Analysis of Tomato Puree

PURPOSE: The aim of this experiment is to analyse the different types of tomato paste with respect to their quality and making a comparison of found result with usual TSE standards.

THEORY: Tomatoe puree was made by concentration the strained liquid pulp of good quality tomatoes. The raw tomato is converted into double concentrate and triple concentrate.

During incoming of tomato, the below parameters should be checked;

Uniformity of color, presence of under or over ripe fruit, presence of mold growth and insect infectation, presence of excessive dirt, presence of incorrect variety of fruit.

 Simply the tomatoe processing can be indicated as in below diagram;

                                               Raw material


                                               Dry sorting






                                   Seed and Peel Separation

                                            Pulp Refining


                                            Juice             Paste

The following discussion applies to the production of tomato paste; however, most factors also apply to diced tomatoes.

(A) Tomato Product Quality that not only meets the user’s specifications, but is consistent from container to container.

(1) Higher quality fresh tomatoes;
(2) Faster and gentler handling of fresh tomatoes from field to hot-break tank;
(3) Good hot-break temperatures followed by lower evaporation and sterilization process temperatures;
(4) Faster movement of product through the process, decreasing the time product is exposed to elevated temperatures, and;
(5) Maximum blending of fresh tomato loads and product through a dedicated process line to equalize the naturally varying quality of incoming fresh tomatoes.

(B) Tomato Product Price that provides a competitive edge in favor of the user.

(C) A Tomato Product Supplier intently responsive to the user’s need for:

(1) prompt, accurate invoicing and shipping service;
(2) sound technical support service for product issues;
(3) quick, authoritative decisions on issues impacting the business relationship;
(4) knowledge of technologies and industry forces impacting their business and the structure of the tomato industry, and;
(5) personnel and ownership intent on maintaining themselves at the forefront of tomato processing–as innovators and true professionals.

(A) Tomato Paste Quality.

The best quality is that which consistently meets the customer’s specifications. However, most customers’ specifications have acceptable parameters rather than absolute targets. For example, viscosity may be specified as 5 to 7 cm. Bostwick, instead of 6 cm. This is due primarily to historical technological limitations, as well as the relative acceptance of product variability by the consumer. However, if such technology and ability were available to the producer, a specific or narrower range of targets would be advantageous in most users’ manufacturing environments. Furthermore, with a narrow range of targets, manufacturing would benefit from using tomato paste that is consistent from container to container during the daily manufacturing process, be it a 5.2 cm. or a 6.5 cm. Bostwick specification.

Aside from individual user’s unique specifications for particular finished products, “high quality” tomato paste is considered to have high color, nutrient retention and serum viscosity (assuming “hot-break” paste), plus low mold and defect levels.

How is the level and consistency of quality achieved by the tomato paste producer?
All manufacturers of tomato paste have similar processes; however, each is unique in the type of equipment utilized and manner in which the equipment is combined to form a “process.” A more consistent and higher level of tomato paste quality will be produced with:

(1) Most critical tomato paste quality attributes are inherent in the fresh tomato. The tomato paste manufacturing process can only be designed and operated with the objective of not deteriorating the natural quality of the fresh tomato–the process can not improve quality attributes not present in the fresh tomato. Therefore, it is critical that “high quality” be present in the fresh tomato in order to obtain “high quality” in the tomato paste.

(2) Assuming a given level of quality in the fresh tomatoes, shorter time and gentler methods of handling, from the growers’ fields to initial processing, will result in a minimum of deterioration of the fresh tomato’s quality. The standard method in the industry is to detour loads of tomatoes to a grading station somewhere between the fields and the facilities, increasing distance and delays. At Morning Star, as well as about 50% of the facilities, tomatoes are hauled directly from the fields to our facility where the weighing and grading of tomatoes takes place by State supervised inspectors, saving precious time.

When tomato loads are weighed and graded, the information is entered into our computer, and a special program operates to blend loads by assigning an unloading order for each load based on its potential viscosity and mold level. Tomatoes are unloaded in a covered shed, elevated over twenty feet above grade, and transferred by gravity between wash systems, eliminating severe handling, which is inherent in processes using elevators. This unloading and handling system is unique to the Morning Star facilities.

(3) The specific impact the tomato paste manufacturing process has on the color and viscosity of tomato paste is in the quantity of heat units applied to the product. This is a combined function of time and temperature. Shorter holding times and lower evaporation and sterilization process temperatures (beyond the initial high temperature “hot-break” stage), result in higher quality tomato paste.

The process times and temperatures in each facility should be compared. Most new facilities have installed four-effect (utilizing steam energy input four times), four or five stage evaporators. We have installed triple-effect evaporators to accomplish ninety percent (90%) of the evaporation task and double-effect finishing evaporators for the balance. The advantages of lower temperatures, less maintenance, and higher operating efficiency with triple and double effect evaporators considerably outweighs any steam energy savings. Morning Star has steam injection sterilizing and standard flash cooling. This sterilization process is very efficient in achieving a rapid increase to sterilization temperature and an immediate decrease in temperature upon achieving sterilization in the flash cooler. Low fill temperatures arrest chemical degradation of the product once packaged.

4) Fast movement of product through the process to minimize the residence time of product at elevated temperatures is achieved by: (a) high and continuous product flow rates, plus (b) a minimum of product “tankage.” One should review facilities for simplicity of design and process, characterized by low energy and low labor input per unit of production as an indication of the amount of work required by the process. This translates into high and continuous flow rates due to fewer breakdowns and complications.

The best measure of residence time is the throughput rate relative to the total tankage in the facility.
(5) A thorough blending of tomato loads from the fields and through the process is absolutely critical in the production of tomato paste that is consistent from container to container! Consistent quality ingredients are required for a using manufacturer to produce consistent quality finished products with minimal formulation changes, resulting in lower costs.

The viscosity (as well as other quality attributes), inherent in each load of fresh tomatoes, varies widely. This is due not only to the many different varieties grown, but to the irregularities within a variety resulting from variable growing conditions. From 20 to 40 different varieties are purchased by a given processor, in a given year, from over 160 commercially grown varieties in California today. Normal variation in the viscosity potential of fresh tomatoes from load to load is one to two centimeters Bostwick.

(One load of fresh tomatoes will produce approximately 8,700 pounds of 31% NTSS tomato paste. Therefore, over five loads of tomatoes are necessary to fill an order for a truck load and 17 tomato loads for a railcar of finished tomato paste. Unloading eight to 20 loads per hour, a truck load of tomato paste is produced every twelve to 35 minutes and a railcar in 0.7 to two hours. Blending throughout the system will result in excellent consistency of quality from container to container. The higher the throughput capacity, the less each fresh tomato load impacts the variability of finished product quality. If one load is high viscosity and the next low viscosity, the production process has enough capacity for blending and the result is higher consistency of the finished product.

Care is required in evaluating process flow lines as an indication of the potential for production consistency, since a few “large” facilities actually consist of a number of smaller process lines, giving a false indication of process flow rates and capacities–appearing high when they are, in fact, quite low.

As one studies tomato paste manufacturing processes, an understanding of the variations and differences between each manufacturing system will be realized. In order to rigorously evaluate the potential of a manufacturer to produce a high quality tomato paste, a number of issues must be analyzed. These issues should include the incentives present for the selection of tomato varieties, tomato handling techniques, and process characteristics such as flow pattern, temperatures, tankage, and rate of throughput.


         For the determination of the quality of the tomato puree, we applied following analysis.

  1. Testing for Black Points: 1 gram of paste was placed between two glasses and pressed. Thus a thin film can be seen through the glass and the black points were counted.

  2. Determination of Sugar Content: this was done by Lane and Eynon’s method

  3. Determination of Color: this was assessed by means of the Lovibon Tintometer.

  4. Determination of Total Solid in Tomato Paste: the total solid was measured in Refractometer by direct measurement.

Determination of Acidity: a 1: 3 dilution was prepared and filtered. Then, 10 ml of filtrate was mixed with 50ml of water and 1 ml of phenolphtalein and this was titrated with 0,1 N NaOH.

  1. Determination of Salt: 10 grams of puree was weighed and it was warmed slightly after addition of 90 ml of water. Then it was cooled and mixed, filtered respectively. To the 50 ml of this filtrate, we added 5% potassium chromate and titrated with 0,05N silver nitrate solution.



No of blac.

Sugar cont.



Salt cont.


A1   (tat)







A2   (öncü)















A5 (demk)






A6 (home)






A7 (demk)












DISCUSSION: In this experiment we tried to analyse some chemical properties of different types of tomato psree types in order to make a comparison with TSE results.

The results of TSE are given in laboratory book. From this table we can make a comparison such that;

From the point of black point, all groups have found suitable values (max.2/g)

From the point of hunter value (a/b) all groups have found suitable values (min.1,8)

From the point of

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