EFFECT OF PROCESSING ON SOME NUTRIENTS AND ANTINUTRIENTS COMPOSITION OF EGYPTIAN RIVERHEMP (SESBANIA SESBAN) SEEDS

Egyptian riverhemp (Sesbania sesban) is widely distributed throughout Africa including Nigeria. Seeds from the plant contain essential nutrients but levels of antinutritional factors in the seeds present a challenge to its use as alternative feeds for livestock. In this study, the effect of processing on some nutrients and antinutrients composition in the seed of Sesbania sesban were assessed using lye. Lye possesses chemical characteristics as slaked lime, which have been used to detoxify or reduce antinutrients in plants. However, slaked lime can not be readily available especially to rural farmers, hence the choice of lye, which can be made readily available for the rural farmers. During processing, the seeds were soaked for (24 hours) and boiled (1 hour) using water, calcium hydroxide and lye. The processed and unprocessed samples were then analyzed using standard methods for proximate, antinutrients, vitamins and minerals composition including in vitro protein digestibility. Results obtained for proximate composition revealed significant (p<0.05) decrease in moisture content of the processed samples with both samples boiled in calcium hydroxide (BC) and those boiled in lye (BL) which had the highest reduction as compared to raw sample (RS). Crude protein content was significantly (p<0.05) higher for sample boiled in water (BW), BC and BL compared to those soaked in water (SW), calcium hydroxide (SC), lye (SL) and RS whereas soluble and insoluble fibre contents were significantly (p<0.05) higher in SC and RS. Carbohydrate content obtained showed significant (p<0.05) reduction in BC compared to the other processed samples and RS. Analysis for antinutritional factors revealed that boiling with lye resulted insignificant (p<0.05) reduction in tannins, saponin, oxalate, cyanogenic glycosides and trypsin inhibitor, while soaking with water revealed more reduction in phytic acid content. Vitamin concentration revealed that processing caused significant (p<0.05) reduction in β-carotene (βC) and water-soluble vitamins, with SC having a higher reduction in βC, B2 and B6 as compared to RS while a significant (p<0.05) increase in vitamin E was noticed in SL as compared to RS. Mineral contents indicate SC had higher Magnesium, Manganese and Copper concentrations compared to RS whereas Potassium and Iron contents were higher in SW. Boiling with water and boiling with lye had higher Sodium and Calcium compared to RS. Iin vitro protein digestibility showed BL had significantly (p<0.05) higher digestibility compared to other processed samples and RS. Based on the findings from this study, samples boiled in lye (BL) had a higher reduction in some of the antinutrients with improved in vitro protein digestibility, hence this may enhance the use of the seed of Sesbania sesban as a potential alternative for livestock feed.

 

 

 

 

 

Egyptian riverhemp (Sesbania sesban) belongs to the family Fabaceae. It is a small perennial tree with woody stems, yellow flowers and linear pods. The origin of Sesbania sesban is unclear but widely distributed and cultivated throughout tropical Africa and Asia (Veasey et al., 1999). It is a fast growing, leguminous nitrogen (N2) fixing, multi-purpose tree adapted to subtropical and tropical environments (Makatiani and Odee, 2007). The centre of diversity is in Africa, and Egyptian riverhemp (Sesbania sesban) probably originated there (Evans, 1994). Genetic analysis of African populations by Jamadass et al. (2005) found the greatest diversity in East Africa.

The dried leaves of Egyptian riverhemp (Sesbania sesban)are known to be used in indigenous medicines and the preparation in the form of tea is believed to have antibiotic, antihelminthic, antitumor and contraceptives properties. The leaves and flowers are consumed as vegetable by humans, while the immature pods and young branches of Sesbania sesban have been reported to be eaten raw by ruminant animals like cattle and goats (Gohl 1981; Verboon, 1966).In India, the mature seeds have been reported to be eaten after cooking by tribal sets of Kharis and Ghondan (Siddhauraju et al., 1995).

Seeds flour has been reported to be used in the treatment of ringworm, skin diseases and wounds (Duke, 1981). The seed endosperm of Sesbania sesban are known to produce exudates (Anderson, 1989), which could have potential application in the food industry.

 

As small-scale farmers cannot afford to use chemicals (Wakjira et al., 2011) and improved feeds in their agricultural production system, they resort to the use of natural ways of replenishing soil fertility and feeding livestock through agroforestry.

Sesbania sesban has chemical constituents such as protein, sterol, saponin, flavonoid, fat, glycoside and good source of vitamins (Chartterjee and Pakrash, 1992). It is used in the treatment of ulcer, fever, purgative demulcent, pain reliever and as astringent (Yusuf et al., 1994).The plants also exhibit anti-inflammatory, and anti-microbial activities (Tatiya et al., 2008; Hossain and Chaudhary 2007: Ibrahim 1992; Sigh 1990;). They are excellent nitrogen fixers and capable of growing rapidly in nitrogen deficient soils, thus possess high utility in agroforestry as inter crop, cover crop, green manure, mulch and folder (Gopalakrishna, 2007).

Agglomeration of chemical, biochemical, clinical, and epidemiological evidences are denoting a positive correlation between the consumption of legume seeds and decreased incidence of several chronic diseases such as cancer, cardiovascular diseases, obesity, and diabetes (Bhathena & Velasquez, 2002). Such conspicuous health benefits of legume grains are ascribed to the existence of certain bioactive compounds, particularly the phenolic constituents (Shahidi & Naczk, 2004).

Flowers of Sesbania sesbanare known to be added to stews and omelettes in some areas in south India, perhaps mainly as a decorative or festive ingredient in foods (Kathiresh et al., 2011; Orwa et al., 2009; Pravin et al., 2012). Alagesaboopathi (2012) reported that decoction of the leaf is mixed with hot milk and given once a day for seven days for treatment of diarrhea, itches and skin diseases.

 

Legume grains play a pivotal role in the customary diets of human beings throughout the world. They are magnificent sources of protein, starch, dietary fibre, micronutrients, and bioactive compounds with low level of fat. The total per capital consumption of legume grains has increased considerably over the past two decades in USA, due to the aggravated attention given to them as functional foods (Luthria and Pastar-Corrales, 2006).

Underutilized crop species have a potential that needs to be exploited to our advantage. Most of these crop species do not require high inputs, can be grown in marginal and degraded lands and at same time contribute to increased agricultural production, crop diversification and a better environment.

It is since 1970s that different exotic multipurpose fodder trees like Sesbania sesban got promoted by different organizations in Africa to alleviate feed shortages (Mekoya et al., 2009b). Sesbania sesbana N2-fixing and deep rooting shrub with good-quality foliage and is one of the most promising species for short-duration cover cropping (Desaeger and Rao, 2001) and serve as protein supplement to poor quality roughages or as substitute for commercial protein supplements (Mekoya et al.,2009a).

Nigeria is one of the importers of agricultural produce, with a total food import bill 0f USD 4.2 billion annually (Olukunle, 2016).Demand for poultry meat, its consumption in the West Africa region outweighed its production; Nigeria being a highly populated country consumes approximately 1.2 million metric tons of poultry meat and produces approximately 290,000 MT of poultry meat (Ayisi and Adu, 2016).

The price of poultry meat in Nigeria may increase by 70% or more, because of increased prices of some foodstuffs (maize and soyabean) used in the production of livestock feeds. As such, there is need to replace these conventional foodstuffs with underutilized plant seeds.

In an attempt to address these challenges, efforts are being made to seek and develop novel feed ingredients in order to reduce the high cost of feeding livestock and competition for conventional feed ingredients. Sesbania sesban seed has potential as animal feed because of its high crude protein, energy and other essential nutrients needed by livestock (Arekemase et al., 2013). It is against this backdrop that the seed of Egyptian riverhemp (Sesbania sesban) was processed so that it can be used for livestock feed.

Several plants exist with high nutritive value and yet remain unexploited for human and animal benefit (Oladele and Oshodi, 2007). The reason for underutilization of Sesbania sesban seed is because of its high antinutrients and lack of awareness.

Egyptian riverhemp (Sesbania sesban) is a good source of protein which can be used to replace soyabean in the formulation of feeds for livestocks, but the major obstacle hindering the utilization is the presence of antinutrients particularly tannin. However, studies have shown that tannin can be reduced to a bearable level using slaked lime (Dakare et al., 2012) but the use of slaked lime to detoxify seeds of this plant may not be economically viable, especially to the people in the rural communities. Hence, there is need to explore the use of other alternatives processing methods such as lye which is cheap and easily available to rural communities.

 

To assess the effect of processing (lye treatment, boiling, soaking and slaked lime) on some nutrients and antinutrients composition of Sesbania sesban seeds

Processing has no effect on the nutrients and antinutrients compositions of Sesbania sesban seeds

Processing has no effect on nutrients and antinutrients composition of Egyptian riverhemp (Sesbania sesban)