Vacuum tumbling is a physical process of energy conversion in meat pieces. It is an indispensable process in modern meat processing and an effective method to speed up the marinating speed. Meat pieces are mechanically processed by tumbling. The distribution of the liquid medium brine is facilitated, the tenderness of the meat is improved, and the extraction and movement of salt-soluble proteins to the surface of the meat piece is enhanced. As a result, the product yield and product quality have been greatly improved.

1. The Principle of Tumbling

Put the meat injected with brine (including phosphates and other ingredients) into the tumbler. With the machine running at full speed, chunks of meat are tumbling in the body. Part of the meat is lifted up by the baffles, and then falls freely, colliding with the lower pieces of meat. Since the rotation is continuous, each piece of meat has a chance to flip, rub against each other, and hit each other. In this way, the original stiff meat can be softened, the muscle tissue can be relaxed, the saltwater can easily penetrate and diffuse, the color of the meat can be uniform. And at the same time, it can play the role of mixing.

Due to the constant rolling and squeezing, the protein in the muscle and the unabsorbed saline can form a colloidal substance. Once heated, this part of the protein coagulates first, preventing the juice inside from leaking and losing. Thereby, the water retention and freshness of meat products are improved, and the yield is also improved. In addition, the extraction of salt-soluble protein increases the adhesiveness and sliceability of the product and improves the quality of the product.

2. Ambient Temperature

Usually, the ambient temperature of tumbling should be 0-4°C. Because at this temperature, the growth and reproduction of various microorganisms can be reduced to a minimum. According to relevant research data, when the meat filling is rolled and kneaded in an environment of 8 ℃ or higher, the binding force, yield, and sliceability of the product will be significantly reduced. Although the meat filling can shorten the tumbling time in a warmer environment, reduce the production cost, and get better color. However, considering the product’s inherent quality, shelf life, safety, etc., the ambient temperature of tumbling should be more appropriate at 0-4°C.

3. Actual Feed Amount

Appropriate tumbling load is the basic factor to achieve the best tumbling effect, and it is also the basic guarantee for equipment maintenance. If the feeding quantity is too large, the falling and movement of the meat pieces will be restricted. The desired effect cannot be achieved within the specified process time. On the contrary, if the amount of feed is too small, the meat will fall too much, which will break the meat. This results in excessive rolling and kneading, the texture of the meat is too soft, and the meat-showing effect of the product is reduced. It will also cause the meat temperature to rise rapidly, resulting in the denaturation of the meat protein, thereby affecting the intrinsic quality of the product.

Therefore, when tumbling, we should determine the actual amount of material feeding according to the design capacity of the tumbler to ensure that the ideal tumbling effect can be achieved. Usually, it is recommended to feed at about 60% of the equipment volume. At the same time, the actual feeding amount can be adjusted slightly according to the size of the meat and the density of the meat to achieve the best rolling and kneading effect.

4. Vacuum Degree

The vacuum is one of the most important functions of a tumbler. The advantage is that it can remove the air between the raw meat and its exudates. In this way, the structure of the product will not be damaged by thermal expansion during subsequent thermal processing. A vacuum tumbler also helps improve the appearance color of cured meat products. The oxidation reaction during the curing process is extremely detrimental to the appearance and color of the meat product. But vacuum tumbling will not occur oxidation reaction in the long-term continuous production process. While the vacuum ensures quick penetration of the brine into the meat, it also helps remove air holes in the meat and expands the meat for increased tenderness. However, the vacuum degree should not be too high, otherwise, the moisture in the meat can be easily drawn out under the high vacuum degree, which will affect the quality of the meat products. Generally, the vacuum degree can be -0.07～-0.08Mpa.

Speed and direction: The tumbler speed controls the falling ability of the meat in the tumbler. According to different types of products, it is generally controlled at 8–12r/min. In addition, the tumbler should gently push, massage, lift and drop pieces of meat for the best tumbler effect.

The tumbling machine should not run continuously, and generally adopts the process of intermittent tumbling. Let the device run for a while and stop for a while. Do this repeatedly (letting the mince “rest” in between) until the desired tumbler effect is achieved. If the equipment has a reverse function, it can also be carried out by the process of forward-reverse-stop intermittent tumbling. The main purpose is to avoid the increase in meat temperature caused by friction and also to make the structural organization of the meatless susceptible to damage.

5. Total Tumbling Time

The total tumble-kneading time is a key factor in achieving the desired effect. The formula for calculating the total tumbling time of a general tumbling machine is T=U×N/L. Among them, T represents the total rotation time of the tumbler (intermittent tumbler time is not included); U represents the inner circumference of the tumbler (the inner diameter of the tumbler can be multiplied by the pi); N represents the tumbler L is a constant, representing the total rotation distance of the tumbler, and this rotation distance L is generally controlled at 10000-12000m.

The total tumbling time is a key factor in achieving the desired results. The general formula for calculating the total tumbling time is T=U×N/L. Among them, T represents the total rotation time (intermittent tumbling time is not included); U represents the inner circumference of the tumbler; N represents the rotational speed; L is a constant, representing the total rotation distance of the tumbler, which is generally controlled At 10000-12000m.