Juice production. General concepts.
Industry fruit juice - it is a relatively young industry. juice production in large industrial scale began with 1940-ies., when the first evaporator was developed in the US apparatus for the concentration of citrus juice. As a result of stricter hygiene standards, the shelf life of the product increased, the main condition for the growth of manufacturing companies.
Today, the markets of China, India and Eastern Europe continue to expand on Western Europe and North America there is a fierce competition. increasing the volume of products becomes a niche in these saturated markets of developed tropical fruits, and the so-called premium juices (NFC - not from concentrate = not outconcentrate) and purees, organic juices and juices containing secondary plant metabolites (substances of plant metabolism products). If you take a look you in the beverage department supermarket, you will find a huge variety of fruit and vegetable juices. AT Indeed, no other sector of the food industry does not differ so high
the degree of product diversification.
Healthy food is the motto of the present time. This explains the popularity of superfruits, like acai, goji, malgipiya, cranberries, cranberries and sea buckthorn.
Juices of these fruits produce not only because they are a sign of «lifystyle - style Life ", but mainly due to their nutritional value. High content antioxidants, which is attributed to the preventive effect of anti-cancer, and, in addition to others, health improvement, it all makes more consumers access these fashionable products.
These innovative products are setting new requirements for the juice industry, which to date high yield from the raw material is absolutely priority.
Now more and more attention is paid to the machines, which can be easily cleaned (CIP CIP cleaning); management process which takes place in a sealed condition at maximum hygiene; corresponding processing technologies, precluding effect of oxygen on the product to reduce oxidation; as well as relevant extremely fast and at the same time sparing the extraction of juice. GEA Westfalia
Separator delivers tailor-made technological projects and system line solutions for the above and many other tasks. centrifugal separation technology It is the core of cost-effective production of high quality juice. it provides optimal primary clarification before filtration with minimal loss of juice.
Centrifuges Westfalia Separator® hydry® hyvol® and provide the necessary concept that meets the all requirements depending on whether to receive a high yield from raw materials needed or maximize throughput. Wesfalia Separator®frupex® method shows
the possibility of combining gentle mode of production and maximum efficiency.
Fig. 1 separator,
2. Fruits and vegetables as raw material
The following is a description of processing of these natural products:
Pome fruits (apples, pears, quince, etc.)
Stone fruit (cherry, plum, peach, apricot, etc.)
Berries (currants, gooseberries, strawberries, raspberries, blackberries, blueberries, etc.)
Tropical fruits (pineapple, mango, banana, pomegranate, etc.)
Vegetables (carrots, red beet, radish, horseradish, celery, etc.)
Fig. 2 shows grapes in a cut.
It can be clearly divided into three separate areas:
And the land with seeds and grains
Peel berries primarily performs protective functions and usually includes
a minor amount of valuable juice. In red grapes, this tissue contains tannins and
anthocyanins. Recent encapsulated pigment such as bags incorporated in
cell membrane. The cells, in turn, are very small and have a stable cell wall. There
virtually no intercellular voids. Although the properties and composition of the starting materials and products,
derived from them, can vary considerably, anatomy and physiology of the fruit of the highest
similar edible plants. Key relationships
between them they will be illustrated by the example of the grape and apple.
Mesocarp (pulp), which accounts for the largest proportion of fruit consisting of many
large cells (which are a thousand times larger skin cells) contain virtually all of the typical
and the necessary components to us. Liquid vacuoles fruits and vegetables contains dissolved sugar
acid and salts thereof. The cell walls of fruit pulp is very thin, and some of them have already
are destroyed in the process of maturation.
In this form intercellular cavities, which in addition to the liquid contains a lot of air.
Even slight mechanical action is usually enough for the destruction of
The third important area contains the seeds and pits. The last is very hard and usually contain
a large amount of tannins, so the processing should be avoided
Thin cell tissue structure is shown by the example of an apple (Fig. 3). Every cell in the force
its morphology in contact with 14-th adjacent cell from which it is separated by a median
partition consisting mostly of pure poligalakturovoy acids (pectin).
The primary wall, is responsible for the stability and the elasticity of the middle abuts the
Mikrovolokontsa cellulose ensure cell stability are enclosed in a pectin,
various proteins and hemicellulose structure. These hydrocolloid education form
bulk amorphous structure, facilitating the flow of the process of metabolism (metabolism)
in a cage.
The structure of the vine:
1 Ekzokarpy (peel) 2 loculi (cell cavity)
Partition 3 4 mesocarp (pulp)
6 peripheral vascular bundle
7 endosperm, testa 8, 9 embryo (embryo)
10 ovular (seed), 11 ventral, dorsal 2
The base of the stalk 13, 14 core (brush)
If the fruit contain large amounts of pectin (for example, black currants, and
Some grape varieties), then they are very much related to the water, making it difficult to extract
fluid from vacuoles. For the profitable production of juice, usually the most profitable
use of enzymes to break down pektinov.Dlya extracting juice from fruits and vegetables
cell wall to be broken, at least in one place. In practice, it is usually
is achieved by a combination of enzymatic and mechanical impact, and for some
products - and even further by using heat. Heating the pulp making
cell membranes more permeable to the juice. In this process, some lectins
are hydrolysed under the influence of heat.
From a technological point of view, the actual extraction of the juice after the destruction of the cells
It represents the separation of solids and liquids
a liquid phase and the pulp or juice and pomace.
If the phase separation occurs in the presses, the operating principle is the difference
pressure. Juice finds a way through the mass of the insoluble components of the fruit (pulp).
The decanter uses the principle of separation by centrifugal force, which
divide the liquid and solids based on the difference of their densities.
Depending on the pretreatment of fruit and phase separation technique
the juice will contain a certain amount of solids. these particles
the solid components are of colloidal size to large or, in other words, from less
one micron to several millimeters. These particles are mainly
fragments of cell walls, mainly skin and therefore contain a large
pectin, cellulose, minerals, proteins, lipids and tannins. So in kind
apple juice, they may also include the reaction products formed from
disrupted cell walls during grinding. In the subsequent processing some or
even all components are removed.
2.2 Determination of raw materials
2.2.1 Fruit and vegetable juices
Only healthy, not fermented fruits and vegetables are suitable for human consumption, with sufficient
maturity, can be used for fruit and vegetable juices and products
(Semi-finished products) produced on their basis. In addition to fresh feed may also be used
refrigerated products to increase their shelf life. Pre-from raw materials can not be
removing any components important for the production of juice.
In Europe, special regulations apply (AIJN Code of Practice), defining the characteristics
Such standards exist, for example, for the following products:
Apple and pear juice (pome fruit)
Apricot juice and sour cherry (stone fruit)
Juice from a black currant and raspberry (berries)
Orange, grapefruit and lemon juice (citrus fruits)
Pineapple and mango juice (tropical fruits)
For the production of vegetable juice can be used:
Root vegetables (carrots, beets dining room red, radish, horseradish, celery, etc.)
Perennial plants (rhubarb, asparagus)
The tubers (potatoes)
Leafy vegetables and flowers (spinach, cauliflower)
The fruits (tomatoes, peppers, cucumbers, pumpkins) and legumes (peas)
Taking into account the production is dominated by carrot and tomato juice. In the production of juice
medicinal plants often use similar technology, and for this reason is also here
should include valerian and nettle. To complete the issue should be noted that
Beverage may also be made from the grain mash treated in various ways.
3. Manufacture of fruit and berry
3.1 production of apple juice by centrifugal separation and dynamic technology
Fig. 4 shows the use of centrifugal separation techniques in various stages
Processing of the apple to the finished product. Currently quantitatively dominates
concentrate transparent, but with a "naturally cloudy" juice production Concentration
or without (Single Strength) recently gaining recognition.
Decanters have been used for decades to produce juice from the fruit, as well as for
increasing the concentration of the pulp or retentate. Polishing to a high gloss after juice extraction and
pasting is performed with the help of self-cleaning separators. ultrafiltration through
ceramic membrane provides the required transparency of the juice.
3.1.1 grinding apples before extracting the juice
The first important technological step in the production of apple juice is grinding
apples. For presses desirable (technologically required) are sized pieces
size of up to 5 8 mm, and for decanters from the 3 5 to mm. Mechanical disruption of cellular tissue
increases their spatial separation and provides contained in the interaction
fruit enzymes liquid vacuoles. Immediately starts the process of uncontrolled
oxidation and destruction of pectin and form a solid reaction slurry.
whole apples grinding system must meet the following requirements:
A sealed system, which should increase the amount of air to exclude excess of
which is already contained in the intercellular space. This will significantly reduce
foaming and consumption of ascorbic acid.
The narrow range of particle size distribution, depending on the degree of ripeness. If
apples particles are too large, it will lead to lower yield of the product; and if they
is too small, it will increase the amount of colloidal particles that complicate phase
The most commonly used high-speed wiping machine or hammer
mills fulfill these requirements to some extent. Fig. 5 shows a system specifically designed according to the requirements mentioned above. Eccentric screw
pump with forced loading of the filled raw material hopper located in front of it,
provide preliminary crushing of apples and their subsequent feeding in Macerator,
proximity within a sealed system; Macerator
It has a removable grid and the cutting head. The number of inserts in the macerators may
be different. This allows you to customize, depending on the state
fruits. Ripe apples should be cut into larger pieces, thus insufficiently
ripe fruit requires a more intensive process grinding.
Bunker on the eccentric screw pump should maintain the capacity for
decanter at a constant level. If necessary it is loaded through a metal detector,
and filling is controlled by sensors min. / max. level. Thus, there is no need
Bridges in the buffer tank to the ground mass in a short interval before the operation phase
separation. The further processing after grinding, the mass depends on the production goals.
The following are possible options:
Direct extraction of juice without collecting or storage, generally, in the production of juices (Single
The introduction of enzymes into the cooled mash
The introduction of enzymes into the pulp heated (approx. To 45 ° C)
In practice, these embodiments involve the addition of ascorbic acid to prevent
3.1.2 production "naturally cloudy" apple juice (Single Strength)
Apple juice with "naturally cloudy" is gaining popularity due to
their image of natural and healthy product. In Germany, from the 20 25 percent to total
apple juice consumed in the form of apple juice with a "naturally cloudy".
Consumers expect that will continue even distribution of pulp in the juice with
"Naturally cloudy", in other words, it should not sag. A number of physical variables
responsible for the stability of suspended particles that determine the haze:
The density of the particles
The viscosity of the liquid phase
The charge of the particles
Fig. 6 compares the particle size distribution of the juice obtained after
decanter and the press. The juice from the decanter 60 percent of the particles have a size below 1 microns, then
While in press juice from all such particles 20 percent.
A key factor in the production of juice from "natural turbidity" is the speed
processing. Pasteurization should be carried out immediately after the extraction of juice to
apples to inactivate the natural enzymes.
Fig. 7 shows the change in the particle size by the action introduced pectolytic
Damaged capsules hydrocolloid particles in the agglomerates leads to the formation of these
particles. This leads to the juice clarification. The same reaction is caused by its own enzymes
fruit contained in the juice when it is left for curing.
For the production of juice with high pulp after conventional milling process
you need to perform ultra-fine grinding. For this purpose various systems.
The following results were obtained in the solution of this problem with the help of the decanter GCE
535 Westfalia Separator®varipond® the device in combination with a toothed colloid mill
The whole process from crushing the apples until the apple juice with a high content of pulp,
performed under sealed conditions, in the ideal case it should only take several minutes.
Studies in College Vadensvil in Switzerland have shown that apple flavor
It begins to grow immediately after grinding. First, it enhanced flavor, and after
some time begins to lose a note of fresh apple.
It is not possible to link such a reaction and the subjective perception of a specific chemical
compound. These results suggest that the most intense and best flavor
It achieved in ten minutes after grinding apples. In the future, these processes should be
stopped by pasteurisation by heating.
The contents of a stable slurry pulp is higher than in conventional compression technology. With another
hand, the viscosity value is typically in the range of up to 1,5 2,5 cSt.
If it is necessary to receive the juice with exceptionally high viscosity exceeding 3 cSt., Should
heat the mass to a temperature of up to 45 50 ° C. Juices light tone with a stable and unevenly
distributed in most pulp require administration in weight of ascorbic acid and
centrifugation, with the exception of weight and no aging
exposure to air, which implies a maximum ingress excluded from the process. AT
some cases, be filled with an inert gas processing line.
The forecast slurry stability juice in bottles
It is possible to predict the change in turbidity of juice with a simple test.
Changes in turbidity as compared to the level that occurs just after
extracting juice due to precipitation of large particles and subsequent structural
Stability turbidity changes when tested by centrifugation. Stability
Turbidity (% T) can be represented as the turbidity of the liquid phase after centrifugation (Tz) the ratio
respect juice turbidity before centrifugation (T) in percent.
The test is based on the correspondence between the turbidity of the liquid phase after centrifugation and juice
turbidity juice stored in the bottle for a year.
We use the following expression:
% T = Tz / That * 100
T0 = juice turbidity after shaking the sample, measured in units of turbidity (TE / F).
Tz = turbidity after centrifugation of the liquid phase (15 minutes at 4200 g in TE / F units).
% T = turbidity Stability = ratio of liquid phase to the turbidity of the initial sample turbidity
juice after shaking.
Fig. 10 shows data of turbidity and suspension stability of two samples of apple juice
to compare methods of production, using a press and decanter.
Fig. 10 turbidity and stable suspension of the two samples of apple juice to compare methods
juice production using the press and dekanteraTest based on the correspondence between
turbid liquid phase after centrifugation turbidity juice and juice stored in the bottle
during the year.
We use the following expression:
These data show that about half of the original amount of solid in both methods
particle remains in a stable suspension, but the juice obtained in the decanter, is three times
Turbidity high intensity compared with the juice obtained in the press.