Tomato (Solanum lycopersicum) Production
Tomato (Solanum lycopersicum), flowering plant of the nightshade family (Solanaceae), cultivated extensively for its edible fruits. Labelled as a vegetable for nutritional purposes, tomatoes are a good source of vitamin C and the phytochemical lycopene. The fruits are commonly eaten raw in salads, served as a cooked vegetable, used as an ingredient of various prepared dishes, and pickled. Additionally, a large percentage of the world’s tomato crop is used for processing; products include canned tomatoes, tomato juice, ketchup, puree, paste, and “sun-dried” tomatoes or dehydrated pulp. https://www.britannica.com/plant/tomato
Deep ploughing is recommended which is to be followed by cross cultivation with cultivator. The land needs to be levelled before transplanting of the tomato Land preparation is the first step before planting tomatoes. Almost all tomatoes are planted on raised beds in some countries.
This facilitates cultivation and irrigation of the tomato crop, as well as improving drainage, which minimizes root diseases. Land preparation consists of proper grading (particularly if furrow irrigation is used), subsoiling to break up compacted layers, listing, and final bed preparation. Tomato beds are most often 60 or 66 inches wide.
Listing is often a critical step, as straight rows allow precision planting and close cultivation. Land preparation is often done in the fall if a spring planting is planned, as wet spring weather may prevent the use of heavy equipment needed for land preparation.
Fallow bed herbicide treatments are sometimes used to prevent winter weed growth, and allow early spring tomato planting. Soils should be prepared early by incorporating organic matter and cover crops well before the planting season.
If a cover crop is in place, it should be turned in at least 3 weeks before transplanting. For more on this see the section (VI) on primary tillage in the tillage basics article. In areas where wind protection is needed, a cover crop (especially rye, wheat, oats, or hairy vetch) can be strip-tilled to provide standing cover crop strips to buffer wind around recent transplants.
Soil Testing within Organic Systems and Organic Soil Fertility. Cover crops play a vital role at Perry winkle Farm. They improve soil quality, provide nutrients, prevent erosion, moderate soil temperatures, conserve moisture, and help control insect, weed, and disease problems.
This tomato crop benefits from a thick layer of mulch grown in place as a rye cover crop from fall to early spring. They do not import straw mulch from off-farm for fear of weed seeds. http://tomatocultivation.com/Tomato-Crop-Land-Preparation.html
Climatic and Soil requirements
Tomato is a warm season crop that is sensitive to frost. An average daily mean of 20 to 24 C is optimum for growth, yield and fruit quality. Fruit set and quality are poor at temperatures below 12 and 35 C. Hot, dry winds cause excessive flower drop while continuous moist, rainy weather conditions result in the occurrence and spread of foliar diseases. It is therefore recommended that tomatoes be grown in dry areas under irrigation. Soils should be rich in organic matter and plant nutrients, with a Ph value of 6 to 7. It has been discovered that tomato, when grown in well-managed sandy loams and heavy clay loams free of hardpan gives a good result but best results are obtained in deep, well-drained loams. The soil should be rich in organic matter and plant nutrients, with a pH value of 6 to 7.
Soil testing and seed:
This involves testing for the soil if it has the nutrient availability need by the crop. There are several seed companies in Nigeria where quality and hybrid tomato seeds can be bought which are:
- The Seed Project Company Ltd a private company in Kano established in 2005.
- Genesis Seed Ltd . The following varieties of tomato are available: Shani, tamar, ella, lola, alegra, deli, betty, perla, sarina, esterina, cuore di bue, marmand, yellow perfection, Burbank,
- Maina Seeds Ltd. sells improved tomato seed to farmers such as UC82B and Romavf,
There are about 7500 tomato varieties worldwide. The varieties of tomato can be local or hybrids which varies from one region to another. The hybrid tomato varieties in south-western part of Nigeria include DT97/162A(R), DT97/215A, Tropical, Roma VF, UC82B etc. The hybrid tomato varieties in Northern part of Nigeria include Lindo, Jaguar, Roma Savana VF, etc. The hybrid tomato varieties in Eastern Nigeria part of Nigeria include Lindo, Jaguar, Roma Savana VF, etc.
Seedlings should be raised in beds 1 – 1.5m wide, and as long as necessary (about 10m). for good seedling emergence and establishment, nemagon 20 should be applied to control soil nematodes. It should be put into the soil at 7g/m2 and the granules incorporated into the seed bed to a depth of 15 – 20 cm. Farenox may also be used at 3 -4 in 1,100 litres of water per ha-1 at 2weekly intervals. For most varieties, double row of 45 x 60 cm spacing is recommended.
Nutrient deficiency symptoms:
Nitrogen deficiency: leaves are light green lower, lower leaves turn yellow and dry up veins become deep purple; stems are hard and purple, flower buds turn yellow and drop
Phosphorus deficiency: leaves are olive green: foliage is sparse; plants are stunted; stalks are slender and may show necrotic areas in extreme cases. Fruit ripens unevenly and lacks solidity
Potassium deficiency: lower leaves become yellowish or greyish-green along margins and at tips, followed by necrosis, dead areas turn brown giving the lower part of the plant a bronzed appearance.
wherever possible, farm yard manure should be used up to 25 tonnes/ha. The recommended fertilizer programmes for tomato are shown below
Methods and time of application:
Nursery- the compound fertilizer 15-15-15 or any alternative should be applied to the seedbed at the rate of 25kg. the fertilizer should be worked into the soil and seed bed gently consolidated. The surface should be raked to leave a fine tilth. If poor growth of seedlings is observed, there may be need for addition of nitrogen fertilizer.
Field- the recommendations are summarized in the table below. Application of combination of farm yard manure and inorganic fertilizers is recommended during land preparation.
Weed control- apply metribuzin (sencor) at the rate of 1.5 – 2.0 kg per hectare at the time of transplanting. Mixtures of metri buzin with diphenamid, metolachlor or alachlor without supplementary hoe – weeding.
Chemical control- Apply fungicides sprays of very low volume (VLV). Although lines with resistance to septaria have been identified of which T420 has been the most outstanding
Farmers obtain about 6t/ha of fresh tomatoes. Under improved management, yields up to 30t/ha are obtainable under irrigation, while up to 15t/ha are obtained under rain fed conditions.
Cultural practices- successful production of tomato involves both nursery and field management. The seeds are usually sown in the nursery and later transplanted into the field to facilitate a good field establishment. Both the wet and dry season productions are feasible provided irrigation water is not limiting in the dry season which produces the best crop due to limited pests and disease infestation
Harvesting and Post-harvest handling
Tomato is a perishable crop and as a result has a short shelf life of about 48 hours under tropical conditions owing to it high moisture content. Specialised postharvest handling practices and treatment methods are needed in order to extend the shelf life of the crop after harvest. Failure to adhere to these specialised handling practices and treatment methods will result in high amount of loss. Losses of up to 50% can be recorded in tomatoes between the harvesting and consumption stages of the distribution chain in tropical countries.
Care must be taken during harvest of tomato fruits in order to attain the best quality as the physiological maturity of any fruit at harvest has an important effect on post-harvest quality of that fruit. Harvesting of fruits should be done in either early or late hours of the day to avoid excessive field heat generation and to reduce losses in tomato production. The inability of producers to follow these simple but vital harvesting procedures coupled with some inefficiencies (like lack of ready market and processing facilities) in the entire value chain may explain the reasons why there are lots of losses in tomatoes harvested at fully ripened state in most developing countries.
Precooling after Harvest
Field heat is usually high and undesirable at harvesting stage of tomato fruits and should be removed as quickly as possible before any postharvest handling activity. Excessive field heat gives rise to an undesirable increase in metabolic activity, therefore, immediate cooling after harvest is important. Precooling minimizes the effect of microbial activity, metabolic activity, respiration rate, and ethylene production, whilst reducing the ripening rate, water loss, and decay, thereby preserving quality and extending shelf life of harvested tomatoes. The suitable temperature ranges of about 13–20∘C for tomato handling can be attained either in the early hours of the morning or late in the evening. Harvested fruit must be precooled to remove excessive field heat if harvested at times other than the recommended periods. A cheap but effective way of precooling harvested tomatoes for producers of developing countries can be by dipping fruits in cold water (hydro cooling) mixed with disinfectants such as Thiabendazole and sodium hypochlorite if availability of clean water is not a challenge. This method is effective in removing field heat whilst reducing microbial loads on the harvested fruits.
Cleaning or Disinfecting.
Proper hygiene is a major concern that must be considered during handling of vegetables like tomato, not only because of its postharvest diseases, but also because of incidence of food-borne illnesses that can be transmitted to consumers. Unfortunately, cleaning or disinfecting tomatoes after harvest is not a common practice for most tomatoes handlers in developing countries especially those from Africa. This practice may be attributed to either the unavailability of portable water at the production sites or the sheer ignorance of the practice.
However, in places where water is not a constraint, post-harvest and food borne diseases in fruits and vegetables can be reduced by the use of disinfectants in water either for washing or for cooling. The use of various disinfectants during postharvest treatment of tomatoes is well documented. For instance, sodium hypochlorite solution has been used to sterilize tomato fruits in order to reduce the incidence of fungal infection before any postharvest treatment was applied. Dipping of tomato fruits in thiabendazole solution reduced the microbial load on the fruits. Fruits and vegetables are usually treated with chlorinated water after washing to reduce the microbial load prior to packaging.
Sorting and Grading.
One of the most important processes in packaging and marketing of fruit and vegetables is sorting and grading. Sorting is the removal of rotten, damaged, or diseased fruits from the healthy and clean ones. The damaged or diseased fruits can produce ethylene in substantial amounts which can affect the adjacent fruits.
Grading: It is also a process of categorising tomato fruits on the basis of colour, size, stage of maturity, or degree of ripening. The two processes are vital in maintaining postharvest shelf life and quality of harvested tomatoes. Sorting limits the spread of infectious microorganisms from bad fruits to other healthy fruits during postharvest handling of tomatoes. Grading also helps handlers to categorise fruits and vegetables in a given common parameter which enables easy handling.
For instance, grading on the basis of colour or maturity stage will help eliminate overripe fruits which will easily produce ethylene to hasten the ripening process in the whole batch. Commercial tomato producers normally use sophisticated systems that require precise sorting and grading standards for their produce. Small-scale producers and retailers in developing countries in contrast may not use written down grading and sorting standards; however, the produce must still be sorted and sized to some degree before selling or processing it.
Packaging is also one of the important aspects to consider in addressing postharvest losses in fruits and vegetables. It is enclosing food produce or product to protect it from mechanical injuries, tampering, and contamination from physical, chemical, and biological sources. Packaging as a postharvest handling practice in tomato production is essential in putting the produce into sizeable portions for easy handling. However, using unsuitable packaging can cause fruit damage resulting in losses. Some common packaging materials used in most developing countries include wooden crates, cardboard boxes, woven palmbaskets, plastic crates, nylon sacks, jute sacks, and polythene bags.
Most of the above mentioned packaging materials do not give all the protection needed by the commodity. Whilst the majority of these packaging materials like the nylon sacks do not allow good aeration within the packaged commodity causing a build-up of heat due to respiration, others like the woven basket have rough surfaces and edges which cause mechanical injuries to the produce. The wooden crate and the woven palm basket are some of the common packaging materials used in many developing countries especially those in Africa for packaging tomatoes. The major shortcoming of the wooden crate is in its height which creates a lot of compressive forces on fruits located at the base of the crate. These undesirable compressive forces cause internal injuries which finally result in reduced postharvest quality of the tomatoes.
Tomato has very high moisture content and therefore is very difficult to store at ambient temperatures for a long time. Meanwhile, storage in the value chain is usually required to ensure uninterrupted supply of raw materials for processors. Storage extends the length of the processing season and helps provide continuity of product supply throughout the seasons.
For short-term storage (up to a week), tomato fruits can be stored at ambient conditions if there is enough ventilation to reduce the accumulation of heat from respiration. For longer-term storage, ripe tomatoes can be stored at temperatures of about 10–15∘C and 85–95% relative humidity. At these temperatures, both ripening and chilling injuries are reduced to the minimal levels. These conditions are also difficult to obtain in most tropical countries and therefore losses of appreciable quantities of harvested tomatoes have been reported.
This is consistent with the claim that the quality of tomato is compromised when exposed to high temperatures and high relative humidity. Very low temperature storage too is detrimental to the shelf life and quality of many tropical fruits like tomatoes. For instance, refrigerating a tomato will reduce its flavour, a quality trait of tomatoes which is largely determined by the total soluble solids (TSS) and pH of the fruit. An understanding of the correct temperature management during storage of tomatoes is vital in extending the shelf life of the fruit whilst maintaining fruit qualities.
In most developing countries, the production sites for many tomato producers are far from the marketing centres and also inaccessible by road. Transporting harvested tomatoes to the market on such bad road network and the lack of proper transportation like refrigerated vans become a big challenge for both producers and distributors.
During transportation, the produce should be immobilized by proper packaging and stacking to avoid excessive movement or vibration. Vibration and impact during transportation as a result of undulations on roads are one of the major causes of postharvest losses to most fruits and vegetables especially tomatoes.
The bad nature of road networks in most developing countries therefore provides these unfavourable factors during transportation resulting in great losses. The wobbling nature of most of the vehicles coupled with the bad nature of roads causes a lot of mechanical damage to the produce before it reaches its destination. Handlers from developed countries on the other hand use refrigerated containers and trailers which travel on reasonably good roads. Transporting tomatoes in refrigerated trucks is not only convenient, but also effective in preserving the quality of fruits. However, both the initial investment and the operation costs of these vehicles are very high and beyond the affordable reach of most producers in developing countries.
Even though handlers from developing countries may not have the capacity to use refrigerated trucks, they should be well educated on the consequences that any other transportation option they use may have on their produce.
Tomatoes Exports by Country
Global sales from tomatoes exports by country in 2016 amounted to US$8.4 billion. Overall, the value of tomatoes exports were up by an average 3.7% for all exporting countries since 2012 when tomatoes shipments were valued at $8.1 billion.
Year over year, the dollar value for exported tomatoes appreciated by 5.8% from 2015 to 2016.
Among continents, European countries raked in the highest number of dollars for tomatoes exports during 2016 with shipments amounting to $3.9 billion or 46.5% of the global tomatoes total. North American exporters were responsible for 33.7% while Asian suppliers came in at 11.6%. A smaller percentage, 7.6% of overall exported tomatoes originated from Africa.
The 4-digit Harmonized Tariff System code prefix for tomatoes is 0702.
Tomato Exporting Companies
Below are large tomato exporting companies that are major players in international trade. Show within parenthesis is the country where the company is headquartered.
Morning Star (United States)
COFCO Group (China)
Xinjiang Chalkis Co. Ltd (China)
California Tomato Export Group (United States)
ConAgra Foods (United States)
Campbell Soup Company (United States)
Fuyuan Agriculture Products Limited (China)
Unilever (United Kingdom)
Heinz (United States)
Conserve Italia (Italy)
Kagome Co., Ltd. (Japan)
Empresas Carozzi (Chile)
Parmalat SpA (Italy)
Xinjiang Tianye Co., Ltd. (China)
Raw material quality
For each of the processes described below the tomatoes should be ripe, red, firm to soft, free of all mould growth (by cutting out infected parts) and free of stems, leaves, dirt and other soils (by washing). It is less important if the tomatoes have surface blemishes or splits/cracks (provided these are not infected) as in most processes they will be cut or pulped.
Traditional methods in hot, dry regions include sun drying. The tomato halves are placed on clean flat surfaces (eg roofs) with the cut side facing up or by threading the halves on to strings and hanging in the sun from a branch or beam. In both cases, drying is relatively rapid (depending on the temperature and humidity of the air) but there may be contamination of the product by insects, dirt and dust, this can be reduced by covering the tomatoes with fine muslin cloth or mosquito netting. The end product is dark, red, leathery pieces with a strong tomato flavour. Re-hydration is relatively slow, but this may be unimportant in cooking applications. Provided that the humidity is low, the dried product will keep without special packaging for several months. If the humidity rises the product will go mouldy and should be protected either by suitable packaging (eg sealed plastic bags – preferably polypropylene or thick polythene, or in sealed pottery jars) or dried slowly
over a fire to a low moisture content. The tomatoes should be far enough away from the fire to prevent cooking they will be fully dried when they are hard and brittle.
If the climate is not hot and dry, an artificial drier could be considered but the cost of the drier and fuel should be carefully calculated to see if it is economic to dry this often low value food.
When tomatoes are dried to a low moisture content, so that they are hard (eg 5% water), they can be pounded or milled to a powder. This is more convenient to use and store (eg sealed glass or pottery jars or sealed polypropylene film bags thin polypropylene – the most common type of plastic will not stop moisture entering the product and subsequent mould growth within a few weeks). Layers of pulp can also be dried to a rubbery fruit leather and stored in plastic film. Alternatively, the post dried pulp can be formed into balls or cubes and then dried in the sun or over a fire.
Tomato pulp can be prepared using a pestle and mortar, some types of mills (eg ‘Posho’ mill in West Africa) or by small pulping machines. It is usually necessary to remove seeds and skins this can be done by sieving through a medium mesh (eg 1-2mm holes) or, in the case of some of the pulpers, these parts are separated by the machine.
Tomato juice can be separated from the pulp by filtering but more commonly the entire pulp is used as ‘juice’. This can be preserved by hot water pasteurising in sealed bottles at 90-100°C for at least 10 minutes followed by cooling to room temperature (Figure 2) or by hot filling into sterile bottles. A certain amount of separation of pulp and liquid during storage is inevitable – with pulp accumulating at the bottom of the bottle. However, clear separation into a pale liquid and a solid pulp layer is evidence of under-pasteurisation. This is not likely to be harmful but is less attractive. Some small-scale producers have found that adding 0.3% thickener (eg sodium alginate) completely prevents separation. This is a permitted additive in most countries but may be expensive and is not really necessary.
Tomato squash is tomato pulp with added sugar syrup to give a concentration of 30-50% total solids (°Brix) measured by refractometer. It is not a widespread product as people tend to prefer squashes made from other fruits but it may well be worth investigating in your own area.
It is processed in a similar way to juice and may in addition contain up to 100ppm of sodium (or potassium) benzoate preservative in most countries (check with your local Bureau of Standards).
Tomatoes can be boiled to evaporate the water. Depending on how much water is removed and what other ingredients are mixed into the pulp, it is possible to obtain a large number of products. Examples are given in Table 1.
Table 1: Products from tomato pulp.
Usually measured by refractometer as °Brix. Figures in brackets are final temperature of boiling at sea level, which is an alternative way of measuring solids content (at higher elevations the boiling point is progressively reduced and separate technical advice is needed if you are above approximately 2000m)
The basic preservation principle behind all of these products is to remove water by boiling to a) heat the product to destroy enzymes and micro-organisms and b) concentrate the product so that contaminating micro-organisms cannot re-grow.
This can be done in an open pan over a fire. It is necessary to heat slowly -especially when the product is more concentrated – to prevent it burning onto the pan. It should also be stirred continuously which is very labour intensive (and hot work). The product will be a dark red paste with a strong taste of tomato.
A better colour and faster process cn be achieved using a steam jacketed boiling pan with steam from a boiler but this is expensive and should only be considered for larger scales of operation. The bright red colour of imported tomato pastes and purées can only be obtained by using vacuum evaporators and at present there is no low-cost small-scale equipment available to our knowledge.
After boiling to the correct solids concentration (usually 65-75° Brix by refractometer or to a temperature of 104-106°C at sea level) the product is filled into pre-sterilised jars (100°C for ten minutes in steam or water) and cooled to room temperature. A selection of typical recipes for each product is given below.
1kg tomato pulp
(pectin and citric acid not usually necessary but 0.1% pectin and adjustment to pH3.3 may be needed).
Green tomato chutney
1kg tomatoes 500g sugar
125g cooking apples 1 level teaspoon salt
500g onions ½ level teaspoon mustard
100g sultanas ¼ level teaspoon pepper
450 ml vinegar 2 level teaspoons curry powder
Peel the tomatoes, chop the apples and onions into small pieces. Mix all the ingredients except the sugar and boil gently until soft. Add the sugar and boil for a further 30 minutes. Pour into jars and tie down.
Tomato ketchup for 1kg
420g tomato puree
300g vinegar (10% acetic acid)
70g onion pulp
30g (garlic puree and other spices to taste)
Tomato soup for 1kg
60g tomato puree
20g spices/garlic puree/onion puree etc to taste
860g water (mix ingredients oil fill into pasteurised jars and pasteurise at 90ºC for 15 minutes.
References and Further Reading
- Semi-processing of Tomatoes, ITDG Technical Brief
- Small-scale Food Processing: A guide to appropriate equipment, P. Fellows & A.
Hampton, IT Publishers/CTA, 1992
- Tomato and Fruit Processing, Preserving and Packaging: An example of a village Factory,
Guus de Klein, CIEPAC/TOOL, 1993
Fresh market tomato requirement
Flavor, color, shape and texture are all important characteristics of fresh tomatoes. Fruit also needs to be clean and clear of blemishes such as decay or disease. They should be of uniform shape, symmetry and size. Tomatoes need to be bright and uniform in color, without green shoulders or immature green spots or blotches.
Uniform colour and shape is important for fresh markets
Uneven ripening is not acceptable for fresh market
Depending upon the relative levels of carotenoid pigments in the fruit, color can range from yellow to orange, pink, red or even white. The specific carotenoid, lycopene provides the fruit with its red color. Higher levels of beta-carotene provide an orange color.
The texture depends upon how tough the skin is, the firmness of the flesh, and the proportion of the locular (gel-like structures) and pericarp tissues. Firmer tomatoes are less prone to damage and have a longer shelf life. Higher levels of calcium in the cell wall will improve fruit firmness and as a result, transportation and storage characteristics. Fresh tomatoes are graded according to their quality characteristics, as table below shows:
Timing of harvest depends upon end market requirements and local practices. Picking can start at the mature-green stage, but practices that harvest before this can result in fruit, once ripened, that has poor color and flavor. Thus, the ‘breaker’ or ‘turning’ stage of fruit development – when color is turning from green to tannish-yellow – is when most fresh fruit is picked, particularly if it is to be shipped considerable distances, e.g. glasshouse production in countries such as the USA, Turkey and Morocco.
Cluster tomatoes are picked when the least mature fruit on the truss begins to show red color. This helps ensure uniformity when the crop reaches the consumer.
Increasing storage temperature and using ethylene can bring ripening forward.
Flavor is generally related to the relative concentrations of sugars and acids in the fruit, mainly fructose and citric acid. The best, most flavorsome combination is a high sugar and high acid content. A normal pH range in tomatoes is 4.0- 4.5 and the lower the pH, the more tart or sour the fruit.
Flavor is normally measured by taste panels who rate the tomato for a range of characteristics including smell, aroma, firmness, juice, mealiness, skin texture, acids and sugars.
In general, smaller, cherry tomatoes have a higher brix ratio and are sweeter than larger round or common tomatoes.
There are a wide range of processed tomato products on the market, from canned tomatoes, juice, soup, sauce, paste, ketchup, pulp to puree.
Color is particularly important for processed tomatoes and fruit need to be of a uniform, strong red, and free of defects such as cracks and bruises. This is measured using a range of methods including spectrophotometry and colorimetry. Processors lay down a strict range of values. Processed crops must ripen evenly and at least 75% of the fruit has to be mature at harvest.
Various countries have different acceptable size ranges for different processed products. In Spain, for example, fruits used for juice usually weigh between 60–100g. For canning as whole tomatoes, fruits are within the 30–60g weight range. When used for canning, fruit must have a thick, firm wall so that they retain their shape when cooked. The peduncle must also be easy to remove from the fruit.
Firmness decreases during fruit maturation. The use of calcium will help minimize breakdown of pectins by holding the pectic matrix together, maintaining the cell wall strength. Firmness is assessed by pressure load or shear press tests. Tomatoes with a Durofel rating of >75 are described as firm, 60-70 are soft, and <60 limp.
Peelability is important for whole or diced processing tomatoes.
Fruit crops with a high TSS content reduce the need for, and costs of, removal of water and disposal of wastewater during processing.
Tomatoes for processing require a minimum °Brix of 4.5. This compares with an acceptable range of 3.5 – 5.5 in fresh tomatoes. The TSS of processed products is measured by refractometry and should follow the ranges on the table next.
The °Brix content of the finished tomato product is largely controlled by the processor and manufacturing process. However, some processors do pay a higher price for higher dry matter tomatoes.
Grading processed tomatoes
Viscosity – which is important in paste products – is related to the level of insoluble solids. It is normally measured using a viscometer or consistometer – with results expressed as Bostwick unit (cm) or centipoises. Acceptable ranges depend on methods and products. In Spain, processors desire a Bostwick reading of 4 – 8 in tomatoes with 12°Brix. Acids – mainly citric and malic acid, determine the flavor of the processed product.
Measurement of acidity is by simple pH assessment with a range of pH 4-5 being typical for tomato. Total acidity, can be measured by chromatography or enzymatic reaction – where 0.35 – 0.40g/100cc juice is required. Alternatively, processors measure total titratable acidity or volatile acidity after distillation.
Acids – mainly citric and malic acid, determine the flavor of the processed product. Measurement of acidity is by simple pH assessment with a range of pH 4-5 being typical for tomato. Total acidity, can be measured by chromatography or enzymatic reaction – where 0.35 – 0.40g/100cc juice is required. Alternatively, processors measure total titratable acidity or volatile acidity after distillation.
Note: This is a selective list of suppliers and does not imply ITDG endorsement.
Pulping machines Food Preservation Systems
FMC Corporation 1604 Old New Windsor Road
P O Box 11178 New Windsor
San Jose Maryland 21776
California 95108 USA
Wet grinding mills Kaps Engineers
Adelphi Manufacturing Company Limited 831 GIDC
Olympus House Makapura
Mill Green Road Vadodara 390 010
Haywards Heath India
Lehman Hardware and Appliances Inc Victorio strainer
P O Box 41 Lehman Hardware and Appliances Inc
4779 Kidron Road P O Box 41
Kidron 4779 Kidron Road
OHI0 44636 Kidron
USA OHI0 44636
Kenwood juicer Steam juicer
Kenwood Limited RRMILL Inc
New Lane 45 West First North
P09 2NH UTAH 84335
Lehman Hardware and Appliances Inc Gebr Rademaker
P O Box 41 P O Box 81
4779 Kidron Road 3640 AB MIJDECHT