Pumpkin leaves (New)

Introduction

Pumpkin is the name given to a group of widely cultivated vegetable plant species in the genus Curcubita and family Cucurbitaceae. The family is of great significance to humans due to its economically important fruits and vegetables. Among the most important genera in the family are Cucurbita (squash, pumpkin, zucchini or courgette, and some gourds). The genus Curcubita includes several other species that are significant in Africa, such as Curcubita pepo, C. moschata and C. ficifolia. These species are cultivated around the world for their edible fruits and leafy vegetables used in a variety of dishes across the continent.
Pumpkins are native to the Americas but are now widely grown in many parts of the world, including the tropical and subtropical regions, where it thrives in warm and humid conditions. It is grown in a variety of soils, but it does best in well-drained soils that are rich in organic matter. Pumpkin is an important vegetable crop in Africa, where it is grown both for its fruit and leaves. The fruit is used in a variety of dishes, including soups, stews, and pies. The seeds are also edible and are often roasted and eaten as a snack. The leaves of the plant are also highly nutritious and are used as a leafy vegetable in many African countries.
Pumpkin leaves are rich in vitamins A and C, iron, calcium, and protein, making them a valuable source of nutrition, especially in areas where access to animal protein is limited. The leaves can be eaten raw or cooked, and they are often used in soups, stews, and other dishes. In some parts of Africa, the leaves are dried and ground into a powder, which is then used as a seasoning.
(Grubben, G.J.H. & Ngwerume, F., 2004, Long., 2015)

Species accounts

Cucurbita moschata is an annual climbing plant with stems growing to a length of up to 5 metres. These stems tend to sprawl over the ground, though they also climb into the surrounding vegetation where they support themselves by means of tendrils. Leaves: large, lobed, and covered with soft hairs, sometimes with white markings often disappearing as the leaves age. Flowers: solitary, unisexual, lemon yellow to deep orange; sepals free. Fruits: may be of varying shapes and colour - globose to ovoid to cylindrical and may weigh up to 10 kg. It  may be green to dark green often covered with grey-white stripes, changing to light green or cream with age. Flesh: yellow to orange, many-seeded; fruit stalk enlarged at apex. Seed: flattened, usually white. The fruit is ideal for roasting and in soups. Cucurbita moschata is the most heat tolerant Cucurbita species and the most widely cultivated in tropical Africa. It is most probably cultivated in all countries of tropical Africa.
C. moschata is commonly used as a leafy vegetable, where the young leaves and shoots are cooked and eaten as a green vegetable. Its fruit can be cooked in a variety of ways, including baking, roasting, and steaming. Its flesh can be used in soups, stews, casseroles and in pies and desserts (Grubben & Ngwerume, 2004).

Related species used as leafy vegetables
Curcubita maxima is an annual vine climbing by lateral, 2–5-branched tendrils, strongly branched. It is a fast-growing plant that can reach up to 10 meters in length. Stems: rounded stems that are long running and softly pubescent. Leaves: alternate ad simple lobed leaves that are rough to the touch. Flowers: yellow flowers of the plant are quite large and showy. Fruit: large, globose to ovoid or obovoid berry that weighs up to 50 kg with a wide range of colors (orange, green etc.), has a thick, hard rind enclosing the pulp and seeds.Seeds: flattened, white to pale brown, surface smooth to somewhat rough, margin prominent. Many cultivars of C. maxima that exhibit various morphological and physiological characteristics exist across in Europe and Africa. The plant prefers warm temperatures and well-drained soil and is often grown in gardens and small farms. 
C. maxima is used as a food source, the mature fruits, leaves, flowers and seeds are used as vegetables. In addition to being grown for its fruit, the species is also grown for its leaves, which are highly nutritious and have a variety of culinary uses. The leaves are regarded as a bit coarse and of lesser quality than those of Cucurbita moschata, although this disappears in cooking. They are used fresh and in some locations dried for use during the off-season. Curcubita maxima is native to South America, perhaps the area around Argentina and Bolivia. It has been introduced into most tropical and sub-tropical countries of the world. In Cameroon, Nigeria and other western African countries, seeds are commonly roasted and salted, or ground into a thick paste that is mixed with vegetables in cooking.

Cucurbita pepo is an annual, scandent herb, climbing by lateral, 3–4-branched tendrils, stro.ngly branched, or with bushy habit and then often without tendrils; Stems: angular and often grooved, prickly hairy. Leaves: alternate, simple, without stipules. Flowers are yellow to orange and unisexual. Fruit: are large, globose to ovoid, obovoid, cushion-shaped or cylindrical berry, weighing up to 50 kg when mature, with a wide range of colours, with small, raised, wartlike spots or smooth, sometimes deeply grooved. Flesh: soft, whitish to yellow or orange, many-seeded. Seeds: obvoid, flattened, usually white 
Principal features distinguishing Cucurbita pepo from other cultivated Cucurbita species are more deeply lobed leaves with silvery markings, prickly hairy stems and leaves and fruit stalk hard and pentagonal in cross-section. Cucurbita pepo tolerates monthly average day temperatures of 18–28°C, but growth is best when day temperatures are between 24°C and 29°C and night temperatures between 16°C and 24°C, as found at high altitudes in East Africa or at higher latitudes. Production is mostly restricted to the beginning of the dry season, when temperatures are relatively low and the pressure of aphids less intense. .C. pepo is less adapted to tropical lowlands than C. moschata, especially during the rainy season. Curcubita pepo; The young leaves and shoots are used as a potherb e.g. in south-western Nigeria, but in general the leaves of Cucurbita moschata are preferred, being less coarse. Male flowers of courgette are sometimes used to make fritters. ‘Vegetable spaghetti’ cultivars are a speciality; when cooked the flesh of mature fruits resolves into thin strands which look like spaghetti. Cucurbita pepo seeds are edible in the same way as those of other cucurbits, either raw or roasted. Cucurbita pepo is less heat resistant than Cucurbita moschata and for that reason less appropriate for tropical Africa, yet it is grown on a limited scale in all countries (Messiaen & Fagbayide, 2004)

Cucurbita ficifolia- also known as fig- leaf gourd is a monoecious, herbaceous, and woody perennial vine with a taproot that can grow up to 2 meters long. Stems: has numerous runners, up to 10 meters long, and is prickly or spiny, hard, and smoothly 5-angled to rounded. The tendrils are long and branched. Leaves: are simple, alternate, and circular-ovate to nearly reniform in outline, measuring 18-25 cm in diameter. Flowers: are solitary, yellow to light orange, up to 7.5 cm in diameter. The calyx and corolla are campanulate with a short tube. Fruits: globular to cylindrical, measuring 15-50 cm in length. It is white to green with white stripes and blotches, and the rind is smooth and hard. Flesh: is white, coarse, tough, fibrous, and rather dry. The fruit stalk is hard, round to 5-angled, without cork development, and not or only slightly enlarged at the point of fruit attachment. Seed; is flattened, oblong-ellipsoidal, measuring 1.5-2.5 cm in length. It is hard, without a spongy epidermis, and is black or sometimes light buff-colored.
Fig-leaf gourd, is mainly grown for its large fruits. The tender immature fruits are used like summer squash or cucumber The flesh of mature fruits is impregnated with sugar for preparation of a candy or jam, mature fruits are fermented for an alcoholic beverage, male flowers and buds are used in soups, stews and salads, and the raw or roasted seeds are eaten as a snack food. The leaves are edible and are consumed as vegetable occasionally mashed in a mixture of maize, pulses, green bananas or Irish potato in Kenyan communities (Maundu et al, 1999).

Ecological information

Pumpkins and squashes are grown in the tropics from lowlands up to altitudes of about 2500 meters above sea level. They are adapted to mean temperatures of 18-27 degrees Celsius. C. maxima is the most tolerant of low temperatures, C. moschata the least, with C. pepo intermediate. C. maxima and C. pepo have long been cultivated in temperate regions. Butternut appreciates shade in very hot conditions, shading can be obtained when intercropped with other crops or grown under fruit trees. 
Pumpkins and squashes do very well in medium to heavy applications of compost or well- decomposed manure. They are cultivated on almost any fertile, well-drained soil with a neutral or slightly acid reaction (pH 5.5 to 7). Pumpkins are drought-tolerant, requiring relatively little water, and are sensitive to waterlogging. Excessive humidity is harmful to pumpkins because of the development of leaf diseases, therefore no pumpkin species does well in the humid tropics. 

Agronomic aspects 

Seed sources and preparation.
Pumpkins are grown from seeds that can be purchased from seed companies, garden centres, or harvested from mature pumpkins. Before planting, it is important to prepare the seeds properly by cleaning and drying them. To do this, remove the seeds from the Pumpkin and separate the pulp from the seeds. Wash and clean the seeds thoroughly to remove any pulp or debris. Lay seeds out for an initial dryging in a cool and dry place for several days, sort through the seeds to remove the bad ones.

Planting
Pumpkin seeds may either be sown in containers and transplanted to the field when they are 10 cm high. The seeds can also be planted directly in the site where they will mature. Pumpkins are usually planted in hills and direct seeding of 2 to 3 seeds per hole about 2,5 cm deep and later thin to one plant per hill is advisable. Spacing varies with variety and vine size – the trailing types are planted at distances of 2-3 m either way; the seed requirement is 2 to 3 kg/ha.

Husbandry
Sole cropping is sometimes used for commercial production. Pumpkins are also planted in home gardens or mixed with field crops such as maize. Cultural practices needed to improve growth and development include the removal of growing tips (in trailing varieties) to check growth, and the bagging of fruits in paper to protect against fruit fly and other pests. Fruit setting may be stimulated by manual pollination. Pumpkin fruits may rot when in contact with moist soil, cutting grass or leaves and placing beneath the fruit will prevent rotting.

Harvest, post-harvest practices and markets

a.    Harvesting 
Pumpkins are harvested when mature in a once-over harvest or in several rounds, about 90 to 120 days after planting depending on variety When grown as leaf vegetable, usually the third and fourth leaves are harvested, while the tip and second leaves are left to grow. Young leaves and shoots are picked when needed. The leaf harvest may start 6 weeks after sowing and may be continued for at least 2 months with one harvest per week. Care should be taken that one does not tread on the stems. Sometimes the tips are removed to promote branching. Occasionally flowers and young immature fruits are harvested for consumption. Pumpkin leaves can be harvested year-round in warm climates or during the summer and early fall in temperate areas (Grubben, G.J.H. & Ngwerume, F., 2004).

b.    Post harvest practices
Once harvested the leaves are tied into desired bunches by the stalks and stored in an airy place. Leaves could be moistened to keep them fresh longer. A wire mesh shelf is recommended to spread the bunches out so that they do not lie on each other. When drying the leaves, the young leaves are cleaned off foreign material and washed. These are then placed on a clean surface to dry under a shade. This ensures that the leaves stay green and keep their nutrients. They are then stored in an air tight container or clean polythene bag. (Grubben, G.J.H. & Ngwerume, F., 2004).
c.    Markets
Pumpkin leaves are widely sold in the local markets and in southern Africa the leaves and the flowers are often sold in dried form.

Nutritional value and recipes 

Pumpkin leaves are highly nutritious and are a good source of essential nutrients that support human health. The leaves are rich in calcium, iron, magnesium, potassium, and manganese. Calcium is essential for bone health and muscle function, while iron is necessary for oxygen transport and the prevention of anemia. Magnesium is involved in numerous biochemical reactions in the body, potassium is crucial for maintaining proper heart function and fluid balance, and manganese contributes to various metabolic processes. 
Pumpkin leaves are particularly rich in antioxidants, such as beta-carotene, which is a precursor of vitamin A, and vitamin C, both of which help protect cells from damage caused by free radicals. They are also a good source of dietary fiber, which helps to promote digestive health, reduce inflammation, and maintain a healthy weight. Consuming pumpkin leaves regularly can also help promote weight loss, and improve overall health and wellbeing. These leaves can be cooked and added to soups, stews, and stir-fries, or eaten raw in salads or smoothies.

Table 1: Approximate nutritional composition of 100 grams of Pumpkin leaves

Source (Nutrient data): FAO/Government of Kenya. 2018. West African food composition table (Stadlmayr, 2012)
$ 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

Complementary recipes.
1.    Fried kahurura.
Kenya recipe. (Source: IPGRI, 2006)
Ingredients
•    1 bunch Kahurura leaves (Cucurbita ficifolia)
•    250 ml water
•    Onions (50 g)
•    2 tablespoonful cooking oil
•    Tomatoes (80 g)

Preparation

1. Peel the outer membrane off the leaf stalks, and then wash the leaves without cutting off the stalks. The stalks are said to be rich in nutrients
2. Chop the vegetables together with the stalks
3. Bring water to boil, add vegetables and boil for 3 minutes. (You may blanch the vegetable instead of boiling)
4. Heat oil, add the dicedonions and fry them lightly
5. Add the vegetables and stir for a minute
6. Add the diced tomatoes and cook for 2 minutes
7. Add salt to taste then stir
8. Serve with ugali
9. Yields 4 servings

Remarks
This vegetable has a reputation as a drought food among the Kikuyu some people however find the leaves bitter. It is very high in beta-carotene, iron, folate, and calcium it is used in mashed food preparation of maize, beans, and potatoes.

2.    Isosek 
Kenya recipe. (Source: IPGRI, 2006)

Ingredients
•    40 g pumpkin leaves (Isosek)
•    200 g green maize
•    200 g irish potatoes
•    5 tablespoonfuls cooking oil
•    50 g onions 
•    60 g tomatoes 
•    Salt to taste

Preparation

1. Do not cut off the leaf stalks, instead peel off the outer covering from the leaf stalks. 
2. Wash the pumpkin leaves and boil them for 3 minutes
3. Boil the maize, 20 minutes for soft maize and 40 minutes for dried maize. Hard maize can be soaked overnight to soften
4. Peel and clean the potatoes, then add them to the maize to boil till nearly soft 
5. Add the pumpkin leaves and salt, and then boil the food till the potatoes are soft..
6. Ensure all the water is evaporated
7. In a separate cooking pot, fry the chopped onions in oil till lighlty golden brown
8. Add the chopped tomatoes and stir them till they are soft
9. Add the cooked potatoes, vegetables and the maize
10. Stir everything and cook for about 5 minutes
11. Using a wooden spoon, mash everything together, until evenly mixed
12. Serve with fresh/sour milk, tea or desired stew
13. Yields 5-6 servings

Remarks
This recipe can be varied by mixing the pumpkin leaves with Nderema (vine spinach -Basella alba).
Add a teaspoonful of butter to flavour (optional).

3.    Pumpkin imifino / Squash Leaves 
South Africa recipe . (Source: IPGRI, 2006)

Ingredients
•    100 g of pumpkin leaves 
•    Pumpkin fruit (150 g), diced
•    1 litre of water
•    1 kg coarsely ground maize meal
•    1 tablespoonful salt

Preparation

1. Mix the young fruit and chopped leaves 
2. Boil the water
3. Add the leaves and fruit to the water and cook till leaves are soft (water becomes greenish), about 10 minutes
4. Add salt then add the maize meal and stir well
5. Cook 5 minutes and stir
6. Simmer for 15 minutes while covered
7. Serve alone as a relish

4.    Umathwane dish 
South Africa dish. (Source: Van Rensburg, 2006).

Ingredients
•    200 g growing points of pumpkin leaves (leafy stems)
•    2 young pumpkin fruits
•    Water to cover the growing points and pumpkins
•    Coarse maize meal to taste
•    ½ -1 teaspoonful of salt

Preparation

1. Harvest the young growing points, remove the twisting parts
2. Peel the skin with the hairs. Do not use the flowers. Wash.
3. Chop growing points finely and pumpkin fruits into small pieces 
4. Place in the pot, add 2 litres of water and cook for 20-30 minutes or until soft
5. Add the coarse maize meal
6. Add ½ -1 teaspoonful of salt
7. Stir 3 times till the mixture is smooth
8. Simmer for 20 minutes
9. Serve alone

5.    Majani ya maboga na bamia 
Tanzania recipe. (Source: IPGRI, 2006).
Ingredients
•    140 g pumpkin leaves
•    100 g okra
•    90 g tomatoes
•    ½ cup groundnut flour
•    1 cup water
•    Salt to taste

Preparation

1. Select the tender leaves of the pumpkin, wash and chop finely
2. Wash, peel and chop the tomatoes
3. Wash and chop the okra
4. Prepare groundnut flour
5. Boil the water and add all the ingredients to cook for 10-15 minutes while covering the pan. Simmer 
6. Stir well until the mixture becomes thick like porridge or slimy
7. Season to taste and serve while hot as a relish

6.    Chibwabwa (IPGRI, 2006)
Zambia recipe. (Source: IPGRI, 2006).

Ingredients
•    150 g (3 ½ bundles) pumpkin leaves
•    150 g (1 big) tomato
•    50 g (1 medium) onion    
•    15 ml (1 tablespoonful) cooking oil
•    Salt to taste
•    ¼ cup water

Preparation

1. Remove stalks from leaves, wash leaves and chop them into small pieces
2. Add salt to the water and bring to boil
3. Add the vegetables; boil for 4 minutes then drain. Immediately place them in cold water then drain and cut them. (Do not cut the vegetables before blanching)
4. In a separate saucepan, heat the cooking oil, add the chopped onions and fry them till they begin to turn golden brown
5. Add the chopped tomatoes then vegetables; allow cooking for 5 minutes then mix
6. Serve with Nshima

Remarks
Blanching vegetables before frying is a common way of making them soft, cook faster and retain the green colour while retaining most of the nutrients
Blanching can be done for most vegetables.