Pure kelp powder extruded puffed food and preparation method thereof

Abstract

The invention discloses a pure kelp powder extruded puffed food and a preparation method thereof, and belongs to the field of food processing. The method comprises the following steps: (1) drying kelp, crushing, and sieving to obtain kelp powder; (2) extruding and puffing the kelp raw material powder by using a twin-screw extruder, and setting the extrusion temperature of each area of the twin-screw extruder, the kelp powder feeding amount, the water inlet amount and the screw rotating speed; and (3) finally, collecting a product obtained in the step (2), and finishing and forming after the product is cooled. The kelp powder is used as the raw material, and no grease is added, so that the prepared puffed food is low in calorie, rich in various components such as dietary fibers, high in nutritional value and balanced in nutrition; through a twin-screw extrusion technology, the raw materials are puffed in a high-temperature and high-pressure state, caramelization and Maillard reaction of the materials are promoted, insoluble dietary fibers are converted into soluble dietary fibers, and the product is endowed with unique flavor and crisp taste.

Description

Technical Field

[0001] The invention relates to pure kelp powder extruded puffed food and a preparation method thereof, belonging to the field of food processing. Background Art

[0002] Kelp is rich in polysaccharides, cellulose, mannitol, iodine and other nutrients. It has the effects of promoting intellectual development, preventing obesity, reducing the three highs, and improving immunity. It is an important marine resource with low cost and rich functions. With the development of science and technology and economy in my country, and the continuous improvement of people's demand for food nutrition, kelp processed food faces further innovation and higher technical requirements. my country's kelp production is high, but the production and processing utilization rate is low, and kelp products generally have a strong fishy smell and are difficult to be accepted by consumers. At present, kelp is mostly sold as a dried product, which is inconvenient to eat, which limits the consumption of kelp to a certain extent. The form of kelp products on the market is relatively single and the innovation ability is insufficient.

[0003] The Chinese journal Food Research and Development Journal, Issue 5, Pages 98-99, disclosed the development of puffed kelp crispy strips, wherein the preparation method of puffed kelp crispy strips is as follows: using dried kelp as raw material, soaking and cutting into kelp strips with a width of 1 cm, removing the fishy smell with 3% citric acid, seasoning, coating with batter, lightly frying, microwave puffing, and oven drying to make kelp crispy strips. This method uses simple processes such as frying, microwave puffing, and oven drying, the product has a high oil content, and the processing process is cumbersome, and the processes such as frying and microwave puffing are prone to cause the loss of nutrients such as vitamins.

[0004] The Chinese invention patent with publication number CN106666500A discloses a method for preparing puffed kelp food, wherein the method for preparing puffed kelp food is as follows: dry kelp is made into 80-mesh kelp powder and then mixed with corn flour in a ratio of 5% to 40%: 95% to 60%, and then the mixed powder is mixed evenly with 2% to 20% of water, extruded and puffed by a screw at a temperature of 60 to 140°C and cut to obtain the puffed kelp food. The main raw material of this method is corn flour containing a large amount of starch, and kelp powder is used as an auxiliary material. The main molding component is starch. Kelp is not used as the main raw material for processing, and a constant temperature extrusion method is adopted.

[0005] In summary, the processing techniques of puffed kelp foods are mainly baking, frying, microwave puffing, etc., or other raw materials such as rice flour are added to the raw materials to promote puffing. Direct puffing processing with kelp as the raw material is very rare, and puffed kelp foods need to be innovated. Summary of the invention

[0006] [Technical issues]

[0007] The technical problem to be solved by the present invention is that the current processing technology of kelp puffed food is mainly baking, frying, microwave puffing, or adding other starch-rich raw materials such as rice flour to the raw materials to promote puffing, and direct puffing processing using kelp as raw material is very rare.

[0008] [Technical solution]

[0009] In order to solve the above problems, the present invention provides a pure kelp powder extruded puffed food and a preparation method thereof. The kelp powder is used as a raw material, and no oil is added during the production process. Twin-screw extrusion is used to help modify the product structure, reduce harmful substances in food, promote the degradation of macromolecules, increase protein digestibility and solubility of dietary fiber, improve product quality and produce flavor substances, thereby providing basic support for the development of low-fat, low-calorie, nutritionally balanced and crispy kelp powder extruded puffed food, and can be used for the development of snack foods.

[0010] The present invention provides a method for preparing pure kelp powder extruded puffed food, which specifically comprises the following steps:

[0011] (1) drying the kelp, crushing it, and sieving it to obtain kelp powder;

[0012] (2) extruding and expanding the kelp powder with a twin-screw extruder, and setting the extrusion temperature, kelp powder feed amount, water intake and screw speed of each area of ​​the twin-screw extruder;

[0013] (3) Finally, the product obtained in step (2) is collected and shaped after being cooled.

[0014] In one embodiment of the present invention, in step (2), the two screws of the twin-screw extruder are co-rotating screws that can perform simultaneous extrusion, and the screw diameter is 22 mm.

[0015] In one embodiment of the present invention, in step (2), the various regions of the twin-screw extruder are divided into: regions two and three are mixing regions, regions four and five are shearing regions, regions six and seven are melting regions, and region eight is an expansion region.

[0016] In one embodiment of the present invention, in step (2), during the extrusion puffing process, the extrusion temperatures of the various regions are: 60-80°C for region 2, 80-100°C for region 3, 100-140°C for region 4, 110-150°C for region 5, 120-160°C for region 6, 130-170°C for region 7, and 140-180°C for region 8.

[0017] In one embodiment of the present invention, in step (2), the feeding amount of kelp powder is 2 to 10 kg / h.

[0018] In one embodiment of the present invention, in step (2), the amount of water intake is 12-16% of the mass of the kelp powder.

[0019] In one embodiment of the present invention, in step (2), the screw speed is 200-260 rpm.

[0020] The invention provides pure kelp powder extruded puffed food prepared by the method described above.

[0021] The present invention provides application of the above-mentioned pure kelp powder extruded puffed food in the food field.

[0022] In one embodiment of the present invention, the application of pure kelp powder extruded puffed food in the food field includes preparing kelp slices, kelp flavored crispy strips, and kelp shreds.

[0023] [Beneficial Effects]

[0024] (1) The extruded puffed food of the present invention is made from kelp powder without any oil added, is rich in polysaccharides, dietary fiber and other nutrients, and has high nutritional value;

[0025] (2) The present invention uses twin-screw extrusion technology to extrude and expand the raw materials under the action of high temperature and high shear force, giving the product a crispy taste, converting insoluble dietary fiber into soluble dietary fiber, which is easy for human body to digest and absorb, and causing caramelization and Maillard reaction, thereby increasing the color and flavor of the product;

[0026] (3) The present invention uses twin-screw extrusion technology for expansion, and adopts a method of combined gradient control of extrusion conditions, which is more conducive to product solidification and molding, with less nutritional loss and high digestion and absorption rate;

[0027] (4) The present invention can promote the extrusion molding of the extrudate by setting the most suitable extrusion and puffing parameters for kelp powder extrusion and puffing, and has a crisp taste. During the extrusion process, the protein in the kelp is degraded, and the macromolecules therein are cut off to form small molecular peptides and some amino acids, which react with kelp polysaccharides to produce a good aroma and attractive color by Maillard reaction; the insoluble dietary fiber in the kelp is converted into soluble dietary fiber after extrusion, which is more conducive to digestion. Extrusion and puffing technology is increasingly used in expanding food resources, and plays an important role in improving the taste and nutritional structure of food.

[0028] (5) The present invention solves the problems of high viscosity and burning in the extrusion of pure kelp powder by adjusting the extrusion conditions in a combined gradient: the extrusion temperature is 60-180°C, the feed rate is 2-10kg / h, the water intake is 12-16% of the mass of the kelp powder, and the screw speed is 200-260rpm, thereby achieving extrusion puffing of pure kelp powder. Kelp contains a large amount of polysaccharides and is often in a molten state during the extrusion process. When the temperature is lower than 60°C, the viscosity of the kelp is high, and the machine is easily blocked, which is not conducive to extrusion. When the temperature is higher than 20 At 0℃, caramelization, carbonization and protein denaturation are likely to occur. Affected by this, the product color may become darker, the taste becomes bitter, and the nutritional value of the protein is reduced. In addition to temperature, the amount of water added must also be strictly controlled. The amount of water added will affect the state of the material in the cavity. When the amount of water added is too low, the material fluidity is poor, the screw is difficult to rotate, and it is easy to burn, affecting the product quality. When the amount of water added is too high, the extrudate is not easy to form, affecting the product expansion effect, resulting in a dense product structure and high hardness, thus affecting the product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the appearance diagram of the extrudates of Examples 1 to 5 of the present invention and Comparative Example 1;

[0030] Figure 2 It is a comparison diagram of the microstructures of Examples 1 to 5 of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0032] Raw materials: The kelp powder used in the examples is commercially available.

[0033] Test method:

[0034] Microstructure test method: The sample falls naturally from a height of 2m, the fracture surface (thickness is about 5mm) is taken, and the sample is sprayed with a vacuum gold coating machine. After spraying, it is observed with a scanning electron microscope (SEM).

[0035] Example 1

[0036] A method for preparing pure kelp powder extruded puffed food comprises the following steps:

[0037] (1) Pretreatment: The kelp is dried, crushed, and sieved to obtain kelp raw material powder, and 3 kg of raw material powder is prepared for extrusion;

[0038] (2) Extrusion: Pour the raw powder obtained in step (1) into the feeder of a twin-screw extruder of model FMHE22-32 (two screws are co-rotating screws, which can be extruded simultaneously, and the screw diameter is 22 mm), turn on the agitator for stirring, set relevant experimental parameters, and the extrusion temperature of each area: area 2 (mixing area) 60°C, area 3 (mixing area) 80°C, area 4 (shearing area) 100°C, area 5 (shearing area) 110°C, area 6 (melting area) 120°C, area 7 (melting area) 130°C, area 8 (expansion area) 140°C; the water mass is 12% of the mass of the raw powder; the screw speed is 220 rpm, the feeding rate is 5 kg / h, and the twin-screw extruder is started after the parameters are set. When the material is extruded evenly in the production stage, the material is collected;

[0039] (3) Collection: The product of step (2) is collected, cooled at room temperature for 30 minutes, and then shaped and cut into strips of 4 to 8 cm.

[0040] Example 2

[0041] A method for preparing pure kelp powder extruded puffed food comprises the following steps:

[0042] (1) Pretreatment: The kelp is dried, crushed, and sieved to obtain kelp raw material powder, and 3 kg of raw material powder is prepared for extrusion;

[0043] (2) Extrusion: Pour the raw powder obtained in step (1) into the feeder of a twin-screw extruder of model FMHE22-32 (two screws are co-rotating screws, which can be extruded simultaneously, and the screw diameter is 22 mm), turn on the stirrer for stirring, set relevant experimental parameters, and the extrusion temperature of each area: area 2 (mixing area) 60°C, area 3 (mixing area) 80°C, area 4 (shearing area) 100°C, area 5 (shearing area) 110°C, area 6 (melting area) 120°C, area 7 (melting area) 130°C, area 8 (expansion area) 140°C; the water mass is 14% of the mass of the raw powder; the screw speed is 220 rpm, the feeding rate is 5 kg / h, and the twin-screw extruder is started after the parameters are set. When the material is extruded evenly in the production stage, the material is collected;

[0044] (3) Collection: The product of step (2) is collected, cooled at room temperature for 30 minutes, and then shaped and cut into strips of 4 to 8 cm.

[0045] Example 3

[0046] A method for preparing pure kelp powder extruded puffed food comprises the following steps:

[0047] (1) Pretreatment: The kelp is dried, crushed, and sieved to obtain kelp raw material powder, and 3 kg of raw material powder is prepared for extrusion;

[0048] (2) Extrusion: Pour the raw powder obtained in step (1) into the feeder of a twin-screw extruder of model FMHE22-32 (two screws are co-rotating screws, which can be extruded simultaneously, and the screw diameter is 22 mm), turn on the stirrer for stirring, set relevant experimental parameters, and the extrusion temperature of each area: area 2 (mixing area) 60°C, area 3 (mixing area) 80°C, area 4 (shearing area) 140°C, area 5 (shearing area) 150°C, area 6 (melting area) 160°C, area 7 (melting area) 170°C, area 8 (expansion area) 180°C; the water mass is 14% of the mass of the raw powder; the screw speed is 220 rpm, the feeding rate is 5 kg / h, and the twin-screw extruder is started after the parameters are set. When the material is extruded evenly in the production stage, the material is collected;

[0049] (3) Collection: The product of step (3) is collected, cooled at room temperature for 30 minutes, shaped, and cut into strips of 4 to 8 cm.

[0050] Example 4

[0051] A method for preparing pure kelp powder extruded puffed food comprises the following steps:

[0052] (1) Pretreatment: The kelp is dried, crushed, and sieved to obtain kelp raw material powder, and 3 kg of raw material powder is prepared for extrusion;

[0053] (2) Extrusion: Pour the raw powder obtained in step (1) into the feeder of a twin-screw extruder of model FMHE22-32 (two screws are co-rotating screws, which can be extruded simultaneously, and the screw diameter is 22 mm), turn on the stirrer for stirring, set relevant experimental parameters, and the extrusion temperature of each area: area 2 (mixing area) 60°C, area 3 (mixing area) 80°C, area 4 (shearing area) 140°C, area 5 (shearing area) 150°C, area 6 (melting area) 160°C, area 7 (melting area) 170°C, area 8 (expansion area) 180°C; the water mass is 16% of the mass of the raw powder; the screw speed is 220 rpm, the feeding rate is 5 kg / h, and the twin-screw extruder is started after the parameters are set. When the material is extruded evenly in the production stage, the material is collected;

[0054] (3) Collection: The product of step (2) is collected, cooled at room temperature for 30 minutes, and then shaped and cut into strips of 4 to 8 cm.

[0055] Example 5

[0056] A method for preparing pure kelp powder extruded puffed food comprises the following steps:

[0057] (1) Pretreatment: The kelp is dried, crushed, and sieved to obtain kelp raw material powder, and 3 kg of raw material powder is prepared for extrusion;

[0058] (2) Extrusion: Pour the raw powder obtained in step (1) into the feeder of a twin-screw extruder of model FMHE22-32 (two screws are co-rotating screws, which can be extruded simultaneously, and the screw diameter is 22 mm), turn on the stirrer for stirring, set relevant experimental parameters, and the extrusion temperature of each area: area 2 (mixing area) 60°C, area 3 (mixing area) 80°C, area 4 (shearing area) 130°C, area 5 (shearing area) 140°C, area 6 (melting area) 150°C, area 7 (melting area) 160°C, area 8 (expansion area) 170°C; the water mass is 12% of the mass of the raw powder; the screw speed is 220 rpm, the feeding rate is 5 kg / h, and the twin-screw extruder is started after the parameters are set. When the material is extruded evenly in the production stage, the material is collected;

[0059] (3) Collection: The product of step (2) is collected, cooled at room temperature for 30 minutes, and then shaped and cut into strips of 4 to 8 cm.

[0060] Comparative Example 1

[0061] A method for preparing pure kelp powder extruded puffed food comprises the following steps:

[0062] (1) Pretreatment: The kelp is dried, crushed, and sieved to obtain kelp raw material powder, and 3 kg of raw material powder is prepared for extrusion;

[0063] (2) Extrusion: Pour the raw powder obtained in step (1) into the feeder of a twin-screw extruder of model FMHE22-32 (two screws are co-rotating screws, which can be extruded simultaneously, and the screw diameter is 22 mm), turn on the stirrer for stirring, set relevant experimental parameters, and the extrusion temperature of each area: area 2 (mixing area) 60°C, area 3 (mixing area) 80°C, area 4 (shearing area) 100°C, area 5 (shearing area) 110°C, area 6 (melting area) 120°C, area 7 (melting area) 130°C, area 8 (expansion area) 140°C; the water mass is 20% of the mass of the raw powder; the screw speed is 220 rpm, the feeding rate is 5 kg / h, and the twin-screw extruder is started after the parameters are set. When the material is extruded evenly in the production stage, the material is collected;

[0064] (3) Collection: The product of step (2) is collected, cooled at room temperature for 30 minutes, and then shaped and cut into strips of 4 to 8 cm.

[0065] The product diagrams of Examples 1 to 5 and Comparative Example 1 are as follows Figure 1As shown. Affected by temperature and moisture, the puffing effect of kelp varies. Compared with Example 1, Comparative Example 1 has a larger amount of water added, and the viscosity is greater during the extrusion process, which is not conducive to the puffing and molding of the product. As can be seen from the figure, Examples 3 and 5 have larger diameters and better puffing effects. The high sugar content and high viscosity of kelp are also factors that affect its puffing. In addition, the low starch content in kelp will also reduce the product puffing rate.

[0066] The microstructure comparison diagram of Examples 1 to 5 is shown in FIG. Figure 2 As shown. It can be seen from Example 1, Example 2 and Example 3 that the product has fewer pores, a dense structure, a thicker air cavity wall, and a greater hardness when the moisture content is higher and the temperature is lower. The higher the temperature and the lower the moisture content, the larger the air cavity structure, the higher the porosity, and the significantly thinner the air cavity wall, indicating that its expansion degree is higher and the puffing effect is better. Example 5 has more pores, a looser network structure, a uniform texture, a high porosity, and a crisper product. It is speculated that this may be due to the fact that when the temperature is low, the sugar content is high, the extrudates are adhered to each other, it is not convenient for air to mix, there are fewer pores, and the structure is relatively dense. As the temperature continues to rise, the sugar in the kelp will continue to degrade or react with the protein to produce the Maillard reaction, resulting in a decrease in the sugar content, reaching an appropriate content, which is more conducive to the entry of air to form pores, making the product structure loose.

[0067] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing pure kelp powder extruded puffed food, characterized in that: The specific steps include: (1) drying the kelp, crushing it, and sieving it to obtain kelp powder; (2) extruding and expanding the kelp powder with a twin-screw extruder, and setting the extrusion temperature, kelp powder feed amount, water intake and screw speed of each area of ​​the twin-screw extruder; (3) Finally, the product obtained in step (2) is collected and shaped after being cooled.

2. The method for preparing a pure kelp powder extruded puffed food according to claim 1, characterized in that: In step (2), the two screws of the twin-screw extruder are co-rotating screws.

3. The method for preparing a pure kelp powder extruded puffed food according to claim 1, characterized in that: In step (2), the various regions of the twin-screw extruder are divided into: regions two and three are mixing regions, regions four and five are shearing regions, regions six and seven are melting regions, and region eight is an expansion region.

4. The method for preparing a pure kelp powder extruded puffed food according to claim 1, characterized in that: In step (2), during the extrusion puffing process, the extrusion temperatures of the various regions are: 60-80°C for region 2, 80-100°C for region 3, 100-140°C for region 4, 110-150°C for region 5, 120-160°C for region 6, 130-170°C for region 7, and 140-180°C for region 8.

5. The method for preparing a pure kelp powder extruded puffed food according to claim 1, characterized in that: In step (2), the feeding amount of kelp powder is 2 to 10 kg / h.

6. The method for preparing pure kelp powder extruded puffed food according to claim 1, characterized in that: In step (2), the water intake is 12-16% of the mass of the kelp powder.

7. The method for preparing a pure kelp powder extruded puffed food according to claim 1, characterized in that: In step (2), the screw speed is 200-260 rpm.

8. Pure kelp powder extruded and puffed food prepared by the method according to any one of claims 1 to 7.

9. Application of the pure kelp powder extruded puffed food according to claim 8 in the food field.

10. The use of the pure kelp powder extruded puffed food according to claim 9 in the food field, characterized in that: The invention comprises the preparation of kelp slices, kelp-flavored crispy strips and kelp shreds.

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