**3. Nutritional characteristics**

#### **3.1. Bambara groundnut**

BGN seeds contain on average 63% carbohydrate, 19% protein and 6.5% fat; amounts which are regarded as sufficient to make the seed a complete food [1]. Reference [4] compared the nutritional composition of BGN with more commonly utilised and commercialised grain legumes, and BGN compared favourably (see Table 4). The high carbohydrate content of BGN is mainly composed of starch and non-starch polysaccharides [1], fractions which are impor‐ tant in the human diet providing energy and imparting several physiological functions. BGN is also rich in calcium, potassium, iron and nitrogen [4, 6]. In [28] the proximate composition of seeds, flour and seed coats from different BGN varieties were compared. Results for BGN seeds and flour showed no big differences, concluding that the inherent nutrients would be provided in either raw or processed (milled) form. Nti [22] evaluated the chemical composition of five BGN varieties as well as the effects of different processing conditions on the chemical, mineral and anti-nutritional composition of BGN flour samples. The moisture content of all varieties (ranging from 8.8 ± 0.22 – 9.8 ± 0.23%) indicated good storage stability of BGN seeds. An increase in tannins content were observed in darker-coloured varieties, with black whiteeye BGN having the highest tannin content (14.92 ± 0.85 mg CE/g).

Figure 3. Some food uses of Moringa tree **Figure 3.** Some food uses of *Moringa* tree

consider for food security [4].

tional value resembles olive oil [20]. The seed powder can be used for water treatment where

The thickened root is used as substitute for horseradish although this is now discouraged as it contains alkaloids, especially moriginine, and a bacteriocide, spirochin, both of which can prove fatal following ingestion. Older roots and root bark are good sources of tanning agents.

**Country BGN food uses Source**

with seasoning, or ground to prepare a traditional pudding

balls followed by frying and adding to stews; BGN is also made into a paste and used in traditional dishes 'tubani' (steamed bean

boiling (with/without capsicum pepper and salt) to produce a type of porridge/blancmange; served with 'gari' or plantain (ripe,

Dry BGN seeds are prepared by removal of the seed coat through pounding, winnowing and boiling the seeds until cooked; cooked

and 'akara' (bean balls); 'okpa' (steamed gel prepared by slurry of

the mixture boiled to form a stiff dough; this dough is salted and made into a ball known as 'tshidzimba' (Venda), 'sekome'

BGN seeds contain on average 63% carbohydrate, 19% protein and 6.5% fat; amounts which are regarded as sufficient to make the seed a complete food [1]. Reference [4] compared the nutritional composition of BGN with more commonly utilised and commercialised grain

seeds are pounded and mixed with coconut juice – this preparation is cooked and stirred until smooth, and served with [21]

[22-23]

[24]

[25-26]

[27]

Cameroon Testa-free fresh seeds – consumed as a complete meal by cooking

sometimes with addition of taro leaves

paste) and 'koose'/'akla' (fried bean paste)

Southern Ghana 'Aboboi' – prepared by soaking BGN seeds overnight followed by

Nigeria Paste prepared from BGN flour used in preparation of 'moi moi'

South Africa BGN (sometimes with peanuts) are added to millet or maize and

(Sesotho) or 'tihove' (Shangaan)

fried or mashed)

'ugali' or rice

**Table 3.** Some food uses of Bambara groundnut in parts of Africa

**3. Nutritional characteristics**

**3.1. Bambara groundnut**

BGN)

Kenya – Kambe & Giriama

tribes

Northern Ghana Dry BGN seeds – boiled and crushed seeds used to form cakes/

the powder coagulates solids and removes 90 – 99% bacteria.

192 Antioxidant-Antidiabetic Agents and Human Health

These anti-nutritional components are mainly found in the seed coat and as in common beans, their concentration are correlated with the colour of the seeds [1]. Dehulling and boiling with dehulling had significant effects on the protein and tannins content of all varieties. Protein content which was highest in the undehulled (27.35 ± 0.27%) black whiteeye variety as compared to the other varieties, increased significantly [p < 0.05] when dehulled (28.55 ± 0.26%) and boiled with dehulling (28.61 ± 0.51%). Tannins content in undehulled black white-eye BGN flour (15.40 ± 0.39 mg CE/g) decreased significantly [p < 0.05] when the sample was dehulled (1.16 ± 0.12 mg CE/g) and even more so when boiling and dehulling (0.09 ± 0.02 mg CE/g). These results demonstrate the positive effect of processing conditions on the nutritional properties of BGN, which could lead to increased utilisation in especially weaning products in which high-protein formulations are important. The highly nutritious content of BGN and its unusually high content of the sulphur-containing essential amino acid methionine, makes BGN an important crop to These anti-nutritional components are mainly found in the seed coat and as in common beans, their concentration are correlated with the colour of the seeds [1]. Dehulling and boiling with dehulling having significant effects on the protein and tannins content of all varieties. Protein content which was highest in the undehulled (27.35 ± 0.27%) black white-eye variety as compared to the other varieties, increased significantly [p < 0.05] when dehulled (28.55 ± 0.26%) and boiled with dehulling (28.61 ± 0.51%). Tannins content in undehulled black white-eye BGN flour (15.40 ± 0.39 mg CE/g) decreased significantly [p < 0.05] when the sample was dehulled (1.16 ± 0.12 mg CE/g) and even more so when boiling and dehulling (0.09 ± 0.02 mg CE/g). These results demonstrate the positive effect of processing conditions on the nutritional properties of BGN, which could lead to increased utilisation in especially weaning products in which high-protein formulations are important.

Table 4. Nutritional composition of BGN and some commonly utilised legumes1

**groundnut Soybean Chickpea Cowpea** 

**Bambara** 

The highly nutritious content of BGN and its unusually high content of the sulphurcontaining essential amino acid methionine, makes BGN an important crop to consider for food security [4].

and cyanidin were absent in BGN seeds. The absence of canavanine is consistent in the species of *Vigna*. The flavonoid profiles revealed that the four BGN varieties studied accumulated four types of kaempferol glycosides. In all *Vigna* species, the prevalent flavonoid appears to be kaempferol. Kaempferol-3-*O*-glucoside-7-rhamnoside seemed to be restricted to BGN. As a polyphenol antioxidant, kaempferol imparts many health benefits and reduces the risk of many chronic illnesses such as cancer [37]. A recently published article by [38] also reveals the possible components in BGN which could have beneficial effects on health in their study on the effects of gas flaring on the African breadfruit and BGN. Valuable information on the phytochemical properties of BGN was found with high concentrations in the unpolluted samples for oxalate (0.38 ± 0.04%), saponin (0.24 ± 0.02%); vitamin E (3.18 ± 0.15 mg/100 g), vitamin C (1.17 ± 0.20 mg/100 g), vitamin A (26.05 ± 0.14 mg/100 g) and niacin (2.10 ± 0.06 mg/ 100 g). The concentrations of oxalate, saponin, alkaloid and flavonoid were increased by gas flaring, whilst the concentrations of vitamins were significantly [p < 0.05] reduced. Vitamin A which is important for maintaining good eye-sight and preventing eye diseases [39], were significantly higher [p < 0.05] in the BGN seeds as compared to the other vitamins detected. The information available on phytochemical components of BGN seeds is promising, and should be further investigated to determine and highlight their specific effects on human

Nutritional, Therapeutic, and Prophylactic Properties of *Vigna subterranea* and *Moringa oleifera*

http://dx.doi.org/10.5772/57338

195

health, which could greatly influence the current underutilised status of this crop.

Strickly speaking, phytochemicals are non-nutritive chemicals produced by plants which may have an impact on health, or on flavour, texture, smell or colour of the plants. Plants produce these chemicals to protect themselves but recent research demonstrates that they can also protect humans against diseases. The phytochemicals include the alkaloids, anthocyanins, carotenoids, coumestans, flavan-3-ols, flavonoids, hydroxycinnamic acids, isoflavones, lignans, monophenols, monoterpenes, organosulfides, phenolic acids, phytosterols and saponins. Each phytochemicals work differently. *M. oleifera* contains various phytochemicals namely, carotenoids, vitamins, minerals, amino acids, sterols, glycosides, alkaloids, flavonoids and phenolics [40, 29]. Table 5 details the phytochemicals found in *M. oleifera*. *Moringa* species are rich sources of various phytochemicals including uncommon sugar-modified glucosino‐ lates, although there are only details on quantity and profiles for *M. oleifera*, *M. peregrine* and *M. stenopetala* [34, 41-42]. The predominant glucosinolate is 4-O-(α-L-rhamnopyranosyloxy) benzylglucosinolate (glucomoringin) and depending on the tissues three mono-acetylrhamnose isomers of this glucosinolate have also been detected [41, 43]. Chlorogenic acids and flavonols have been reported in different tissues of *M. oleifera* and *M. stenopetala* but there is no information for other *Moringa* species [34, 40-41, 44-45]. The flavonoid profile was found to be quite complex and was predominated by flavonol glycosides (glucosides, rutinosides and malonylglucosides of quercetin, kaempferol and isorhamnetin). The predominant core aglycones are flavonols: quercetin > kaempferol > isorhamnetin. The leaves had the highest and most complex flavonoid contents, and no flavanoids were detected in roots or seeds. The antioxidant activity of leaves from *M. oleifera* was shown to be very high due to the high concentrations of polyphenolics [46-47]. Therefore *M. oleifera* tissues could be an important

**4.2.** *Moringa oleifera*

dietary source of antioxidant polyphenolics.


**Table 4.** Nutritional composition of BGN and some commonly utilised legumes1

#### **3.2.** *Moringa oleifera*

*M. oleifera* leaves are good source of protein, β-carotene, vitamins, A, B, C and E, riboflavin, nicotinic acid, folic acid, pyridoxine, amino acids, minerals and various phenolic compounds [29-30]. *Moringa oleifera* leaf powder (25 g daily) is said to give a child the recommended daily allowance for protein (42%), calcium (125%), magnesium (61%), potassium (41%), iron (71%), vitamin A (272%), and vitamin C (22%). Gram for gram, *M. oleifera* leaves contain seven times the vitamin C in oranges, four times the calcium in milk, four times the β-carotene in carrots, twice the protein in milk and three times the potassium in bananas [31-33].

Leaves of *M. oleifera* are rich in palmitic (16:0) and linolenic (18:3) acids whereas the seeds are predominated by oleic acid (18:1). The roots are rich in palmitic and oleic acid whereas the stems and twigs are rich in palmitic acid [34]. It is becoming popular not only among the lower socio-economic class, but in the entire society irrespective of one's socio-economic background and health status.
