The preparation of Tomato preserve
The principals behind the preparation of tomato preserve are very simple – boiling, sieving and pasteurisation – but become complex and laborious once the quantities of tomato to be processed are elevated. The processing can be divided into 7 phases: selection and grading, cleansing, washing, scalding, sifting or pressing, pasteurisation, canning or packaging, preserving treatment. These passages, obviously different in terms of execution, are essentially the same in both household and industrial production.
Selection and grading
Processing begins with the selection and grading of tomatoes and the elimination of unsuitable fruit and the pedicles.
This is carried out by dipping the tomatoes repeatedly into water filled tubs and rinsing them.
Emerging the tomato in boiling water allows the skin to be peeled off. After scalding the fruit is drained.
Sifting or pressing
Using the appropriate machine which has a cylindrical sieve at one end, the tomatoes are inserted on one side and the squeezed juice and pulp pass through the sieve and fall into containers while from a second opening emerge the seeds and skins.
This is the most delicate phase of the production process and entails boiling the product for a variable period between 15 and 30 minutes. This procedure, in industry, takes place in a vacuum in the “boules” and then are passed to the concentrators.
Canning or packaging
The concentrated product thus obtained is inserted in containers of glass, metal or cartons and then sealed. In domestic production basil and olive oil can be added to keep the preserve from contact with the air. The industrial product is sterilised after packaging, unless this has been done in an aseptic environment.
This treatment allows the containers to be gradually brought to room temperature. Following this treatment the containers can be moved, stored, packaged up and sent to their destinations.