Tomatoes and Tomato Products

Nutritional, Medicinal and Therapeutic Properties

V R Preedy, Ronald R. Watson

• Publisher: CRC Press
• Year: 2008
• eBook ISBN: 9781000737974
• Topic: Medicine
• Subtopic: Nutrition, Dietics & Bariatrics

The contributors to this book are authors of international and national standing, leaders in the field and trendsetters. The book covers emerging fields of science and important discoveries relating to tomatoes and related products. This represents a one-stop shopping of material related to tomatoes. This book will be essential reading for plant sc

PART 1

Characterization and Composition of Tomato Plant and Fruit

1

Tomatoes: Origin, Cultivation Techniques and Germplasm Resources

Derly José Henriques da Silva¹*, Flávia Barbosa Abreu², Fabiano Ricardo Brunele Caliman¹, Adilson Castro Antonio¹ and Vinood B. Patel³

¹Universidade Federal de Viçosa, Departamento de Fitotecnia, Avenue P.H. Rolfs s/n, Viçosa, MG 36571-000, Brazil

²Universidade Federal de Mato Grosso do Sul, Campus de Chapadão do Sul, Caixa Postal 112, Cep: 79560-000, Chapadão do Sul, MS, Brazil

³University of Westminster, School of Biosciences, 115 New Cavendish Street, London, UK

_______________

* Corresponding author

ABSTRACT

The tomato originated from South America and its most widely known scientific name is Lycopersicon esculentum, but it can also be identified as Solanum lycopersicon, as originally classified by Linnaeus in 1753, because of the similarity between tomatoes and potatoes. This fruit contains a variety of micro-components, such as lycopene (an antioxidant), potassium, vitamins (A, C, E and K), sucrose and folic acid.

Among several climatic factors affecting tomato cultivation, the temperature should be emphasized. This is because the rate of liquid assimilation, i.e., efficiency of growth, is observed when the temperature is 18-28°C. In this temperature range optimum tomato production is carried out using appropriate techniques, such as the production of seedlings, soil preparation, application of organic matter, transplanting, planting and coverage, chemical nutrition, staking, pruning and pest control.

Factors such as temperature, relative air humidity, luminosity and genetics can affect the tomato fruit content of organic acids (citric and malic acids), sugars (glucose, fructose and sucrose), solids insoluble in alcohol (proteins, celluloses, pectin and polysaccharides), carotenes, and lipids, among others. Finally, many physiological, phytopathological and entomological disturbances can be resolved by genes that are in germplasm banks.

INTRODUCTION

In legends and stories from pre-Columbian America the tomato was known as a fruit eaten by wolves and werewolves. It was later domesticated in Mexico and introduced in Europe, where initially it was considered a poisonous fruit. The tomato is now acquiring more and more consumers because of its versatility of use, in domestic cooking and in commercial production of processed and packaged soups, sauces and condiments.

The use of tomato in the modern diet is so extensive that it is almost impossible to dissociate it from the menus of fast foods and pizza parlours. Its per capita consumption in fresh and processed form surpasses 20 kg/yr (Jones et al. 1991). The fruit is a source of potassium, vitamin C, folic acid and carotenoids, with lycopene (antioxidant) being predominant. It also contains vitamin E, vitamin K and flavonoids. It has a low calorie content of around 20 kcal/100 g of fruit. Its flavour comes mainly from its sugars (fructose, glucose, sucrose) and organic acids (malic and citric). As the fruit ripens the content of fructose and glucose increases and the content of acids decreases (Jones et al. 1991).

BOTANICS AND ORIGIN

Officially the cultivated tomato belongs to the order Scrophulariales, suborder Solanineae, family Solanaceae, tribe Solaneae, genus Lycopersicon, subgenus Eulycopersicon, species Lycopersicon esculentum (lycopersicon = wolf peach, esculentum = edible).

The following subspecies are recognized:

Lycopersicon esculentum var. esculentum is the main plant of commercial interest, with great variability in form, colour and size of fruits. Lycopersicon esculentum var. cerasiforme is typically known as cherry tomato; the fruits are small, normally with diameters from 2 to 5 cm. Lycopersicon esculentum var. pyriforme has a pear-shaped fruit, with an average length of 4 cm. Lycopersicon esculentum var. grandifolium is known as “potato leaves”; leaves are large with few follicles. Lycopersicon esculentum var. validium plants are erect and compact with very short internodes. At present the scientific name is undergoing evaluation because Linnaeus (1753) was the first author of the scientific name that related the tomatoes to the genus Solanum, which includes the potato (S. tuberosum L.). One year later, Miller (1754) classified the tomato in the genus Lycopersicon. Today, Miller’s classification is still used by the majority of botanists and plant breeders.

However, according to Peralta and Spooner (2000), a minority of authors (Spooner et al. 1993, Bohs and Olmstead 1999, Knapp and Spooner 1999, Olmstead at al. 1999) still name tomatoes Solanum. Supporting this molecular data is DNA from chloroplasts (Spooner et al. 1993, Bohs and Olmstead 1997, 1999, Olmstead and Palmer 1997, Olmstead et al. 1999), which reinforces the close genetic relationships of tomatoes and potatoes, justifying Linnaeus’s original denomination of tomato as Solanum (Peralta and Spooner 2000). The continuation of the name Lycopersicon has been justified by the convenience and stability of the nomenclature. For this reason, Spooner et al. (1993) transferred Lycopersicon to Solanum sect. Lycopersicon and proposed new combinations of names for many of the species of Lycopersicon (Table 1).

As to the origin, the tomato plant has a possible centre of variability along the Pacific coast between the Equator and the north of Chile, including the Galapagos Islands, to an elevation of approximately 2,000 m in the Andes mountain range. However, the domestication and cultivation were carried out by Indian tribes that inhabited Mexico (Giordano and Silva 2000), where the name tomato originated.

Table 1 List of species of the genus Solanum, with the equivalents of species previously designated Lycopersicon.

CLIMATIC DEMANDS AND PLANTING SEASONS

The crop can be grown under different conditions, but the most suitable are high altitudes, with low humidity and high luminosity. In regions with altitudes of 500-900 m, the tomato plant may be cultivated for the whole year. At altitude less than 300 m it is preferably cultivated in the winter and at altitude above 1200 m it is best cultivated in the summer (Fontes and Silva 2002). Among the diverse climatic factors, temperature merits emphasis, because higher net assimilation rate, that is, greater growth efficiency, is observed when the temperature is between 18 and 28°C (Jones et al. 1991).

The temperature requirement of the tomato plant varies with the development of the plant. In the germination phase the ideal temperature is 16-29°C. Close to 5°C or 40°C the germination is inhibited. For plant development the ideal average temperature is 21 to 24°C and for fruit set the optimum temperature is 24°C during the day and 14-17°C at night. With temperatures above 35°C at day and 30°C at night, fruit abortion occurs, resulting in the production of small fruits with few seeds, and low liberation and germination of the pollen grain. The negative effect of this temperature is more intense from 8 to 13 d before anthesis and is enhanced with increasing temperatures (Jones et al. 1991).

The range of temperatures ideal for the formation of lycopene, the main carotenoid responsible for the intense red colour of the fruit, is 20-24°C during the day and around 18°C at night. Temperatures above 30°C inhibit the formation of lycopene and favour the formation of other carotenoids, which gives a yellow-orange colour to the fruit.

SEEDLING PRODUCTION

Commercial production of tomato for the fresh market is highly regulated, beginning with the seedlings, which should originate from high quality seeds. The seedlings are produced in trays and in a substrate free of pests and diseases. However, for domestic production less rigorous formulae may be used for the production of seedlings.

Containers

The containers may be perforated polyethylene bags or made from newspapers that will be filled with substrate. To manufacture a bag out of newspaper, a strip of newspaper is cut to a width of 12 cm and a length of 60 cm and rolled around a PVC tube of 6 cm diameter. The lower part of the strip is bent into the interior of the PVC tube, making up the bottom. In this way a bag is produced to hold 170 cm³ of substrate. The bags are filled with the appropriate substrate. A sample formula for substrate contains 60 L subsoil, 10 L sand, 20 L cured farmyard manure, 700 g dolomite and 300 g 2-20-2 fertilizer. Alternatively, the subsoil and sand mixture can be 2 parts soil and 1 part cured manure (Fontes and Silva 2002).

Trays

Normally trays made of polystyrene are used for the production of seedlings with cells shaped like a cone or inverted pyramid and the bottom open so as to allow for trimming of the roots by air. It is common to use trays with 128 cells, with cell volumes of 35 cm³. Alternatively, trays with 72 cells might be used with volumes of 113 cm³. After receiving the substrate and the seeds, the trays should not be in contact with the ground, but be held up by supports. The cells are planted and irrigated manually. Before trays are reused, they should be washed, immersed in 1% sodium hypochlorite solution for 30 min, washed again in clean water and allowed to air dry.

The seedlings should be produced in sites with abundant illumination in a protected environment covered with new plastic free of dust, fenced by anti-aphid lateral screens to reduce insect transmitters of viruses, and irrigated with pathogen-free water (Fontes and Silva 2002). The seedlings must be irrigated daily and are sprayed weekly with a protective insecticide. Currently, seedlings are vaccinated against virus-transmitting insects by means of systemic insecticides. However, such a practice is not officially recognized.

The nutrients in the substrate may not be sufficient for full development of the seedling. In this case the plant may be sprayed weekly with a nutrient solution. For example, the following nutrients may be mixed in 1 L water: 100 mg super simple fertilizer, 100 mg potassium chloride, 100 mg magnesium sulphate, 5 mg iron sulphate, 4 mg borax, 2 mg manganese sulphate, 2 mg zinc sulphate, 0.4 mg copper sulphate, 0.2 mg sodium molybdate and eventually 150 mg nitrocalcium.

PLANTING METHODS

Site

The ideal site will be easily accessible for labourers and equipment such as tractors or ploughs. The other requirements are ample sunshine, a good quality water supply, and a slightly inclined topography to facilitate drainage.

Soil Preparation

The tomato plant needs a structured soil, medium texture and good drainage so as to allow for good development of roots, thus avoiding phytosanitary problems. The most widespread procedure of soil preparation is the conventional one, which consists of ploughing twice and one passage of roto tiller. Direct planting of the tomato plant has been investigated: however, the results are still being assessed.

Liming

The tomato plant adapts well to soil with a pH of 5.5 to 6.0. This is because in these conditions it is possible to reduce the prejudicial effects of high concentrations of aluminium and manganese ions, as well as increase the availability of phosphorus and molybdenum. On the other hand, the tomato plant is demanding of calcium and magnesium, such that the application of calcium to the ...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Foreword
• Preface
• Table of Contents
• List of Contributors
• Part 1 Characterization and Composition of Tomato Plant and Fruit
• Part-2 Cellular and Metabolic Effects of Tomato and Related Products or Components
• Part-3 Analysis and Methods
• Index