In the food industry, evaporation plays a major role in production. In fact, through evaporation water can be removed from liquid solutions, whether sugar or salt. In this way, foods with a higher content of active ingredients are produced.

Each vegetable has its own natural percentage of water, which can vary depending on the product. Here are some examples:

1. tomato (and the like): 95 percent
2. apple, peach or apricot: 78-80%
3. grape: 78-80%

The remaining part of soluble solids consists of sugars, acids and salts in different proportions depending on the type of product.

OPTIONS FOR INCREASING CONCENTRATION

Usually the concentration of food solutions can be increased through one of these methods:

1. Reverse osmosis: is a membrane system that allows water to be subtracted by osmotic pressure difference between one side of the membrane and the other;
2. Direct evaporation: takes place at high temperature in a spray dryer chamber;
3. Indirect evaporation: works by vacuum evaporation. This type of evaporator is the flagship of Opportunity’s range of branded designs.

THE ROLE OF EVAPORATORS IN FOOD

As mentioned, what enables evaporation are precisely evaporators, also called concentrators. These machines are used in multiple food applications such as in the production of:

1. fruit juices;

2. musts;

3. jams;

4. sauces;

5. tomato concentrates.

    

In its processes, the wine industry uses evaporators to concentrate must for later use in correcting the potential alcohol content of wines. This occurs through the addition of the sugars necessary for the frothing of sparkling and semi-sparkling wines.

Another use of concentration is marketing in food sectors that value products with 50% fructose in the total volume of sugars.

THE TYPES OF EVAPORATORS

Evaporators, such as the one in the photo, come in different shapes and sizes, depending on the needs of the application. Among the most common types are:

1. film folling evaporators;
2. forced circulation evaporators;
3. also with agitated surface always in the vacuum version and with a variable number of effects, i.e., steam reuse.

INDIRECT EVAPORATION

So let’s talk about indirect evaporation and how it allows the increase in concentration.

In conventional closed systems, when conditions for evaporation are created, usually the pressure in the liquid must be increased. Thus the ebullioscopic point is raised and the evaporative point is reached.

In indirect evaporation, on the other hand, which is present in Opportunity concentrators, exactly the opposite happens. Using vacuum pumps, pressure is removed from the solution, managing to evaporate water, even at temperatures below 100°C.

WHAT ARE THE ADVANTAGES OF INDIRECT EVAPORATION?

The advantages of indirect evaporation are manifested in that the heat exchange between the heating source and the product occurs through an AISI 304/316 stainless steel wall, of which the entire machine is composed. More precisely, this happens through tubes, where inside circulates the product while outside is steam.

An additional advantage of indirect evaporation is that the steam used can be exploited several times within the same plant. Through a hydraulic circuit specially designed to compensate for the pressure differences that exist between one effect and the next, all the condensate produced is conveyed to the final extraction pump. This allows important gains in final yield.

These features allow for greater efficiency and versatility in production, taking full advantage of this state-of-the-art concentration system now made available by Opportunity.