THE POTENTIALS OF AFRICAN WALNUT LEAVES IN SOUP PREPARATION

THE POTENTIALS OF AFRICAN WALNUT LEAVES IN SOUP PREPARATION

           Fig. 1: Prepared Soup with African Walnut Leaves

Traditional meals and culinary practices are an essential part of African cultural heritage, reflecting the history, traditions, and flavors of a particular region or community. Over time, culinary traditions have evolved, adapting to changing lifestyles, availability of ingredients, and the exploration of new flavors (Williams, 2023). In recent years, there has been an increased interest in exploring alternative ingredients that offer unique flavors, nutritional benefits, and sustainability.

Soup is a primarily liquid food, generally served warm (but may be cool or cold), that is made by combining ingredients such as meat and vegetable with stock, juice, water, or another liquid. There is a great need for us to know the nutrient composition of local vegetables used as foods. to understand their nutrient composition. Some vegetables are very rich in protein, calorie, vitamin, phytochemical, nutrients. As such there is a constant need for research into the nutrient composition of local vegetable used as food.

Vegetables are very essential constituents of any type of nutritional diet in many homes. Apart from being an important ingredient in food preparation, vegetable add variety, flavor, colour and taste to the menu. As valuable sources of nutrients, they contribute substantially to protein, mineral, vitamins, fibre and other nutrients which are usually in short supply in most daily diets (Mepba, and Banigo, 2007). Vegetables have gained a widespread acceptance as a dietary constituent in Nigeria, generally forming a substantial portion of the diet in the preparation of soups and stews (Hart et al., 2005).

Fig. 2: Walnut Leaves

Walnut (Juglans regia L.) is one of the most common tree nuts in the world. The tree is commonly referred to as the white walnut, Persian walnut, English walnut or common walnut. It belongs to family juglandaceae and has the scientific name Juglans regia.

Walnut leaves have been used for centuries in traditional medicine to lower blood sugar and improve diabetes. Walnut leaves contain health promoting components, and they are commonly used in traditional medicine to treat venous insufficiency and hemorrhoids symptoms. They are sometimes used as an anti-diarrheal and anti-parasitic medication, as well as a blood purifier (Mohammadi et al., 2011)

Chemical Composition/Health Benefits of Walnut Leaves

Chemical compositions of the essential oils of Plukenetia conophora leaves revealed that the oil is dominated by oleic (9-octadecenoic) acid (29.78%) and palmitic (hexadecanoic) acid (14.36%). As a result of the presence of ascorbic acid in the leaf, the plant can be used in herbal medicine for the treatment of skin conditions, including eczema, pruritus, psoriasis and parasitic skin conditions (Amelio, 1999). The presence of vitamin E in the leaf supports its use in southern Nigeria ethnomedicine as a male fertility agent (Ajaiyeoba, 2006). The presence of other vitamins, though in trace amount are which is very essential for body metabolism. The african walnut leaf is a good source of vitamins, especially the B group. Alkaloids are one of the most efficient plant substances used therapeutically. Pure isolated alkaloids and the synthetic derivatives are used as the basic medicinal agent because of their analgesic, antispasmodic and bacterial properties (Stray, 1999). The presence of tannins in the leaf of the P. conophora plant can support its strong use for healing of haemorrhoids, frost bite and varicose ulcers in herbal medicine (Igboko, 1983, Maduiyi, 1983). The result of the determination of mineral compositions in african walnut leaves clearly shows that it is a rich source of mineral elements. The presence of copper may be responsible for the absorption of iron, it is therefore often seen with iron naturally. Copper is important for cellular defence and protection of the mucous membrane, antianaemic and essential for the formation of haemoglobin from iron (Claude et al., 1979). The presence of manganese shows that the plant can be used to protect bone disease. The activity of this element is noticed in the metabolism of food incorporated into the bone. The presence of zinc is an indication that the leaf may have some effect on the nerve function and male fertility. It is important for normal sexual development, especially for the development of testes and ovaries, it is also essential for reproduction.

A study reported by Akomolafe et al. (2015a) showed that anti peroxide activity of the leaves of T. conophorum was seen to diminish malondialdehyde (MDA) level in reproductive organs and accessory organs of rodents. Adult male rodents were managed orally with the watery leaf extract from T. conophorum at 50, 500 and 1000 mg/kg body weight for 21 continuous days while clomiphene citrate (1.04 mg/kg body weight), The results of the study indicated that there was increment in relative organ weight, body weight, average total food and water consumed by the treated groups of rodents. Kanu and Okorie (2015), reported that extract from T. conophorum leaves had more capacity to diminish lipid peroxidation in conceptive organs and frill organs. In this way, the plant might be valuable in the treatment of reproductive cellular damage.

Ogbonna et al. (2013) indicated a significant decrease in blood glucose level and proposed that the leaf and the root extracts of T. conophorum are progressively active in bringing down blood glucose in alloxan- induced diabetic rodents when compared and oral hypoglycaemic agents. Experiments have shown that African walnut is outstanding amongst other natural products for individuals that need to keep up a healthy blood sugar level and prevent the risk of obesity.

Amino acid and fatty acid compositions of the nut and the use of its leaf juice for the treatment of prolonged and constant hiccups and the methods of processing the P. conophora nuts has also been reported (Oyenuga, 1997, Okpero, 2001). Walnuts plants are mostly considered to be herbs often used in traditional Chinese medicine. They are also said to tonify kidneys, strengthen the backbone, knees, and moisten the intestines. It is believed to stop asthma and is prescribed to be taken between bouts of asthma, but not for acute asthma. It is used for elderly as a constipation cure and the bark is used as tea for laxative and chewed for toothache, it also helps to prevent and control high blood pressure (Wikipedia, 2008).

Tetracarpidium conophorum promotes quality rest. Anosike et al. (2015) reported that Walnut can be utilized for treatment of the gastrointestinal tract, and helps reduce premature deliveries in pregnant women because it has culinary purposes, for example, soup preparation; it can boost cognitive function because of the presence of vitamin B6 and omega-3 unsaturated fats and furthermore helps as an anti-ageing agent (Global Food Book, 2015).

Fig. 3: Cooked Walnut Seeds

Chemical Composition/Health Benefits of Walnut Leaves

The result of proximate analysis shows that the fresh leaves contained 29±0.71% moisture, 5.63±0.08% fat, 14.92±0.04% fibre, 16.62±0.30% protein, 12.89±0.02% Ash, 20.94±0.01% carbohydrate. The phytochemical screening and subsequent quantification leaves revealed the presence of tannin, 0.560±0.01mg/kg, alkaloid, 2.670±0.02, gallic acid, 0.180±0.02mg/kg. There were no traces of flavonoids, cardiac glycosides, anthraquinones, ellagic acid and caffeinic acid in the leave. The mineral analysis revealed the constituents to be K, 15937±0.02,

Fig. 4: Peeled African Walnut Seed ready to be Eaten.

Na, 7980±0.01mg/kg, Ca, 18700±0.02mg/kg, Mg, 1766.25±0.1mg/kg, Fe, 4610±0.10mg/kg, Zn, 61.15±0.08mg/kg, Mn, 79.50±0.03mg/kg, Cu, 8.60±0.10mg/kg for the fresh leaves. Vitamin composition results showed that the fresh leaves contained Thiamine (B1)

0.29±0.01μg/100g, Riboflavin (B2) 0.34±0.01μg/100g, Niacin, 0.12±0.3μg/100g, Cyanocobalamin (B12), 0.23±0.03μg/100g. Ascorbic acid (C) 16.28±0.04mg/100g, tocopherol (E), 2.67±0.008μg/100g. The results proved that Plukenetia conophora fresh leaves can serve as foods and could also be potential sources of useful drugs formulation (Ayoola et al., 2013).

Ekwe and Ihemeje (2013) in their findings reported the proximate composition of the African walnut (T. conophorum) on wet basis, which revealed protein (14.92%), oil (45.84%), crude fibre (1.14%), ash (3.52%) and carbohydrate (15.38%), while the anti-nutritional factors revealed tannins (0.89 mg/100 g), oxalate (1.28 mg/100 g), phytic acid (3.105 mg/100 g), trypsin inhibitors (1.84 mg/100 g), saponin (985.0 mg/100 g) and alkaloid (40.91 mg/100 g).

Suara et al. (2016) assessed the nutraceutical properties of the methanol concentrate of P. conophora leaves and reported some mineral components. The result showed that proximate analysis was 6.86% moisture content, 11.78% protein, 8.57% complete ash, 20.12% unrefined fiber, 1.56% total fat and 51.8% total carbohydrate. The study concluded that the leaves can served as an anti-venom agent because of its relatively high content of cardiac glycosides, alkaloids, saponins and phenols, which are active substances for detoxification of venoms in the human system (Bowsher, et al., 2008).

Types of Nigerian Paster eaten with Nigerian Soup