provides a beneficial longan dried fruit prepared by the above-mentioned preparation method.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. Additive-free healthy food

[0032] The preparation method of the present invention does not use any chemical additives at all, which is in sharp contrast to the traditional sulfurization color protection method and the conditioning liquid color protection method. This additive-free method fundamentally guarantees the edible safety of the prepared dried longan, greatly improves the quality of the dried longan, and allows consumers to eat it with confidence.

[0033] 2. Rich health care functions

[0034] Chickpea prebiotics: Chickpeas are rich in protein, dietary fiber, vitamins, minerals and other nutrients. Making them into prebiotics and adding them to dried longan fruit increases the nutritional value of the product, allowing consumers to get more comprehensive nutrition while enjoying delicious food.

[0035] Natto Bacteria fermentation products: Combined with Natto Bacteria fermentation, the nutrient content in dried longan fruit can be effectively increased. During the fermentation process, Natto Bacteria will produce a large number of beneficial metabolites, which further enrich the nutritional content of dried longan fruit, making it more diversified, providing consumers with a better quality and richer source of nutrition, helping to enhance human immunity and promote physical health.

[0036] 3. Processing technology optimization

[0037] By using the juice of fresh longan fruit to activate Bacillus natto, sufficient nutrients are provided for the reproduction of Bacillus natto. Subsequently, the fermented mixed liquid is used to prepare chickpea homogenate. This innovative processing technology is not only simple to operate and effectively reduces production costs, but also retains the nutrients and unique flavor of longan itself to the greatest extent, ensuring the original flavor of the product.

[0038] 4. Low temperature fermentation preserves nutrients to a greater extent

[0039] The present invention adopts low-temperature fermentation and biological drying technology to prepare dried longan fruit, which is completely different from the traditional high-temperature baking and drying method. The dried longan prepared by the traditional high-temperature method has a serious dehydration problem, resulting in a large loss of sugar and nutrients, the loss of the original flavor of the longan, and the color of the dried product is dull. The method of the present invention uses the action of microorganisms to slowly dehydrate the longan, basically retaining the original flavor and nutrients of the longan, while increasing the probiotic effect.

[0040] 5. Enrich product flavor

[0041] The sour taste and special aroma produced during the fermentation process of Natto Bacillus blend with the natural fruity aroma of longan, and the fine-textured chickpea powder wrapping enriches the taste of the product.

[0042] 6. Product form innovation

[0043] The invention changes the single product form of traditional dried longan fruit. The invention combines natto bacteria fermentation with chickpea prebiotics, making the dried longan fruit different from traditional products in taste, texture and flavor, bringing a new eating experience to consumers, meeting the market demand for diversified and characteristic foods, and improving the market competitiveness of the product.

[0044] In summary, the probiotic longan dried fruit of the present invention has the outstanding advantages of food safety, rich health functions, excellent processing technology, good nutritional ingredients, unique flavor, novel product form, etc. by abandoning chemical additives, using natto bacteria fermentation, low-temperature fermentation, using longan juice to activate natto bacteria, using fermented pulp to prepare packaging liquid, and adding chickpea prebiotics. Compared with the prior art, the present invention has significant advantages in ensuring product quality and improving market competitiveness, bringing consumers a new type of food that integrates health, deliciousness, and characteristics, meeting consumers' demand for high-quality healthy food, and has important innovation value and application prospects in the field of food. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a process flow chart of the present invention.

[0046] Figure 2A flow chart was prepared for each example.

[0047] Figure 3 It is the preparation process diagram and the finished product diagram. DETAILED DESCRIPTION

[0048] The following examples are provided to further illustrate the present invention, rather than to limit the present invention.

[0049] The present invention provides a preparation process of biologically dried beneficial longan fruit, the overall process flow is as follows: Figure 1 As shown, the specific operation process of each embodiment is as follows Figure 2 As shown in the figure, the preparation process and the obtained beneficial longan dried fruit product are as follows Figure 3 shown.

[0050] Example 1

[0051] A method for preparing biological dried probiotic longan fruit comprises the following steps: step 1, selecting and washing; step 2, surface sterilization and drying; step 3, shelling; step 4, preparing a suspension of Bacillus natto; step 5, inoculating Bacillus natto; step 6, low-temperature fermentation; step 7, draining; step 8, preparing chickpea homogenate; step 9, wrapping; step 10, low-temperature fermentation and drying, specifically:

[0052] (1) Selection and cleaning: Select fresh longan fruits with moderate maturity, no pests or diseases, and intact skin, and clean them with clean water until there are no obvious stains, and then continue cleaning at an ultrasonic frequency of 40 kHz for 10 minutes.

[0053] (2) Surface sterilization and drying: The fresh longan fruit prepared in step (1) is immersed in a 75% by volume ethanol solution for 1 minute for surface sterilization, and then subjected to a room temperature air drying treatment.

[0054] (3) Shelling: Shell the fresh longan fruit in step (2) and place it in a sterile container.

[0055] (4) Preparation of Natto Bacillus suspension: Natto Bacillus strain (purchased from Guangdong Shunde Shangchuan Biotechnology Co., Ltd.) was added to a small amount of seed liquid culture medium to prepare Natto Bacillus seed liquid. The seed liquid culture medium was composed of 2% by mass glucose, 1% by mass yeast powder, and the solvent was purified water.

[0056] (5) Inoculating Bacillus natto: Inoculate the Bacillus natto seed liquid obtained in step (4) onto the shelled longan flesh.

[0057] (6) Low temperature fermentation: The longan pulp and natto bacteria mixture obtained in step (5) is subjected to low temperature fermentation culture at 35° C. for 12 hours.

[0058] (7) Draining: Drain the longan pulp in step (6).

[0059] (8) Preparing chickpea homogenate: adding 100 parts of chickpea flour and 1 part of α-amylase to the mixed liquid remaining after draining in step (7), adding sterile water according to the amount of the mixed liquid produced in step (7), the total amount of liquid is 90 parts, and homogenizing into a slurry.

[0060] (9) Wrapping: Add the longan pulp obtained in step (7) to the chickpea homogenate prepared in step (8) and wrap evenly.

[0061] (10) Low-temperature fermentation and drying: The longan pulp obtained in step (9) with the chickpea slurry uniformly coated on the surface is subjected to low-temperature fermentation at 40° C. for 24 hours to obtain probiotic longan dried fruit.

[0062] Example 2

[0063] A preparation method of biological dried probiotic longan fruit comprises the following steps: step 1, selection and cleaning; step 2, surface sterilization and drying; step 3, shelling; step 4, preparation of natto bacteria suspension; step 5, inoculation of natto bacteria; step 6, low-temperature fermentation; step 7, draining; step 8, preparation of enzyme solution; step 9, packaging; step 10, low-temperature fermentation and drying, specifically:

[0064] (1) Selection and cleaning: Select fresh longan fruits with moderate maturity, no pests or diseases, and intact skin, and clean them with clean water until there are no obvious stains, and then continue cleaning at an ultrasonic frequency of 40 kHz for 10 minutes.

[0065] (2) Surface sterilization and drying: The fresh longan fruit prepared in step (1) is immersed in a 75% by volume ethanol solution for 1 minute for surface sterilization, and then subjected to a room temperature air drying treatment.

[0066] (3) Shelling: Shell the fresh longan fruit in step (2) and place it in a sterile container.

[0067] (4) Preparation of Natto Bacillus suspension: Natto Bacillus strain (purchased from Guangdong Shunde Shangchuan Biotechnology Co., Ltd.) was added to a small amount of seed liquid culture medium to prepare Natto Bacillus seed liquid. The seed liquid culture medium was composed of 2% by mass glucose, 1% by mass yeast powder, and the solvent was purified water.

[0068] (5) Inoculating Bacillus natto: Inoculate the Bacillus natto seed liquid obtained in step (4) onto the shelled longan flesh.

[0069] (6) Low temperature fermentation: The longan pulp and natto bacteria mixture obtained in step (5) is subjected to low temperature fermentation culture at 35° C. for 12 hours.

[0070] (7) Draining: Drain the longan pulp in step (6).

[0071] (8) Preparation of enzyme solution: Add 1 part of α-amylase and 10 parts of sterile water to the remaining mixed solution after draining in step (7), and mix well.

[0072] (9) Coating: Add the longan pulp obtained in step (7) to the enzyme solution prepared in step (8) and coat evenly.

[0073] (10) Low-temperature fermentation and drying: The longan pulp obtained in step (9) with the surface evenly coated with the enzyme solution is fermented at 40° C. for 24 hours to obtain beneficial longan dried fruit.

[0074] Example 3

[0075] A method for preparing biological dried probiotic longan fruit comprises the following steps: step 1, selecting and washing; step 2, surface sterilization and drying; step 3, shelling; step 4, preparing a suspension of Bacillus natto; step 5, inoculating Bacillus natto; step 6, low-temperature fermentation; step 7, draining; step 8, preparing chickpea homogenate; step 9, wrapping; step 10, low-temperature fermentation and drying, specifically:

[0076] (1) Selection and cleaning: Select fresh longan fruits with moderate maturity, no pests or diseases, and intact skin, and clean them with clean water until there are no obvious stains, and then continue cleaning at an ultrasonic frequency of 40 kHz for 10 minutes.

[0077] (2) Surface sterilization and drying: The fresh longan fruit prepared in step (1) is immersed in a 75% by volume ethanol solution for 1 minute for surface sterilization, and then subjected to a room temperature air drying treatment.

[0078] (3) Shelling: Shell the fresh longan fruit in step (2) and place it in a sterile container.

[0079] (4) Preparation of Natto Bacillus suspension: Natto Bacillus strain (purchased from Guangdong Shunde Shangchuan Biotechnology Co., Ltd.) was added to a small amount of seed liquid culture medium to prepare Natto Bacillus seed liquid. The seed liquid culture medium was composed of 2% by mass glucose, 1% by mass yeast powder, and the solvent was purified water.

[0080] (5) Inoculating Bacillus natto: Inoculate the Bacillus natto seed liquid obtained in step (4) onto the shelled longan flesh.

[0081] (6) Low temperature fermentation: The longan pulp and natto bacteria mixture obtained in step (5) is subjected to low temperature fermentation culture at 35° C. for 12 hours.

[0082] (7) Draining: Drain the longan pulp in step (6).

[0083] (8) Preparation of chickpea slurry: 100 parts of chickpea flour, 1 part of α-amylase, and 90 parts of sterile water, homogenized into slurry.

[0084] (9) Wrapping: Add the longan pulp obtained in step (7) to the chickpea homogenate prepared in step (8) and wrap evenly.

[0085] (10) Low-temperature fermentation and drying: The longan pulp obtained in step (9) with the chickpea slurry uniformly coated on the surface is subjected to low-temperature fermentation at 40° C. for 24 hours to obtain probiotic longan dried fruit.

[0086] Example 4

[0087] A method for preparing biological dried probiotic longan fruit comprises the following steps: step 1, picking and washing; step 2, surface sterilization and drying; step 3, shelling; step 4, low-temperature fermentation; step 5, draining; step 6, preparing chickpea homogenate; step 7, wrapping; step 8, low-temperature fermentation and drying, specifically:

[0088] (1) Selection and cleaning: Select fresh longan fruits with moderate maturity, no pests or diseases, and intact skin, and clean them with clean water until there are no obvious stains, and then continue cleaning at an ultrasonic frequency of 40 kHz for 10 minutes.

[0089] (2) Surface sterilization and drying: The fresh longan fruit prepared in step (1) is immersed in a 75% by volume ethanol solution for 1 minute for surface sterilization, and then subjected to a room temperature air drying treatment.

[0090] (3) Shelling: Shell the fresh longan fruit in step (2) and place it in a sterile container.

[0091] (4) Low temperature fermentation: The longan pulp obtained in step (3) is subjected to low temperature fermentation culture at 35° C. for 12 hours.

[0092] (5) Draining: Drain the longan pulp in step (4).

[0093] (6) Preparing chickpea homogenate: adding 100 parts of chickpea flour and 1 part of α-amylase to the mixed liquid remaining after draining in step (5), adding sterile water according to the amount of the mixed liquid produced in step (5), the total amount of liquid is 90 parts, and homogenizing into a slurry.

[0094] (7) Wrapping: adding the longan pulp obtained in step (5) to the chickpea homogenate prepared in step (6) and wrapping evenly.

[0095] (8) Low-temperature fermentation and drying: The longan pulp obtained in step (7) with the chickpea slurry uniformly coated on the surface is subjected to low-temperature fermentation at 40° C. for 24 hours to obtain probiotic longan dried fruit.

[0096] The sensory evaluation scores and nutritional components of each example are shown in Tables 1 and 2.

[0097] Table 1 Flavor, taste and sensory evaluation results of each example

[0098]

[0099] Table 2 Nutritional composition of each example

[0100] Water content (%) Dietary fiber (g / 100g) Effective colony count (cfu / g) Example 1 23.8 4.92 <![CDATA[>10 6 ]]> Example 2 18.2 3.37 <![CDATA[>10 6 ]]> Example 3 22.5 4.14 <![CDATA[>10 4 ]]> Example 4 22.9 4.26 <![CDATA[<10 3 ]]>

[0101] It can be seen from the results that the product prepared in Example 1 has the best flavor and taste, and the score is better than other embodiments. Compared with Example 1, Example 2 does not add chickpea flour, does not have the chickpea flavor and mellow taste, and the dietary fiber content is reduced. Compared with Example 1, Example 3 does not use the mixed liquid produced by longan fermentation, but uses sterile water to prepare the chickpea homogenate coating liquid. The flavor is not as rich as Example 1 in fruit flavor, the sweetness is slightly lower, and the effective colony count is lower. Compared with Example 1, Example 4 is not inoculated with natto bacteria, and the endophytic bacteria of longan are used for fermentation. The drying time is longer, and the obtained longan dried fruit does not have the special aroma of natto bacteria fermentation, and the effective colony count is also lower.

[0102] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing bio-dried beneficial longan dried fruit, characterized in that: The following steps are involved: (1) Selection and cleaning: Select fresh longan fruits with moderate maturity, no pests or diseases, and intact skin, wash them with clean water until there are no obvious stains, and then perform ultrasonic cleaning; (2) Surface sterilization and drying: The fresh longan fruit in step (1) is surface sterilized and then dried with air at room temperature; (3) Shelling: Shelling the fresh longan fruit in step (2) and placing it in a sterile container; (4) Preparation of Bacillus natto suspension: adding Bacillus natto seeds to a seed liquid culture medium to obtain a Bacillus natto seed liquid; (5) Inoculating Bacillus natto: inoculating the Bacillus natto seed solution obtained in step (4) onto the shelled longan flesh; (6) low temperature fermentation: subjecting the longan pulp and Bacillus natto mixture obtained in step (5) to low temperature fermentation culture; (7) Draining: Drain the longan pulp in step (6); (8) preparing chickpea homogenate: adding sterile water, chickpea flour and α-amylase to the remaining mixed solution after draining in step (7), and homogenizing into a slurry; (9) wrapping: adding the longan pulp obtained in step (7) to the chickpea homogenate prepared in step (8) and wrapping evenly; (10) Low-temperature fermentation and drying: The longan pulp obtained in step (9) with the chickpea slurry uniformly coated on the surface is subjected to low-temperature fermentation to obtain probiotic longan dried fruit.

2. The method for preparing the bio-dried beneficial longan dried fruit according to claim 1, characterized in that: In step (1), the ultrasonic cleaning is carried out at an ultrasonic frequency of 40 kHz for 10 minutes.

3. The method for preparing the bio-dried beneficial longan dried fruit according to claim 1, characterized in that: In step (2), the surface sterilization is performed by soaking the fresh longan fruit in 75% ethanol for 1 minute.

4. The method for preparing the bio-dried beneficial longan dried fruit according to claim 1, characterized in that: In step (4), the formula of the seed liquid culture medium is: 2% glucose, 1% yeast powder, and the solvent is purified water.

5. The method for preparing the bio-dried beneficial longan dried fruit according to claim 1, characterized in that: In step (6), the low-temperature fermentation is carried out at 35° C. for 12 hours.

6. The method for preparing the bio-dried beneficial longan dried fruit according to claim 1, characterized in that: In step (8), the chickpea flour and α-amylase are added in a ratio of: 100 parts of chickpea flour and 1 part of α-amylase to every 90 parts of liquid.

7. The method for preparing the bio-dried beneficial longan dried fruit according to claim 1, characterized in that: In step (8), the amount of sterile water added is adjusted according to the amount of mixed liquid produced in step (7).

8. The method for preparing the bio-dried beneficial longan dried fruit according to claim 1, characterized in that: In step (10), the low-temperature fermentation is carried out at 40° C. for 24 hours.

9. The beneficial longan dried fruit prepared according to the preparation method according to any one of claims 1 to 8.

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