Page 1 of 19
Discoveries in Agriculture and Food Sciences - Vol. 11, No. 5
Publication Date: October 25, 2023
DOI:10.14738/dafs.115.15501.
Michel, N. A., Ricardo, D., & Joseph, D. A. (2023). Characterisation of the Physico-Chemical Properties, Antioxidants, Anti-Nutrients
and Minerals of Two (2) Varieties of Tomato (Solanum lycopersicum L.): the African Tomato and the Salad Tomato Sold on Markets
in Korhogo in the North of Côte d'Ivoire. Discoveries in Agriculture and Food Sciences, 11(5). 15-33.
Services for Science and Education – United Kingdom
Characterisation of the Physico-Chemical Properties,
Antioxidants, Anti-Nutrients and Minerals of Two (2) Varieties of
Tomato (Solanum lycopersicum L.): the African Tomato and the
Salad Tomato Sold on Markets in Korhogo in the North of Côte
d'Ivoire
Niamke Arthur Michel
Department of Biochemistry- Genetics, Biological Sciences Training and Research
Unit, Peleforo Gon Coulibaly University, PO Box 1328, Korhogo, Côte d’Ivoire
Dion Ricardo
Department of Biochemistry- Genetics, Biological Sciences Training and Research
Unit, Peleforo Gon Coulibaly University, PO Box 1328, Korhogo, Côte d’Ivoire
Djaman Allico Joseph
Department of Biochemistry, Biosciences Training and Research Unit,
Félix Houphouët-Boigny University, 22 PO Box 582, Abidjan, Côte d’Ivoire
ABSTRACT
Two varieties of tomato (the African tomato and the salad tomato) are sold on the
markets of Korhogo, in the north of Côte d'Ivoire. The African tomato is the least
popular. The people who eat them are unaware of the nutritional value of the two
varieties of tomato. There has been no comparative study of the physico-chemical
parameters, antioxidants, anti-nutrients and minerals of the two (2) varieties of
tomato. This study is an enhancement of the African tomato. The physico-chemical
properties of African tomatoes and salad tomatoes respectively showed high
humidity (93.36% and 95.81%), acid pH (3.99 and 4.2), low fibre (0.81% and
0.68%), lipid (0.38% on average), protein (1.71% and 1.58%), total carbohydrate
(3.4% and 1.4%) and calorie (23.65 Kcal/100g and 15.63 Kcal/100g) content. The
study also revealed that tomatoes are high in polyphenols (123.64mg/100g and
101.98mg/100g), flavonoids (54.37mg/100g on average) and carotenoids
(41.17mg/100g and 39.84mg/100g). Tomatoes also contain vitamin C
(12.49mg/100g and 10.52mg/100g). Phytates (2.92mg/100g and 2.23mg/100g)
and oxalates (9.19mg/100g and 6.79mg/100g) were determined in small
quantities. Determination of the minerals by atomic absorption showed the
presence of several minerals such as magnesium, potassium, calcium, iron, copper
and zinc with potassium predominating. Based on this study, we can say that the
African tomato has a higher nutrient content, while the salad tomato has a higher
mineral content. Both varieties of tomato contain fibre, macronutrients,
antioxidants and minerals that are beneficial to the people of Korhogo.
Keywords: African tomato, salad tomato, Solanum lycopersicum L, Korhogo, antioxidants,
minerals
Page 2 of 19
16
Discoveries in Agriculture and Food Sciences (DAFS) Vol 11, Issue 5, October- 2023
Services for Science and Education – United Kingdom
INTRODUCTION
The tomato belongs to the Solanaceae family, which comprises 102 genera with around 2,500
species of annuals, woody and non-woody perennials, small shrubs and trees. Depending on
the 7 subfamilies, the genera and their species are either widespread throughout the world
(Solanoidae), or native to South America (Schwenckioidae, Petunioidae), Central America
(Petunioidae), the West Indies and Australia (Nicotianoidae). The tomato is an herbaceous
plant that tends to lignify as it ages. It grows upright when first planted, but becomes naturally
bushy if not staked as it matures. The alternate leaves can take on very different shapes,
depending on the variety [1].
Tomatoes are one of the most widely grown vegetable crops in the world, both in the field and
in the garden [2]. In 2001, 3.7 million hectares of tomato were planted, with production
estimated at 100 million tonnes [3,4]. However, this production is unevenly distributed. Asia
ranks first with 45% of world production, Europe 2nd with 22%, followed by America 19% and
Africa 12% [4]. Tomatoes play an important role in the human diet. They are eaten either raw,
in salads, mixed with other ingredients or in juice, or cooked in countless culinary preparations.
In 2003, worldwide consumption of tomatoes (fresh and processed) totalled 102.8 million
tonnes. China is the biggest consumer (25.27 million tonnes in 2003), followed by the United
States and India (10.11 and 6.84 million tonnes respectively). In terms of per capita
consumption, Libyans and Greeks consume the largest quantities of tomatoes (117 and 115
kg/year/capita respectively) [5].
In Côte d'Ivoire, tomatoes (Solanum lycopersicum L.) are grown in the north, centre and east
on loose soils rich in organic matter. It reacts strongly to temperature variations [6].
According to Ildefonse (1995) [7], tomatoes are the second most important fruiting vegetable
in terms of range and relative importance after the "N'drowa" variety (Solanum aethiopicum
L.) of traditional vegetables found on Ivorian markets. Fresh tomato production in Côte d'Ivoire
rose from 34,734 tonnes in 2013 to 44,078 tonnes in 2018, an increase of around 31%. Over
the same period, imports of tomato paste fell by 30%, from 21,033 tonnes in 2013 to 14,818
tonnes in 2017[8].
In Korhogo, in the north of Côte d'Ivoire, two (2) varieties of tomato are sold on the markets:
the ribbed African tomato and the round salad tomato without ribs. The African tomato is
undervalued and sold at a lower price than the salad tomato. The African tomato is used to
prepare local sauces, while the salad tomato is used in fruit salads, as an accompaniment to
lettuce and for other special dishes. Unfortunately, the people who eat them are unaware of
their nutritional value, and there is a lack of scientific data on these Ivorian tomato varieties.
This study is about promoting the African tomato. This study will consist of determining for
these two (2) varieties of tomatoes:
• Physico-chemical properties
• Antioxidants
• Anti-nutrients
• Minerals
And to compare the results obtained.
Page 3 of 19
17
Michel, N. A., Ricardo, D., & Joseph, D. A. (2023). Characterisation of the Physico-Chemical Properties, Antioxidants, Anti-Nutrients and Minerals of
Two (2) Varieties of Tomato (Solanum lycopersicum L.): the African Tomato and the Salad Tomato Sold on Markets in Korhogo in the North of Côte
d'Ivoire. Discoveries in Agriculture and Food Sciences, 11(5). 15-33.
URL: http://dx.doi.org/10.14738/dafs.115.15501
MATERIAL AND METHODS
Material
Biological Material:
The biological material used consists of two varieties of the species Solanum lycopersicum L:
the African tomato and the salad tomato sold on the three (3) main markets in Korhogo: The
Sinistré market, the Grand Marché and the Koko market.
Methods
Sampling:
Samples of the two (2) varieties of Solanum lycopersicum were purchased in three (3) markets
in the town of Korhogo, namely the Sinistre market, the Koko market and the large market. For
each market, 4kg of samples of each variety of the species Solanum lycopersicum were
purchased from three different sellers (traders), making 12kg of each variety of tomato
purchased per market. The total was 36 kg of each variety of Solanum lycopersicum for all three
markets. The samples were then taken to the laboratory for analysis.
Determination of Physico-Chemical Properties:
Size and Circumference:
The size and the circumference of the full fruit were estimated using a meter tape, and allowed
the deduction of the general fruit shape.
Weight:
The fruit weight was measured using a 2 digits scale (Sartorius).
Moisture Content [9]:
The method used for determining the moisture was that suggested by AOAC [9]. The moisture
was assessed by drying 5 g of tomato into an oven at 105°C till constant weight resulted after
24 h.
Ash Content [9]:
The ash content was measured by incinerating five (5) g of oven-dried tomato into a muffle
furnace at 550°C for 12 h.
pH:
The pH was determined using the AOAC (1990) method [9].
Ten (10) grams of ground sample are diluted in 100 mL of distilled water. The solution obtained
is filtered through Whatman filter paper. The pH is measured directly by immersing the
electrode of a previously calibrated pH meter (HANNA) in the filtrate obtained.
Total Sugar and Reducing Sugar Contents:
Extraction of Ethanosoluble Sugars
Ethanosoluble sugars were extracted from 1 g of ground dried tomato with 20 mL of 80% (v/v)
ethanol, 2 mL of 10% (m/v) zinc acetate and 2 mL of 10% (m/v) oxalic acid, according to the
method of Agbo et al., 1985 [10]. The extract was centrifuged at speed of 3,000 rpm for 10 min.
The ethanol residue was evaporated from the extract upon a hot sand bath.