Physical properties and chemical composition of soursop (Annona Muricata L.), Sugar apple (Annona Squamosal L.) and pomegranate (Punica Granatum L.) fruits of Tanzania

The physical properties and chemical composition of soursop (Annona Muricata L.). Sugar apple (Annona squamosal L) and pomegranate (Punica Granatum L) fruits from Dar es salaam and Coast regions were determined. Proximate composition (moisture, titratable acidity, sugars, ash, crude fibers and crude fat content) were determined by proximate analysis, the ascorbic acid contents were determined using the 2,6- dichlorophenol – indophenol dye method, and minerals (Ca, Na and K) together with heavy metals (Fe, Cu, Zn, Pb and Cd) were determined by Flame Atomic Absorption Spectrophotometry. The results showed that pomegranate fruits from Kimara, Dar es Salaam had the highest average moisture content range of 77.45% - 89.63% followed by soursop from Mkuranga with a range of 73.08%-80.53% and lastly sugar apple fruits from Kibaha with a range of 63.95%-73.13%. Sugar apple fruits had the highest total sugar content 31.05% - 49.70%) and reducing sugar content (18.57%-43.17%) while soursop had the highest sucrose content (15.48% -30.03%). All the fruits had moderate titratable acidity (<1.25%) however sugar apple fruits were the least acidic (0.12%). The ash content of the fruits ranged from 0.35 to 1.44g/100 g fresh weigh. The crude fat content was low in all the fruits (<0.51 g/100 g-fw) and the crude fiber content ranged between 0.18 – 6.06 g/100 g-fw. On harvest the ascorbic acid content was highst (53.70 mg/100 g-fw) in pomegranate fruits, followed by sugar apple fruits (51 mg/100 g-fw) and lowest (34.01 mg/100 g-fw) in soursop fruits. The measured ascorbic acid levels were lower than the Recommended Daily Allowance (RDA) of 75-90 mg of ascorbic acid per day. Of the mineral elements measured, calcium content was the highest (2838 mg/100 g-fw) in sugar apple followed by 1450 mg/100 g-fw in pomegranate and 87030 mg/100 g-fw) in soursop fruits. Except for potassium the contents of sodium and calcium in all the fruits were higher than the RDA. Heavy metal content was low in all the fruits. These heavy metal levels were below the RDA and FAO values for the fruits.