Tomato Paste Production

The objective is preservation and density together. Tomatoes are perishable, watery, and arrive in an intense, short harvest window that no fresh market could absorb. Concentrating them into paste converts a crop that would spoil within days into a material that can be stored between seasons, shipped worldwide, and diluted back into sauces, soups, and juices wherever they are made. Paste is, in effect, how a tomato harvest is made to last a year.

Three principles operate in sequence. First, crushed tomatoes are heated, and this is not merely a warming step: it determines what the tomato’s own pectin-degrading enzymes are allowed to do. Heating quickly enough to arrest them preserves pectin and yields a thick, viscous product, while allowing them to act first gives a thinner one — the classic hot-break and cold-break distinction, chosen according to what the customer wants the paste to do. Second, the heated pulp is screened, so skins and seeds are separated from the fluid pulp on the basis of size. Third, the pulp is evaporated under reduced pressure, exploiting the fact that water is volatile while the sugars, acids, pigments, and solids are not.

Two streams leave the plant. The paste is the product the factory exists for. The pomace — the skins and seeds taken off at the screening stage — is a by-product with real outlets, and notably it is the only material stream here that is separated out rather than evaporated away.

Tomato paste

The primary product: concentrated tomato pulp, specified on soluble solids, colour, consistency, and acidity. Traded internationally in bulk and reconstituted into finished foods elsewhere.

Tomato pomace

The skins and seeds removed during screening. A by-product with established uses: livestock feed, a source of oil pressed from the seeds, and a raw material for lycopene and fibre recovery.

The quality of paste is set long before the evaporator. Soluble solids, colour, and acidity arrive with the crop and reflect cultivar, growing conditions, and ripeness at harvest — and because concentration removes water rather than defects, everything that arrives in the fruit is concentrated along with the good. Under-ripe fruit, mould, and field debris do not disappear into the paste; they become more prominent in it. This is why processing-tomato contracts specify incoming fruit so tightly.

What the process itself controls is thermal damage and separation efficiency. Prolonged heating darkens the paste through non-enzymatic browning and degrades the red pigment that buyers judge it on, while screening decides how much usable pulp leaves with the skins. There is also a distinctively seasonal loss point: the crop arrives faster than it can be processed, so fruit waiting to be run is fruit deteriorating, and delivery-to-processing delay is a genuine quality variable rather than a logistical detail.

• Deterioration of harvested fruit waiting to be processed during the peak of a short season
• Non-enzymatic browning and pigment degradation from thermal exposure during evaporation
• Usable pulp carried out with the skins and seeds at screening
• Product retained in evaporator surfaces, pipework, and transfer lines
• Fouling of heating surfaces, which degrades heat transfer and can scorch product

Water and energy both matter here. Tomatoes arrive from the field carrying soil and are washed and flumed in volume, so wash-water and its organic load are the dominant water issue; evaporation then makes the plant energy-intensive for the same thermodynamic reason as any concentration duty, which is why energy recovery between evaporator effects is standard engineering. The pomace stream is substantially valorised into feed, seed oil, and pigment recovery. A further structural point is that the plant runs as a seasonal campaign, so its water, energy, and effluent loads are concentrated into a short annual window rather than spread across the year — which is what shapes the demands it places on local infrastructure.