Slurry coating and ice glaze coating vacuum freeze-drying preparation process of food

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a slurry coating and ice glaze coating vacuum freeze-drying preparation process of food, which comprises the following steps: raw material pretreatment, raw material quick freezing, slurry juice blending, slurry coating and ice glaze coating, quick freezing, vacuum freeze-drying, and delivery out of a warehouse. The process comprises the following steps: quickly freezing raw materials, quickly coating slurry and coating ice glaze on the raw materials, quickly condensing a thicker slurry juice ice layer on the surface of the raw materials, quickly freezing again, completely quickly freezing slurry juice hung on the outer surface to form uniform and fine ice crystals, performing vacuum freeze-drying, and removing moisture of the slurry juice ice glaze hung on the outer surface. By means of the technology, the pulp juice can be wrapped on the surface of the product in a freeze-drying mode, the appearance of the manufactured product is similar to the shape of natural food raw materials, the structure layer is clear, the texture is novel and high-end, the taste is delicious and unique, and the food preparation technology has creativity and commercial popularization value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food processing, and particularly relates to a vacuum freeze-drying preparation process for food coating with slurry and ice clothes. BACKGROUND

[0002] In recent years, food innovation has entered a stage of rapid development in China. Food innovation includes product taste innovation and product process innovation. Product process innovation will lead and create the development of a new food category, so the innovation of food preparation process is particularly important.

[0003] Developing a new food freeze-drying preparation process is a multi-dimensional and multi-disciplinary frontier development field. The development of a new food freeze-drying process is the result of consumer demand and market-driven change. Traditional vacuum freeze-drying processes have exposed many problems in practical application. From the perspective of product appearance structure, the products produced by the traditional freeze-drying process are single in structure and lack of hierarchy, and the appearance is not novel. With the increasing demand for high-quality and low-cost products in various industries, it is urgent to develop a new vacuum freeze-drying process. The new process needs to overcome the shortcomings of the traditional freeze-drying process, thereby improving product quality, meeting market demand, and promoting the development of related industries. The vacuum freeze-drying preparation process for coating with slurry and ice clothes is an innovative approach to changing the traditional simple freeze-drying method. This process enriches the freeze-drying form of products and creates a new field of food categories. The process can coat the slurry juice on the surface of the food raw material in the form of freeze-drying. The product has a shape similar to that of natural food raw materials, clear structure hierarchy, novel high-end taste, unique delicious taste, and natural and attractive aroma. In some product combination forms, such as freeze-drying slurry juice on the surface of cooked nuts, beans and other foods, the water content of cooked nuts, beans and other foods is low and does not need to be freeze-dried. Therefore, the freeze-drying of slurry juice accounts for a small proportion of the overall product, and thus the freeze-drying time of such products can be reduced by about 80%. At the same time, due to the short freeze-drying time, the nutritional ingredients, color, aroma and flavor of the freeze-dried slurry juice are also maximally preserved. SUMMARY

[0004] The purpose of the present application is to provide a vacuum freeze-drying preparation process for food coating with slurry and ice clothes to solve the problems in the prior art. The freeze-dried product produced according to the process has a shape similar to that of natural food raw materials and clear structure hierarchy, novel high-end taste, and unique delicious taste. The freeze-drying time of some products can be reduced by about 80%, greatly reducing freeze-drying energy consumption and cost.

[0005] To achieve the purpose of the present application, the present application provides the following technical solution, a vacuum freeze-drying preparation process for food coating with slurry and ice clothes, comprising the following steps:

[0006] (1) Raw material pretreatment: the raw material needs to be selected and impurities removed for pre-treatment process;

[0007] (2) Raw material quick freezing: the pre-treated raw material is quick frozen, the quick freezing temperature is required to be below-18℃, and the time is determined according to the size of the raw material, and the raw material needs to be prevented from adhering to each other during quick freezing;

[0008] (3) Slurry juice blending: one or more raw materials are mixed and blended uniformly, and the slurry juice concentration after blending is required to be 10%-30%;

[0009] (4) Slurry coating and ice coating: the blended slurry juice is coated and ice coated, since the surface temperature of the quick-frozen food is low, the slurry juice can be quickly frozen into an ice layer on the surface of the food after being coated;

[0010] (5) Quick freezing: the semi-finished product after slurry coating and ice coating is quickly frozen, the quick freezing temperature is required to be below-18℃, and the semi-finished product needs to be prevented from adhering to each other during quick freezing;

[0011] (6) Vacuum freeze-drying: the semi-finished product after slurry coating and ice coating is pushed into the pre-started vacuum freeze-drying machine, the door is tightly closed, the vacuum pump is started, and the vacuum freeze-drying program is started;

[0012] (7) Discharging: after the vacuum freeze-drying program is completed, the material is discharged, and then the unqualified semi-finished products such as broken and concave products are selected.

[0013] As a preferred embodiment of the present application, in step (1), the raw material to be pre-treated can be one or more of nuts, grains, beans, fruits, aquatic products, etc., such as cashews, shrimp, sea cucumber, bananas, etc., and the raw material of raw nuts, aquatic products and other food materials not suitable for direct consumption needs to be added with a pre-treatment process such as cooking; and the raw material of fruits and other food materials suitable for direct consumption needs to be added with a pre-treatment process such as sterilization.

[0014] As a preferred embodiment of the present application, in step (3), the slurry juice can be one or more of blended raw materials such as mango, banana, durian, yogurt, probiotics, corn, medlar, sea buckthorn, trehalose, allulose, etc., and the blended slurry juice needs to be treated by a sterilization process if the workshop cleanliness is not high.

[0015] As a preferred embodiment of the present application, in step (4), during slurry coating and ice coating, the blended slurry juice needs to be cooled to-5℃ to 20℃ for use, the thickness of slurry coating and ice coating is adjusted by adjusting the contact time of the quick-frozen raw material with the slurry juice and multiple slurry coating and ice coating, and the slurry juice coated each time can be the same or different.

[0016] As a preferred embodiment of the present application, in step (6), the parameters of the freeze-dried product need to be adjusted according to different materials and the performance of the vacuum freeze dryer of different equipment manufacturers during the vacuum freeze drying, so that the freeze-dried product is crisp and delicious.

[0017] The present application has the following advantages: through the process of the present application, the slurry juice can be wrapped on the outer surface of the food raw material in the form of freeze-drying, and the product has the shape similar to the natural food raw material, clear structure, novelty, high-end, mellow taste, unique delicious taste, and natural and attractive smell. In some product combination forms, for example, when the slurry juice is freeze-dried on the surface of the cooked nuts, beans and other foods, since the cooked nuts, beans and other foods have low water content and do not need to be freeze-dried, only the slurry juice with low proportion in the overall product needs to be freeze-dried, therefore, the freeze-drying time of the product can be reduced by about 80% when freeze-drying such products, which greatly reduces the freeze-drying energy consumption and cost, and at the same time, the nutritional ingredients, color, aroma and flavor of the freeze-dried slurry juice are also maximally preserved. The vacuum freeze-drying preparation process of the slurry coating and ice clothing is an innovative change from the traditional simple freeze-drying method, which enriches the freeze-drying form of the product and opens up a new field of food types. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The process flow chart of the present application is shown in the following figure. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and characteristics of the present application clearer and more understandable, the process of the present application will be described clearly and completely in combination with the embodiments. It should be understood that the specific embodiments described below are only used to explain the present application and do not limit the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative labor achievements are within the protection scope of the present application.

[0020] Embodiment 1

[0021] A vacuum freeze-drying preparation process of corn and shrimp, wherein the raw materials include: 10 parts of peeled raw shrimp and 1 part of corn juice, and the preparation method includes the following specific steps:

[0022] (1) Raw shrimp pretreatment: the raw shrimp needs to be selected and impurities removed before being put into a steamer for steaming for about 25 minutes, and then cooled to room temperature for standby after being cooked;

[0023] (2) Quick freezing of shrimp: the pretreated shrimp is quick frozen at a temperature of-35℃ or lower for about 1 hour, and the quick freezing needs to prevent the shrimp from sticking to each other;

[0024] (3) Slurry juice blending, sterilization: corn juice is added to drinking water and mixed and blended uniformly, the slurry juice concentration after blending is required to be 15%, and then the slurry juice is fed into a sterilization machine for sterilization, and after sterilization, the slurry juice is cooled to about 4°C and fed into a bag ice machine;

[0025] (4) Slurry bagging and ice coating: the bag ice machine is started, and the corn slurry juice is subjected to slurry bagging and ice coating, since the surface temperature of the quick-frozen shrimp meat is low, the corn slurry juice can quickly freeze an ice coating on the surface of the shrimp meat after being coated on the shrimp meat;

[0026] (5) Quick freezing: the shrimp meat after slurry bagging and ice coating is quickly frozen, the quick-freezing temperature is required to be below -40°C, and the quick-freezing time is about 3 hours, and the quick freezing needs to prevent the shrimp meat from adhering to each other;

[0027] (6) Vacuum freeze-drying: the slurry bagging and ice coating semi-finished product after quick freezing is pushed into a vacuum freeze-drying machine started in advance, the cold trap temperature of the freeze-drying machine is required to be below -35°C, the door of the freeze-drying machine is tightly closed, the vacuum pump is started, and a vacuum freeze-drying program is started, a 7-stage freeze-drying curve is designed, and the design parameters of the freeze-drying curve are as follows: First stage: time 30 minutes, heating temperature 15°C, vacuum degree 45 Pa; Second stage: time 90 minutes, heating temperature 45°C, vacuum degree 50 Pa; Third stage: time 500 minutes, heating temperature 65°C, vacuum degree 50 Pa; Fourth stage: time 200 minutes, heating temperature 65°C, vacuum degree 60 Pa; Fifth stage: time 200 minutes, heating temperature 65°C, vacuum degree 60 Pa; Sixth stage: time 100 minutes, heating temperature 50°C, vacuum degree 80 Pa; Seventh stage: time 120 minutes, heating temperature 45°C, vacuum degree 90 Pa.

[0028] (7) Discharging: after the vacuum freeze-drying program is completed, the material is discharged, and then unqualified semi-finished products such as broken and concave products are selected out.

[0029] Example 2

[0030] A sea cucumber vacuum freeze-drying preparation process of sea buckthorn and medlar sea cucumber, wherein the raw materials include: 10 parts of raw sea cucumber, 0.5 parts of sea buckthorn juice, and 0.5 parts of medlar juice, and the preparation method includes the following specific steps:

[0031] (1) Raw sea cucumber pretreatment: the sea cucumber to be coated with slurry and ice is selected, impurities are removed, and seasoning is added, and then the sea cucumber is fed into a steaming pot, steamed for about 35 minutes, cooled to room temperature after cooking, and used as a semi-finished product;

[0032] (2) Sea cucumber quick freezing: the pretreated sea cucumber is quickly frozen, the quick freezing temperature is required to be below -35℃, and the quick freezing time is about 2 hours. The quick freezing needs to prevent mutual adhesion;

[0033] (3) Slurry juice blending: the wolfberry juice and sea buckthorn juice are mixed and blended with drinking water. After blending, the slurry juice concentration is required to be 18%, and it is cooled to about 4℃ for standby;

[0034] (4) Slurry hanging and ice coating: the blended slurry juice is hung and coated with ice. Since the surface temperature of the quick-frozen sea cucumber is low, the slurry juice can quickly freeze a layer of ice on the surface of the sea cucumber after being hung and coated;

[0035] (5) Quick freezing: the semi-finished product hung and coated with slurry and ice is quickly frozen. The quick freezing temperature is required to be below -40℃, and the quick freezing time is about 4 hours. The quick freezing needs to prevent mutual adhesion;

[0036] (6) Vacuum freeze-drying: the semi-finished product hung and coated with slurry and ice is quickly frozen and then pushed into the vacuum freeze-drier started in advance. The cold trap temperature of the freeze-drier is required to be below -35℃. The door is tightly closed, the vacuum pump is started, and the vacuum freeze-drying program is started. A 7-stage freeze-drying curve is designed, and the design parameters of the freeze-drying curve are as follows: First stage: 30 minutes, heating temperature 15℃, vacuum degree 45Pa; Second stage: 90 minutes, heating temperature 45℃, vacuum degree 50Pa; Third stage: 500 minutes, heating temperature 65℃, vacuum degree 50Pa; Fourth stage: 200 minutes, heating temperature 65℃, vacuum degree 60Pa; Fifth stage: 200 minutes, heating temperature 60℃, vacuum degree 60Pa; Sixth stage: 100 minutes, heating temperature 45℃, vacuum degree 80Pa; Seventh stage: 120 minutes, heating temperature 40℃, vacuum degree 90Pa.

[0037] (7) Out of the warehouse: after the vacuum freeze-drying program is completed, the material is taken out of the warehouse, and then the unqualified semi-finished products such as broken and concave are selected out.

[0038] Example 3

[0039] A mango and cashew kernel vacuum freeze-drying preparation process, wherein the raw materials include: 10 parts of raw cashew kernels and 1 part of mango juice. The preparation method includes the following specific steps:

[0040] (1) Raw cashew kernel pretreatment: the cashew kernels for slurry hanging and ice coating are selected and impurities are removed, and then baked at 145℃ for about 25 minutes. After cooking, the semi-finished product is cooled to room temperature for standby;

[0041] (2) Cashew kernel quick freezing: The pretreated cashew kernel is quickly frozen, the quick freezing temperature is required to be below-35℃, and the quick freezing time is about 1 hour. The quick freezing needs to prevent mutual adhesion;

[0042] (3) Slurry juice blending: The mango juice is mixed with drinking water to blend uniformly. The slurry juice concentration after blending is required to be 16%, and it is cooled to about 4℃ for standby;

[0043] (4) Slurry coating and ice coating: The blended mango slurry juice is coated and ice coated. Since the surface temperature of the quick-frozen cashew kernel is low, the slurry juice can quickly freeze a layer of ice coating on the surface of the cashew kernel after being coated;

[0044] (5) Quick freezing: The semi-finished product after slurry coating and ice coating is quickly frozen. The quick freezing temperature is required to be below-40℃, and the quick freezing time is about 1 hour. The quick freezing needs to prevent mutual adhesion;

[0045] (6) Vacuum freeze-drying: The semi-finished product after slurry coating and ice coating is quickly frozen and then pushed into the vacuum freeze-drying machine which is started in advance. The cold trap temperature of the freeze-drying machine is required to be below-35℃. The door is tightly closed, the vacuum pump is started, and the vacuum freeze-drying program is started. A 7-stage freeze-drying curve is designed, and the design parameters of the freeze-drying curve are as follows: First stage: 10 minutes, heating temperature 10℃, vacuum degree 45Pa; Second stage: 15 minutes, heating temperature 20℃, vacuum degree 50Pa; Third stage: 30 minutes, heating temperature 65℃, vacuum degree 50Pa; Fourth stage: 20 minutes, heating temperature 65℃, vacuum degree 60Pa; Fifth stage: 20 minutes, heating temperature 60℃, vacuum degree 60Pa; Sixth stage: 30 minutes, heating temperature 45℃, vacuum degree 80Pa; Seventh stage: 20 minutes, heating temperature 40℃, vacuum degree 90Pa.

[0046] (7) Discharging: After the vacuum freeze-drying program is completed, the material is discharged, and then the unqualified semi-finished products such as broken and concave are selected out.

[0047] Example 4

[0048] A vacuum freeze-drying preparation process of durian red pitaya macadamia kernel, wherein the raw materials include: 10 parts of raw macadamia kernel, 1 part of durian pulp, and 1 part of red pitaya juice. The preparation method includes the following specific steps:

[0049] (1) Raw macadamia kernel pretreatment: The macadamia kernel to be coated with slurry and ice is selected and impurities are removed, and then it is put into an oven and baked at 140℃ for about 30 minutes. After cooking, the semi-finished product is cooled to room temperature for standby;

[0050] (2) Macadamia nuts quick freezing: the pretreated macadamia nuts are quickly frozen, the quick freezing temperature is required to be below -35℃, and the quick freezing time is about 1 hour, and the quick freezing needs to prevent mutual adhesion;

[0051] (3) Slop juice blending: the durian pulp is mixed with drinking water to blend uniformly, the concentration of the blended durian pulp juice is required to be 16%, and the blended pulp juice is cooled to about 4℃ for standby;

[0052] (4) Slop coating and ice coating: the blended durian pulp juice is coated and ice coated, since the surface temperature of the quick-frozen macadamia nuts is low, the durian pulp juice can quickly freeze a layer of ice coating on the surface of the macadamia nuts after being coated;

[0053] (5) Quick freezing: the half-finished product after being coated and ice coated is quickly frozen, the quick freezing temperature is required to be below -35℃, and the quick freezing time is about 1 hour, and the quick freezing needs to prevent mutual adhesion;

[0054] (6) Slop juice blending: the red date juice is blended with drinking water uniformly, the concentration of the blended red date pulp juice is required to be 16%, and the blended pulp juice is cooled to about 4℃ for standby;

[0055] (7) Slop coating and ice coating: the blended red date pulp juice is coated and ice coated, since the surface temperature of the quick-frozen half-finished product is low, the red date pulp juice can quickly freeze a layer of ice coating on the surface of the half-finished product after being coated;

[0056] (8) Quick freezing: the half-finished product after being coated and ice coated is quickly frozen, the quick freezing temperature is required to be below -35℃, and the quick freezing time is about 2 hours, and the quick freezing needs to prevent mutual adhesion;

[0057] (9) Vacuum freeze-drying: the half-finished product after being coated and ice coated is quickly frozen and then pushed into the vacuum freeze-dryer which is started in advance, the cold trap temperature of the freeze-dryer is required to be below -35℃, the door of the freeze-dryer is closed tightly, the vacuum pump is started, and the vacuum freeze-drying program is started, and a 7-stage freeze-drying curve is designed, and the design parameters of the freeze-drying curve are as follows: First stage: time 10 minutes, heating temperature 10℃, vacuum degree 45Pa; Second stage: time 15 minutes, heating temperature 20℃, vacuum degree 50Pa; Third stage: time 30 minutes, heating temperature 65℃, vacuum degree 50Pa; Fourth stage: time 30 minutes, heating temperature 65℃, vacuum degree 60Pa; Fifth stage: time 25 minutes, heating temperature 60℃, vacuum degree 60Pa; Sixth stage: time 35 minutes, heating temperature 45℃, vacuum degree 80Pa; The seventh stage: time 20 minutes, heating temperature 40 DEG C, vacuum degree 90Pa.

[0058] (10) Warehouse: after the end of the vacuum freeze-drying process, the material is discharged from the warehouse, and then the unqualified semi-finished products such as broken and concave are selected out.

[0059] The products obtained in Examples 1-4 are subjected to sensory evaluation, which is carried out in a sensory evaluation room. The sensory evaluation experiment is composed of 30 taste experienced evaluators, and the samples are evaluated from three aspects of appearance, taste and flavor. Extremely like is 9-10 points, very like is 8 points, like is 7 points, slightly like is 6 points, neither like nor dislike is 5 points, slightly dislike is 4 points, generally dislike is 3 points, very dislike is 2 points, and extremely dislike is 0-1 points.

[0060] Table 1 Sensory evaluation results

[0061] appearance mouthfeel aroma total score Example 1 9 8 9 26 Example 2 8 9 8 25 Example 3 9 9 9 27 Example 4 10 10 9 29

[0062] As can be seen from Table 1, the products prepared by the process of the present application have very high praise degree in sensory evaluation. The obtained products are novel and high-end attractive, the product taste is delicious and unique, the flavor is naturally attractive, and the products prepared by the process of the present application are highly recognized from three aspects. The process of the present application can wrap the pulp juice in the form of freeze-drying on the outer surface of the food, so that the appearance of the freeze-dried product is close to the shape of the natural food raw material, and the structure is clear and novel, high-end, and the freeze-dried pulp juice has maximum retention of nutritional ingredients, color and flavor, so it has been highly recognized by everyone.

[0063] Finally, it is particularly emphasized that the above description is only some specific embodiments of the present application, and is not any form of limitation on the present application. The protection scope of the present application is not limited thereto. For those skilled in the art, some changes and modifications made without departing from the technical solutions of the present application should be considered as the protection scope of the present application.

Claims

1. A vacuum freeze-drying process for preparing a food product with a coating and ice-covering effect, characterized in that, Includes the following steps: (1) Raw material pretreatment: Pretreatment processes such as selecting and removing impurities are required for raw materials that need to be coated with slurry and ice coating; (2) Quick-freezing of raw materials: Quick-freeze the pre-treated raw materials at a temperature below -18℃. The time is determined according to the size of the raw materials. During quick-freezing, it is necessary to prevent the raw materials from sticking together. (3) Preparation of slurry: Mix one or more raw materials evenly, and the concentration of the slurry after preparation should be 10%-30%; (4) Coating with slurry and ice coating: Coating the prepared slurry with slurry and ice coating. Because the surface temperature of the food is low after quick-freezing, the slurry can quickly freeze a layer of ice coating on the surface of the food. (5) Quick-freezing: Quickly freeze the semi-finished products after coating with slurry and ice. The quick-freezing temperature should be below -18℃. During quick-freezing, prevent them from sticking together. (6) Vacuum freeze drying: After the semi-finished product with slurry coating and ice coating is quick-frozen, it is pushed into the vacuum freeze dryer that has been turned on in advance. The door is closed tightly, the vacuum pump is turned on, and the vacuum freeze drying program is started. (7) Unpacking: After the vacuum freeze-drying process is completed, the material is unpacked and then unqualified semi-finished products such as damaged or dented products are selected.

2. The process according to claim 1, characterized in that, In step (1), the raw materials that need to be pretreated can be one or more of nuts, grains, beans, fruits, aquatic products, such as cashews, shrimp, sea cucumbers, bananas, etc. If the raw materials are raw nuts, aquatic products, etc., which are not suitable for direct consumption, a pretreatment process such as cooking is required; if the raw materials are fruits, etc., which are suitable for direct consumption, a pretreatment process such as sterilization is required.

3. The process according to claim 1, characterized in that, In step (3), the slurry can be made from one or more raw materials, such as mango, banana, durian, yogurt, probiotics, corn, goji berries, sea buckthorn, trehalose, allulose, etc. If the cleanliness of the workshop is not high, the slurry needs to be sterilized.

4. The process according to claim 1, characterized in that, In step (4), when coating with slurry and ice, the prepared slurry needs to be cooled to -5°C to 20°C before use. The thickness of the coating can be adjusted by adjusting the contact time between the quick-frozen raw material and the slurry and by coating with slurry multiple times. When coating with slurry multiple times, the slurry used each time can be the same or different.

5. The process according to claim 1, characterized in that, In step (6), the parameters of the freeze-dried product need to be adjusted according to different materials and the performance of the vacuum freeze dryer from different equipment manufacturers during vacuum freeze drying, so that the freeze-dried product is crisp and delicious.

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