Fruit juice aseptic packaging process

Aseptic packaging technology is a packaging technique for filling and sealing in a sterile environment under the condition that the package, the packaged object and the packaging auxiliary equipment are aseptic.

Aseptic packaging technology enables the packaged products to be free of preservatives. It can be kept for half a year or more without deterioration after being kept at room temperature without deterioration. It also has low energy consumption, less packaging materials, low manufacturing cost and high packaging efficiency. The advantages of good economic efficiency and light weight, as well as the recycling and recycling of waste packaging, are suitable for long-distance transportation.

Aseptic packaging is used more and more widely, from packaging liquids to fluids, semi-fluids and pastes; from general juices to milk, tea, vegetable juices, soups, wines, water, liquids, etc. Here we mainly introduce the aseptic packaging application of juice.

Aseptic packaging of fruit juice is a packaging system in which sterile juices, packaging containers and packaging auxiliary materials are placed in a sterile environment and filled and sealed with an aseptic filling machine. The juice food is sterilized by high temperature and then the temperature is lowered to 20 ° C ~ 30 ° C, which is the sterility requirement.

The process of aseptic packaging of juice can be roughly divided into three parts: pre-work, sterilization and packaging.

1 juice aseptic packaging pre-work

The preliminary work of aseptic packaging of juice includes selecting composite materials, designing brick and carton structure drawings, and decorating the design, and then delivering the packaging materials. The professional factory prints according to the pattern, text and color of the decoration design, according to the structural design. The indentation is cut and finally transported to the packaging factory as web.

1) Select materials

The packaging containers used for aseptic packaging of juices include cups, boxes, bags, barrels, etc. Here, brick-type packaging containers are mainly introduced.

The juice aseptic packaging material mainly uses a composite film composed of six layers of materials, namely polyethylene/paper/polyethylene/aluminum foil/polyethylene/polyethylene composite. The packaging carton made of composite film weighs only 8% of the same volume of glass bottles, which not only has lower cost, but also produces less waste, which is beneficial to environmental protection.

2) Design brick carton

The common brick-shaped aseptic packaging carton on the market has a capacity of 250 ml. The solid line in the structural design diagram indicates the contour cutting line, the broken line indicates the inner folding indentation line, and the dotted line indicates the outer folding indentation line. The packaging material roll delivered to the packaging factory has a diameter of 0.8m, and can produce 250ml brick-shaped aseptic packaging cartons of about 5,000.

3) Decoration design

When designing the decoration, we must first consider the requirements of the product packaging, choose the appropriate style; secondly, consider the correct and appropriate use of the pattern, text and color, follow the principle of “scientific, beautiful, applicable, economic, and promotion”, and strive to design beautiful and have Time sense, decoration and nationality.

At the same time, in order to achieve the above design goals, advanced process technologies such as CAD (Computer Aided Design), CAM (Computer Aided Manufacturing), and professional software such as Flunder-Pack for packaging carton structure design must be used.

4) Printing

Paper containers can be printed using traditional analog printing and new digital printing. Most of the current models still use analog printing.

Among the four conventional printing methods, lithography is most commonly used, and the lithographic version mainly uses the PS plate. Because the PS plate is simple and fast, the plate is light and inexpensive, and with the application of new light sources, new photosensitive materials and new equipment, the quality of plate making is constantly improving. Among them, flexographic printing has also been widely used in packaging printing.

5) Compound

The compounding process is of the utmost importance throughout the process because it plays a decisive role in the packaging function of the entire container. For example, the semi-finished product printed by the paper container Tetra Pak is placed on the composite unwinding frame. After four times of laminating, the aluminum foil (the aluminum foil can prevent ultraviolet light to ensure the quality of the contents) is bonded. The coil portion is wound into a roll shape. The four layers of plastic from Tetra Pak are made from polyethylene, modified polyethylene resin of different thicknesses from outer layer, composite layer, inner layer and inner layer 2, respectively, and extruded by four extruders, about 1300mm wide. The film is bonded to paper and aluminum foil. It is then finished by the professional manufacturer through cutting and indentation, and finally delivered to the packaging factory in a roll.

2 sterilization treatment of aseptic packaging of juice

Fruit juices are made from different fruits and their composition and characteristics vary. The main factors associated with packaging are the acidity, enzymes, vitamin C, color and aroma of the juice. The deterioration of the juice is mainly caused by yeast and mold.

The sterilization process controls the amount of microorganisms in the product through high temperatures. Currently commonly used sterilization methods include high temperature short time (HTST) and ultra high temperature transient (UHT) sterilization. Selection should be based on product characteristics. Improper handling can result in incomplete microbial killing or eclipse, loss of fragrance, and damage to nutrients.

At the same time, the environment of the operation workshop should be sterilized before and after packaging, and the air pressure in the workshop environment should be slightly higher than the external atmospheric pressure to prevent outside air from entering the workshop and reduce the invasion of bacteria and dirt.

The floor, walls, consoles, tools, etc. of the production workshop should also be sterilized regularly. At the same time, the material circulation pipe and the storage should be fully automatic cycle cleaning.

3 juice aseptic packaging process

The juice aseptic packaging process mainly includes the following processes.

1) Filling

Filling is the most important process in the entire packaging process. It consists of a series of processes and is completed on a filling machine for the aseptic filling machine.

1 paper roll loading. Use a special trolley to push the paper roll to the machine and use the automatic paper bar. When the old paper roll runs out, connect the old and new paper rolls without stopping the machine. The paper roll 1 is fed by a motor-driven feed roller 3 which can start or stop the feed roller 3. The tape travels to 4 print production dates and creases the crease.

2 seals. In order to prevent leakage after the back of the aseptic carton is heat-sealed, the heat-sealed portion is further sealed with tape. The specific method is to use a seal applicator to attach half of the 8 mm wide PP tape to the edge of one side of the wrapper, and the other half to the other side edge of the wrapper during the longitudinal seal to obtain a tight and firm seal.

3 sterilization. The wrapper is immersed in a H2O2 (hydrogen peroxide) tank 6 prior to filling and sterilized. The concentration of H2O2 is generally 25% to 30%: increasing the sterilization temperature can accelerate the sterilization of the initial ecological oxygen, preferably 80 °C.

4 dry. A pair of rollers 7 are used to squeeze off the hydrogen peroxide on the wrapper. At the same time, the air curtain 8 is used to spray high-temperature sterile air of 140 ° C to 150 ° C to blow dry the H 2 O 2 which remains on the surface of the wrapping paper after being extruded, and decompose it into harmless water vapor and oxygen, and then the high temperature air It also enhances the sterilization efficiency of new ecological oxygen and kills some of the remaining bacteria.

5 heat sealing and filling. The wrapping paper is formed into a tubular shape by four guide rolls and a former. At this time, the edges of the wrapping paper are overlapped by about 8 mm, and the PE film outside the wrapping paper is continuously heat-sealed at the lap joint by the longitudinal sealing device 10, and will be pre-posted. The PP tape on the inner edge is firmly bonded. At the same time, the juice which has been sterilized and transported from the sterile pipe is injected into the paper tube through the filling tube 9, and the end of the filling tube is always submerged in the juice in order to meet the requirements of aseptic packaging.

6 constant volume, pressure edge, horizontal seal. The device is composed of two pairs of jaws that continuously move up and down. When a pair of jaws are engaged, 250ml of juice is enclosed in the body cavity of the press-formed paper cylinder, and the bottom is horizontally sealed, and the two layers of the inner surface of the wrapping paper are horizontally sealed. The PE film was heat-sealed, and the heat-sealing width was about 16 mm. The width was cut into upper and lower portions by a cutting knife, the upper half was used as the bottom sealing of the previous one, and the other half was used as the top sealing of the latter one. When the jaws are synchronized to the lowermost position with the paper tube, the other pair of jaws are opened and the above work is repeated on the top surface of the preceding pair of jaws. The bottom surfaces of the two jaws are spaced apart from the top surface by a gap of about 0.7 mm. In this way, the vertical sealing into a cylindrical filling, constant volume, and embossing forming - transverse sealing cuts are continuously circulated in the continuous operation of the paper tube, greatly improving the productivity, and can pack 100 to 120 boxes per minute.

7 fold angle. The side corners of the top and bottom of the small package are respectively folded into the side and the bottom surface in the brick folder 14, and are sprayed at four positions of the bottom surface and the side surface by using 160 ° C high-temperature steam, so that the top and bottom sides of the top surface are pasted. Paste the sides of the bottom surface and the bottom surface. In the folder, the bottom of the carton is facing up, and when the folder is unloaded onto the conveyor 15, the top of the product is facing up.

2) Aseptic packaging inspection of juice

Strict inspection measures are also an important guarantee to ensure the smooth implementation of the aseptic cold filling process. The operation requirements of the aseptic filling room are extremely strict and must be carried out in accordance with the operating procedures. During the filling process, the laboratory personnel must perform an online inspection of the aseptic package of juice. Immediately after the filling machine is adjusted, two boxes are inspected every 10 minutes before the pipe is attached, and the molding, sealing and pasting quality and filling capacity are checked. After the operation is normal, two boxes are inspected every 30 minutes, and the contents of the inspection are the same.

3) Sticker pipette

The straw is made for the convenience of consumers. It is made by a professional factory. It is made of polyethylene plastic and has a length of 115mm and a diameter of 4mm. It is pre-packed in two layers of polyethylene plastic film suitable for its length and is sealed side by side. Ready to use. The straw is attached to the diagonal line on the back of the aseptic package and is completed by a dedicated tube applicator.

4) Medium packaging

The corrugated paper tray is made of E-shaped corrugated cardboard, and its size is 395 mm × 193 mm × 110 mm according to the arrangement of the carton. First arrange the products on the tray machine, a total of 3 × 9 = 27 aseptic carton. The packaging unit composed of the tray and the product is then formed on the heat shrink packaging machine using a PVC film to form a shrink wrap.

5) Outer packaging

Stacking the corrugated pallets on the stacking machine on the intermodal flat pallets into 8 layers, the layers are staggered, so that one tray can hold 12×8=96 packages and 2592 aseptic packages. Finally, the film is stretched on a wrap-around stretch packaging machine with a linear low-density polyethylene of 500 mm width, spirally wound from top to bottom, or stretched on a rotary stretch packaging machine with a stretch film of 1 m width. package.