Whole-grain steamed bun and preparation method thereof

Abstract

The invention provides whole-grain steamed buns and a preparation method thereof, and belongs to the technical field of food processing. The whole-grain steamed bun is prepared by taking black whole wheat flour as a base raw material, compounding the black whole wheat flour with complete coarse grains such as oat grains, sorghum rice and three-color brown rice, and only adding yeast, lactobacillus plantarum and water, and does not contain other modifiers. Physical treatments such as baking, water activation and pre-gelatinization are carried out on the coarse cereal grains, so that the compatibility of the coarse cereal grains and a dough system is improved on the premise of keeping the complete structure of the grains; and through combination of multi-strain synergistic fermentation and a secondary fermentation process under temperature and humidity control conditions, stable forming and fermentation of high-proportion whole coarse cereals under an additive-free condition are realized. The method effectively improves the problems of rough tissue, insufficient bulkiness and unstable structure of the whole grain steamed bun, and the prepared whole grain steamed bun has good tissue structure, whole grain taste and balanced nutrition characteristics, and is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food processing, and in particular to a whole grain steamed bun and a preparation method thereof. BACKGROUND

[0002] With the improvement of residents' health awareness, whole grain food gradually becomes an important development direction of staple food consumption because it is rich in dietary fiber, minerals and various bioactive substances. Among them, whole grain steamed buns, as a representative product of the combination of traditional fermented flour products and modern nutritional concepts, have a good market prospect.

[0003] At present, the preparation methods of whole grain steamed buns mainly include the following two methods: one is to prepare steamed buns by compounding whole grain powder or coarse grain powder with wheat flour, and increasing the whole grain content by increasing the proportion of coarse grain powder; the other is to introduce the grain into the dough system after crushing, beating or enzymatic treatment to improve the processing performance and fermentation stability. In addition, there is also a scheme of preparing whole grain steamed buns by compounding fresh eating waxy corn kernels with wheat flour after beating and enzymatic viscosity reduction.

[0004] However, whether it is crushing, beating or enzymatic treatment, the fiber structure of the grain is easily damaged during the processing, the dietary fiber preservation rate is low, resulting in loss of nutritional ingredients and weakening of flavor. At the same time, the addition of a high proportion of whole grain kernels will cause poor compatibility with the dough, easy sedimentation, difficulty in forming, rough taste and other technical problems, and the industry generally relies on chemical additives to improve quality, which is difficult to meet the market demand for clean label healthy staple food.

[0005] Therefore, how to use whole grain kernels as the core raw material without adding chemical additives, to realize good compatibility of high proportion of whole grain kernels and dough system through physical means and reasonable fermentation process, to prepare whole grain steamed buns with nutritional value, flavor and scale production, is still a technical problem to be solved in the field. SUMMARY

[0006] In view of the technical problems that the existing whole grain steamed buns are prone to forming difficulty, unstable fermentation and rough taste under the condition of high proportion of whole grain kernels, and generally rely on food additives and are difficult to meet the clean label demand, the present application provides a whole grain steamed bun and a preparation method thereof.

[0007] This invention primarily utilizes whole grains as the core raw material, selecting oat rice, sorghum rice, and tricolor brown rice as the main whole grain sources, and black whole wheat flour as the base flour. These are compounded with physically modified whole grains to form a dough system that combines structural support and nutritional integrity. Simultaneously, physical modification methods such as baking, moisture activation, and pregelatinization are used to treat the grains, improving the compatibility between the whole grains and the dough system without damaging the grain structure or introducing enzymes or chemical modifiers. Furthermore, combined with multi-strain synergistic fermentation and a secondary proofing process under controlled temperature and humidity conditions, stable fermentation and shaping of a high proportion of whole grains are achieved without additives, effectively improving the problems of insufficient fluffiness and uneven air pocket distribution in traditional whole grain steamed buns.

[0008] The technical means employed in this invention are as follows: A whole-grain steamed bun, by weight, comprises the following components: 100 parts whole wheat flour; 25-35 parts oat groats; 25-35 parts sorghum groats; 35-45 parts tricolor brown rice; 1.0-1.5 parts yeast; 0.05-0.2 parts Lactobacillus plantarum; 200-250 parts water; The oat rice, sorghum rice, and tricolor brown rice retain their identifiable grain shape inside the steamed bun. Oat rice is rich in β-glucan, which helps regulate blood lipids; sorghum is rich in polyphenols, which have antioxidant effects; and brown rice retains its germ and seed coat, and is rich in γ-aminobutyric acid, which helps regulate nerve function. The three complement each other in terms of amino acid composition, synergistically enhancing the biological value of protein.

[0009] Further, by weight, it includes the following components: 100 parts black whole wheat flour; 25-35 parts oat rice; 25-35 parts sorghum rice; 35-45 parts tricolor brown rice; 1.2 parts yeast; 0.1 parts Lactobacillus plantarum; and 200-250 parts water. Furthermore, the whole grain steamed buns are made from dough that has undergone one proofing, shaping, and a second proofing before steaming.

[0010] This invention also provides a method for preparing the above-mentioned whole grain steamed buns, comprising the following steps: (1) Pretreatment of mixed grains: Mix whole grains of oat rice, sorghum rice and tricolor brown rice and bake at 120~140℃ for 1.5~2.5h; (2) Moisture activation treatment: After roasting, add some water to soak the grains to cool them down. After cooling, discard the soaking water and add the remaining water to continue soaking for 4-8 hours. (3) Pregelatinization treatment: Steam the water-absorbing grains at 95~105℃ for 5~10 minutes, and then cool them for later use; (4) Dough preparation: Mix black whole wheat flour, mixed grains treated in step (3), yeast, Lactobacillus plantarum and water to make dough; (5) Proofing and steaming: The dough is proofed, shaped, proofed again and steamed in sequence to obtain the whole grain steamed bun product.

[0011] Furthermore, in step (4), the black whole wheat flour and miscellaneous grains are mixed in a 1:1 ratio in a mixing tank.

[0012] Furthermore, in step (4), the yeast is first activated with warm water before being added to the dough system.

[0013] Furthermore, the first proofing is carried out at 28~32℃ and 75~85% relative humidity for 30~45 minutes, until the dough volume increases to 1.5 times its original size.

[0014] Further, the dough after the first proofing is fed into a forming machine and rolled into round steamed bun blanks with a diameter of 7cm, a weight of 80g, and a smooth surface.

[0015] Further, the shaped steamed bun dough is sent into a proofing box, where it undergoes a second proofing process for 10-20 minutes at 35-38°C and 80-90% relative humidity.

[0016] Furthermore, after the proofing is complete, place the raw dough into a steamer, leaving enough space for expansion. Place the steamer over cold water and wait for steam to emerge for 15-25 minutes. After the time is up, turn off the heat and let it sit for 2-6 minutes before transferring the steamed buns to the freezer for quick freezing.

[0017] Compared with the prior art, the present invention has the following advantages: 1. This invention achieves physical modification of whole grains such as oat rice, sorghum rice, and tricolor brown rice by sequentially subjecting them to low-temperature baking, moisture activation, and pre-steaming. The low-temperature baking process induces a mild Maillard reaction within the grains, generating flavor compounds such as pyrazines, thereby fully stimulating the natural aroma of the grains. The subsequent soaking process softens the hard grains by fully absorbing water, opening the starch crystal structure through hydration and eliminating the hard core of the grains. This not only facilitates complete cooking during subsequent steaming but also improves the final taste. The pre-steaming process gelatinizes some of the starch in the grains, increasing the softness and edibility of the grains, while enhancing their binding ability with the dough system, avoiding a noticeable "hard" texture in the finished steamed buns, and shortening the final steaming time, resulting in energy savings.

[0018] 2. This invention achieves synergistic optimization of taste and nutrition through the scientific proportioning of different grains. In terms of taste, the soft and chewy texture of oats, the firm and chewy feel of sorghum, and the springy texture of brown rice complement each other, avoiding the fatigue associated with single-grain flavors and significantly improving the overall palatability and acceptability of whole-grain steamed buns. Nutritionally, different grains are complementary in terms of amino acid composition, dietary fiber type, and mineral content. Their combined use can enhance the biological value of protein and promote the diversified intake of dietary fiber, trace elements, and other nutrients, thus helping to meet the nutritional balance requirements of whole-grain staple foods.

[0019] 3. This invention, without adding enzymes, thickeners, emulsifiers, or other modifiers, involves water absorption and pre-steaming of whole grains to form a pregelatinized starch structure with certain gelation properties, which is then introduced into the dough system as a stable water carrier. This structure effectively compensates for the insufficient water-holding capacity of whole wheat flour and, by reducing the starch retrogradation rate, stably locks moisture within the whole grain starch network. This maintains good dough extensibility and processing adaptability even without additives. Simultaneously, the formed composite starch-gluten network helps delay the aging process of steamed buns, improving the quality stability of the finished product during storage and reprocessing, and enabling the preparation of whole grain steamed buns that meet clean label requirements.

[0020] In summary, this invention achieves a high-proportion stable application of whole grains in steamed buns by rationally modifying whole grain kernels through physical treatment and compounding them with a black whole wheat flour system, combined with multi-strain synergistic fermentation and a secondary proofing process under controlled temperature and humidity conditions, without relying on food additives. This technical solution effectively solves the common problems in existing whole grain steamed buns, such as difficulty in shaping, coarse texture, and unstable quality. The resulting whole grain steamed buns possess good structural stability, whole grain texture, and balanced nutrition, making them highly valuable for promotion and application. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a diagram of the raw materials for the whole grain steamed bun of the present invention.

[0023] Figure 2 This is a diagram of the raw dough for the whole grain steamed bun of the present invention.

[0024] Figure 3This is a picture of the finished product of the whole grain steamed bun of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1 This invention provides a whole grain steamed bun and its preparation method.

[0027] By weight, take 100 parts black whole wheat flour, 30 parts oat rice, 30 parts sorghum rice, 40 parts tricolor brown rice, 1.2 parts yeast, 0.1 parts Lactobacillus plantarum, and 200 parts water.

[0028] (1) Pretreatment of miscellaneous grains like Figure 1 As shown, whole grains of oat rice, sorghum rice, and tricolor brown rice are mixed and baked in a 130℃ oven for 2 hours to completely dry them and develop a caramelized flavor. The baked grains are then soaked in 100 parts water to cool them down. After they have completely cooled, the hot water is drained, and the remaining 100 parts room temperature water is added to continue soaking for 6 hours to allow the grains to fully absorb water and soften. The soaked grains are drained of excess water and steamed at 100℃ for 7 minutes until the surface becomes translucent, which pregelatinizes the surface of the grains. The steamed grains are then removed from the steamer and spread out to cool to below 30℃ at room temperature for later use.

[0029] (2) Dough preparation and first proofing Add the whole wheat flour and cooled mixed grains to the mixing bowl in a 1:1 mass ratio. Add the activated yeast (dry yeast needs to be activated with 2 parts warm water for 7 minutes) and Lactobacillus plantarum. Mix evenly at low speed, then add 20 parts water and knead at medium speed to form a smooth and elastic dough. Proof the dough in a proofing box at 30°C and 80% humidity for 35 minutes, until the dough volume increases to 1.5 times its original size.

[0030] (3) Shaping, secondary proofing and steaming After the first proofing, the dough is fed into a shaping machine and rolled into round steamed buns with a diameter of 7 cm and a weight of 80g, with a smooth surface. The buns are then placed in a proofing box and proofed for another 15 minutes at 37℃ and 85% humidity to ensure that the air pockets inside the buns are evenly distributed and that the buns feel light to the touch and slowly spring back when lightly pressed.

[0031] After proofing, place the raw material (such as...) Figure 2Place the whole grain steamed buns (as shown) in a steamer, leaving enough space for expansion. Place the buns in the steamer with cold water and steam for 20 minutes after steam starts to rise. After 20 minutes, turn off the heat and let them sit for 4 minutes to obtain the finished product. Figure 3 (As shown in the image) and then put the steamed buns into the freezer for quick freezing.

[0032] The whole grain steamed buns prepared in Example 1 were subjected to the following performance tests.

[0033] (a) Comparison data of textural properties (texture analyzer - TPA test) The whole grain steamed buns prepared in Example 1 were tested using a texture analyzer and compared with commercially available ordinary whole wheat steamed buns and ordinary white steamed buns. The results are shown in Table 1.

[0034] Table 1

[0035] It can be seen that the steamed bun of the present invention has successfully optimized the textural properties while maintaining the nutrition of whole grains, achieving a perfect balance of moderate hardness, good elasticity, and strong chewiness, thus solving the pain points of ordinary whole wheat steamed buns being "hard, crumbly, and loose".

[0036] (II) Comparison of Nutritional Indicators Nutritional analysis was performed on the whole grain steamed buns prepared in Example 1, and the results are shown in Table 2.

[0037] Table 2

[0038] The results showed that, compared with ordinary white steamed buns and commercially available whole wheat steamed buns, this invention, due to the use of whole grains, retains dietary fiber to the maximum extent, containing 3.4 times more dietary fiber than white steamed buns and 1.7 times more than ordinary whole wheat steamed buns. The physical barrier and high fiber content of whole grain particles significantly slow down the rate of blood sugar rise, resulting in a lower GI value. Meanwhile, oats, sorghum, and brown rice are rich in β-glucan, which has the functions of controlling blood lipids and enhancing immunity, advantages that ordinary products do not possess.

[0039] (III) Sensory Evaluation Comparison Thirty professional evaluators conducted a blind evaluation based on three dimensions: grain flavor, chewing satisfaction, and overall acceptance. The results are shown in Table 3.

[0040] Table 3

[0041] Evaluation results show that this invention, due to its unique low-temperature baking process, greatly enhances the natural aroma of the grains, making it far more palatable than the "bran taste" of ordinary whole wheat. At the same time, its rich grain texture and chewy consistency provide a pleasant chewing experience, satisfying chewing enthusiasts while avoiding the roughness of ordinary whole wheat. While retaining the nutrients of whole grains, its flavor and texture have been recognized by the vast majority of consumers, achieving a combination of health and deliciousness. Sensory evaluation proves that this invention successfully transforms "health" into "deliciousness," with its overall acceptability significantly surpassing traditional whole wheat steamed buns, providing core consumers with a staple food option that they can both consistently consume and truly enjoy.

[0042] (iv) Comparison of pore uniformity Scanning electron microscopy was used to observe the distribution of pores in the cross-section of the steamed buns. The diameter, density, and uniformity of the pores were statistically analyzed using ImageJ software. The experimental results (as shown in Table 4) show that the whole grain steamed buns of the present invention have larger and more uniformly distributed pores. Combined with the physical structure of the grains, they form a "honeycomb" support network, which significantly improves elasticity and chewiness. At the same time, the synergistic effect of yeast and Lactobacillus plantarum not only ensures the expansion of the dough and the formation of pores, but also helps to degrade phytic acid and improve flavor. The two complement each other.

[0043] Table 4

[0044] Example 2 Based on Example 1, the amount of oat rice was adjusted to 25 parts, and the amount of tricolor brown rice was adjusted to 45 parts, while other conditions remained unchanged. The resulting whole-grain steamed buns were basically consistent with those of Example 1 in terms of structural integrity and taste, with a slight increase in dietary fiber content and further enhanced chewiness, indicating that the present invention has good process adaptability to changes in the proportion of mixed grains.

[0045] Example 3 Based on Example 1, the first proofing time was adjusted to 40 minutes, the second proofing time was adjusted to 12 minutes, and other conditions remained unchanged. The resulting whole-grain steamed buns still maintained good shapeability and texture, indicating that the preparation method of the present invention has good stability and repeatability within a reasonable range.

[0046] As can be seen from the above embodiments and corresponding test results, the present invention achieves a comprehensive improvement in the textural properties, nutritional characteristics and sensory quality of whole grain steamed buns through physical modification of whole grain kernels and reasonable fermentation process design without relying on food additives.

[0047] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A whole grain bun, characterized by, By weight parts, comprising the following components: Black whole wheat flour 100 parts; oat rice 25~35 parts; sorghum rice 25~35 parts; three-color brown rice 35~45 parts; yeast 1.0~1.5 parts; Lactobacillus plantarum 0.05~0.2 parts; Water 200~250 parts; Among them, the oat rice, sorghum rice and three-color brown rice maintain identifiable grain morphology inside the steamed buns.

2. The whole grain bun of claim 1, wherein, By weight parts, comprising the following components: black whole wheat flour 100 parts; oat rice 25~35 parts; sorghum rice 25~35 parts; three-color brown rice 35~45 parts; yeast 1.2 parts; Lactobacillus plantarum 0.1 parts; Water 200~250 parts.

3. The whole grain bun of claim 1, wherein, The whole grain steamed buns are steamed from the dough after one-time leavening, shaping and two-time leavening.

4. A method of preparing the wholegrain steamed bun according to any one of claims 1 to 3, characterized in that, Comprising the following steps: (1) Pre-treatment of mixed grain seeds: mix the intact seeds of oat rice, sorghum rice and three-color brown rice, and bake at 120~140℃ for 1.5~2.5h; (2) Moisture activation treatment: soak the baked mixed grain seeds in part of water to cool down, discard the soaking water after cooling, and then continue to soak in the remaining water for 4~8h; (3) Pre-gelatinization treatment: steam the water-absorbed mixed grain seeds at 95~105℃ for 5~10min, and then cool down for standby; (4) Preparation of dough: mix and stir the black whole wheat flour, mixed grain seeds treated in step (3), yeast, Lactobacillus plantarum and water to obtain the dough; (5) Leavening and steaming: the dough is subjected to one-time leavening, shaping, two-time leavening and steaming in sequence to obtain the finished whole grain steamed buns.

5. The preparation method according to claim 4, characterized in that, In step (4), the black whole wheat flour and mixed grain seeds are put into the stirring cylinder in a ratio of 1:1 for mixing.

6. The preparation method according to claim 4, characterized in that, In step (4), the yeast is first activated in warm water and then added to the dough system.

7. The preparation method according to claim 4, characterized in that, The one-time leavening is carried out at 28~32℃ and relative humidity of 75~85% for 30~45min, and the volume of the dough is increased to 1.5 times.

8. The production method according to claim 7, wherein The dough after one-time leavening is sent to a molding machine to be rubbed into a circular steamed bun green body with a diameter of 7cm, a mass of 80g and a smooth surface.

9. The production method according to claim 8, characterized by, The molded steamed bun green body is sent to a leavening box, and the two-time leavening is carried out at 35~38℃ and relative humidity of 80~90% for 10~20min.

10. The method of claim 9, wherein, After leavening, the steamed bun green body is placed in a steaming box with sufficient expansion space, and cold water is added to the pot until steam comes out, and then timing is started for 15~25min. After the time is up, the fire is turned off for 2~6min, and the steamed bun is sent to a freezer for quick freezing.

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