CN108065287A - A kind of preparation method of purple sweet potato dilated food rich in anthocyanin and products thereof - Google Patents

Abstract

The invention belongs to the technical field of puffed food, and relates to a preparation method of puffed purple sweet potato food rich in anthocyanins and a product thereof. Specifically, the preparation method comprises the following steps: 1) material preparation; 2) steaming; 3) peeling and beating; 4) drying and powdering; 5) mixing; dry. The preparation method of the present invention uses purple sweet potato as the main raw material, deploys a reasonable proportion of purple sweet potato flour, corn flour, millet flour, wheat flour, glucose and whole milk powder, properly adjusts the moisture content of the raw material, and adopts a unique twin-screw extruder The product is prepared by pressing and puffing technology, and the obtained product has strong flavor and unique taste, and has high concentration of anthocyanin, which is rich in nutrition, improves the added value of purple sweet potato, and is a snack food with high antioxidant capacity.

Description

A preparation method and product of purple sweet potato puffed food rich in anthocyanins

technical field

The invention belongs to the technical field of puffed food, and relates to a preparation method of puffed purple sweet potato food rich in anthocyanins and a product thereof.

Background technique

Purple sweet potato, also known as "purple sweet potato", "purple sweet potato" or "purple sweet potato", is a class of fine varieties developed in recent years. It was developed by Chinese sweet potato researchers in the 1990s. Introduced from the Kyushu Agricultural Experimental Field in Japan. Because it is rich in a large amount of anthocyanins (anthocyanin is a kind of compound formed by combining sugar with glycosidic bonds), the skin of purple sweet potato is purple black, and the potato flesh is purple to dark black. It is a kind of food collection, A unique sweet potato with both medicinal and health functions. Purple potato tubers not only contain various nutrients contained in ordinary sweet potatoes, but also the content of lysine, copper, manganese, potassium, and zinc is 3 to 8 times higher than that of ordinary sweet potatoes; in addition, purple potatoes are also rich in The content of anthocyanin with strong anti-oxidation and selenium with anti-cancer effect is more than 20 times higher than that of ordinary sweet potatoes, which can remove active oxygen, inhibit the production of carcinogens, improve liver function, and improve vision. Therefore, deep processing and utilization of purple sweet potato have broad development prospects in both domestic and foreign markets.

Puffed food is a new type of food that appeared in the late 1960s. It is also called extruded food, explosive food, and light food abroad. Puffed food uses cereals, potatoes, beans, etc. with less moisture as the main raw materials. After pressurization and heat treatment, the volume of the raw materials themselves expands, and the internal structure changes. to make. Because of the porous and fluffy tissue structure of this kind of food, the taste is crispy and sweet, and has certain nutritional value, it is deeply loved by people.

Extrusion and puffing technology is one of the high-tech of modern food engineering. Its principle is that the material is under high pressure and high temperature due to shearing and friction in the machine, so that the material is in a molten state. Once extruded from the die hole, the pressure suddenly drops to normal pressure, and the moisture will evaporate instantly, and the product will expand accordingly. Unlike other puffing technologies, extrusion puffing technology is a non-fried processing method. At the same time, due to its many advantages such as high production efficiency, low energy consumption, good product quality, and no waste, it is widely used in the research of starch-based grain puffing such as corn, and is a scientific and nutritious processing method.

Contents of the invention

In view of the current situation that there is no puffed purple sweet potato food rich in anthocyanin and purple sweet potato as the main raw material in the market, the present invention aims to provide a preparation method and product of purple sweet sweet potato puffed food rich in anthocyanin. The method uses the purple sweet potato rich in anthocyanin as a main raw material, and obtains the purple sweet potato puffed food rich in anthocyanin through a twin-screw extrusion technology.

Specifically, the present invention adopts the following technical solutions:

A preparation method of purple sweet potato puffed food rich in anthocyanin, it comprises the following steps:

1) Prepare materials: select purple sweet potatoes without mildew, no pests and diseases, and no buds, and wash them with water to obtain washed purple sweet potatoes;

2) steaming: steaming the cleaned purple sweet potato obtained in step 1) to obtain cooked purple sweet potato;

3) Peeling and beating: remove the skin of the cooked purple sweet potato obtained in step 2), cut the peeled purple sweet potato into pieces, add 1 to 2 times the volume of water to the purple sweet potato pieces, and then make a beating to obtain purple sweet potatoes pulp;

4) Drying and milling: use a drum dryer, use water vapor as a heat supply medium, and make the purple sweet potato pulp obtained in step 3) into a thickness of 0.5-1.5 mm under the condition of a steam pressure of 0.3-0.4 MPa The film is peeled off from the surface of the drum and crushed, and the coarse powder is collected and passed through a 60-80 mesh sieve to obtain purple potato powder;

5) Mixing: according to the weight ratio of purple sweet potato flour: corn flour: millet flour: wheat flour: glucose: whole milk powder = 100:15～25:25～35:30～40:2～4:12～18, to Add corn flour, millet flour, wheat flour, glucose and whole milk powder to the purple sweet potato flour obtained in step 4), and mix well to obtain the mixed material;

6) Extrusion and puffing: using a twin-screw extrusion puffing machine, the mixture obtained in step 5) is made into Extruding to obtain extruded puffed purple potato strips with an expansion rate of 8-12;

7) Granulation and drying: cut the extruded and puffed purple potato strips obtained in step 6) according to the predetermined shape and size, and dry them at 45-60°C until the moisture content is below 5%wt to obtain Purple potato puffed food with anthocyanins, in which the total anthocyanins content is 2.0-3.5mg/g.

In the above preparation method, the water described in step 1) is tap water.

In the above preparation method, the steaming described in step 2) is accomplished by using a steamer, a steamer or a steamer.

In the above preparation method, the water described in step 3) is deionized water.

In the above preparation method, the beating described in step 3) is completed by using a multifunctional cooking machine, a wall breaker or a tissue masher.

In the above preparation method, the pulverization in step 4) is accomplished by using a screw pulverizer.

In the above preparation method, the fat content in the whole milk powder in step 5) is 25%-30%.

In the above-mentioned preparation method, the mixing described in step 5) is accomplished using a household dough mixer, a V-shaped mixer or a double-helix conical mixer.

In the above preparation method, the cutting in step 7) is completed with a cutter; preferably, the rotation speed of the cutter is 400-800 rpm.

In the above preparation method, the drying in step 7) is accomplished by using a fluidized bed.

In a preferred embodiment, the preparation method of the present invention further includes a packaging step after step 7); preferably, the packaging is nitrogen-filled packaging.

A purple sweet potato puffed food rich in anthocyanins is prepared by the above preparation method.

Compared with the prior art, the present invention adopting the above-mentioned technical scheme has the following beneficial effects: the preparation method of the present invention uses purple sweet potato as the main raw material, and according to the texture difference, starch content difference, amino acid ratio and other factors of various raw materials, The reasonable ratio of purple sweet potato flour, corn flour, millet flour, wheat flour, glucose and whole milk powder is formulated, the moisture content of the raw materials is properly adjusted, and a unique twin-screw extrusion process is used for preparation. The resulting product has a strong flavor and taste It is unique and has high concentration of anthocyanins, which is rich in nutrition and increases the added value of purple sweet potato. It is a snack food with high antioxidant capacity.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with specific embodiments. The following examples are only used to explain and illustrate the present invention, and should not be considered as limiting the scope of the present invention. Unless otherwise specified, the instruments, reagents, materials, etc. used in the following examples can all be obtained through conventional commercial means.

Example 1: Preparation of puffed purple sweet potato balls rich in anthocyanins.

Prepare the target product according to the following method:

1) Prepare materials: select 895g of purple sweet potatoes without rot, diseases and insect pests, and no buds, and wash them with tap water after removing impurities such as soil;

2) Steaming: Put the washed purple sweet potato into a steamer and steam for about 30 minutes to fully ripen the purple sweet potato, so as to reduce the activity of endogenous enzymes and at the same time retain the flavor of the purple sweet potato to the greatest extent;

3) Peeling and beating: tear off the skin of the ripe purple sweet potato, cut the peeled purple sweet potato into small pieces, add 800mL deionized water to the purple sweet potato pieces, and use a multi-function cooking machine to beat it to a suitable consistency thick slurry;

4) Drying and milling: use a drum dryer, use water vapor as the heating medium, and dry the thick slurry into a film with a thickness of 0.73mm under the condition of a steam pressure of 0.4MPa. After peeling the film from the surface of the drum, The purple sweet potato film is pulverized by a screw grinder, and the coarse powder is collected and passed through a 60-mesh sieve to obtain 292 g of purple sweet potato powder;

5) Mixing: Weigh 58.40g of corn flour, 87.60g of millet flour, 102.2g of wheat flour, 11.68g of glucose and 41.42g of whole milk powder (wherein the fat content is 28.2%wt), and then add them to the purple sweet potato flour. Mix the above powder evenly with a household noodle mixer to obtain 593.30 g of the mixed material;

6) Extrusion and puffing: use a twin-screw extrusion puffing machine to extrude the mixed material under the conditions of a liquid feed rate of 20%, a temperature of 130°C, and a pressure of 5 MPa to obtain an extrusion with an expansion ratio of about 11. Puffed purple potato chips 500g;

7) Granulation and drying: Cut the extruded and puffed purple potato strips into spherical shapes with a diameter of about 12mm by using a cutter with a rotating speed of 400rpm, and then place them in a fluidized bed and dry them at 50°C until the moisture content drops to 4%. So far, 473g of puffed purple sweet potato balls rich in anthocyanins have been obtained, wherein the total anthocyanin content is 2.523mg/g;

8) The purple sweet potato balls are packaged in a nitrogen-filled manner so as not to be crushed during transportation.

Example 2: Preparation of puffed purple sweet potato balls rich in anthocyanins.

Prepare the target product according to the following method:

1) Material preparation: select 1025g of purple sweet potatoes without rot, diseases and insect pests, and no buds, remove impurities such as soil, and wash them with tap water;

2) Steaming: Put the washed purple sweet potato into a steamer and steam for about 30 minutes to fully ripen the purple sweet potato, so as to reduce the activity of endogenous enzymes and at the same time retain the flavor of the purple sweet potato to the greatest extent;

3) Peeling and beating: tear off the skin of the ripe purple sweet potato, cut the peeled purple sweet potato into small pieces, add 1000mL deionized water to the purple sweet potato pieces, and use a wall breaking machine to beat it into a suitable consistency. Thick stock;

4) Drying and milling: use a drum dryer, use water vapor as the heating medium, and dry the thick slurry into a film with a thickness of 0.68mm under the condition of a steam pressure of 0.3MPa. After peeling the film from the surface of the drum, The purple sweet potato film is pulverized by a screw grinder, and the coarse powder is collected and passed through an 80-mesh sieve to obtain 340 g of purple sweet potato powder;

5) Mixing: Weigh 61.20g of corn flour, 102g of millet flour, 136g of wheat flour, 10.2g of glucose and 60.28g of whole milk powder (wherein the fat content is 28.2%wt), and then add them to the purple sweet potato flour, using a double helix Mix the above-mentioned powders evenly with a conical mixer to obtain 709.68g of mixed materials;

6) Extrusion and puffing: using a twin-screw extrusion puffing machine, under the conditions of 22% liquid feed rate, 125°C temperature and 2.8MPa pressure, the mixed material is extruded to obtain an extruded puff with an expansion ratio of about 9. Pressed puffed purple potato chips 295g;

7) Granulation and drying: Cut the extruded and puffed purple potato strips into spherical shapes with a diameter of about 10mm by using a cutter with a rotating speed of 600rpm, and then place them in a fluidized bed and dry them at 50°C until the moisture content drops to 4%. So far, 272g of puffed purple sweet potato balls rich in anthocyanins have been obtained, wherein the content of total anthocyanins is 2.711mg/g;

8) The purple sweet potato balls are packaged in a nitrogen-filled manner so as not to be crushed during transportation.

Comparative example: comparative test of the anthocyanin content of the purple sweet potato puffed food of the present invention and common purple sweet potato puffed food.

The puffed purple sweet potato balls in Examples 1 and 2 were used as the sample to be tested, and the common Benbengou brand coarse grain sandwich rice cracker (sweet purple sweet potato flavor, manufacturer: Henan Huazhong Food Co., Ltd.) was used as the reference substance. Determination of the content of total anthocyanins by pH differential method, the specific process is as follows:

Extraction: crush the purple sweet potato balls and pass through a 60-mesh sieve, weigh about 2g of the sample, add 50mL of 1.6% citric acid solution, stir continuously at 60°C, extract for 2h, 5000r/min, centrifuge at 4°C for 20min, and separate the supernatant . Extract 4 times in total according to the above steps, centrifuge until the supernatant is colorless, combine the obtained supernatants, filter with suction and dilute to 250mL to obtain anthocyanin extract, and store in a refrigerator away from light.

Determination: Prepare pH=1.0 buffer solution (KCl-HCl) and pH=4.5 buffer solution (NaAc-HAc), draw 1mL diluted anthocyanin extract into the test tube respectively, then add 9mL pH1.0 and pH4 respectively .5 buffer solution, mix well and equilibrate for 90min, use deionized water as blank, measure the absorbance at 510nm and 700nm respectively. Each sample was measured 4 times in parallel, and the total anthocyanin content was calculated according to the following formula, and the results are shown in Table 1.

In the formula: A = (A ₅₁₀ -A ₇₀₀ ) _pH1.0 -(A ₅₁₀ -A ₇₀₀ ) _pH4.5 ; ε = molar extinction coefficient of cyanidin-3-glucoside, 26900; M _w = cyanidin Molar mass of inulin-3-glucoside, 449.2 g/mol; D _f = dilution factor; V = final volume, mL; W _t = sample mass, mg; L = thickness of cuvette, 1 cm.

Table 1. The results of total anthocyanin content in purple potato puffed food

Example 1 Example 2 Reference substance Content (mg/g) 2.523 2.711 0.069

As can be seen from Table 1, the anthocyanin-rich purple sweet potato puffed food of the present invention has a higher concentration of anthocyanins, which makes the product of the present invention more prominent in anti-oxidation and further improves the added value of purple sweet potato. A snack food with health benefits.

Claims (8)

1. a kind of preparation method of the purple sweet potato dilated food rich in anthocyanin, comprises the following steps：

1) stock up：It selects without mildew and rot, no disease and pests harm, the purple sweet potato without bud, washes with water, obtain clean purple sweet potato；

2) steam：The clean purple sweet potato obtained in step 1) is cooked, obtains ripe purple sweet potato；

3) remove the peel and be beaten：The potato skin of the ripe purple sweet potato obtained in step 2) is removed, by the purple sweet potato stripping and slicing of peeling, into purple sweet potato block It is beaten after adding the water of 1~2 times of volume, obtains purple sweet potato slurry；

4) dry and processed powder：It is 0.3~0.4MPa in vapour pressure by the use of vapor as heating medium using roller drier Under conditions of, the film that thickness is 0.5~1.5mm is made in the purple sweet potato obtained in step 3) slurry, film is shelled from cylinder surface Fall behind and crush, cross 60~80 mesh sieves after collecting coarse powder, obtain purple sweet potato powder；

5) batch mixing：According to purple sweet potato powder:Corn flour:Millet powder:Wheat flour:Glucose:Whole milk powder=100:15~25:25~ 35:30~40:2~4:12~18 weight ratio adds corn flour, millet powder, wheat in the purple sweet potato powder obtained into step 4) Powder, glucose and whole milk powder, obtain mixed material after mixing；

6) extrusion：Using twin-screw extruder, liquid feeding capacity is 18~22%, temperature is 120~130 DEG C, Under conditions of pressure is 2~5MPa, the mixed material obtained in step 5) is squeezed out, it is swollen to obtain the extruding that expansion rate is 8~12 Change purple chips；

7) it is granulated and dry：The extrusion purple chips obtained in step 6) are cut according to predetermined shape and size, Cutting finish after 45~60 DEG C it is dry to moisture in below 5%wt, obtain the purple sweet potato dilated food rich in anthocyanin, Middle Anthocyanin content is 2.0~3.5mg/g.

2. preparation method according to claim 1, it is characterised in that：

Water described in step 1) is tap water；

Water described in step 3) is deionized water.

3. preparation method according to claim 1, it is characterised in that：

Fat content described in step 5) in whole milk powder is 25%~30%.

4. preparation method according to claim 1, it is characterised in that：

It is steamed described in step 2) using steamer, steam box or food steamer to complete；

Mashing is completed using Multifunctional cooking machine, wall-breaking machine or tissue mashing machine described in step 3)；

It crushes described in step 4) and is completed using spiral pulverizer；

Mixing is completed using family expenses dough mixing machine, V-Mixer or double helix conical mixer described in step 5)；

Cutting is completed using cutter described in step 7)；

Drying is completed using fluid bed described in step 7).

5. preparation method according to claim 4, it is characterised in that：

The rotating speed of the cutter is 400~800rpm.

6. preparation method according to claim 1, it is characterised in that：

The preparation method is additionally included in the packaging step after step 7).

7. preparation method according to claim 6, it is characterised in that：

It is described to be packaged as nitrogen-filled packaging.

8. a kind of purple sweet potato dilated food rich in anthocyanin, passes through preparation side according to any one of claim 1 to 7 Method is made.