Structural (gross and micro), physical and nutritional properties of Trichilia emetica and Trichilia dregeana seeds

Abstract

This study assessed the gross-structure, micro-structure, physical characteristics and nutritional composition of Trichilia emetica and Trichilia dregeana seeds. T. emetica and T. dregeana seeds have potential for commercialization and improved food security, yet they are under-utilized and under-researched. The gross- and micro-structure of the seeds was assessed using stereo microscopy, light microscopy (LM), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Protein, fat, ash, and mineral content of the seeds were also assessed. T. emetica and T. dregeana seeds had lower bulk density (393.5 kgm−3 & 433.6 kgm−3 respectively) and lower porosity (55.07% & 54.38% respectively) than soybean. Geometric mean diameter (29.7 mm & 16.9 mm) and aspect ratio (1.72 and 1.85) of T. emetica and T. dregeana seeds respectively, were higher than soybean, while they had lower sphericity (0.66 and 0.66 respectively) than soybean (0.99). Microscopy analysis showed that Trichilia species had larger-sized and more round-shaped protein bodies than soybean seeds. T. emetica and T. dregeana protein contents (25.6% and 17.3% w/w, respectively) were lower than soybean (45.4%) while fat contents (49% and 51.5% w/w, respectively) were higher than soybean (20.2% w/w). Potassium (1075–1350 mg100g−1) and calcium (285–300 mg100g−1) where the main macro-minerals while iron (6.33–6.83 mg100g−1) and zinc (2.30–2.90 mg100g−1) were the main micro-minerals. The research demonstrated that the structural and nutritional characteristics of T. dregeana and T. emetica seeds could facilitate their commercial utilization and application for food security alleviation.

Keywords

• oilseeds
• trichilia species
• seed microstructure
• indigenous seeds
• seed physical properties
• proximate composition
• micro-minerals
• macro-minerals