Exercise

Practical 31 - Tomato Juice, Paste and Puree

Aim: To prepare products from tomato fruits.

Theory: Commercial products from tomatoes include juice, puree and paste. Processing of tomato is now practiced from home scale level to a large scale enterprise. As a semi finished product, tomato puree is prepared on a small scale while at large scale tomato paste has gained commercial significance. Both puree and paste are used for preparation of different finished products like ketchup, juice, soup etc. The method for preparation of these products are well standardized, however, some modification with respect to recipes are made in the processing plants owing to variation in the quality of the raw material. The method for preparation and recipe of different tomato products are as under:-

Raw material, ingredients and utensils required
  1. Tomatoes.
  2. Stainless steel knives, utensils, juicer, pulper, sterilization tank, glass bottles, corking machine, crown corks, muslin cloth, boiler/gas bhatti, etc.
Procedure for preparation of different products

A. Tomato juice/pulp
Tomato juice is the un-concentrated product consisting of the liquid with a substantial portion of the pulp, expressed from ripe tomatoes with or without the application of heat and addition of salt. The juice should be deep red in colour with a characteristic taste and flavor. The juice shall have about 0.4% acidity expressed as citric acid. Cane sugar (1%) is added to further improve the taste and flavor of the finished product.

Method for preparation of tomato juice
  1. Tomatoes should be washed in plenty of running water. Rotary washers or trough washers fitted with moving conveyer belt are generally employed commercially.
  2. Tomatoes, after trimming are cut into pieces for extraction of pulp through the fruit grater. Tomato pulp can be extracted either by passing through the pulper after crushing without heating (cold pulping) or after boiling the crushed or whole tomatoes till softening followed by extraction of pulp in a pulper (Hot pulping).
  3. Tomato juice/pulp is extracted either by passing the crushed tomatoes through a continuous spiral press.
  4. After extraction, edible common salt (0.4-0.6 %) and sugar (1%) are added to the extracted pulp /juice to improve the taste and flavour of the finished product.
  5. The finished juice is then heated to 82-880C and filled hot in pre-sterilized glass bottles. The bottles are then sealed using crown corks and then sterilized in boiling water (1000 C) for about 25-30 minutes.
  6. After sterilization, the bottles are cooled and stored in a cool dry place. Glass bottles are allowed to air cool.
B. Tomato puree
Tomato puree is prepared from tomato pulp without skin and seeds, with or without salt addition after evaporation/concentration of the juice or pulp to desired total soluble solids.

Method for preparation of tomato puree
  1. The preparation of tomato puree involves grating/crushing, heating to soften the tissue and straining of heated mass through a pulper finisher.
  2. Tomato pulp is prepared from ripened tomatoes is concentrated either by using open cooking method or cooking by using vacuum pan or by using steam jacketed kettle.
  3. Boiling should be done at much lower temperature (710C) to retain the original red colour, flavour with natural vitamin C.
  4. The juice is sterilized and packaged in pre-sterilized glass bottles.
  5. The bottles are crown corked and processed in boiling water for 25-30 minutes.
  6. Tomato puree can also be preserved by adding sodium benzoate (250 ppm benzoic acid).
C. Tomato paste
Method for preparation of tomato paste
Tomato pulp or juice is concentrated to 14-15% soluble solids in open pans followed by concentration in vacuum pans and packing in pre-sterilized bottles while still hot. In large scale processing units, the tomato paste is manufactured by using vacuum evaporators and finally packed either in glass bottles or in bulk aseptic packages. The tomato paste is utilized for manufacture of deferent tomato products like ketchup, soup etc.


31.1

FPO specifications

Product

FPO Specification

Tomato juice
  • It shall be free from pieces of skin, seeds, coarse tissue and extraneous matter.
  • The minimum total soluble solids free of salt shall be 5 % (w/w). 
  • Shall have good flavour of tomato and be free from burnt or any other objectionable flavour.
  • The mould count shall not exceed 30 % of the field examined
  • Harmful poisonous metals in tomato juice shall not be more than 1.0 ppm (lead) 100 ppm (copper on the dried tomato solids basis). 2.0 ppm (arsenic), 250 ppm (tin) and 19.0 ppm (zinc).

Tomato Puree
  • It shall contain minimum of 9 % solids excluding salt.
  • The percentage of TSS required to be declared on the level of the product.
  • Shall have good flavour of tomato and be free from burnt or any other objectionable flavour.
  • Mould count should not be excess of 60% of field count

Tomato Paste
  • Properly prepared and strained tomatoes shall be free from skin and seeds.
  • The finished products shall have good flavour characteristics of the tomato and be free from any other objectionable flavour.
  • It shows no sign of fermentation, when incubated at 370C for seven days.
  • The mould count in the finished product shall not exceed 60% of field examined.
  • It shall contain minimum of 25 % solids excluding salt.

Depending on the degree of concentration, tomato paste can be grouped as:

  • Light tomato paste containing 25-29% of salt free tomatoes.
  • Medium tomato paste containing 29-33% of salt free tomatoes.
  • Heavy tomato paste containing not less than 33% of salt free tomatoes.

Last modified: Friday, 9 March 2012, 9:31 AM