A method for preparing a slow-digesting corn cake

Abstract

The application discloses a preparation method of a slowly-digestive corn cake and belongs to the corn flour processing field. The preparation method comprises the following steps: S1, beating egg liquid; S2, mixing; S3, sieving and stirring; S4, adjusting paste and entering a mold; and S5, baking. The slowly-digestive corn cake prepared by the method has modified waxy corn flour as raw material, is mixed with wheat flour, and then is added with procyanidins, so that the preparation method is simple and easy to implement. The slowly-digestive corn cake improves the phenomenon that the cake is easy to collapse and has poor elasticity due to poor gas and water holding properties and unstable protein network structure, improves product quality, adjusts the digestion characteristics, and makes the product have a soft and sweet taste while the addition amount of waxy corn flour is much higher than that of existing corn cake products on the market.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of corn flour processing, and particularly relates to a preparation method of a slowly-digestible corn cake. BACKGROUND

[0002] With the improvement of people's living standards, diabetes, obesity, cardiovascular diseases and other serious diseases have a great impact on the health of residents. The cost of related prevention and treatment drugs is relatively high and there are some potential side effects, so functional foods have gradually gained the favor of consumers. Slowly-digestible foods have the characteristics of slow digestion, and the postprandial blood glucose and insulin level responses are relatively stable after eating. They can improve the blood glucose control of diabetic patients and also help with weight management. Studies have shown that long-term slowly-digestible dietary intervention has the effects of stabilizing blood glucose, improving insulin resistance and weight loss control. Therefore, reducing the digestibility of food is one of the main directions of current research.

[0003] Waxy corn, also known as waxy corn or sticky corn, is a superior variety of corn and a low-fat food. Waxy corn contains essential amino acids, proteins, fats and various trace elements for human growth and development, including 70-75% starch, 8-9% protein, 4-5% fat and 2% various vitamins, thus greatly improving the nutritional value and food quality of waxy corn. However, there are few products on the market that are processed from waxy corn flour, because the starch branch content in waxy corn flour is relatively high (up to 95-100%), which is easily digested and absorbed by the human body. The fast digestion rate can easily cause a high blood glucose response after intake, limiting the intake of people with high blood glucose, greatly limiting the application of waxy corn flour in staple foods, and leading to the waste of waxy corn resources.

[0004] In practical applications, waxy corn flour is often mixed with wheat flour to optimize the overall flavor and texture of the cake. By adjusting the ratio of the two, the softness and flavor of the cake can be significantly enhanced while maintaining good structure. However, due to the lack of gluten, poor water and gas holding properties, and other reasons, it can cause instability of the protein network structure of the food, resulting in easy collapse and poor elasticity of the cake. The main means for improving the quality of corn cakes at present is to add baking powder, which can act as a leavening agent in the baking process, causing the dough to expand and bake soft and fluffy bread and cakes. However, baking powder also has some defects, such as the component sodium bicarbonate in baking powder, which may cause allergic reactions in some people, triggering allergic diseases or discomfort; some baking powder contains aluminum salt components, which may have an impact on human health if consumed in excess over a long period of time, causing neurological diseases. Therefore, a safe, environmentally friendly, simple and high-quality preparation method of slowly-digestible corn cake needs to be researched. SUMMARY

[0005] [Technical problem]

[0006] The present application is to solve the problem that the cake prepared from waxy corn flour and wheat flour is easy to collapse and poor in elasticity, and the long-term excessive intake of food additives in corn cake is harmful to human health.

[0007] [Technical scheme]

[0008] In order to solve the above problems, the present application provides a preparation method of slow-digestion corn cake, which uses modified waxy corn flour as raw material, mixes with wheat flour, and then adds procyanidins. The preparation method is simple and easy to operate, improves the phenomenon that the cake is easy to collapse and poor in elasticity due to the lack of gluten protein, improves the product quality, adjusts the digestion characteristics, makes the product have a soft and sweet taste, and the addition amount of waxy corn flour is much higher than that of existing corn cake products on the market, effectively improves the processing utilization rate of waxy corn, provides a new technical method for the digestion characteristic regulation of waxy corn flour products and the development of slow-digestion functional food, and the procyanidins can improve the product quality and adjust the digestion characteristics in the food processing process.

[0009] The present application provides a preparation method of slow-digestion corn cake, which includes the following steps:

[0010] S1, whipping of egg liquid: whipping the whole egg liquid, and adding sugar in 2-3 times during the whipping process to obtain the whipped egg liquid;

[0011] S2, mixing: fully emulsifying the vegetable oil and skimmed milk, adding the whipped egg liquid in S1, and mixing uniformly to obtain the egg liquid containing vegetable oil and skimmed milk;

[0012] S3, sieving and stirring: mixing the modified waxy corn flour, wheat flour and procyanidins, then sieving and adding into the egg liquid containing vegetable oil and skimmed milk in S2 in 2-3 times, and then mixing and stirring uniformly to obtain the batter;

[0013] S4, batter adjustment, mold filling and baking: pouring the batter in S3 into the mold, removing the bubbles, and then baking to obtain the slow-digestion corn cake.

[0014] In an embodiment of the present application, the mass ratio of whole egg liquid to sugar in S1 is 100:18-40.

[0015] In an embodiment of the present application, the mass ratio of whole egg liquid to corn oil in S2 is 100:6-18.

[0016] In an embodiment of the present application, the vegetable oil in S2 includes but is not limited to one or more of corn oil, rapeseed oil and soybean oil.

[0017] In one embodiment of the present application, the mass ratio of whole egg liquid to skimmed milk in S2 is 100:8-24.

[0018] In one embodiment of the present application, the type of wheat flour in S3 is medium gluten wheat flour.

[0019] In one embodiment of the present application, the preparation method of modified waxy corn flour in S3 is as follows: waxy corn is crushed, sieved, and water is added to prepare a waxy corn flour suspension with a mass concentration of 5-10%, the waxy corn flour suspension is continuously stirred at 70-100℃ water bath for 15-35 min to obtain a gelatinized waxy corn flour suspension, 30-60% sodium fatty acid of waxy corn flour is added, and the mixture is stirred in a hot water bath at 95℃ for 30-60 min to obtain a complex solution; finally, the complex solution is dried, crushed, and sieved to obtain modified waxy corn flour.

[0020] In one embodiment of the present application, the mass ratio of modified waxy corn flour to wheat flour in S3 is 1:1, and the addition amount of procyanidins is 0.8-4% of the total mass of modified waxy corn flour and wheat flour.

[0021] In one embodiment of the present application, the mesh size of sieving in S3 is 50-60 mesh.

[0022] In one embodiment of the present application, the baking temperature in S4 is 140-150℃, and the time is 40-50 min.

[0023] The present application provides a slow-digestion corn cake prepared according to the above-mentioned method.

[0024] The present application provides the use of the above-mentioned slow-digestion corn cake in the field of food.

[0025] [Advantages]

[0026] (1) The present application improves the poor gas and water retention of cakes, the instability of protein network structure, the phenomenon of easy collapse and poor elasticity of cakes, and the product quality by adding procyanidins and interacting with wheat flour gluten protein.

[0027] (2) The addition amount (50%) of waxy corn flour in the corn cake prepared by the present application is much higher than that (20-25%) of existing corn cake products on the market, effectively improving the processing utilization rate of waxy corn.

[0028] (3) The present application can significantly reduce the digestibility of cakes by adding modified waxy corn flour, which reaches about 45% at 250 min.

[0029] (4) The corn cake prepared by the method has no additive, is safe and healthy, has simple preparation method, and can prepare the slowly-digestive corn cake with excellent quality, so that the modified waxy corn powder is used as raw material, mixed with wheat flour, and then proanthocyanidin is added, the preparation method is simple and easy to implement, and a new technical method is provided for the digestion characteristic regulation of waxy corn powder products and the development of slowly-digestive functional food. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 Figure is the texture characteristics of corn cakes with different proanthocyanidin contents in embodiments 1-4 and comparative example 1 of the present application, and different letters in the figure represent significant differences (p<0.05).

[0031] Figure 2 Figure is the specific volume of corn cakes with different proanthocyanidin contents in embodiments 1-4 and comparative example 1 of the present application, and different letters in the figure represent significant differences (p<0.05).

[0032] Figure 3 Figure is the tissue morphology of corn cakes with different proanthocyanidin contents in embodiments 1-4 and comparative example 1 of the present application.

[0033] Figure 4 Figure is the pore density and porosity of corn cakes with different proanthocyanidin contents in embodiments 1-4 and comparative example 1 of the present application.

[0034] Figure 5 Figure is the microstructure of corn cakes with different proanthocyanidin contents in embodiments 1-4 and comparative example 1 of the present application.

[0035] Figure 6 Figure is the in-vitro enzymatic digestion rate diagram of corn cakes in embodiment 2 and comparative examples 1-2 of the present application. DETAILED DESCRIPTION

[0036] The present application will be further described below through specific implementation examples.

[0037] The waxy corn used in the embodiments and comparative examples of the present application is Wanlu 2000 corn kernels, which is purchased from Yangling Endian Qianke Seed Industry Company; the eggs are purchased from Beijing Zhengda Food Co., Ltd.; the sugar is purchased from Guangzhou Fu Zhengdonghai Food Co., Ltd.; the medium-gluten wheat flour is purchased from Henan Liangrun Mac Industry Technology Co., Ltd.; the skimmed milk is purchased from Inner Mongolia Yili Industrial Group Co., Ltd., and the corn oil is purchased from Dongguan Peizhiyou E-commerce Co., Ltd.

[0038] The whole egg liquid used in the embodiments of the present application is directly collected by breaking the shell of the egg.

[0039] Texture: The center part of the cake after cooling for 2 h was taken, cut into 1 cm x 2 cm x 2 cm thick and uniform slices, and the texture parameters thereof were determined by a texture analyzer (Stable Micro System, TA-XT PLUS Z, UK). The texture analyzer was set as follows: TPA mode, test probe P50, pre-test speed 2.0 mm / s, mid-test and post-test speed 1.0 mm / s, compression ratio 30%, induction force 8 g, and compression interval 5 s. The hardness, chewiness and elasticity of the sample were obtained.

[0040] Specific volume: The specific volume of the cake was calculated by the rapeseed replacement method. After cooling at room temperature, the cake was weighed and measured for volume. The specific volume of the cake was calculated according to the following formula: P = V / m, wherein P is the specific volume of the cake (mL / g), V is the volume of the cake (mL), and m is the mass of the cake (g).

[0041] Tissue morphology: After cooling for 30 min, the corn cake was demolded and placed in a bright and clean background, and the appearance and inner surface were photographed by a camera to observe the changes in the tissue morphology of the corn cake under different amounts of procyanidins.

[0042] Pore density and porosity: After slicing the cake, the slices were scanned by a scanner, and the middle part (3 cm x 3 cm) of each picture was cut. The pictures were analyzed by Image J software. The image resolution was set to 600 dpi, and the pore density and porosity were calculated.

[0043] Microstructure: A hot field emission scanning electron microscope system (JSM-7800F (equipped with an X-Max 50 energy spectrometer and a backscattered electron diffraction analyzer of Oxford Instruments, UK)) was used to study the microstructure of sodium fatty acid-glutinous corn flour. After gold palladium coating of the sample in an argon atmosphere using a gold sputtering module in a high vacuum evaporator, the sample was placed on a tray for observation.

[0044] In vitro enzymatic digestion rate: The in vitro enzymatic digestion efficiency of the corn cake was evaluated by the dinitrosalicylic acid (DNS) colorimetric method. 0.2 g of porcine pancreatic alpha-amylase was accurately weighed and mixed with 5 mL of phosphate buffer (10 mmol / L) at pH 7.0 in a vortex mixer for 3 min to prepare a digestive enzyme solution. The mixture was centrifuged at 8000 rpm / min for 20 min at 4°C. 0.2 mL of supernatant was taken and diluted to 10 mL with phosphate buffer in a 4°C refrigerator. 80 mg of sample powder was taken and added to 12 mL of phosphate buffer of the same concentration, and stirred at 37°C for 30 min to reach equilibrium. Then 1 mL of enzyme solution was added to start the reaction. At specific time points (0, 10, 20, 40, 60, 90, 120, 150, 180, 210 and 270 min), 1 mL of reaction mixture was taken, reacted with 1.5 mL of DNS reagent in a boiling water bath for 5 min, quickly cooled with ice water, added to 25 mL of ultrapure water, mixed well and measured the absorbance at 540 nm wavelength with a microplate reader. The content of reducing sugar produced by starch hydrolysis was calculated according to the standard curve, and each experiment was determined in triplicate.

[0045] Example 1

[0046] A method for preparing a slowly digestible corn cake, comprising the following steps:

[0047] S1, preparation of modified waxy corn flour: Wannuo 2000 corn kernels were ground and passed through a 100 mesh sieve, water was added to prepare a waxy corn flour suspension with a mass concentration of 6%, the waxy corn flour suspension was continuously stirred at 95°C water bath for 30 min to obtain a gelatinized waxy corn flour suspension, then 50% sodium fatty acid (sodium oleate) of the mass of waxy corn flour was added, and the mixture was stirred in a 95°C hot water bath for 40 min to obtain a complex solution; finally, the complex solution was dried, pulverized and sieved to obtain modified waxy corn flour;

[0048] S2, whipping of egg liquid: 100 g of whole egg liquid was placed in an instrument without water, and whipped with a beater, 20 g of sugar powder was added evenly in two times, 2 min each time, to obtain whipped egg liquid;

[0049] S3, mixing: 10 g of corn oil and 12 g of skimmed milk were fully emulsified and added to the whipped egg liquid of S2, and whipped for 1 min to make them uniformly mixed, to obtain egg liquid containing corn oil and skimmed milk;

[0050] S4, sieving and stirring: 30 g of modified waxy corn flour, 30 g of medium-strength wheat flour and 0.5 g of procyanidins were mixed and then added to the egg liquid containing corn oil and skimmed milk of S3 in three times through a 50 mesh sieve, and then stirred and mixed uniformly to obtain a batter;

[0051] S5, mixing, into the mold: the batter described in S4 is quickly poured into the mold, each mold is loaded with the same mass of batter (35 g), slightly shaken a few times to remove air bubbles, and then placed in the oven for baking, the temperature is set to 145°C, and baked for 40 min to obtain a slow-digestion corn cake.

[0052] Example 2

[0053] Prepared according to the preparation process of Example 1, with the only difference being that 0.5 g of procyanidins in S4 is replaced by 1 g of procyanidins.

[0054] Example 3

[0055] Prepared according to the preparation process of Example 1, with the only difference being that 0.5 g of procyanidins in S4 is replaced by 1.5 g of procyanidins.

[0056] Example 4

[0057] Prepared according to the preparation process of Example 1, with the only difference being that 0.5 g of procyanidins in S4 is replaced by 2 g of procyanidins.

[0058] Comparative Example 1

[0059] Prepared according to the preparation process of Example 1, with the only difference being that no procyanidins are added in S4.

[0060] Comparative Example 2

[0061] Prepared according to the preparation process of Example 1, with the only difference being that 30 g of modified waxy corn flour in S4 is replaced by 30 g of unmodified waxy corn flour.

[0062] The corn cakes prepared in Examples 1-4 and Comparative Examples 1-2 are subjected to the following performance tests:

[0063] 1. Texture profile analysis: Figure 1 The texture profile of corn cakes with different amounts of added procyanidins is shown in the figure. From the figure, we can clearly see that the hardness and chewiness of the corn cakes change in the same trend, both increasing with the increase of the amount of procyanidins, while the elasticity of the corn cakes changes slightly first and then decreases slightly with the increase of the amount of procyanidins. The hardness, chewiness and elasticity of Example 2 are all in a moderate state, with good palatability. Therefore, the amount of procyanidins added will have different effects on the structure and properties of the gluten protein in the wheat flour in the mixed flour, thereby affecting the texture properties of the corn cake.

[0064] 2. Specific volume analysis: Figure 2The specific volume diagram of corn cakes with different procyanidin contents is shown in the figure. It can be seen from the figure that, compared with the comparative example 1, the specific volumes of the examples 1, 2, 3 and 4 first increase and then decrease, and the greater the specific volume of the cake is, the higher the cake score is. It is shown that the addition of appropriate procyanidin can react with the wheat flour in the mixed powder, so that the amino groups, carboxyl groups and other groups in the protein molecules are activated, interact with the adjacent proteins, and aggregate more closely to form a continuous three-dimensional network structure, so that the dough formed has better extensibility.

[0065] 3. Morphological observation: Figure 3 The morphological diagram of corn cakes with different procyanidin contents is shown in the figure. It can be seen from the figure that, compared with the comparative example 1, the examples 1, 2, 3 and 4 show deeper color and volume increase at first and then shrinkage. From the cross-sectional observation, the appropriate addition of procyanidin leads to the decrease and more uniform distribution of the pores in the cake. The phenolic hydroxyl groups in procyanidin are rich, which can promote the combination of starch and water molecules, accelerate the swelling and gelatinization process of starch granules, so that the cake can wrap more water and air during fermentation, thereby shaping a fuller shape and smaller and more uniform pores.

[0066] 4. Pore density and porosity observation: Figure 4 The pore density and porosity diagram of corn cakes with different procyanidin contents is shown in the figure. It can be seen from the figure that, compared with the comparative example 1, the pore density and porosity of the examples 1, 2, 3 and 4 are significantly reduced. Too high pore density and porosity can cause the cake to be too soft and collapse, while too low pore density and porosity can make the cake too hard and have poor taste. It is shown that the appropriate addition of procyanidin can make the internal hydroxyl and carbonyl groups interact with starch through hydrogen bonds and van der Waals forces to form intermolecular aggregates, thereby affecting the spatial structure and gluten structure of the cake and affecting the pore density and porosity of the whole cake.

[0067] 5. Scanning electron microscope observation: Figure 5 The microstructure of corn cakes with different procyanidin contents under the scanning electron microscope is shown in the figure. It can be seen from the figure that, compared with the comparative example 1, the examples 1, 2, 3 and 4 can be observed that with the increase of the amount of procyanidin added, the starch gradually completely gelatinizes and gelatinizes uniformly, resulting in fewer and fewer starch particles on the surface and the holes on the pore wall first becoming smaller and denser, and then gradually increasing and becoming larger. The example 2 has the best effect, which shows that the addition of procyanidin helps the cake to diffuse gas to the outside of the pores during the baking process, resulting in an increase in the gas expansion rate during the baking process of the cake.

[0068] 6. In vitro enzymatic digestion property analysis: Figure 6The in vitro enzymatic hydrolysis rate of the corn cake is shown in the figure. It can be seen from the figure that the digestion rate of Comparative Example 2 is the highest, and the rising rate is also the fastest, reaching 66% at 250 min; the rising rate of Comparative Example 1 is relatively slow, and finally reaches about 50% at 250 min, indicating that the modified flour can significantly reduce the digestion rate of the cake; the hydrolysis rate of Example 2 is fast first and then slow, reaching about 45% at 250 min, which is significantly lower than that of Comparative Example 1 (p<0.05). It is shown that the combination of procyanidins and starch molecules changes the physical structure of the starch molecules, forms a more compact and complex network structure, and makes it more difficult for the enzyme to contact and decompose the starch molecules, thereby better reducing the digestion rate of the starch.

[0069] In summary, the corn cake with appropriate amount of procyanidins (the optimal addition amount is 1%) is prepared by a simple and easy method, which improves the poor water and air holding properties of the cake, the unstable protein network structure, the easy collapse and poor elasticity of the cake, and improves the product quality, adjusts the digestion characteristics, and makes the product have a soft and sweet taste. The addition amount of waxy corn flour is much higher than that of the existing corn cake products on the market, effectively improves the processing utilization rate of waxy corn, and provides a new technical method for the digestion characteristic regulation of waxy corn flour products and the development of slow-digestion functional food.

[0070] The above provided examples are not intended to limit the scope covered by the present application, and the described steps are not intended to limit the execution order. Those skilled in the art can make obvious improvements to the present application in combination with the existing common knowledge, which also falls within the protection scope defined by the claims of the present application.

Claims

1. A method of making a slow-digesting corn cake, characterized by, It comprises the following steps: S1, whipping of egg liquid: whipping whole egg liquid and adding sugar during the whipping process to obtain whipped egg liquid; S2, mixing: fully emulsifying vegetable oil and skimmed milk, adding the whipped egg liquid in S1, and mixing uniformly to obtain egg liquid containing vegetable oil and skimmed milk; S3, sieving and mixing: mixing modified waxy corn flour, wheat flour and procyanidins, sieving and adding to the egg liquid containing vegetable oil and skimmed milk in S2, and then mixing and stirring uniformly to obtain batter; the mass ratio of modified waxy corn flour to wheat flour is 1:1; The addition amount of procyanidins is 1-2% of the total mass of modified waxy corn flour and wheat flour; the preparation method of modified waxy corn flour is: crushing and sieving waxy corn to obtain waxy corn powder, adding water to prepare waxy corn powder suspension with a mass concentration of 5-10%, continuously stirring the waxy corn powder suspension at 70-100℃ water bath for 15-35min to obtain gelatinized waxy corn powder suspension, adding 30-60% sodium fatty acid of the mass of waxy corn powder, stirring in hot water bath at 95℃ for 30-60min to obtain complex solution; finally drying, crushing and sieving the complex solution to obtain modified waxy corn flour; S4, batter adjustment, mold filling and baking: pouring the batter in S3 into a mold, removing air bubbles, and then baking to obtain slow-digestion corn cake.

2. A method of preparing a slow-digesting corn cake according to claim 1, characterized by, The mass ratio of whole egg liquid to sugar in S1 is 100:18-40.

3. A method of preparing a slow-digesting corn cake according to claim 1, characterized by, The mass ratio of whole egg liquid to vegetable oil in S2 is 100:6-18.

4. The method of claim 1, wherein the corn cake is a slow digesting corn cake. The mass ratio of whole egg liquid to skimmed milk in S2 is 100:8-24.

5. The method of claim 1, wherein the corn cake is a slow digesting corn cake. The type of wheat flour in S3 is medium gluten wheat flour.

6. Slow-digestion corn cake prepared by the method of any one of claims 1-5.

7. Use of the slow-digestion corn cake of claim 6 in the field of food.

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