The difference between hot filling and sterile cold filling of PET bottles

Abstract: This paper mainly summarizes the process technology of PET hot filling and aseptic cold filling. On this basis, the process technology of PET hot filling and aseptic cold filling is compared in detail from various aspects such as sterilization, PET bottle requirements, raw materials and production costs.

Key words :PET hot filling aseptic cold filling hot sauce ketchup squeeze sauce bottle

At this stage, in the market, aseptic cold filling has become a hot topic. Compared with PET hot filling, aseptic cold filling has great differences in all aspects of facilities, technology and process. For example, the sterilization mode used in PET hot filling is to keep the material at a higher temperature for a long time, while the material of aseptic cold filling technology is at room temperature, and does not add any preservatives for canning, and does not need to implement follow-up measures to achieve the product shelf life requirements of the filling technology.

1. Overview of PET hot filling and aseptic cold filling technology

The so-called PET hot filling technology is based on the commercialization of heat-resistant PET bottles as a prerequisite, the traditional hot filling is usually divided into two kinds, one is the direct application of high temperature heat for filling, the temperature is controlled between 85 ° C and 95 ° C, and finally about 30 seconds of pouring the bottle for bottle cap sterilization. The other is to fill at medium temperature, and then control the indoor temperature between 65 ° C and 75 ° C, using pasteurization for disinfection. The advantage of PET hot filling technology is that the requirements for the filling environment and the requirements for PET bottle filling facilities are relatively low, and the process technology is relatively simple to operate.

2. Overview of aseptic cold filling technology

Aseptic filling technology has gained a relatively good momentum of development in recent years, and some matching filling facilities are the key to achieve large-scale promotion of aseptic filling. The packaging materials used in the aseptic canning technology of PET bottles can be used in ordinary PET bottles, because they do not need to withstand the pressure of PET bottles generated by the completion of hot filling and cooling. Therefore, when making PET bottles, the weight can be controlled below 30g, making the bottles obtain excellent cost control, and the bottle sample selection is more abundant. The effective control of the packaging cost of the product itself can obtain the core competitiveness for the enterprise in the highly competitive beverage market.

3. Comparison of hot filling and aseptic cold filling technology

Generally speaking, the material in PET hot filling will be maintained in a high temperature environment for a period of time, which can destroy most microorganisms and bacteria, and it also needs to add related preservatives, making the beverage obtain a high safety factor. The heat treatment time of PET hot filling is relatively long, and it will have varying degrees of influence on some nutritional trace elements, taste, color and quality of the beverage. In addition, because of the impact of the production line configuration, if the filling machine fails, during the shutdown period, some materials in the hot filling will have reflux conditions, and these reflux parts will be heated for too long, which will have a greater impact on the batch of drinks.

Aseptic cold filling technology relies on building a good aseptic environment to sterilize materials. Compared with PET hot filling technology, aseptic cold filling material sterilization is the application of UHT ultra-high temperature instant sterilization, the material heating time is very short, generally speaking, the heat treatment time is less than half a minute, less lost nutrients, taste and quality changes little. And because the production environment of aseptic cold filling is a conventional temperature, even if the filling machine fails to stop, the material reflux will not affect the batch of drinks.

The sterilization of packaging materials uses PET hot filling technology, which does not need to be sterilized again for bottles, bottle caps and products, and drinks only need to be retained in a high temperature environment for enough time to achieve the goal of sterilization. Using aseptic cold filling technology, it is not only necessary to sterilize the bottle and the bottle cap separately, but also put forward higher sterilization requirements for the bottle production process. The inside of the bottle is sterilized with acetic acid disinfectant, and the outside of the bottle must also be sterilized. The disinfectants usually include automatic recovery system and concentration measurement system, which can ensure that the disinfectant is within the normal concentration range. After sterilization, the remaining disinfectant should be cleaned with sterile water, and then dry with sterile air after completion, completely eliminate the disinfectant, and finally soak the bottle cap with disinfectant.

4. Comparison of PET bottle requirements

PET hot filling technology and aseptic cold filling technology have great differences in the requirements of PET bottles. Because the PET hot filling process is filled in a high temperature environment, which requires that the PET bottle can carry a high temperature of 85 ° C ~95 ° C, it is necessary to increase the crystallinity of the PET material, and when blowing the bottle, it is necessary to effectively limit the generation of induced stress. The main characteristics of PET bottles are: the bottle wall is thick, and there is a more obvious bottle wall frame to prevent heat contraction; The requirements must have a crystal bottle mouth, etc., and the design of the bottle type is greatly restricted. The aseptic cold filling technology is filled at room temperature conditions, can apply ordinary PET bottles, because it does not need to withstand the stress change of PET bottles caused by hot filling cooling, so it can reduce the weight of the bottle to less than 30g, and can also choose the bottle type more freely.

5. Comparison of raw material and production line costs

There is a great difference between PET hot filling technology and aseptic cold filling technology in production line input cost. The hot filling blowing machine has a slow blowing speed and relatively high power consumption, while the sterile cold filling blowing machine has a faster blowing speed and low power consumption. Under the premise of the same production capacity, the investment of hot filling is significantly higher than that of cold filling blowing machine. However, the process of aseptic cold filling is extremely complex, and the filling auxiliary facilities need to be used are higher. From the overall analysis, the investment in the production line of aseptic filling is much higher than the investment in the hot filling production line. From the level of raw material cost, due to the large difference in the quality gap between the two PET bottles, and because the hot filling has higher requirements for the PET bottle mouth, the raw material cost of aseptic cold filling is lower. Mainly, the quality of the two bottles is very different, saving raw materials to reduce costs, due to the special requirements of hot filling PET bottle mouth, the weight of the two bottle caps is not the same.

In summary, aseptic cold filling technology has a high capital investment in the initial stage of investment, but because the raw material cost and operating cost of aseptic cold filling technology are relatively low, it can recover the higher part of the capital in a short time. With the continuous increase in the use time of production facilities, the low-cost advantage of aseptic cold filling will be amplified indefinitely.

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By comparison, compared with PET hot filling technology, aseptic cold filling has higher requirements for technical processes, but in terms of beverage preservation and nutrition, it has advantages that hot filling technology is difficult to compare, and has broad development prospects in the future market, and with the continuous development of modern filling technology, Aseptic cold filling will inevitably gradually replace PET hot filling technology.