Waterleaf (New)

Introduction

Water leaf (Talinum fruticosum) is a leafy vegetable that belongs to the Talinaceae family. The genus Talinum comprises about 40 species, primarily found in Mexico and the southern United States, and 7 species in tropical Africa with Talinum fruticosum being one of the most notable and economically significant species. A related species also used as a leafy vegetable in Eastern and Southern Africa is Talinum portulacifolium. 

T. fruticosum is widely distributed in tropical and subtropical regions around the world, particularly in tropical America, the Caribbean, Tropical Africa and South Asia. Waterleaf is well adapted to different ecological conditions and can thrive in both moist and dry environments. In its natural habitat, waterleaf often grows as a weed in farmlands and is common in cultivated or disturbed land, including roadsides and near people's homes.
Waterleaf has various uses, primarily as a food source. The leaves are tender and succulent, making them suitable for consumption as a vegetable. The leaves are widely incorporated into traditional cuisines and are particularly popular in West African countries such as Nigeria, where they are known as "Gbure" or “soko”. The vegetable is typically harvested when young and tender, as the leaves become tougher with age. Culinary practices for preparing waterleaf can vary, but common methods include stir-frying, boiling, or adding it to soups and stews. The vegetable can be combined with other vegetables, meats, or fish to enhance the overall taste of a dish. It is often used as a key ingredient in various traditional dishes, including soups like egusi and Efo Riro. Waterleaf is a rich source of essential vitamins and minerals. It contains significant amounts of vitamins A, C, and E, as well as minerals such as calcium, potassium, and iron. Additionally, it is low in calories and high in dietary fibre, making it a nutritious choice for those seeking a healthy diet.
In addition to its culinary uses, waterleaf also holds medicinal significance. It is believed to possess various health benefits, including anti-inflammatory, diuretic, and antioxidant properties. Traditional medicine practitioners often use water leaf to treat ailments such as gastrointestinal disorders, malaria, and high blood pressure. In addition to its food and medicinal uses, waterleaf can also serve as fodder for livestock, particularly in areas where it is abundantly available (Schippers, 2000, Fontem & Schippers, 2004).

Species account

1. Talinum fruticosum
Waterleaf is an erect perennial herb species with swollen roots and hairless, and succulent stems, which can grow to 1-3 m in height. Leaves -are arranged spirally and clustered at the stem's top. The leaf blades are usually spoon-shaped, succulent, and occasionally indented at the apex. Flowers- pink, bisexual, and primarily self-pollinate with limited outcrossing. The inflorescences are triangular. Fruits- light-green, ellipsoid capsules, dehiscent with many dark brown seeds that break open (Nya and Eka, 2015, Schippers 2000, Aja et al. 2010).

2. Talinum portulacifolium
Talinum portulacifolium is a fleshy perennial herb, sometimes creeping, loosely rooted, often growing up through thorny bushes, also shrub-like with woody basal stems, 1.5 m. Leaves are alternate, succulent, without stalks, very variable in size but wider at the tip, about 4 -7 cm long. Flowers arise from terminal stalks, one or more together, bright purple-pink, over 2 cm across with 5 petals around many central yellow stamens. The fruit is an ovoid capsule about 8 mm long, shiny yellow-brown, breaking across to set free tiny brown seeds.
The species is common in dry bushland especially in coastal environments. Also found on floodplains, steep rocky slopes and disturbed roadsides. It is quite common in coastal clay soils. This Talinum is found from Ethiopia and Somali south to the Eastern Cape South Africa. Also on the Arabian Peninsula and India.
The fleshy leaves and stems are chopped and cooked with other vegetables such as Bidens or Cleome, and may be mixed with coconut milk or pounded groundnuts and served with a staple such as ugali. The plant is animal fodder and a good ornamental. It is picked from the wild during and soon after the rainy season. It may be propagated by seed and cuttings (Ruffo et al, 2002, Fondo et al, 2011).

Ecological information

The ideal environment for waterleaf growth is humid, with temperatures of about 30°C. While growth slows significantly during the dry season, it accelerates during the wet season. It thrives in the shade and overcast conditions. Although it may grow in fully exposed areas, the plants there are still tiny. When the soil's water content is just below the field's carrying capacity, growth is at its most abundant. The number of leaves, area of leaves, size of stems, and several branches are all severely impacted by dryness and high temperatures (>35°C). Though often used as fodder, Talinum may contain some hydrocyanic acid that may affect cattle (Fontem, D.A. & Schippers, R.R., 2004).

Agronomic aspects

Waterleaf is usually propagated by seeds or vegetative cuttings. The seeds often have low germination due to poor seed viability or dormancy and should be pregerminated. Seedlings can be transplanted to the field when 3 weeks old. As a result of the difficulty in establishing the crop using seeds, vegetative propagation is encouraged. Vegetative cuttings are taken from the mature stem in 5-to-8-inch segments and can be directly planted 2 inches deep on raised beds without rooting. Waterleaf is frequently intercropped with other vegetable crops; however, it can also be cultivated solely at a spacing of about 15 cm × 15 cm A close spacing reduces competition from weeds and is possible because pressure from diseases is limited Germination takes place after about 5 days and subsequent growth is very rapid if adequate water is supplied. Animal manure such as rabbit or chicken droppings may be added to enhance rapid growth. Waterleaf seeds or cuttings can also be raised in small containers for transplant production before transferring into containers (Schippers 2004; Orluchukwu and Poripo 2014). After removing the leaves, the remaining stem may be planted (Fondo et al, 2007). 

Harvest, post-harvest practices and markets

a.    Harvesting
Waterleaf has a short cultivation cycle, with the first harvest achievable within 3 weeks after planting. Subsequently, shoots can be harvested every 1-2 weeks for about two months. The size of the leaves diminishes as the plant ages and undergoes multiple harvests. The initial 1-3 harvests yield the highest quality leaves for marketing. On average, farmers can harvest from a single plant up to 4 times before its growth declines. For optimal regeneration, it is recommended to harvest the crop by cutting the stem just above ground level rather than solely harvesting the upper portion and side shoots. Even if the lower parts of the stem turn brown and shed leaves due to delayed harvest, cutting just above the ground ensures better quality for subsequent harvests. When waterleaf is planted using cuttings, it is best harvested by cutting the new side shoots. A rain-fed waterleaf crop can be left in the field for a duration of 60-180 days. (Fontem & Schippers, 2004.).

b.    Post-harvest practices
Waterleaf shoots may begin to wither within a few hours after being plucked since the plant is so perishable. The shoots can be kept in a cool dry place at room temperature of stored in a plastic bag in a refrigerator for a few days.
c.    Markets
Waterleaf has gained popularity not only in local markets but also in international markets, particularly in regions with a significant African diaspora. African grocery stores and specialty food markets in Europe, North America, and other parts of the world often carry waterleaf due to the demand from African communities.
In Africa, waterleaf enjoys wide marketing and consumption, with notable popularity in West Africa, including Nigeria, Ghana, and Sierra Leone. In Nigeria, it is a common ingredient in soups, stews, and vegetable sauces, and it plays a central role in traditional dishes like "Efo Riro" and "Edikang Ikong." In East Africa, particularly in countries such as Kenya, Tanzania, and Uganda, waterleaf is often incorporated into stir-fries, salads, and served as a side dish. Additionally, waterleaf is valued for its medicinal properties in traditional herbal medicine practices. (E.J. Nya et al., 2010).

Nutritional value and recipes

Waterleaf offers remarkable nutritional value and a wide range of health benefits. Waterleaf has low-calorie content, making it an excellent choice for individuals seeking a vegetable with weight management benefits. Moreover, waterleaf is an abundant source of dietary fibre, promoting healthy digestion, preventing constipation, and supporting overall gastrointestinal health. 
The leaves are abundant in various beneficial compounds, including noteworthy quantities of vitamin C, vitamin E, Omega-3 fatty acids, calcium, magnesium, soluble fibres such as pectin, potassium, β-carotene, proteins, and dietary fibre. Vitamins A, C, and E, which are potent antioxidants, protecting the body from harmful free radicals. Waterleaf's high vitamin A content makes it beneficial for eye health. The vitamin C content in waterleaf enhances the immune system's function, protecting the body against infections and illnesses. Additionally, waterleaf contains vitamin K, which aids in calcium absorption and helps maintain healthy bone density. 
Talinum fruticosum has garnered considerable attention in ethnobotanical studies. Further scientific investigation is necessary to identify the specific chemical constituents responsible for these reported benefits. In particular, there is a need for focused research on the plant's antioxidant activity, as it holds promising potential in this area (Bioltif, 2020, Fontem & Schippers, 2004).

Table 1: Approximate nutritional composition of 100 g of waterleaf (Talinum fruticosum) leaves.

Source (Nutrient data): FAO/Government of Kenya. 2018. West African food composition table, https://www.fao.org/3/ca7779b/CA7779B.PDF
$ Draining the water several times leaches away water soluble nutrients significantly.
a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO
b NHS (refers to saturated fat)
c https://www.hsph.harvard.edu/nutritionsource/water/
d British Heart Foundation
e FDA
f NIH
g Mayo Clinic

Complimentary recipes
Talinum portulacifolium is a slimy vegetable and is not usually cooked alone. Waterleaf is usually mixed with meat or other leaves and it is not a practice to cook it alone. It is a slimy, leafy vegetable. The Giriama and Chonyi people of Coastal Kenya cook Talinum leaves with amaranth or cassava leaves. The cooked mixture is used as an accompaniment for ugali (stiff porridge). It is said to be good for digestion.

1.    Waterleaf soup- Gbure soup
Yoruba recipe, Nigeria. 

Ingredients 
•    5 medium-sized beef pieces
•    4 pieces of shaki (beef tripe)
•    1 small bunch of waterleaf
•    A handful of washed bitter leaves
•    1/2 cup of crayfish pieces
•    2 scotch bonnet chillies, chopped
•    Seasoning cubes
•    1 tablespoon of grounded crayfish
•    1.5 cooking spoons of palm oil

Cooking procedure 
•    Season and simmer beef, tripe, and any other desired proteins.
•    When water reduces, add crayfish powder, chopped pepper, crayfish pieces, and additional seasoning cubes if desired. Reduce heat.
•    Thinly shred waterleaves and bitter leaf.
•  Once beef broth significantly reduces, add oil and immediately incorporate bitter leaf and water leaf. 
•    Stir, remove from heat, and let vegetables cook in the residual heat to preserve their nutrients.
(Serves 2 people)
Source: (afrolem, 2015)
2.  Waterleaf, Ceylon spinach
Ingredients
½ cup of water
Salt to taste
4 tablespoonfuls of oil
6 small-sized tomatoes
1 fruit of sweet pepper diced
1 onion
1 kg waterleaf (Talinum fruticosum)
300 g of smoked fish or smoked meat

Preparation

1. Clean leaves with water to remove dirt
2. Cut the leaves and the tender stems
3. Without adding any water, put the vegetables on low heat and boil the vegetables for about 15 minutes or until the vegetable is reasonably soft
4. Drain off any excess water in a container by pressing the vegetable by hand
5. Heat the palm oil in a pan, add the onions and fry till they begin to turn golden brown
6. Add the tomatoes and pepper and cook till they become tender
7. Add the boiled leaves and cook briefly for 5 minutes
8. Add the smoked fish and salt to taste
9. Add fresh water or the water drained from the vegetables
10. Stir and cook for about 10 minutes or until much of the water has evaporated
11. Remove from fire and serve with fufu, rice, etc.

Remarks
Consumed by communities found in the central parts of DRC especially popular with the Baluba community. 

Source: Cyrille Okulungu, Congo Recipes in: A Cookbook of African Leafy Vegetables. Maundu et al, IPGRI, 2006. 

3.    Edikang Ikong soup
Nigerian soup recipe.
Ingredients 
•    1kg Pumpkin leaves
•    500g Waterleaf (Talinum)
•    600g Beef, Kanda (Cow skin), shaki (Stripe) and Dry fish
•    Pepper, Salt and ground crayfish: to taste
•    200ml Palm oil
•    1 cup Periwinkle
•    2 medium onions
•    2-3 stock cubes
Cooking procedure

1. Wash and cut the pumpkin and water leaves into small pieces. Place them in separate sieves to remove excess water.
2. Cut the Kanda into small pieces. In a pot, cook the beef, Kanda, and dry fish along with two diced onions and stock cubes, using minimal water.
3. Once the meat is cooked, add a generous amount of palm oil, crayfish, and pepper. Allow it to boil for approximately 10 minutes. The palm oil will serve as the primary liquid in the Edikang Ikong soup, so it's important to minimize the presence of other liquids.
4. Introduce the periwinkle and water leaves and let them cook for an additional 5 minutes. Be careful not to overcook the water leaves, so a shorter cooking time may be necessary.
5. Incorporate the pumpkin leaves and season with salt to taste. Thoroughly stir the contents of the pot, then turn off the heat. Cover the pot and let it sit for about 5 minutes.
6. Serve the Edikang Ikong soup with accompaniments such as Garri (Eba), Semolina Fufu, Amala, Cassava Fufu, or Pounded Yam.

Source: All Nigerian Recipes. (2019).
Note: Waterleaf has oxalate, which can cause kidney stones if consumed excessively without proper preparation. Cooking or blanching can remove a substantial amount of the soluble oxalate. It also contains some hydrocyanic acid much of which is removed during preparation. It may have nitrates and nitrites, which are unaffected by cooking, hence requires caution when including waterleaf in infant diets. Saponins are abundant in waterleaf (Fontem, D.A. & Schippers, R.R., 2004).