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Fruit juice production process
Fruit and vegetable juice contains all kinds of nutrients that human body needs, especially the content of vitamin C is more abundant. It can prevent arteriosclerosis, anti-aging, and increase the immunity of the body. Fruit and vegetable juice is a popular drink. The common fruit and vegetable juices are orange juice, pineapple juice, grape juice, apple juice, guava juice and carrot juice.
Natural fruit juice (original juice) drink, fruit juice drink or fruit juice drink with pulp, the basic principle and process of their production are roughly the same. Fruit juice production process mainly includes fruit raw material pretreatment, juice extraction, clarification and filtration, homogenization, deoxidization, concentration, ingredient adjustment, packaging and sterilization.
Selection of fruit raw materials
- Fruit raw materials should have good flavor and aroma, stable color and moderate acidity. In the process of processing and storage, they still maintain these excellent qualities and have no obvious adverse changes.
- The fruit juice is rich and easy to take, and the extraction rate of juice is high.
- The fruit is fresh and not rotten.
Fruit juice extraction
- The purpose of crushing is to increase the yield of the juice.
- Pretreatment before squeezing: Heating or adding pectinase.
- The method of juice extraction varies according to the structure of the fruit, the existence part of the fruit juice, the nature of the tissue and the quality requirement of the finished product.
Most fruit juices are contained in the whole fruit, which can be crushed and pressed directly. Fruits with thick skins (Citrus and pomegranates, etc.), extracting the juice one by one or firstly removing the peel. The yield of fruit juice depends on the quality, variety, maturity and freshness of the fruit, the processing season, the method of squeezing and the efficiency of the juice.
Clarification of fruit juice
- Natural clarification.
- Gelatin tannin clarification.
- Enzymatic clarification.
- Frozen clarification.
- Heating condensation clarification (Simple and effective).
Homogenization and degassing of fruit juice
Homogenization is special requirements of cloudy juice production, used for glass bottle packaging products, tinplate products rarely used. Frozen preserved fruit juice and concentrated juice do not have to be homogeneous.
There is a large amount of oxygen in the juice, which will destroy vitamin c in the juice. The reaction of oxygen to various components in fruit juice makes the aroma and color worse, will cause internal corrosion of tinplate. It is more obvious at the time of heating. The method of vacuum degassing and nitrogen exchange are often used.
The adjustment and mixing of sugar and acid in fruit juice
Adding a proper amount of sugar and edible acid (citric acid or malic acid) into the fresh juice.
- Determination and adjustment of sugar degree.
- Determination and adjustment of acid content.
Concentration of fruit juice
- Vacuum concentration method.
- Freeze concentration method.
- Reverse osmosis concentration method.
- Aromatics recovery.
Sterilization and packaging of fruit juice
- The selection principle of sterilization process is to kill the microorganism and reduce the effect on the quality of the product as much as possible.
- The most commonly used method is high temperature and short time.
- High temperature filling (hot filling) and low temperature filling (cold filling). Carbonated beverages generally use low temperature filling. The fruit drinks, except for the paper containers, are almost filled with hot filling.]
Typical fruit and vegetable juice production process
Washing and sorting, apple juice extraction, apple juice clarification, concentration and sterilization, apple juice filling and packing.
Fruit elevator, fruit sorter, brush type citrus cleaning, fruit bubble washing machine, pineapple peeling and squeezing, fruit pulping.
Sorting and washing equipment, essential oil extraction machine, peeling and squeezing machine, refining machine, filling machine.
Washing, sorting, peeling, destoning, pulping, filtration, degassing, homogenization, concentration, sterilization and packaging.
Frozen concentrated sweet orange juice
The difference of processing technology between concentrated juice and pure juice is that flesh pulp of concentrated juice must be as few as possible. Otherwise, it can not only reduce the concentration efficiency, but also cause the phenomenon of coking and so on.
Hawthorn pectin content is rich, so it can not be processed by the method of crushing and extracting juice. The technologies used at present are hot soaking and enzymatic treatment.
The process of production of juices and concentrates
We'll describe this production process for apple juice. In Poland, every year, there are tones of apples from plantations. Their vast portion is exported and the remaining part is sold unprocessed or it is used as a raw material for producing juice and concentrates.
I. Acceptance of raw material
The production process of fruit juice and concentrates begins with raw material purchasing. Fruit is verified in terms of quality before unloading. It should look healthy and be ripe. There are two unloading methods: wet (known as hydro-unloading) and dry. Both methods are used for unloading and transporting apples to silos of pre-production warehouse. B&P Engineering delivers and installs both types of unloading system at the customer's site.
Hydro-unloading system consists of:
- automatically controlled water cannon used for rinsing fruit from a car
- operator's rooms with control and pneumatic cabinet for system operation
- bucket conveyor for vertical transport of raw material and separating water
- floatable chute with draining devices which accepts raw material from bucket conveyor and the flap system directs it to respective silos
The delivery scope of dry unloading system includes:
- hydraulic tipper for vehicles. Raw material is unloaded from a car through lifting the front part of the platform and emptying fruit to the hopper
- operator's cabin
- spiral sorter - separates impurities such as: leaves, branches, sand and stones
- diagonal belt conveyor - takes raw material from the hopper
- unloading belt conveyor - located above silos, directs the accepted raw material to respective storage chambers
Apples should be stored in small prisms. The producer aims at the fastest processing of the raw material received in order to prevent putrefactive processes and quality deterioration.
Fruits are washed depending on the unloading method applied: in two or in three stages
- during hydro-transport from silos
- through water spraying in front of the vertical elevator which transports fruits to the inspection belt
- at the end of the inspection belt of tables through the system of spray nozzles
Fruits taken from silos by a sorting unit are transferred to the pulp preparation section. Another stage of juice production starts: fruit pulp preparation and processing.
II. Fruit pulp preparation and processing
Raw materials from pre-production warehouse are transferred to the dosing units (known as sorting units). The task of the sorting unit is to dose apples evenly to the vertical screw feeder (known as elevator). Sorting units have designs individually adjusted to the capacity of elevator and floatable chutes.
Apples transported by a feeder made of acidproof materials and plastics suitable for use with food are transferred to the inspection belt or roller table Trained employees carry out inspection and reject raw material which does not satisfy the requirements.
Sorted material falls down to the mill. Replaceable or adjustable mill elements, such as: knives, sieves, pressing rollers enable adjusting to the quality of raw material and obtaining optimal pulp parameters.
A cutting line is controlled by the system automated with visualisation and operated from a touch panel on the control cabinet.
During pulp milling with the use of a membrane pump, enzyme preparations are added which aid the effectiveness of the pressing process.
In technologically justified cases, fruit pulp from the mill is directed to B&P Engineering pulp pipe heater. Pulp flows in the internal module pipe and it is heated by hot water to a set temperature.
Then, fruit pulp is pumped to pulp tanks and it will be taken to the next step in the production of juice and concentrates.
III. Juice yielding.
A correctly performed pressing stage guarantees maximum yield of juice from raw material.
An extrusion process starts with pre-filling. Pulp is pumped to a closed cylinder, filling up the pressure chamber space. It is a fully automated process owing to the self-optimising press control system, which determines the level of product extrusion at each process stage.
After completing the press filling-up cycle, pressing takes place. Piston presses the pulp and juice flows out through filtering elements to both juice chambers encased in the resistance board and press-down board. Then, the piston retracts, while the cylinder is rotating, thus, the entire pulp is carefully loosened. This phase is repeated in cycles and each piston feed is a few millimetres longer than the previous one.
Constant cylinder rotation during pressing cycles and expanding ensures the most advantageous loosening of the pulp pressed, thus guaranteeing maximum pressing efficiency.
IPS 10000 press enables extraction in one operating cycle through their watering and additional pressing. Pressing cycle is completed. Coat is opened and pressing pomace are discharged. Pressing pomace reach a screw feeder which transports them to their storage site.
Closed system guarantees the process hygiene without juice losses as well as a simple and automated washing process. Juice pressed in the press flows down to intermediate tanks.
IV. Pasteurisation and dearomatisation
Unclarified juice from presses is directed from intermediate tanks to the section of pasteurisation and aroma recovery in evaporation station.
Pasteurisation takes place in the temperature from 95-105°C and it is to inactivate enzymes, obtain juice microbiological stabilisation, starch gelatinisation and protein denaturation.
At the same time, aromatic substances are evaporated in the dearomatization process. One to two hundredfold aroma concentrate is obtained.
Evaporation station ensures high process efficiency, rapid evaporation and low steam consumption. Automatic controlling with visualisation enables the operator to control the parameters of pasteurised juice on a current basis. Pasteurised juice is pumped to depectinisation tanks.
Depectinisation process is carried out in acid-proof tanks made by B&P Engineering which are equipped with stirrers.
Tanks have perfect dimensions, ensuring correct dosing of enzymatic preparations through the station preparing fining agents.
Fining agent preparation station consists of four tanks. Two tanks are used for preparing bentonite solution and the third one for sol. The fourth tank is designed for mixing and heating gelatin solution. In order to dose the agent, it is enough to set the dose, specify water amount and choose a process tank.
Fining agent preparation station is a fully automated and compact device with visualisation system. Control system guarantees precise dosing of fining agents and limitation of losses.
After dosing the solution, a feeding line is rinsed and fining agent preparation station is automatically switched off. All the data are archived in compliance with the production control requirements, including but not limited to HACCP system. Depectinisation process is finished with pumping of unclarified juice to the batch tank from which is then taken to Ultrafiltration System.
Ultrafiltration stage starts with pumping of unclarified juice from depectinisation tanks to the batch tank. B&P Engineering ultrafiltration system is a fully automated Cross-Flow filtration device.
Depectinised unclarified juice reaches the batch tank and a high-efficiency centrifugal pump pumps juice with high velocity through membrane modules. A thin top layer is formed on the surface of membranes and some liquid penetrates through membrane channel as a ready product to the permeate tank. Retentate is condensed to obtain maximum concentration. Then it may undergo diafiltration to obtain extraction. After ultrafiltration process, juice is fed to fined juice tanks and it is taken again to evaporation station in order to condense it.
The heart of the line for producing fruit concentrates is multi-staged evaporation station with a dropping juice film used for condensing apple juice and soft fruit (coloured).
During the entire juice production process, raw material reaches the evaporation station twice:
- for the first time, as unclarified juice before ultrafiltration process in order to be pasteurised and dearomatised
- for the second time, as fined juice in order to be subjected to processes of initial and final condensation, inter-stage filtration and product cooling
Condensing process consists in feeding fined juice to the heating columns which flows down as a dropping film. Hot steam heats the column from the outside, reaches a boiling point and evaporating point of liquid which is released to the next condensation level.
Vapours are directed to the separator and used for further heating. The product goes through subsequent evaporation stages to obtain an appropriate concentration degree.
Modern and intuitive interface ensures simple and safe operating; it selects parameters in a fully automated manner for production cycles.
Juice condensed in the evaporation station is cooled down and pumped in pipelines to the equalisation tank and after standardisation to storage tanks.
VII. Standardisation and Storage
Concentrate condensed in the evaporation station is cooled down to the temperature of approx 5-8°C and transported to the warehouse.
Modern warehouses have a complete pipeline installation and controls which enable information archiving. The operating status of devices and respective systems in the room are visualised on the touch panel, thus enabling the supervision and control of the system from one place.
Before transferring the concentrate to storage tanks, standardisation takes place. It is an important stage which enables controlling concentrate quality and parameters. Laboratory tests the extraction, acidity, NTU and colour on the basis of intermediate tank sample.
Concentrates are distributed and dispatched from the warehouse through equalisation tanks. It allows for complete control over the quality and repeatability of load batches. Therefore, there are no product losses, it is easier to maintain cleanliness and tank truck filling takes less time.
VIII. Washing equipment and piping in production line
CIP (clean in place) station is used for washing installations, devices and pipelines in the production line in CIP system.
In the production process of juice and concentrates, washing station ensures cleanliness and hygiene in process tanks and storage tanks as well as in pipelines transporting raw material in pipelayers.
Washing products are prepared in the station in the form of working solutions and pumped to the device or installation which is to be cleaned. Then, they circulate in a closed circuit between CIP station and a given device within the time which ensures thorough cleaning at a set temperature. Washing temperature and solution concentration undergoes ongoing verification and automatic adjustment.
A washing procedure consists of the following phases:
- recovery of the products remains from the technological system,
- pre-rinsing of superficial staining,
- washing with the use of cleaning agents (acid washing and alkali washing),
- rinsing with clean water,
- optional disinfection
Closed circuit washing allows for cleaning agent economy and reduction of sewage discharged. Working solutions are prepared in the CIP station in the concentrations recommended by the manufacturer and in adequate temperatures. Solutions are retained in three tanks insulated with a double coat and fed by a pump as needed.
In the case of citrus, this is easily done with a hand presser or a revolving citrus 'rose', Figure 1. Other fruits such as mango, guava, soursop, etc require pulping - that is, after peeling and stone removal, the flesh of the fruit is pushed through a perforated metal plate. For this process, there is a range of equipment available from the small 'Mouli Legume' and several versions of hand-powered pulper/sieves, all of which force the fruit pulp down through interchangeable metal strainers, Figures 2 and 3.
At slightly higher production levels, it is necessary to use a power source, and the multi-purpose Kenwood Chef food mixer, is strongly recommended. This has a pulping attachment rather similar to the Mouli Legume and in addition can be used for liquidising etc. For large-scale production, an industrial pulper-sieving machine is necessary. This also acts by forcing the fruit pulp through a fine cylindrical mesh. These cost, however, upwards of £2,500.
When the juice or pulp has been collected, it is necessary to prepare the batch according to the chosen recipe. This is very much a matter of choice and judgement, and must be done carefully to suit local tastes. Juices are sold either pure or sweetened. Fruit squashes would normally contain about 25% fruit material mixed with a sugar syrup to give a final sugar concentration of about 40%. These are diluted with water prior to use and as the bottle is opened, partly used and then stored, the addition of a preservative is necessary (for example 800ppm sodium benzoate). Cordials are simply crystal clear squashes.
Another range of products that has proved popular is fruit nectars which are consumed on a 'one shot' basis. Essentially, these consist of a 30% mix of fruit pulp and sugar syrup so as to give a final sugar level of about 12-14%. All fruits contain sugar, usually around 8-10%, with variations not only from fruit to fruit but also in the same fruit grown in different parts of the world. The addition of sugar to give the recommended levels must take into account the sugar already in the juice. However, the amount of sugar added in practice is finally decided by what the purchasers actually want.
In all cases, sugar syrups should be filtered through muslin cloth prior to mixing to remove particles of dirt which are always present.
All the products mentioned above need to be pasteurised at 80-95°C for 1-10 minutes prior to filling hot*. At the simplest level, this may be carried out in a stainless steel, enamelled or aluminium saucepan over a gas flame, but this can result in localised overheating at the base of the pan, with consequent flavour changes. To avoid the use of large expensive, stainless steel pans, a large aluminium pan can be used to boil sugar syrup. A given amount of the syrup is then mixed with fruit juice in a small stainless steel pan and this increases the temperature to 60-70°C. The juice/syrup mixture is then quickly heated to pasteurising temperature. The next industrial jump in pasteurisation is, unfortunately, expensive in that it involves the purchase of a double-jacketed steam kettle in stainless steel and a small boiler. The total cost is likely to be in the region of £5-10,000.
ITDG had some success with the development of a low-cost continuous pasteuriser that would, at about £300, fall in between the saucepan and the steam kettle. Further information is given in Appropriate Technology Journal 12,7. 1985.
Filling & bottling
In all cases, the products should be hot-filled. A stainless steel bucket, drilled to accept a small outlet tap, has proved to be a very successful filler. Output can be doubled quite simply by fitting a second tap on the other side of the bucket. This system has been used to produce 500-600 bottles of fruit juice per day in the West Indies. After filling hot, the bottles are capped and laid on their sides to cool prior to labelling.
- Care is needed when producing pineapple juice due to a heat resistant enzyme in the juice. The enzyme damages skin after prolonged contact and workers should therefore wear gloves to protect their hands. The juice must be heated to a higher temperature for a longer time to destroy the enzyme (eg boiling for 20 minutes).
As in all food processing enterprises it is necessary to ensure that the fruit products are correctly formulated and priced to meet the customer's requirements, and that production costs are minimised to ensure that a profit is made. The quality of each day's production should be monitored and controlled to ensure that every bottle of juice has the correct keeping and drinking qualities. In particular the following points should be observed:
• Only fresh, fully ripe fruit should be used; mouldy or insect damaged fruit should be thrown away. All unwanted parts (dirt, skins, stones etc) should be removed.
• All equipment, surfaces and floors should be thoroughly cleaned after each day's production.
• Water quality is critical, if in doubt use boiled water or add one tablespoon of bleach to each gallon of water to sterilise it. If water is cloudy, a water filter should be used.
• Pay particular attention to the quality of re-usable bottles, check for cracks, chips etc and wash thoroughly before using. Always use new caps or lids.
•The concentration of preservative should be carefully controlled for correct preservation of squashes and cordials, and may be subject to local laws. Check first and use accurate scales to measure the preservative.
• The temperature and time of heating are critical for achieving both the correct shelf life of the drink and retaining a good colour and flavour. A thermometer and clock are therefore needed.
• The correct weight should be filled into the bottles each time.
Pomegranates getting washed prior to processing in an Afghanistan fruit concentrate factory.
Juice is prepared by mechanically squeezing or macerating (sometimes referred to as cold pressed) fruit or vegetable flesh without the application of heat or solvents. For example, orange juice is the liquid extract of the fruit of the orange tree, and tomato juice is the liquid that results from pressing the fruit of the tomato plant. Juice may be prepared in the home from fresh fruit and vegetables using a variety of hand or electric juicers. Many commercial juices are filtered to remove fiber or pulp, but high-pulp fresh orange juice is a popular beverage. Additives are put in some juices, such as sugar and artificial flavours (in some fruit juice-based beverages); savoury seasonings (e.g., in Clamato or Caesar tomato juice drinks). Common methods for preservation and processing of fruit juices include canning, pasteurization, concentrating, freezing, evaporation and spray drying.
Although processing methods vary between juices, the general processing method of juices includes:
- Washing and sorting food source
- Juice extraction
- Straining, filtration and clarification
- Blending pasteurization
- Filling, sealing and sterilization
- Cooling, labeling and packing
After the fruits are picked and washed, the juice is extracted by one of two automated methods. In the first method, two metal cups with sharp metal tubes on the bottom cup come together, removing the peel and forcing the flesh of the fruit through the metal tube. The juice of the fruit, then escapes through small holes in the tube. The peels can then be used further, and are washed to remove oils, which are reclaimed later for usage. The second method requires the fruits to be cut in half before being subjected to reamers, which extract the juice.
After the juice is filtered, it may be concentrated in evaporators, which reduce the size of juice by a factor of 5, making it easier to transport and increasing its expiration date. Juices are concentrated by heating under a vacuum to remove water, and then cooling to around 13 degrees Celsius. About two thirds of the water in a juice is removed. The juice is then later reconstituted, in which the concentrate is mixed with water and other factors to return any lost flavor from the concentrating process. Juices can also be sold in a concentrated state, in which the consumer adds water to the concentrated juice as preparation.
Juices are then pasteurized and filled into containers, often while still hot. If the juice is poured into a container while hot, it is cooled as quickly as possible. Packages that cannot stand heat require sterile conditions for filling. Chemicals such as hydrogen peroxide can be used to sterilize containers. Plants can make anywhere from 1 to 20 tonnes a day.
A variety of packaged juices in a supermarket.
High intensity pulsed electric fields are being used as an alternative to heat pasteurization in fruit juices. Heat treatments sometimes fail to make a quality, microbiological stable product. However, it was found that processing with high intensity pulsed electric fields (PEF) can be applied to fruit juices to provide a shelf-stable and safe product. In addition, it was found that pulsed electric fields provide a fresh-like and high nutrition value product. Pulsed electric field processing is a type of nonthermal method for food preservation.
Pulsed electric fields use short pulses of electricity to inactivate microbes. In addition, the use of PEF results in minimal detrimental effects on the quality of the food. Pulse electric fields kill microorganisms and provide better maintenance of the original colour, flavour, and nutritional value of the food as compared to heat treatments. This method of preservation works by placing two electrodes between liquid juices then applying high voltage pulses for microseconds to milliseconds. The high voltage pulses are of intensity in the range of 10 to 80 kV/cm.
Processing time of the juice is calculated by multiplying the number of pulses with the effective pulse duration. The high voltage of the pulses produce an electric field that results in microbial inactivation that may be present in the juice. The PEF temperatures are below that of the temperatures used in thermal processing. After the high voltage treatment, the juice is aseptically packaged and refrigerated. Juice is also able to transfer electricity due to the presence of several ions from the processing. When the electric field is applied to the juice, electric currents are then able to flow into the liquid juice and transferred around due to the charged molecules in the juice. Therefore, pulsed electric fields are able to inactivate microorganisms, extend shelf life, and reduce enzymatic activity of the juice while maintaining similar quality as the original, fresh pressed juice
Manufacturing Fruit Juice, Direct Juice And Vegetable Juice
Economical production of fruit juice, direct juice and vegetable juice is characterised by more than just outstanding juice quality. It is just as important to achieve a high raw material yield with the lowest possible complexity for operation, maintenance and servicing of the centrifuges, belt presses and lines used.
The following advantages result from using Flottweg decanters, separators and belt presses in the manufacture of fruit juice, direct juice and vegetable juice:
- Achieving a high yield of fruit juice, vegetable juice and direct juice by optimum juice extraction
- Cost reduction in the entire beverage manufacturing process
- Improvement in juice quality
- Reduction in the settleable solid content
- Optimum clarification of the fruit juices, vegetable juices and direct juices
- Efficient processing of fruit, fruit pulp and vegetables
Outstanding Juice Quality By Having The Right Centrifuge Or Belt Press
For excellent juice quality, Flottweg supplies complete processing lines and machines for juice manufacture:
- Belt press lines with pomace extraction for increasing yield
- Decanter for separating off the solids from the pulp or juice
- Separators for clarifying beverages and extracted juices
Flottweg belt presses, separators and decanters for fruit and vegetable processing have proven themselves as outstanding machines for flexible application in juice manufacture.
Flottweg - Your Strong Partner For Juice Manufacture
When it comes to healthy beverages, fruit and vegetable juices are the first choice. To enable the juices to have a healthy effect and achieve their full flavour, it is recommended for the vegetables and the fruits to be pressed and processed carefully. Flottweg has many years of experience in the beverage industry and thus offers numerous advantages:
- Decanters, separators, belt presses and lines specifically adapted to the beverage industry
- Many years of experience and relevant expertise in the use of centrifuges and belt presses in juice manufacture
- A high standard of hygiene and the best product quality through consistent use of stainless steel - Made in Germany
- Robust durability and a long service life of the machines
- Clear design, easy access, simple cleaning, operation and maintenance