What is Food Concentration?
Foods concentration is method in which water is removed by the from the food by using of heat. Food concentration is a kind of preservation method in which the shelf life food is increases. Food concentration reduces weight and volume and results in immediate economic benefits like increases its shelf life, transportation load and health of the product
Nearly all liquid foods to be dehydrated are concentrated before they are dried as a result of within the early stages of water removal, moisture is additional economically removed in extremely economical evaporators than in dehydration instrumentality.
Further, increased body from concentration usually is required to prevent liquids from running off drying surfaces or to facilitate foaming or puffing. Also, some focused foods are desirable elements of diet in their claim.
for instance concentration of fruit juices and sugar yields jelly. Several focused foods, like frozen fruit juice concentrate and canned soups, are simply recognized as a result of the necessity to feature water before they’re consumed.
The additional common focused foods embody gaseous and sweet ened condensed milks, fruit and vegetable juices and nectars, sugar syrups and seasoned syrups, jams and jellies, fixings.
Many varieties of fruit purees employed by bakers, candy manufacturers, different food makers, and plenty of additional.
Methods of Food Concentration
(i) solar food Concentration
As in food dehydration, one in every of the only ways of evaporating water is with solar power. This was done to derive salt from ocean water from earliest times and continues to be practiced these days within the us in unreal lagoons.
However, star evaporation is incredibly slow and is appropriate just for concentrating salt solutions.
(ii) Open Kettles
Some foods is satisfactorily focused in open kettles that are heated by steam. this is often the case for a few jellies and jams and sure as shooting kinds of soups. However, high temperatures and long concentration times harm most foods.
Additionally, thickening and burn-on of product to the tration method. Kettles and pans are still wide employed in the manufacture of kettle wall bit lower the potency of warmth transfer and slow the concen syrup. However here high heat is fascinating to supply colour from caramel ized sugar and to develop typical flavour.
(iii) Flash Evaporators
Subdividing the food material and transferral it into direct contact with the heating medium will markedly speed concentration. this is often done in flash evaporators. Clean steam superheated at regarding 150°C is injected into food that is pumped-up into an evaporation tube wherever boiling happens.
The boiling mixture then enters a setup vessel within which the focused food is drawn off at the lowest and also the steam and water vapor from the food is exhausted through a separate outlet.
As a result of temperatures are high, foods that lose volatile flavour constituents can yield these to the exiting steam and water vapor. These is separated from the vapour by essence-recovery instrumentality on the idea of various boiling points between the essences and water.
(iv) Thin-Film Evaporators
In thin-film evaporators, food is pumped up into a vertical cylinder that incorporates a rotating part that spreads the food into a skinny layer on the cylinder wall. The cylinder wall of double jacket construction typically is heated by steam.
Water is quickly flashed from the skinny food layer and therefore the focused food is at the same time wiped from the cylinder wall. The concentrated food and water vapour are continuously discharged to an external apparatus, from that product is removed at very cheap and water vapor passes to a con denser.
In some systems the water vapour temperature is raised by mechani cal vapour recompression to yield steam for apply to avoid wasting energy. Product temperature could reach 85°C or higher. However since duration of the con centrating food within the heated cylinder could also be but a minute, heat dam age is minimal .
(v) Vacuum Evaporators
Heat-sensitive foods are most typically concentrated in low-tempera ture vacuum evaporators. Thin-film evaporators frequently global organization or operated under vacuum by connecting a air pump or steam ejector to the condenser.
Even with economical vacuum evaporators wherever water could boil at 30°C or slightly lower, lost with the evaporating water vapour. These volatile essences are often recovered, or “stripped”, from the water vapor and came back to the cool concentrated food.
However, it’s potential to concentrate foods at still lower temperatures and more minimize heat harm and volatile flavour loss; one technique of doing therefore is understood as freeze concentration.
(vi) Freeze food concentration
When a solid or liquid food is frozen, all of its parts don’t freeze quickly. Initial to freeze is a few of the water that forms ice crystals within the mixture. The remaining melting food resolution is now higher in solids concentration.
It is potential, before the complete mixture freezes, to separate the at the start shaped ice crystals. A method of doing this can be to centrifuge the part frozen slush through a fine-mesh screen.
The focus melting food resolution passes through the screen whereas the frozen water crystals are maintaine and may be discard. Repetition this method many times on the concentrated melting food solution will increase its final concentration several-fold.
Freeze concentration has been known for several years and has been applies commercially to fruit crush.
(vii) Ultrafiltration and Reverse Osmosis
Low-temperature separation and concentration processes using perm selective membranes are more and more being employe within the food business.
These applications dependent on for the most part enthusiastic about membrane properties like water permeableness rate, matter and macromolecule rejection rates, and length of helpful membrane life. Completely different membranes are need for various liquid foods.
There are 2 kinds of pressure-driven membrane separation processes:
(a) reverse osmosis/hyperfiltration
Micromolecular solutes are by selection removes, whereas the latter separates out comparatively larger matter molecules or colloids.
Changes during food concentration
Concentration processes that expose food to 100°C or higher tempertures for prolonged periods will cause major changes in organoleptic and organic process properties. Cooked flavours and darkening of colour are 2 of the additional common results.
With most foods the lower the concentration temperature the higher. Since the reconstituted focused food should resemble as closely as doable the natural product. Even at the bottom temperatures. However, concentration will cause different changes that are undesir ready. two such changes involve sugars and proteins.
All sugars have an higher limit of concentration in water on the far side that they’re not soluble. For or instance, at temperature, saccharose is soluble to the extent of regarding two components sugar in one part water.
If water is removes on the far side this concentration level, the sugar crystallizes out. This could end in gritty, sugary jellies or jams. It additionally results in a condition is aware of as “sandiness” in bound milk products. nce milk sugar crystallizes because of overconcentration.
INTERMEDIATE-MOISTURE FOODS (IMF)
Adjustment and management of water activity to preserve semimoist foods has attracted increasing attention. Intermediate-moisture foods or semimoist foods, in one kind or another, are necessary things of diet for a really while.
Generally, they contain moderate levels of wet, of the order of 20 % by weight. hat is a smaller amount than is generally gift in natural fruits and vegetables.
However moisture is left in conventionally dehydration products. additionally, intermediate-moisture foods contain enough dissolves solutes to decrease water activity below that need to support microorganism growth.
As a consequence, intermediate-moisture foods don’t need refrigeration to pre vent microorganism deterioration. There are numerous kinds of intermediate-mois ture foods: natural products like honey; factory-made confectionery products high in sugar, jellies, jams, and workplace things like fruit cakes; and part dried products together with figs, dates etc.
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