1, dough preparation technology

Dough preparation is also called "kneading dough", "mixing powder" and "stirring".

Its main function has two aspects:

1) All kinds of raw and auxiliary materials are mixed evenly and interact with each other.

2) Flour absorbs water, generates gluten and forms a network structure, and then gets stretched, and finally forms dough with certain properties.

According to the actual situation, we should ensure enough strength and time to achieve the best dough state. In general, kneading cannot be used instead of stirring.

2. Dough fermentation technology

Dough fermentation can proliferate yeast, make dough creep, produce flavor and increase nutrition.

Traditional steamed bread production technology attaches great importance to dough fermentation and requires dough to be completely initiated. Therefore, many individual steamed bread production enterprises still adopt the old flour fermentation technology. However, excessive fermentation may cause the dough to produce too much acid. Because the process conditions are difficult to control, emerging steamed bread enterprises often adopt the production process of rapid fermentation or dough non-fermentation. Instead of fermentation, the cost increases, the appearance is not good, and the steamed bread loses its traditional flavor and taste. Practice has proved that its competitiveness is poor.

3. Mixing powder for the second time

After the dough is fermented, flour and the remaining auxiliary materials should be properly added in front of the dough.

After fermentation, the yeast in the dough will consume all nutrients and oxygen, which is very unfavorable for the later proofing. Therefore, it is necessary to supplement proper nutrition and stir more fresh air.

Additives that are not conducive to yeast growth are added in the second kneading, which will reduce the influence on fermentation.

Add pH regulator to avoid the influence of dough acidity on the product.

Adjusting the relaxation state and viscosity of dough is beneficial to molding operation and ensuring the shape of products.

Step 4 knead dough

Generally, dough needs to be kneaded before dough forming to ensure the structure and appearance of steamed bread. Hand molding must be done by kneading machine or by hand. When the steamed bread machine is formed, the extrusion of the screw in the feed hopper and the torsion of the kneading roller have already finished kneading the dough, and there is no need to set up another kneading process.

Kneading can remove the gas from the dough, make the texture fine, make the surface of the product smooth and white, and avoid bubbles on the surface of steamed bread.

Knead the dough until the dough surface is smooth and the inside is fine.

5. Forming and shaping

After the dough is kneaded, it is very necessary to properly shape the cut or kneaded steamed bread blank in order to keep the appearance of steamed bread products straight and full and avoid the possibility of flat during proofing and steaming. Round steamed bread is quantitatively divided and kneaded into shapes, and square steamed bread is kneaded and cut into shapes. Hand-shaping of family steamed bread is to knead the steamed bread blank into a certain shape by hand and make the surface as smooth as possible; In the steamed bread production line, the steamed bread forming machine is usually arranged behind the steamed bread machine, that is, the "steamed bread kneading machine" is used to knead the height and polish the steamed bread blank. 6. Proofing of steamed bread blanks

Proofing, also known as final fermentation, is an essential and important process in steamed bread production. A series of biochemical reactions occurred in the process of proofing, which made steamed bread reach a certain volume, appearance and internal organizational structure.

We should master the temperature, humidity and time when proofing: Higher temperature (35~42℃) is beneficial to quick proofing and reduce the deformation of steamed bread blank. But the temperature should not exceed 45℃ to prevent yeast inactivation at high temperature.

Humidity control should be controlled on the soft surface of the blank without sticking hands. General relative humidity is 75%~95%.

The degree of proofing should be determined according to the requirements of the product. Zhengzhou steamed bread is twice as big, southern steamed bread is bigger, and hard-faced steamed bread is lighter. 7. Steaming steamed bread

Steamed bread can be steamed by steamer, steamer, steamer and steamer.

During the steaming process, a slight pressure state and gas circulation are maintained in the container to ensure the steaming temperature. Keep the container airtight, but also ensure that a proper amount of gas is discharged and steam continues to enter the steamer. The steam pressure should not be too high, so as to avoid dew splashing directly on the surface of the blank and causing local burns.

Analysis of Common Problems in Steamed Bread Quality

Common and important quality problems of steamed bread are: poor flavor, poor taste, steamed bread shrinkage, uneven surface, bad color and so on. 1, steamed bread flavor

The aroma of steamed bread should have pure wheat flavor and fermented flavor, full of flavor, sweet taste and no peculiar smell. Common problems are: insufficient fragrance, unpleasant aftertaste and bad flavor (sour, alkaline, astringent, rancid and other smells). Improper use of additives, pollution of odor components, deterioration of flour, poor fermentation, inappropriate pH value, and deterioration of products may all lead to flavor problems. It should be solved according to the actual situation.

2. The internal structure and taste of steamed bread

The taste of steamed bread is also one of the most important indicators to determine the quality. High-quality steamed bread should be soft and firm, elastic, non-sticky, and have a layered microporous structure inside. The common structural problems of steamed bread are: sticky but inelastic, too hard but not empty, too hard at the bottom, too weak elasticity, poor or non-layered, and insufficient internal cavity.

The main factors affecting the texture of steamed bread are: water addition, dough mixing degree, dough fermentation, dough mixing operation, proofing degree and so on. By adjusting the technological parameters, the taste of steamed bread can be obviously improved.

3. The steamed bread has shrunk

Steamed bread will shrink and turn black when steamed or re-steamed, like steamed bread with hot surface and dead surface, which occasionally appears when steamed bread is kept warm. It is strange that people can't explain this phenomenon. They call it "pinching ghosts" and think it is unlucky. The appearance of this phenomenon has increased the number of defective products in steamed bread factories, which has seriously affected the reputation of enterprises. Especially during the Spring Festival, families store a large number of cold steamed bread, and "ghost pinching" has the greatest psychological impact on consumers.

The root cause of atrophy is the lack of gluten skeleton support. When there is enough internal pressure and tissue strength, steamed bread can maintain a large expansion, and when it is cooled and decompressed, it will inevitably shrink when the retraction force is greater than the support force.

To prevent steamed bread from shrinking, we should start with raw materials and work hard on the technology. The key to solve the shrinkage of steamed bread is to make the dough reach the best state in kneading and kneading, adjust the pH value of the dough to a suitable range, ensure the moderate proofing degree and ensure the steaming process conditions.

4. The surface of steamed bread is not smooth

High-quality steamed bread should have smooth surface, no cracks, no bubbles, no obvious depressions and bulges. Whether the surface is smooth or not has a great influence on the sales of commercial steamed bread.

Common surface problems of steamed bread are: cracks, cracks, blisters and so on.

Cracks in steamed bread are mostly caused by low humidity. It can be solved by adjusting the proofing humidity.

Cracks may be caused by factors such as too low dough moisture, too high dough pH value, insufficient kneading, too much cloth and insufficient dough proofing.

Foaming is mainly caused by low pH value of dough, too much kneading, too much humidity during proofing, too much proofing and too high air pressure during steaming.

5. The color of steamed bread is not good

The skin of high-quality steamed bread should be milky white, uniform in color, translucent and shiny, without yellow spots and black spots. The interior should also be pure white, with fine structure and uniform color.

Common color problems are: the color of steamed bread is dark but not white, yellow and with black spots.

The quality of raw materials and the effect of additives are the key factors affecting the color of steamed bread, but the process operation is also very important. Insufficient mixing and kneading of dough and too sour dough may lead to darker color. Alkaline, colored substance pollution, mildew, etc. It may make the steamed bread yellow. Dark spots are mainly caused by insufficient moisture and excessive proofing of dough. Of course, there will be black spots when steamed bread shrinks.

Some steamed bread processing points have encountered this situation: steamed bread is good when it is just processed, but it will shrink after cooling or reheating, and some steamed bread will be small or shrunk in a drawer. What is the reason? To analyze this situation, we must understand the principle of steamed bread processing. Steamed bread processing is to use enzymes and yeast in flour to generate gas in dough under external moisture and temperature conditions, and to use the elasticity and ductility of gluten in flour to form bubbles, and then heat to shape and fix the shape of steamed bread. From this, it can be analyzed that if the drawer of steamed bread is intact, it means that there is no problem with the starting ability, and the shrinkage after cooling means that there is a problem with the strength of gluten skeleton, that is, the quality of gluten is not good, which may be due to the variety or the processing and preservation. If individual steamed bread shrinks, it is more likely to happen during processing. For example, when the steam pressure is low, condensed water is easy to form in the steamer, and water drops on the immature steamed bread, resulting in local overheating and "dead noodles", which makes the steamed bread smaller.