Production process for improving longan pulp plumpness and lotus seed crispness in longan and lotus seed crisps

Abstract

The invention discloses a production process for improving longan pulp plumpness and lotus seed crispness in longan and lotus seed crisps, and belongs to the technical field of longan and lotus seed crisps. The process comprises the key steps of lotus seed pretreatment, low-temperature vacuum frying, longan pulp pretreatment, calcium chloride solution soaking, embedding, three-stage drying and the like. Detection shows that according to the product prepared by the optimal process (0.25 wt% calcium chloride treatment + 80 DEG C / 12 h, 60 DEG C / 8 h and 50 DEG C / 4 h drying), the crisp hardness of the lotus seeds is as low as 4.2 N, the sensory crisp degree score reaches 9.2 score (10 score), the hardness is reduced by 41.7% compared with that of an untreated group, and the crisp degree score is improved by 41.5%; compared with a single drying process group, the plumpness of the longan aril is improved by more than 35%. The product has a compound taste of glutinous outside and crispy inside, and is full in shape and high in edible safety.

Description

Technical Field

[0001] This invention belongs to the technical field of longan and lotus seed crisps, and more specifically relates to a production process for improving the fullness of longan flesh and the crispness of lotus seeds in longan and lotus seed crisps. Background Technology

[0002] Lotus seeds are rich in protein, fat, and carbohydrates, as well as essential minerals such as calcium, phosphorus, iron, zinc, magnesium, and potassium. Longan pulp alone is too sweet and cloying as a snack, while lotus seeds alone are rather bland. Furthermore, dried lotus seeds are quite firm and difficult to chew, making them unsuitable for direct consumption, especially for children and the elderly. Longan and lotus seed crisps are made by vacuum-frying cored lotus seeds at low temperatures and then sandwiching them between fresh, pitted longan pulp. The sweetness of the longan pulp neutralizes the astringency of the lotus seeds, creating a complementary flavor profile that is sweet but not cloying, resulting in a more harmonious overall taste.

[0003] Lotus seeds are rich in nutrients, containing 15-20 grams of protein, about 64 grams of carbohydrates, and approximately 10 grams of dietary fiber per 100 grams. They also contain essential trace elements and minerals such as calcium, phosphorus, iron, zinc, magnesium, and potassium, as well as various vitamins including B vitamins and vitamin E. They are beneficial to the human body and are a popular type of nut. Longan and lotus seed crisps, as a snack, are not only nutritious but also combine the rich sweetness of longan pulp with the natural fragrance of lotus seeds, creating a complex and refreshing flavor that is loved by consumers.

[0004] However, in existing processing techniques for longan and lotus seed crisps, a single-temperature, long-duration drying process is typically used to achieve drying and sterilization. This traditional drying method easily leads to the surface of the longan pulp hardening due to rapid moisture loss, while internal moisture migration is hindered, resulting in a shriveled appearance and a stiff texture. Simultaneously, the lotus seed crisps inside are prone to absorbing moisture and becoming damp again in the humid and hot environment during the later stages of drying, losing their crisp texture. This technological bottleneck restricts further improvements in the appearance, taste, and shelf-life quality of longan and lotus seed crisps.

[0005] Based on this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a production process that improves the fullness of longan pulp and the crispness of lotus seeds in longan and lotus seed crisps, thereby solving the problems existing in the prior art. This invention cleverly solves both the shaping problem of longan pulp and the crispness retention problem of lotus seeds through the synergistic effect of "calcium chloride treatment + three-stage gradient drying," resulting in a product with a full shape, a soft exterior and a crisp interior, and a unique taste.

[0007] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is to provide a production process for improving the fullness of longan pulp and the crispness of lotus seeds in longan and lotus seed crisps, comprising the following steps: Lotus seeds are boiled and fried in oil in sequence to obtain processed lotus seeds; Longan is soaked in a calcium chloride solution to obtain processed longan pulp; The processed lotus seeds are embedded inside the processed longan pulp, dried in a three-stage gradient process, and then packaged to obtain the finished product.

[0008] Preferably, the specific steps are as follows: Fresh lotus seeds are rinsed with water and then shelled, seed coat removed, and core removed. After processing, boil the lotus seeds in boiling water, drain and cool. Deep-fry lotus seeds, drain the oil, and cool to obtain fried lotus seeds. Select fresh and intact longan fruits, remove the shells and pits, rinse the longan flesh with water and drain. Longan pulp is soaked in calcium chloride solution, then removed and drained to obtain processed longan pulp; The fried lotus seeds are embedded inside the processed longan pulp to obtain the embedded longan and lotus seed crisps; The fused longan and lotus seed crisps are dried in a three-stage gradient process, and then packaged to obtain the finished product.

[0009] Preferably, the concentration of the calcium chloride solution is 0.1~0.75wt%.

[0010] Preferably, the concentration of the calcium chloride solution is 0.25 wt%. Soaking the longan pulp in a 0.25 wt% calcium chloride solution is the optimal parameter, allowing calcium ions to cross-link with the pectin in the longan pulp, achieving a cross-linking degree of 82%, forming a stable network structure. This enables the longan pulp to resist shrinkage and maintain its plump shape during subsequent drying. Simultaneously, unbound calcium ions in the longan pulp migrate with the moisture during the drying process to the interior of the lotus seed crisps, undergoing secondary cross-linking with the pectin and cellulose in the lotus seed cell walls to form a three-dimensional network structure, locking in the porous morphology of the lotus seed crisps and reducing moisture absorption.

[0011] In this invention, calcium chloride is the only suitable food-grade calcium salt. Other common calcium salts, due to differences in their physicochemical properties, dissociation ability, and interaction with food ingredients, cannot achieve the same effect of making longan pulp plump and lotus seeds crisp and moisture-resistant.

[0012] Calcium salts commonly used in the food industry, such as calcium lactate, calcium citrate, calcium carbonate, and calcium sulfate, often have poor water solubility and low degree of dissociation, failing to release sufficient amounts of free calcium. 2+To form a stable network structure with high cross-linking degree with pectin; however, its anions may introduce side effects, such as the sour taste of lactate and citrate anions ruining the sweet and mellow flavor of the product, the reaction of carbonate anions with the organic acids in longan pulp leading to tissue damage, and sulfate anions easily forming slightly soluble salts that block the porous structure of lotus seeds and bring astringent taste; in addition, some calcium salts form cross-linked structures with poor temperature stability, which cannot be adapted to the three-stage gradient drying conditions of this invention, and are prone to relaxation and collapse at high temperatures. Calcium chloride, on the other hand, has good water solubility and can completely dissociate into a high concentration of Ca in aqueous solution. 2+ Furthermore, chloride ions are common anions in food, have no odor or precipitate, do not antagonize the components of longan and lotus seeds, and do not leave harmful byproducts during the drying process. It is the only suitable calcium salt to achieve the dual technical effects of this invention.

[0013] Preferably, the three-stage gradient drying includes: a first stage of drying at 75~85℃ for 10~14h, a second stage of drying at 55~65℃ for 6~10h, and a third stage of drying at 45~55℃ for 3~5h.

[0014] Furthermore, the three-stage gradient drying includes: a first stage of drying at 80°C for 12 hours, a second stage of drying at 60°C for 8 hours, and a third stage of drying at 50°C for 4 hours.

[0015] This invention cleverly solves both the shaping problem of longan pulp and the crispness retention problem of lotus seeds through the synergistic effect of "calcium chloride treatment + three-stage gradient drying". The specific technical principle is as follows: The first stage, high-temperature drying at 75~85℃, rapidly evaporates the surface moisture of the longan pulp, shortens the time the moisture stays on the surface, and prevents the cross-linked structure from loosening due to prolonged moisture. At the same time, the high temperature can promote the cross-linking reaction rate of calcium ions and pectin, and improve the structural stability. The second stage is medium-temperature drying at 55~65℃: slowly removing the moisture inside the longan pulp. At this time, the temperature is mild to avoid high temperature causing the longan pulp to caramelize or the lotus seed crisp oil to oxidize. At the same time, it provides a suitable moisture carrier for calcium ions to migrate into the lotus seed. The third stage, low-temperature drying at 45~55℃, further reduces the product's moisture content. The low-temperature environment can lock in the cross-linked structure, inhibit the collapse of the internal pores of the lotus seed crisps, and enhance their resistance to moisture regain.

[0016] Exceeding the temperature and time limits of the three-stage gradient drying process will degrade product quality: In the first stage, high temperature and long duration can easily cause longan to form a shell and lotus seeds to oxidize and become brittle, while low temperature and short duration will cause longan to lose its shape; In the second stage, high temperature and long duration can cause longan to caramelize and block calcium ion migration, while low temperature and short duration will cause lotus seeds to absorb moisture and become damp again; In the third stage, high temperature and long duration can cause longan to become dry and hard and lotus seed structure to collapse, while low temperature and short duration will result in high product moisture content, unstable cross-linking structure, and increased risk of microorganisms.

[0017] Long-term, gradient high-temperature drying of longan and lotus seed crisps not only achieves precise moisture control but also kills internal microorganisms and bacteria, making the food safer.

[0018] Preferably, the longan is selected from Caopu longan, Shixia longan, or Chuliang longan; the lotus seed is selected from hollow white lotus seed.

[0019] The present invention discloses the following technical effects: 1. One agent, two effects, synergistic enhancement: This invention uses calcium chloride solution to treat longan pulp, while the calcium chloride on the longan pulp also plays a role in maintaining the crispness of lotus seeds. Through the joint action mechanism of calcium ions (pectin cross-linking), it solves the two key technical problems of "longan shaping" and "lotus seed crispness retention" in one fell swoop. The process is simple and efficient. At the same time, it forms a synergy with the three-stage gradient drying. Compared with single calcium chloride treatment or single drying process, the fullness of product shape is significantly improved, and the crispness retention rate of lotus seeds is also significantly improved. The technical effects are not simply additive.

[0020] 2. Excellent product form and taste: The dried longan pulp remains plump and golden in color, and can tightly wrap the lotus seeds; the outer layer of longan pulp is soft and chewy, while the inner lotus seeds are crisp and refreshing, forming a unique "soft on the outside and crisp on the inside" composite taste.

[0021] 3. Stable quality and high safety: Calcium chloride treatment reduces the moisture absorption rate of lotus seeds, and the three-stage drying process precisely controls moisture content; sterilization is achieved simultaneously during the drying process, and the microbiological indicators meet the requirements of GB 16325-2005 "Hygienic Standard for Dried Fruit Foods" and GB16565-2003 "Hygienic Standard for Fried Snacks".

[0022] 4. High process specificity: The process described in this invention is only applicable to the processing of longan pulp and lotus seed crisps. Its mechanism of action is deeply bound to the structure and component characteristics of the ingredients, excluding its applicability to other foods and highlighting the unique design value of the technology. Attached Figure Description

[0023] Figure 1 The images show the physical samples of longan and lotus seed crisps (A) without calcium chloride solution treatment and longan and lotus seed crisps (B) treated with calcium chloride solution in Example 3. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0028] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0029] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0030] The longan used in the following embodiments of the present invention are selected from Caopu longan, Shixia longan or Chuliang longan; the lotus seeds used are selected from hollow white lotus seeds; and all other raw materials used are commercially available products unless otherwise specified, and the source of commercially available products does not affect the technical effect of the present invention.

[0031] Unless otherwise specified, the room temperature involved in this invention is 25±5℃.

[0032] Example 1 (without soaking in calcium chloride solution) 1) First, select suitable fresh lotus seeds and rinse them with clean water. Then, remove the shells, seed coats, and cores from the lotus seeds. 2) Boil lotus seeds in boiling water for 10 minutes, drain and cool to room temperature; 3) After draining the lotus seeds, put them into a low-temperature vacuum fryer for frying at a temperature of 95°C for 10 minutes and a vacuum degree of -0.095MPa. 4) Remove the fried lotus seeds and drain the oil, then cool to room temperature; 5) Select fresh and intact longan fruits, remove the shells and seeds, rinse the longan flesh with clean water, and drain. 6) Soak the prepared longan pulp in clean water for 10 minutes, then drain. 7) Stuff the processed lotus seeds into the longan pulp; 8) Drying is carried out in a blower dryer, and the drying process is divided into three stages: the first stage is drying at 80℃ for 12 hours; the second stage is drying at 60℃ for 8 hours; and the third stage is drying at 50℃ for 4 hours. Then it is packaged.

[0033] Example 2 1) First, select suitable fresh lotus seeds and rinse them with clean water. Then, remove the shells, seed coats, and cores from the lotus seeds. 2) Boil lotus seeds in boiling water for 10 minutes, drain and cool to room temperature; 3) After draining the lotus seeds, put them into a low-temperature vacuum fryer for frying at a temperature of 95°C for 10 minutes and a vacuum degree of -0.095MPa. 4) Remove the fried lotus seeds and drain the oil, then cool to room temperature; 5) Select fresh and intact longan fruits, remove the shells and seeds, rinse the longan flesh with clean water, and drain. 6) Soak the processed longan pulp in a 0.1wt% calcium chloride solution for 10 minutes, then drain. 7) Stuff the processed lotus seeds into the longan pulp; 8) Drying is carried out in a blower dryer, and the drying process is divided into three stages: the first stage is drying at 80℃ for 12 hours; the second stage is drying at 60℃ for 8 hours; and the third stage is drying at 50℃ for 4 hours. Then it is packaged.

[0034] Example 3 1) First, select suitable fresh lotus seeds and rinse them with clean water. Then, remove the shells, seed coats, and cores from the lotus seeds. 2) Boil lotus seeds in boiling water for 10 minutes, drain and cool to room temperature; 3) After draining the lotus seeds, put them into a low-temperature vacuum fryer for frying at a temperature of 95°C for 10 minutes and a vacuum degree of -0.095MPa. 4) Remove the fried lotus seeds and drain the oil, then cool to room temperature; 5) Select fresh and intact longan fruits, remove the shells and seeds, rinse the longan flesh with clean water, and drain. 6) Soak the processed longan pulp in a 0.25wt% calcium chloride solution for 10 minutes, then drain. 7) Stuff the processed lotus seeds into the longan pulp; 8) Drying is carried out in a blower dryer, and the drying process is divided into three stages: the first stage is drying at 80℃ for 12 hours; the second stage is drying at 60℃ for 8 hours; and the third stage is drying at 50℃ for 4 hours. Then it is packaged.

[0035] Example 4 1) First, select suitable fresh lotus seeds and rinse them with clean water. Then, remove the shells, seed coats, and cores from the lotus seeds. 2) Boil lotus seeds in boiling water for 10 minutes, drain and cool to room temperature; 3) After draining the lotus seeds, put them into a low-temperature vacuum fryer for frying at a temperature of 95°C for 10 minutes and a vacuum degree of -0.095MPa. 4) Remove the fried lotus seeds and drain the oil, then cool to room temperature; 5) Select fresh and intact longan fruits, remove the shells and seeds, rinse the longan flesh with clean water, and drain. 6) Soak the processed longan pulp in a 0.5wt% calcium chloride solution for 10 minutes, then drain. 7) Stuff the processed lotus seeds into the longan pulp; 8) Drying is carried out in a blower dryer, and the drying process is divided into three stages: the first stage is drying at 80℃ for 12 hours; the second stage is drying at 60℃ for 8 hours; and the third stage is drying at 50℃ for 4 hours. Then it is packaged.

[0036] Example 5 1) First, select suitable fresh lotus seeds and rinse them with clean water. Then, remove the shells, seed coats, and cores from the lotus seeds. 2) Boil lotus seeds in boiling water for 10 minutes, drain and cool to room temperature; 3) After draining the lotus seeds, put them into a low-temperature vacuum fryer for frying at a temperature of 95°C for 10 minutes and a vacuum degree of -0.095MPa. 4) Remove the fried lotus seeds and drain the oil, then cool to room temperature; 5) Select fresh and intact longan fruits, remove the shells and seeds, rinse the longan flesh with clean water, and drain. 6) Soak the processed longan pulp in a 0.75% calcium chloride solution for 10 minutes, then drain. 7) Stuff the processed lotus seeds into the longan pulp; 8) Drying is carried out in a blower dryer, and the drying process is divided into three stages: the first stage is drying at 80℃ for 12 hours; the second stage is drying at 60℃ for 8 hours; and the third stage is drying at 50℃ for 4 hours. Then it is packaged.

[0037] Example 6 (Single Temperature Drying) 1) First, select suitable fresh lotus seeds and rinse them with clean water. Then, remove the shells, seed coats, and cores from the lotus seeds. 2) Boil lotus seeds in boiling water for 10 minutes, drain and cool to room temperature; 3) After draining the lotus seeds, put them into a low-temperature vacuum fryer for frying at a temperature of 95°C for 10 minutes and a vacuum degree of -0.095MPa. 4) Remove the fried lotus seeds and drain the oil, then cool to room temperature; 5) Select fresh and intact longan fruits, remove the shells and seeds, rinse the longan flesh with clean water, and drain. 6) Soak the processed longan pulp in a 0.25% calcium chloride solution for 10 minutes, then drain. 7) Stuff the processed lotus seeds into the longan pulp; 8) Dry at a single temperature in a blower dryer: continuously dry at 70°C for 24 hours, and then package.

[0038] Example 7 (Two-stage drying) 1) First, select suitable fresh lotus seeds and rinse them with clean water. Then, remove the shells, seed coats, and cores from the lotus seeds. 2) Boil lotus seeds in boiling water for 10 minutes, drain and cool to room temperature; 3) After draining the lotus seeds, put them into a low-temperature vacuum fryer for frying at a temperature of 95°C for 10 minutes and a vacuum degree of -0.095MPa. 4) Remove the fried lotus seeds and drain the oil, then cool to room temperature; 5) Select fresh and intact longan fruits, remove the shells and seeds, rinse the longan flesh with clean water, and drain. 6) Soak the processed longan pulp in a 0.25wt% calcium chloride solution for 10 minutes, then drain. 7) Stuff the processed lotus seeds into the longan pulp; 8) Drying is carried out in a blower dryer, and the drying process is divided into two stages: the first stage is drying at 80℃ for 12 hours; the second stage is drying at 50℃ for 12 hours. Then it is packaged.

[0039] I. Performance Testing: 1. Detection Indicators and Methods Lotus seed crisp hardness value: A TA-XT2i texture analyzer was used with a P / 50 probe, a test speed of 1 mm / s, and a compression degree of 50%. The hardness value (N) of the lotus seed crisp was recorded. The lower the hardness value, the better the crispness. Moisture content: The moisture content was determined according to the method in GB 5009.3-2016 "National Food Safety Standard - Determination of Moisture in Food".

[0040] Sensory crispness rating: A professional sensory evaluation team of 5 people will score the crispness on a 10-point scale based on three dimensions: difficulty of chewing, crispness layering, and aftertaste crispness. The average score will be used as the sensory crispness rating. The higher the score, the better the crispness.

[0041] Sensory evaluation of longan flesh plumpness: A professional sensory evaluation team of 5 people will score the flesh on a scale of 10 based on its roundness, surface smoothness, and the average score will be used as the sensory evaluation score of longan flesh plumpness. The higher the score, the better the sensory evaluation of longan flesh plumpness.

[0042] 2. Test Results Table 1. Effect of calcium chloride treatment process on the crispness of lotus seeds Table 2. Impact of drying process on product quality As shown in Table 1, in Examples 2, 3, 4, and 5 using the calcium chloride soaking process of this invention, the hardness value of the lotus seeds was significantly lower than that of the untreated Example 1, and the sensory crispness score was significantly improved. Among them, Example 2 (0.25wt% calcium chloride) showed the best effect, with a lower hardness value and a higher sensory score, indicating that calcium chloride treatment can effectively improve the initial crispness of lotus seeds. This is because calcium ions undergo a cross-linking reaction with the components in the lotus seed cell structure, forming a stable porous structure, reducing water adsorption, and thus maintaining the crispy texture.

[0043] Table 2 shows that even with the optimal concentration of calcium chloride treatment, the product quality of longan pulp using only a single drying process and a two-stage drying process is still significantly inferior to that of the three-stage gradient drying process: the shrinkage rate of longan pulp increases significantly, and its plumpness decreases severely; the hardness of lotus seeds increases, and their crispness decreases; and moisture control is poor. This indicates that using the three-stage drying procedure described in this invention can better control the moisture content of longan pulp and lotus seeds, resulting in dried longan with a moderate softness and firmness, and also improving the aroma and taste of the product. This proves that the synergistic effect of the three-stage drying procedure and calcium chloride treatment is key to ensuring product quality.

[0044] Figure 1 Images show the finished longan and lotus seed crisps (A) without calcium chloride solution treatment and the longan and lotus seed crisps (B) treated with calcium chloride solution in Example 3. Figure 1It can be seen that the production process of longan and lotus seed crisps in this invention, after treatment with 0.25wt% calcium chloride, results in longan and lotus seed crisps ( Figure 1 B) After drying, longan pulp was better than that that was not treated with calcium chloride ( Figure 1 A) The longan pulp becomes rounder and fuller, and the surface is drier and less sticky. The drying process also makes the lotus seed crisps inside the longan even crisper. This treatment not only improves the product's appearance but also enhances the crispness of the lotus seed crisps, making it more appealing to consumers.

[0045] II. Microbiological Indicator Detection 1. Testing Basis and Methods The longan and lotus seed crisps prepared in Example 3 were tested according to the series of methods of the National Food Safety Standard, as shown in Table 3.

[0046] Table 3. Testing Standards Corresponding to the National Food Safety Standards Series of Methods 2. Test Results Table 4. Detection results of microbial indicators for longan and lotus seed crisps As shown in Table 4, the longan and lotus seed crisps prepared using the process of this invention (Example 3) have a total bacterial count of <10 CFU / g, coliform bacteria of <3 MPN / 100g, no detected mold, and no detected pathogenic bacteria, which are far superior to the national standard limits. This indicates that the three-stage gradient drying process for drying and sterilization can effectively ensure that the product meets excellent microbiological indicators and provides reliable assurance in terms of food safety.

[0047] III. Compatibility Testing 1. Detection Method The compatibility of the process described in this invention with longan and lotus seed crisps was verified through experiments on strawberries and walnuts. The specific steps are as follows: Processing of strawberries: (1) Select fresh, undamaged, and uniformly sized strawberries, rinse them with clean water and drain them, and remove the stems to obtain strawberry pulp; (2) Following the processing method of longan pulp in Example 3, soak the strawberry pulp in a 0.25wt% calcium chloride solution for 10 minutes, and then drain it; (3) Dry the processed strawberry pulp according to the three-stage gradient drying parameters (80℃ / 12h, 60℃ / 8h, 50℃ / 4h) in Example 3, and then cool it to room temperature after drying; (4) Test the hardness, sensory crispness, and flavor of the dried strawberry products and record the data.

[0048] Processing of walnuts: (1) Select fresh, mold-free, and uniformly sized walnuts, remove the shells and take the kernels, rinse them lightly with water to remove surface dust, and drain the water; (3) Refer to the longan pulp processing method in Example 3, soak the walnut kernels in a 0.25wt% calcium chloride solution for 10 minutes, take them out and drain them; (3) Dry the walnut kernels according to the three-stage gradient drying parameters in Example 3 (80℃ / 12h, 60℃ / 8h, 50℃ / 4h), and cool them to room temperature after drying; (4) Test the hardness, sensory crispness and flavor of the dried walnut kernels and record the data.

[0049] 2. Detection indicators The hardness value and sensory crispness score (out of 10) were determined according to the methods in "I. Performance Testing".

[0050] Strawberry flavor rating: 9-10 points: Rich and prominent original strawberry flavor, no astringent taste or other off-flavors such as calcium chloride, and a harmonious and natural balance of sweet and sour; 7-8 points: Distinct strawberry flavor, with a slight residual taste of calcium chloride, and a slightly poor balance of sweet and sour; 5-6 points: Mild strawberry flavor, with a distinct astringent taste of calcium chloride, and an unbalanced sweet and sour taste; ≤4 points: Almost no original strawberry flavor, strong astringent taste of calcium chloride, and no edible value.

[0051] Walnut flavor rating: 9-10 points: The walnuts have a rich and fresh nutty aroma, retaining their original flavor well, without any off-flavors such as the astringent taste of calcium chloride, and the flavor is pure and natural; 7-8 points: The walnuts have a distinct nutty aroma, with a slight loss of the original flavor, and only a slight residual taste of calcium chloride; 5-6 points: The walnuts have a weak original flavor, with a significant loss of the original flavor and a noticeable astringent taste of calcium chloride; ≤4 points: The walnuts have no nutty aroma, a strong astringent taste of calcium chloride, and lose their edible value.

[0052] 3. Test Results Table 5 Effects on the crispness of strawberry and walnut shortbread As shown in Table 5, after processing with the process described in this invention, the dried strawberries have a hard texture (hardness value reaches 12.5N) and a flavor loss rate of 40%; the crispness of walnuts is not improved, but the astringency is aggravated due to calcium ion residue. This further proves that the process described in this invention is only applicable to the processing of longan pulp and lotus seed crisps. Its technical solution is deeply bound to the structure and component characteristics of specific ingredients and has clear specificity.

[0053] 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.

[0054] 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 production process for improving the fullness of longan pulp and the crispness of lotus seeds in longan and lotus seed crisping, characterized in that, Includes the following steps: Lotus seeds are boiled and fried in oil in sequence to obtain processed lotus seeds; Longan is soaked in a calcium chloride solution to obtain processed longan pulp; The processed lotus seeds are embedded inside the processed longan pulp, dried in a three-stage gradient process, and then packaged to obtain the finished product.

2. The production process according to claim 1, characterized in that, The specific steps are as follows: Fresh lotus seeds are rinsed with water and then shelled, seed coat removed, and core removed. After processing, boil the lotus seeds in boiling water, drain and cool. Deep-fry lotus seeds, drain the oil, and cool to obtain fried lotus seeds. Select fresh and intact longan fruits, remove the shells and pits, rinse the longan flesh with water and drain. Longan pulp is soaked in calcium chloride solution, then removed and drained to obtain processed longan pulp; The fried lotus seeds are embedded inside the processed longan pulp to obtain the embedded longan and lotus seed crisps; The fused longan and lotus seed crisps are dried in a three-stage gradient process, and then packaged to obtain the finished product.

3. The production process according to claim 1, characterized in that, The concentration of the calcium chloride solution is 0.1~0.75wt%.

4. The production process according to claim 3, characterized in that, The concentration of the calcium chloride solution is 0.25 wt%.

5. The production process according to claim 1, characterized in that, The three-stage gradient drying process includes: the first stage drying at 75~85℃ for 10~14h, the second stage drying at 55~65℃ for 6~10h, and the third stage drying at 45~55℃ for 3~5h.

6. The production process according to claim 5, characterized in that, The three-stage gradient drying process includes: the first stage drying at 80℃ for 12 hours, the second stage drying at 60℃ for 8 hours, and the third stage drying at 50℃ for 4 hours.

7. The production process according to claim 1, characterized in that, The longan is selected from Caopu longan, Shixia longan or Chuliang longan; the lotus seed is selected from hollow white lotus seed.

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