Structural, nutritional and protein functional properties of trichilia emetica and trichilia dregeana seeds=Izakhiwo Zesakhiwo, Ukudla Kanye Namaprotheni Asebenzayo Embewu ye-Trichilia emetica ne-Trichilia dregeana.

Abstract

Food and nutrition insecurity are prevalent in developing regions, especially in the predominantly low-economic status of sub-Saharan Africa. Yet, several edible domesticated and wild plants are grossly under-utilised as food sources. The woody plants Trichilia species are indigenous to Africa and are also found in other developing countries. Although the oily seeds of Trichilia species seem to have great potential for contributing towards the alleviation of malnutrition in the developing regions, they are grossly under-utilised and there is a dearth of scientific literature regarding their nutritional potential. To improve the utilisation of Trichilia seeds on a commercial scale, it is vital to study their physical characteristics and the nutritional and food-related (functional) physico-chemical properties of their components. In this study, the structural and chemical composition of Trichilia emetica (T. emetica) and Trichilia dregeana (T. dregeana) seeds, in addition to the nutritional and functional properties of their proteins, were investigated and compared with the soybean. The results of the seeds analysis showed that Trichilia seeds had difficulty sliding on surfaces due to their oblate shape. Trichilia seeds showed lower sphericity (0.66) than soybean (0.99), with higher bulk density (645.9 kg/m3 and 433.6 kg/m3, respectively) and lower true density (875.8 kg/m3 and 950.4 kg/m3, respectively). The porosities for T. emetica and T. dregeana were significantly lower (55.07% and 54.38%), with a higher geometric mean diameter (29.7mm and 16.9 mm) than soybean. Trichilia species showed similar shapes, but different localisation of the seeds‟ protein bodies when compared with soybean. Trichilia seeds‟ protein bodies were larger in size and more round in shape than those of the soybean. The other investigations in this study determined the nutritional properties of the flour and protein of T. emetica and T. dregeana seeds, and compared the chemical structure and functional properties of protein in the Trichilia seeds with the soybean. The results showed that T. emetica and T. dregeana seeds contained substantial protein (25.6% and 17.3%, respectively) and high concentrations of fat (49% and 51.5%, respectively). Potassium, calcium, iron and zinc were the major minerals in the Trichilia seeds. T. emetica and T. dregeana protein had substantial concentrations of Phenylalanine, Leucine, Isoleucine, Valine and Lysine and Methionine, which were comparable with those of the soybean. The concentrations of essential amino acids in Trichilia seeds, similar to their concentrations in soybean, were above the recommended Food and Agricultural Organisation standards for adults. The proportion of essential amino acids to total amino acids of T. emetica and T. dregeana seeds was similar to that of the soybean. The Trichilia spp protein had more β-conformation than α-helices (21%) comparable with soybean protein. The protein concentrates of T. emetica seed had higher Water holding Capacity, Foaming Capacity and Foaming Stability with lower Oil holding Capacity and Emulsion activity Index when compared with soybean and T. dregeana seeds. The findings of the current study indicate that the physical and nutritional properties of T. emetica and T. dregeana seeds and their protein properties had comparable properties to existing commercial oilseeds. This could improve the utilisation of the seeds as complementary foods and can cause an increase in the number of available food sources for food and nutrition security, thereby improving the livelihoods of individuals. However, there would be a need to modify the existing technologies for drying, milling, packaging and transportation to accommodate the Trichilia seeds. Furthermore, the bioavailability of the minerals and protein of the Trichilia seeds should be assessed.

Iqoqa Izitshalo ezinokhuni eziyizinhlobo zeTrichilia ziyindabuko e-Afrika futhi zitholakala nakwamanye amazwe asathuthuka. Nakuba imbewu enamafutha yezinhlobo zeTrichilia ibonakala inamandla amakhulu okufaka isandla ekunciphiseni ukungondleki ezifundeni ezisathuthuka, isetshenziswa kancane kakhulu, ikakhulukazi ngoba ayicwaningwa kakhulu, ngokwesayensi. Kulolu cwaningo, ukwakheka kwesakhiwo namakhemikhali eTrichilia emetica (T. emetica) kanye nembewu yeTrichilia dregeana (T. dregeana), ngaphezu kwezakhi zokudla nokusebenza kwamaprotheyni ako, kwaphenywa futhi kuqhathaniswa nobhontshisi wesoya.

Imiphumela ibonise ukuthi imbewu yeTrichilia yayinesphericity ephansi (0.66) kunesoybean (0.99), enenqwaba ephezulu (645.9 kg/m3 and 433.6 kg/m3, ngokulandelana) kanye nobuningi beqiniso obuphansi (875.8 kg/m3 and 950.4 kg/m3, ngokulandelana). Amaporosities e-T. emetica ne-T. dregeana ayephansi kakhulu (55.07% no-54.38%), ngegeometric ephakeme isho ububanzi (29.7 mm no-16.9 mm) kunobhontshisi wesoya. Imizimba yamaprotheyni yembewu yezinhlobo zeTrichilia yabonisa izimo ezifanayo, kodwa indawo ehlukile futhi yayinkulu futhi ijikeleza kakhulu uma iqhathaniswa nobhontshisi wesoya.

Ucwaningo lwathola ukuthi imbewu ye-T. emetica ne-T. dregeana iqukethe amaprotheyni amakhulu (25.6% no-17.3%, ngokulandelana) kanye nokujiya okuphezulu kwamafutha (49% no-51.5%, ngokulandelana). IPotassium, icalcium, i-iron nezinc kwakungamaminerali amakhulu embewini yeTrichilia. Amaprotheyni embewu yeTrichilia spp emibili ayenokujiya okukhulu kwama-amino acid abalulekile iPhenylalanine, iLeucine, i-Isoleucine, iValine neLysine neMethionine, eyayiqhathaniswa naleyo kabhontshisi wesoya futhi ngaphezu kwamazinga Enhlangano Yokudla Nezolimo anconyiwe kubantu abadala. Amaphrotheyni embewu yeTrichilia spp ayene-β- conformation kakhulu kune-α-helices (21%), eyayiqhathaniswa namaprotheyni kabhontshisi wesoya. Amaprotheyni okugxila kwembewu ye-T. emetica kwakunezinga eliphakeme lokumumatha amanzi, iFoaming Capacity kanye neFoaming Stability ene-Oil holding Capacity ephansi kanye nomsebenzi we-Emulsion Index uma kuqhathaniswa nembewu yesoybean ne-T. dregeana.

Sekukonke, okutholakele kubonisa ukuthi, ngemuva kokuguqulwa okuthile okudingekayo kwemishini yokucubungula yamanje, imbewu yeTrichilia ssp ingasetshenziswa endaweni yezimbewu zikashukela zokuhweba ezisetshenziswa njengamanje njengesoyabean, ezifundeni ezisathuthuka lapho iTrichilia ssp ivuma kakhulu.