Tomato paste is made by de-seeding and de-skinning the tomatoes and cooking/ concentrating them for several hours. Sometimes it can be sweetened for flavor. It is a thick, dark red concentrate. Tomato paste is made from whole processing tomatoes generally containing between 4.5 to 6.0 percent tomato solids. With regard to solid content, the industry normally refers to TSS (total soluble solids), a measure which excludes all insoluble solids. In accordance with generally accepted market standards, tomato paste must contain at least 14 percent TSS. On average, 6kg of fresh tomatoes are required to make 1 kg of tomato paste at 26 to 28o Brix. Most common tomato paste in is “concentrate” or double concentrate with 26 to 28o Brix, but “concentrate” or triple concentrate with 36 to 38o Brix is also present in the market.

Tomato puree differs from tomato paste in consistency and depth of flavor. Tomato paste is more concentrated and has got a very strong flavor, whereas tomato puree had diluted flavor and is thinner in consistency. Tomato puree contains between 11 and 14 percent TSS, and differs from paste only because of the lower concentration.

Figure 1: Processing Flow-Sheet for Tomato Puree/Paste

This above technology aims at processing and preservation of glut season tomato for use during the off-season. Tomatoes, suitable for the production of tomato concentrate/ paste, are made into pulp in a pulper. The pulp is concentrated to puree (1215OBrix) or paste (25OBrix) in an open steel vessel / a steam kettle.  Sodium benzoate is added as a preservative @ 250 ppm or 0.1% and packed for storage. 

Table 1: Tomato puree and paste at various level of Total soluble solids (TSS %)

Tomato pulp without skin on seeds, with or without added salt and containing not less than 9.0 percent of salt free tomato solids is known as “medium tomato puree”. It can be concentrated further to “heavy tomato puree” which contains not less than 12 percent solids. If this is further concentrated so that it contains not less than 25 percent tomato solids, it is known as tomato paste. On further concentration to 33 percent or more of solids, it is called concentrated tomato paste.

Shelf Life Stability of Tomato Puree/ Paste

Tomato is processed in the forms of pulp, paste, juice, ketchup, puree (Hayes et al 1998). A number of studies have used hedonic measurements to determine the end of shelf life for tomato products. However, many of these studies did not go long enough to find the end of shelf life.

Food processors store tomato pulp under conditions available in their premises. It has been observed that temperatures varying from as high as 20 to 40oC, refrigeration (4 to 10 o C) to as low as 20 o C are employed for storage purpose. High temperature storage is detrimental to product quality while lower temperature adds cost to the product (Jamil, 1990). No significant differences were found between the flavor of tomato concentrates stored for six months at 4°C and those stored at 21°C for the same period

Tomato paste could be stored at varying storage condition for 240 days (8 months) with minimum damage to the product quality at lowest possible cost. It was observed that samples stored at low temperature such as 6o C and 10o C remained acceptable after 240 days’ storage and samples were rejected organleptically at higher temperatures storage at 25 o C (Muhammad et al., 2010). 

Quality problems

• If the tomato paste is too dark, it indicates that it has been overcooked.
• If it is too liquid, the temperature of the hot break is too low.
• A yoghurt taste indicates the presence of lactic acid bacteria, which results from the raw tomato standing for too long before being processed.

All these problems can be overcome with proper technology

Salient Features of Tomato Paste / Puree

• Paste recovery is 14%
• Can be stored up to 6 months in bottles and pouches and up to one year in cans
• Most suited during the market glut, when the process go down.
• Tomatoes can be used during off –season
• Paste is suitable for manufacture of other products from tomato

Due to increasing standards of living in the cities and the rapid urbanization taking place in the rural areas, consumption of tomato based products is expected to go up steadily. Tomatoes and tomato-based foods are considered healthy for the reason that they are low in calories, but possess a remarkable combination of antioxidant micronutrients. A number of tomato products e.g. ketchup, juice, puree, paste, sauce, pickles are items of common use

Marketing of Tomato Paste

Zambia is a major consumer of tomato paste of which only between 20-30 percent is produced domestically; however, 25-50 percent of the input for this domestic paste is imported from China (CBN, 2011). This leaves the market for domestically produced tomato paste underserved. The country has a huge market for tomato paste; the size of the Zambian market for tomato paste is about 200,000 tonnes per annum and this goes up if the West African market is included i.e. the size of the market rise to around 400,000 tonnes per annum.

Consumer will buy more if the price is relatively low but may be willing to pay a higher price if product is of good quality. It is advisable for producers of tomato paste to control sale of the product when tomato is in season but rather intensify production. The ability to produce and stock pile can help to minimize seasonal fluctuation by placing on the market only amount of produce sufficient to maintain a given price. It is therefore important to know ‘when’ and ‘what amount’ to produce and sell at any given time bearing the mind the market price. A producer must have access to information on market and price.

Potential Market for Tomato Paste includes Hotels, Restaurants, Caterers, Supermarkets, School (Boarding houses), Market Wholesalers

It should be noted that marketing of the product should not be limited to one region of the country as the demand for the product is nationwide.