Determination of some engineering properties, proximate composition and phytochemical properties of African star apple (chrysophyllum albidum)

Abstract

African star apple (Chrysophyllum albidum) is a popular tree in tropical region with all the parts used for food and medicinal purposes. This study focused on the determination of some physical properties, mechanical properties, proximate composition, and phytochemical properties of the fruit. The experiment was conducted using standard procedures. Results for the physical properties of the fruits have values as follows: length per fruit 3.41 – 5.53 cm, width per fruit 3.31 – 5.08 cm, and thickness per fruit 2.93 – 4.73 cm, respectively. The density was found to be 1.073 gcm^-3. The volume, angle of repose, geometric mean diameter, arithmetic mean diameter, sphericity was 47.55 cm³, 4.74 cm³, 4.13 cm³, 4.85 cm³ and 0.88 cm³ respectively. The seed constituted 24.1 – 27.8 % of the weight of fruit, while the pulp, peel and juice 52.5 – 55.5 %, 19.7 – 22.5 %, and 3.8 – 5.3 % respectively. The result for the mechanical properties for maximum compressive stress (MPa) was 0.0519 – 0.1193 and mean of 0.0908 with standard deviation and coefficient of variation of 0.0252 and 0.2775 % respectively for the longitudinal orientation, and 0.062 – 0.0854 and mean of 0.0739 with standard deviation and coefficient of variation of 0.0094 and 0.1299 % respectively for the transverse orientation. The coefficient of internal friction for the fruit was 0.083. The result of the proximate composition of the fruit showed that the juice component contained 76.20 – 76.50 % moisture, 4.20 – 4.40 % fat, 3.4 – 3.6 % crude protein, 2.00 – 2.20 % ash, 10.00 – 10.10 % carbohydrate and 3.6 - 3.9 % crude fibre. The African star apple was also found to contain high nutrients and minerals such as calcium, 413.20; potassium, 654.21; sodium, 53.61; magnesium, 203; iron, 2.160; and β -carotene content 367.92 - 368.11 mg/100 g with low anti nutrient such as tannin, alkaloid, flavoid, steroid etc. and this make it advisable to be consumed as snacks by all.