Pickled Chinese cabbage fish sauce and watermelon sauce, as new categories in the seasoning market in recent years, are gradually entering the home kitchen and catering kitchen. Pickled Chinese cabbage and fish sauce is characterized by its sour, hot and delicious flavor, while watermelon sauce has won consumers' favor by virtue of its unique sweet and slightly salty flavor. Although the two types of sauces have different flavors, they face the same technical requirement at the end of the production process, which is how to achieve efficient, stable, and hygienic vacuum capping packaging. The vacuum capping machine is the key equipment to meet this demand, and its performance directly affects the shelf life, flavor retention, and market circulation safety of the product.

As for pickled Chinese cabbage fish paste, it contains more oil, pickled Chinese cabbage chips and spices. If there is air left in the bottle after filling, it is easy to lead to oxidative rancidity of oil, discoloration of pickled Chinese cabbage particles, and even breeding of aerobic microorganisms. The vacuum capping machine can significantly reduce residual oxygen by extracting air from the bottle and injecting inert gas or directly creating a negative pressure environment, and then tightly biting the bottle cap with the bottle mouth thread using a capping head. Generally, the vacuum degree of pickled Chinese cabbage and fish sauce is controlled between minus 0.06 and minus 0.08 MPa, and the screw cap torque needs to be stable between 0.8 and 1.2 Nm to ensure reliable sealing and avoid damaging the bottle cap or mouth due to excessive torque. In view of the problem that particles in pickled Chinese cabbage and fish sauce are easy to block the pipeline, the vacuum capping machine should be equipped with an anti blocking air extraction filter device, and the intermittent vacuum pumping procedure should be used to prevent the sauce from being sucked into the vacuum pump.

Watermelon sauce faces different challenges. Watermelon sauce has a high water content, rich in sugar, and often contains fruit pulp fibers. During the vacuum capping process, if the pumping rate is too fast, the liquid inside the bottle may boil and splash, contaminating the threads of the bottle mouth and causing poor sealing after capping. Therefore, a vacuum capping machine suitable for watermelon sauce should have a slow vacuum pumping function, which gradually reduces the pressure inside the bottle in stages, allowing the dissolved gases in the sauce to slowly escape. Meanwhile, the capping head should adopt a flexible gripping structure to avoid crushing glass bottles or deforming plastic bottles. It is recommended that the vacuum degree be controlled from minus 0.05 to minus 0.07 MPa, and the torque of screw cap is slightly lower than that of pickled Chinese cabbage fish sauce, about 0.6 to 0.9 Nm. In addition, watermelon sauce is prone to fermentation and gas production. If it is not vacuum sealed in a timely manner after filling, carbon dioxide may be produced inside the bottle due to microbial activity, forming positive pressure and causing the bottle cap to bulge. Therefore, the interval time from filling to capping should be minimized as much as possible, ideally not exceeding thirty seconds.

Vacuum capping machine prototype display:

From the perspective of equipment selection, pickled Chinese cabbage fish sauce and watermelon sauce can share the same vacuum capping machine, but the parameters need to be adjusted according to the product characteristics. A qualified vacuum capping machine shall be equipped with PLC, which can store multiple groups of process formulas, respectively corresponding to pickled Chinese cabbage fish sauce, watermelon sauce and other sauces. The capping head should be able to be quickly replaced to accommodate different bottle cap diameters, such as common specifications such as 38mm, 43mm, 53mm, etc. The vacuum pump should be an oil-free dry pump to avoid oil mist contamination of the sauce. The speed of the conveyor belt needs to be synchronized with the filling machine and labeling machine to form a continuous production line. For small and medium-sized sauce production enterprises, semi-automatic vacuum capping machines are a cost-effective choice, capable of processing 600 to 1200 bottles per hour; Large enterprises should adopt fully automatic rotary vacuum capping machines, with a production capacity of up to 3000 to 6000 bottles per hour.

In actual production, operators need to regularly check whether the sealing ring of the vacuum capping machine is aging, whether the exhaust pipeline is blocked, and whether the capping claw is worn. At least ten bottles of products should be randomly inspected per shift, and the torque tester should be used to measure the screw cap torque, and the vacuum gauge should be used to check the vacuum degree inside the bottles. If the bottle cap of pickled Chinese cabbage and fish sauce is loose or the mouth of the watermelon sauce bottle leaks, stop the machine immediately for adjustment. In addition, the cleaning and disinfection process should not be ignored, especially when changing the product variety, the contact parts of the vacuum capping machine should be cleaned to prevent cross contamination of the sour and hot taste of pickled Chinese cabbage and fish sauce and the clear and sweet taste of watermelon sauce.

The vacuum capping technology of pickled Chinese cabbage fish sauce and watermelon sauce has both generality and individuality. Reasonable selection of vacuum capping machine and optimization of operating parameters can extend the shelf life of two types of sauces, maintain their original flavor, and reduce losses during transportation and storage. For seasoning enterprises, investing in a vacuum capping machine with strong adaptability and high control accuracy is an important measure to enhance product competitiveness and ensure food safety.