A kind of preparation process of frozen corn dough

Abstract

The present invention relates to a preparation process of frozen corn dough, and belongs to the technical field of food processing. First, corn flour is subjected to alkali heat treatment, and then sieved and used as raw material, and water, enzyme and other ingredients are added. Frozen corn dough can be prepared through enzyme treatment, frozen storage, thawing and shaping, baking and other processes. The preparation method of the present invention adopts enzyme preparation combined with alkali heat treatment, improves the gelatinization characteristics of corn flour and promotes protein cross-linking polymerization, thereby improving the processing characteristics of corn dough and delaying the quality deterioration of corn dough during frozen storage. The hardness, baking loss and aging rate of corn rolls made from the frozen corn dough are reduced, the taste is soft and elastic, and the storage stability is improved, which meets consumers' expectations for corn tortilla products.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to a preparation process of frozen corn dough. Background Art

[0002] Frozen dough technology refers to a new technology for baked foods that uses flour as the main raw material to knead and freeze to form commercial semi-finished products. When used, they are thawed, baked, and processed to obtain finished products. The advantage of frozen dough technology is that the factory can mass-produce frozen dough of standardized quality, which can not only unify product quality but also save labor costs. Each store can also reasonably arrange baking time and quantity according to sales, so that baked foods can be made and sold on the spot, ensuring consumers' requirements for freshness. Therefore, frozen dough technology has a strong market vitality. However, frozen dough will deteriorate in quality during frozen storage, affecting the quality of the final product. The main reason is that the formation and growth of ice crystals will cause the quality of key components in the dough to deteriorate, mainly including the destruction of gluten protein network structure and starch granules. These reasons have caused the product to have a corresponding decline in quality in terms of sensory quality, processing performance and product stability. Therefore, there is a certain gap compared with fresh food, resulting in a decrease in consumer acceptance of frozen dough products.

[0003] As one of the three major food resources of mankind, corn is not only rich in carbohydrates, proteins, fats, vitamins, minerals, and dietary fiber, but also contains functional factors such as carotenoids, phytosterols, and glutathione. The content of niacin is 4 times higher than that of rice. It has the effect of reducing the risk of chronic diseases such as obesity, type 2 diabetes, cardiovascular disease, and tumors. It is recognized as a "golden crop" in the world. However, due to the lack of gluten protein in corn, it is unable to form a good protein network structure, resulting in poor viscoelasticity and plasticity of corn dough, which affects the application of corn flour.

[0004] Glutamine transaminase (TGase) and glucose oxidase (GOD) can strengthen the protein network structure by promoting protein cross-linking and polymerization, producing stronger and more elastic dough. In addition, it can effectively improve the handling performance of the dough, make the dough structure more stable, and improve the quality of the final product. Researchers pointed out that GOD has a good anti-aging effect, can reduce the aging rate of grain products, and can delay the aging process during freezing treatment. Therefore, these two enzymes can make up for the problems related to the processing of corn products and the deterioration of the quality of frozen dough to a certain extent, and are enzyme additives with great research value. Alkaline wet milling is to soak corn kernels in water containing food-grade lime and boil them, and then wash them to make masa dough, tortillas, corn chips and other products. We use the alkaline wet milling technology to perform alkali heat treatment on the corn flour raw materials. After alkali heat treatment, the corn flour is more fully gelatinized and the nutrients in the corn are more easily absorbed by the human body.

[0005] In summary, the present invention improves the rheological properties, gelatinization properties, dough strength and baking quality of frozen corn dough by adding a certain proportion of TGase and GOD and combining alkali heat treatment. The obtained corn rolls with rich nutrition, good texture properties and storage stability will be popular among people. Summary of the invention

[0006] In order to solve the above problems of difficult corn dough processing and deterioration of frozen dough quality, the present invention provides a preparation process of frozen corn dough corn rolls, adds enzyme preparations such as TGase and GOD, and processes corn flour in combination with alkali heat treatment, provides a method for improving the quality of frozen corn dough and a corn roll product with good taste and storage stability.

[0007] The first object of the present invention is to provide a method for preparing frozen corn dough, comprising the following specific steps:

[0008] (1) Grinding and sieving: The selected high-quality corn kernels are ground with a high-speed grinder and then passed through an 80-mesh sieve to obtain corn flour;

[0009] (2) Alkali heat treatment: adding calcium hydroxide to the corn flour obtained in step (1), adjusting the moisture content of the corn flour to 25% to 35%, and sealing and placing for 1 to 2 hours to balance the moisture, heating at a temperature range of 80 to 100° C. for 2 hours, cooling the corn flour after heat treatment, passing it through an 80-mesh sieve and putting it into a ziplock bag for later use;

[0010] (3) Preparation of corn dough: adding boiling water to the alkali-heat-treated corn flour obtained in step (2) at a mass ratio of 3:2 (corn flour: water), adding 0.5% to 2% TGase and 0.008% to 0.012% GOD after slightly cooling, mixing evenly, and stirring until the surface of the dough is smooth to obtain corn dough;

[0011] (4) Enzyme treatment: the corn dough obtained in (3) was placed at a temperature of 50° C. and a humidity of 75% to 85% for 2 h to allow the enzyme to fully act;

[0012] (5) Frozen storage treatment: Wrap the corn dough obtained in step (4) with plastic wrap and put it into a refrigerator for quick freezing, and then transfer it to a refrigerator at -20°C for frozen storage;

[0013] (6) Thawing and shaping: Thawing the corn dough frozen in step (5), and dividing and shaping the thawed dough into specified sizes and shapes.

[0014] In one embodiment of the present invention, the variety of corn in step (1) is selected from: Lidan 5, Jingke 968, Xiangyu 998. The corn is selected from high-quality corn, and the high-quality refers to clean and full, complete grains, and a protein content greater than 10%.

[0015] In one embodiment of the present invention, the amount of calcium hydroxide added in step (2) is 0.1% to 0.5% of the mass of corn flour.

[0016] In one embodiment of the present invention, when adjusting the moisture content in step (2), water can be added using a spray bottle so that the water is evenly dispersed in the corn flour.

[0017] In one embodiment of the present invention, the method for balancing the moisture in step (2) can be to put the corn flour into a plastic bag for balancing, or to put it into a container and seal it with plastic wrap for balancing.

[0018] In one embodiment of the present invention, the enzyme activity of TGase in step (3) is 120 U / g, and the enzyme activity of GOD is 10000 U / g.

[0019] In one embodiment of the present invention, the quick freezing in step (5) is performed in a -40°C refrigerator until the center temperature of the dough reaches -18 to -20°C.

[0020] In one embodiment of the present invention, the thawing in step (6) is performed at 25-28° C. for 1-2 hours.

[0021] In one embodiment of the present invention, the specified size of the dough in step (6) is 40 g / piece, and the shape is a round dough sheet with a thickness of 1.1 to 1.3 mm and a diameter of 10 to 12 cm.

[0022] The invention discloses a frozen corn dough prepared by the method.

[0023] The second object of the present invention is to use the frozen corn dough to make food.

[0024] The invention uses the frozen corn dough for making corn rolls: the dough sheets of the frozen corn dough are put into a pan and baked for 2 to 3 minutes to obtain the corn rolls.

[0025] In one embodiment of the present invention, the preparation of corn rolls comprises the following steps:

[0026] (1) Grinding and sieving: The selected high-quality corn kernels are ground with a high-speed grinder and then passed through an 80-mesh sieve to obtain corn flour;

[0027] (2) Alkali heat treatment: adding 0.1% to 0.5% calcium hydroxide to the corn flour obtained in step (1), adjusting the moisture content of the corn flour to 25% to 35%, and sealing and placing for 1 to 2 hours to balance the moisture, heating at a temperature range of 80 to 100° C. for 2 hours, cooling the corn flour after heat treatment, passing it through an 80-mesh sieve and putting it into a ziplock bag for later use;

[0028] (3) Preparation of corn dough: adding boiling water to the alkali-heat-treated corn flour obtained in step (2) at a mass ratio of 3:2 (corn flour: water), adding 0.5-2% TGase and 0.008-0.012% GOD after slightly cooling, mixing evenly, and stirring until the surface of the dough is smooth to obtain corn dough; the enzyme activity of the TGase is 120 U / g, and the enzyme activity of the GOD is 10000 U / g;

[0029] (4) Enzyme treatment: the corn dough obtained in (3) was placed at a temperature of 50° C. and a humidity of 75% to 85% for 2 h to allow the enzyme to fully act;

[0030] (5) Frozen storage treatment: Wrap the corn dough obtained in step (4) with plastic wrap and place it in a -40°C refrigerator for quick freezing until the center temperature of the dough reaches -18 to -20°C, then transfer it to a -20°C refrigerator and store it for 0 weeks, 3 weeks, and 6 weeks respectively;

[0031] (6) Thawing and shaping: Thawing the corn dough frozen for different times in step (5) at 25-28° C. for 1-2 h, dividing and shaping the thawed dough into round dough sheets of 40 g each, 1.1-1.3 mm thick and 10-12 cm in diameter;

[0032] (7) Preparation of corn rolls: Place the shaped dough obtained in step (6) into a frying pan at a temperature of 220 to 260° C., bake one side for 15 to 18 seconds, turn it over and bake the other side for 50 to 60 seconds, then turn it over again and bake it for 15 to 17 seconds to obtain the corn roll product.

[0033] The invention provides a frozen corn dough corn roll, wherein the raw material of the corn roll is composed of dry material and water in a mass ratio of 3:2, wherein the dry material comprises 100% corn flour, 0.1-0.5% calcium hydroxide, 0.5-2% TGase, and 0.008-0.012% GOD in terms of mass percentage. The enzyme activity of the TGase is 120 U / g, and the enzyme activity of the GOD is 10000 U / g.

[0034] In one embodiment of the present invention, the corn rolls may be baked in an electric baking pan in addition to using a frying pan.

[0035] [Beneficial Effects]

[0036] (1) TGase can improve the properties of corn flour by promoting protein cross-linking polymerization, increasing the viscoelasticity, plasticity and stability of corn dough; GOD can oxidize the sulfhydryl groups in protein molecules into disulfide bonds, thereby enhancing the network structure and dough strength of corn dough. The processing characteristics of corn flour were improved by the treatment of these two enzymes, providing a new idea for improving the utilization of corn flour. In addition, the promotion of protein cross-linking polymerization by TGase and GOD alleviated the destruction of the protein network structure caused by ice crystals and ice recrystallization during long-term frozen storage, and also promoted the close combination of water and various components in the dough, enhancing the water holding capacity of the dough, delaying the negative migration of water during frozen storage, and effectively improving the quality of frozen corn dough.

[0037] (2) Alkali heat treatment changes the binding state of starch and protein in corn flour and exposes the wrapped starch, allowing the starch to fully absorb water and swell, thereby improving the gelatinization properties of corn flour. After alkali heat treatment, the gelatinization ability of corn flour decreases, the regeneration tendency of starch decreases, and the corn rolls made are not easy to age. In this process, the flavor and aroma of corn are enhanced, and the nutrients in it are more easily absorbed by the human body. Therefore, alkali heat treatment comprehensively improves the nutritional value and storage quality of corn rolls, and also avoids the high cost and food safety problems that may exist in the use of food additives in the prior art.

[0038] (3) Corn rolls can be eaten as staple food or with other dishes, enriching people's daily dietary choices and increasing nutritional intake. Corn rolls made from the frozen corn dough of the present invention have reduced hardness, baking loss and aging rate, good sensory evaluation, and meet consumers' expectations for corn roll products. The convenience and timeliness of frozen dough also make corn rolls made by the method of the present invention more likely to be liked by consumers. Therefore, it is of great production significance to improve the quality of frozen corn dough corn rolls by adding enzyme preparations and combining alkali heat treatment. DETAILED DESCRIPTION

[0039] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not intended to limit the present invention.

[0040] Test method:

[0041] Test of hardness, elasticity and cohesion: The slices in the middle of the corn roll were selected for testing, and the hardness was determined using a texture analyzer (TPA); the experimental parameters were set as follows: pre-test speed 3.0 mm / s, test speed 1.0 mm / s, post-test speed 5.0 mm / s, compression degree 40%, trigger force 5 g, and interval time between two compressions 5 s.

[0042] Aging rate test: The aging rate is calculated based on the hardness change of corn rolls stored at 4°C for 7 days. The calculation formula is: aging rate (%) = hardness (7th day - 0th day) / storage days.

[0043] Moisture loss test: The moisture content of the corn rolls was measured on the day of production (day 0) and after storage at 4°C for 7 days. The moisture loss of the corn rolls was calculated according to the following formula: Moisture loss (%) = moisture content (day 7 - day 0) / number of storage days.

[0044] Baking loss test: Measure the weight of the corn roll before baking and the corn roll cooled to room temperature after baking. The difference between the two is the baking loss.

[0045] The TGase used in the following examples was purchased from Jiangsu Yiming Biotechnology Co., Ltd., and GOD was purchased from Novozymes (China) Biotechnology Co., Ltd. The enzyme activity of TGase was 120 U / g, and the enzyme activity of GOD was 10000 U / g.

[0046] The corn dough used to make corn rolls in the following examples was stored frozen for 6 weeks.

[0047] Example 1 Frozen Corn Dough Tacos

[0048] (1) Grinding and sieving: The selected high-quality corn kernels are ground with a high-speed grinder and then passed through an 80-mesh sieve to obtain corn flour;

[0049] (2) Alkali heat treatment: 0.2% calcium hydroxide is added to the corn flour obtained in step (1), the moisture content of the corn flour is adjusted to 35%, and the corn flour is sealed and placed for 2 hours to balance the moisture, and heated at a temperature range of 90° C. for 2 hours. After the heat treatment, the corn flour is cooled, passed through an 80-mesh sieve, and packed into a ziplock bag for later use;

[0050] (3) Preparation of corn dough: adding boiling water to the alkali-heat-treated corn flour obtained in step (2) at a mass ratio of 3:2 (corn flour: water), adding 1.5% TGase and 0.010% GOD after slightly cooling, mixing evenly, and stirring until the surface of the dough is smooth to obtain corn dough;

[0051] (4) Enzyme treatment: the corn dough obtained in (3) was placed at a temperature of 50° C. and a humidity of 83% for 2 h to allow the enzyme to fully act;

[0052] (5) Frozen storage treatment: Wrap the corn dough obtained in step (4) with plastic wrap and place it in a -40°C refrigerator for quick freezing until the center temperature of the dough reaches -20°C, and then transfer it to a -20°C refrigerator for frozen storage;

[0053] (6) Thawing and shaping: Thawing the corn dough frozen for different periods of time in step (5) at 25° C. for 1.5 h, dividing the thawed dough and shaping it into round dough sheets of 40 g each, 1.2 mm thick and 12 cm in diameter;

[0054] (7) Preparation of corn rolls: Place the shaped dough obtained in step (6) into a frying pan at a temperature of 260° C. and bake one side for 18 seconds, turn it over and bake the other side for 50 seconds, then turn it over again and bake it for 15 seconds to obtain the corn roll product.

[0055] Example 2 Referring to Example 1, the moisture content of step (2) was changed to 20%, 25%, 30%, and 40%, and the other conditions remained unchanged.

[0056] Table 1 Performance parameters of frozen corn dough tacos at different moisture contents

[0057] Moisture content Hardness(g) elasticity Cohesiveness Baking loss (%) Aging rate (g / day) 20％ 914 0.741 0.418 7.83 76.52 25％ 856 0.753 0.421 7.24 75.36 30％ 739 0.766 0.435 7.72 75.12 35％ 724 0.764 0.491 7.35 68.94 40％ 817 0.758 0.472 7.53 73.53

[0058] According to the data in Table 1, different moisture contents had no significant effect on the elasticity, cohesiveness and baking loss of corn rolls, but the corn rolls showed the lowest hardness and aging rate at a moisture content of 35%, so 35% is considered to be the optimal moisture content.

[0059] Example 3

[0060] Referring to Example 1, the addition of enzyme in step (3) was changed, and the TGase was changed to 0%, 0.5%, 1.0%, 1.5%, and 2.0%, while the other conditions remained unchanged.

[0061] Table 2 Performance parameters of frozen corn dough tacos at different TGase addition levels

[0062]

[0063]

[0064] According to the data in Table 2, when the TGase addition amount was 1.5%, the hardness, baking loss and aging rate of the corn rolls all reached the lowest values, while the elasticity and cohesion increased to the maximum value at this addition amount. This may be due to the cross-linking effect of TGase on protein, which enhanced the water holding capacity of the dough and thus changed the quality of the corn rolls.

[0065] Example 4

[0066] Referring to Example 1, the addition of enzyme in step (3) was changed, and GOD was changed to 0%, 0.008%, 0.010%, and 0.012, while the other conditions remained unchanged.

[0067] Table 3 Performance parameters of frozen corn dough tacos at different GOD addition levels

[0068] GOD addition amount Hardness(g) elasticity Cohesiveness Baking loss (%) Aging rate (g / day) 0％ 956 0.713 0.421 7.83 87.53 0.008％ 876 0.725 0.453 7.62 74.12 0.010％ 724 0.764 0.491 7.35 68.94 0.012％ 757 0.726 0.479 7.13 76.64

[0069] From the data in Table 3, it can be seen that when the addition amount of GOD is 0.010%, the hardness, baking loss and aging rate of corn rolls show the lowest values, while the elasticity and cohesion also increase to the maximum value. In addition, it can be seen that the addition of GOD has a very obvious effect on reducing the aging rate of corn rolls.

[0070] Comparative Example 1

[0071] Step (2) in Example 1 is omitted, and the remaining steps (1), (3) to (7) are the same as in Example 1.

[0072] Comparative Example 2

[0073] (1)~(2) are the same as Example 1.

[0074] (3) adding boiling water to the alkali-heat-treated corn flour obtained in step (2) at a mass ratio of 3:2 (corn flour: water), mixing evenly, and stirring until the surface of the dough is smooth to obtain corn dough;

[0075] (4) placing the corn dough obtained in (3) at a temperature of 50° C. and a humidity of 83% for 2 h;

[0076] (5)~(7) are the same as Example 1.

[0077] Comparative Example 3

[0078] (1) Same as Example 1.

[0079] (2) preparing corn dough: adding boiling water to the corn flour obtained in step (1) at a mass ratio of 3:2 (corn flour: water), mixing well, and stirring until the surface of the dough is smooth to obtain corn dough;

[0080] (3) placing the corn dough obtained in (2) at a temperature of 50° C. and a humidity of 83% for 2 h;

[0081] The remaining steps are the same as (5) to (7) in Example 1.

[0082] The obtained frozen dough corn rolls were subjected to performance tests, and the test results are shown in Table 4:

[0083] Table 4 Performance test results of corn rolls

[0084] example Hardness(g) elasticity Cohesiveness Baking loss (%) Aging rate (g / day) Example 1 724 0.764 0.491 7.35 68.94 Comparative Example 1 812 0.733 0.480 7.44 69.14 Comparative Example 2 863 0.732 0.485 7.85 81.57 Comparative Example 3 1056 0.704 0.473 8.20 85.54

[0085] Compared with the frozen corn dough tacos prepared in Comparative Examples 1 to 3, the frozen corn dough tacos prepared in Example 1 of the present invention have lower hardness, greater elasticity and cohesiveness, and a softer and chewier taste; the moisture loss, baking loss and aging rate are reduced, and the quality and storage stability of the tortilla are improved. The results show that the preparation method of the present invention has a significant improvement effect on the quality of the frozen corn dough tacos, and can effectively slow down the quality deterioration of the frozen corn dough during frozen storage.

[0086] Although the present invention has been disclosed as above in the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the technical scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing frozen corn dough, It is characterized in that The following specific steps are included: (1) Grinding and sieving: The selected high-quality corn kernels are ground with a high-speed grinder and then passed through an 80-mesh sieve to obtain corn flour; (2) Alkali heat treatment: Calcium hydroxide is added to the corn flour obtained in step (1), the moisture content of the corn flour is adjusted to 35%, and the corn flour is sealed and placed for 1 to 2 hours to balance the moisture, and heated at a temperature range of 80 to 100° C. for 2 hours. After the heat treatment, the corn flour is cooled, passed through an 80-mesh sieve, and packed into a ziplock bag for later use; (3) Preparation of corn dough: adding boiling water to the alkali-heat-treated corn flour obtained in step (2) at a mass ratio of corn flour to water of 3:2, adding 1.5-2.0% TGase and 0.01% GOD after slightly cooling, mixing evenly, and stirring until the surface of the dough is smooth to obtain corn dough; (4) Enzyme treatment: The corn dough obtained in (3) was placed at a temperature of 50°C and a humidity of 75% to 85% for 2 h to allow the enzyme to fully function; (5) Frozen storage: Wrap the corn dough obtained in step (4) with plastic wrap and put it into a refrigerator for quick freezing, and then transfer it to a refrigerator at -20°C for frozen storage; (6) Thawing and shaping: Thawing the corn dough frozen in step (5), and dividing and shaping the thawed dough into specified sizes and shapes.

2. The method according to claim 1, It is characterized in that The variety of corn in step (1) is selected from: Lidan 5, Jingke 968, and Xiangyu 998.

3. The method according to claim 1, It is characterized in that The amount of calcium hydroxide added in step (2) is 0.1% to 0.5% of the mass of the corn flour.

4. The method according to claim 1, It is characterized in that When adjusting the moisture content in step (2), water can be added using a spray bottle so that the water is evenly dispersed in the corn flour.

5. The method according to claim 1, It is characterized in that The method for balancing the moisture in step (2) can be to put the corn flour into a plastic bag for balancing, or to put it into a container and seal it with plastic wrap for balancing.

6. The method according to claim 1, It is characterized in that The enzyme activity of TGase in step (3) is 120 U / g, and the enzyme activity of GOD is 10000 U / g.

7. The method according to claim 1, It is characterized in that The quick freezing in step (5) is performed in a -40°C refrigerator until the center temperature of the dough reaches -18 to -20°C.

8. A frozen corn dough prepared according to the method according to any one of claims 1 to 7.

9. The frozen corn dough according to claim 8 is used in making food.

10. A method of making corn rolls, It is characterized in that The specific steps include: (1) Grinding and sieving: The selected high-quality corn kernels are ground with a high-speed grinder and then passed through an 80-mesh sieve to obtain corn flour; (2) Alkali heat treatment: add 0.1% to 0.5% calcium hydroxide to the corn flour obtained in step (1), adjust the moisture content of the corn flour to 35%, seal and place for 1 to 2 hours to balance the moisture, heat at a temperature range of 80 to 100° C. for 2 hours, cool the corn flour after heat treatment, pass it through an 80-mesh sieve and put it into a ziplock bag for later use; (3) Preparation of corn dough: adding boiling water to the alkali-heat-treated corn flour obtained in step (2) at a mass ratio of corn flour to water of 3:2, adding 1.5-2.0% TGase and 0.01% GOD after slightly cooling, mixing evenly, and stirring until the surface of the dough is smooth to obtain corn dough; the enzyme activity of the TGase is 120 U / g, and the enzyme activity of the GOD is 10000 U / g; (4) Enzyme treatment: The corn dough obtained in (3) was placed at a temperature of 50°C and a humidity of 75% to 85% for 2 h to allow the enzyme to fully function; (5) Frozen storage treatment: Wrap the corn dough obtained in step (4) with plastic wrap and place it in a -40°C refrigerator for quick freezing until the center temperature of the dough reaches -18 to -20°C, then transfer it to a -20°C refrigerator and freeze it for 0 weeks, 3 weeks, and 6 weeks respectively; (6) Thawing and shaping: Thaw the corn dough frozen for different periods of time in step (5) at 25-28° C. for 1-2 h, and divide and shape the thawed dough into round dough sheets of 40 g each, 1.1-1.3 mm thick and 10-12 cm in diameter; (7) Preparation of corn rolls: Place the shaped dough obtained in step (6) into a frying pan at a temperature of 220-260° C. and bake one side for 15-18 seconds, flip it over and bake the other side for 50-60 seconds, then flip it over again and bake it for 15-17 seconds to obtain a corn roll.

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