Postharvest Changes in Physicochemical Properties and Levels of Some Inorganic Elements in Sugar Apple (<i>Annona squamosal</i> L.) Fruits of Coast Region, Tanzania

Abstract

The physicochemical composition of sugar apple (Annona squamosa L.) fruits from Kibaha, Coast Region during open air storage ripening process were determined. The ash, titratable acidity, crude fat, crude fiber, moisture and sugars content were determined by proximate analysis. Ascorbic acid contents were determined using the 2,6-dichlorophenol-indophenol dye method while mineral elements and heavy metals were determined by Flame Atomic Absorption Spectrophotometry (FAAS). The fruits were always harvested at the mature stage and allowed to ripen during open air storage. The determinations were done immediately after arrival at the laboratory and thereafter at intervals of two days from the day of harvest to the 8th day. The results showed that fresh sugar apple fruits had high moisture content range of (64% - 73%), low titratable acidity (<0.28% ca), low crude fat (0.51 g/100 g-fw), high ash content (1.44 g/100 g-fw), low crude fibre content (0.185 g/100 g-fw), high ascorbic acid content (51-34 mg/100 g-fw), high total sugars content (49.7% - 31.1%), moderate reducing sugar content (43.17% -18.57%) and sucrose content (11.8% - 0.9%). Of the mineral elements (K, Ca and Na) determined, the highest content was of Ca (2838.82 mg/100 g-fw.). Heavy metals (Fe, Zn, Cu, Pb and Cd) content was very low in the sugar apple fruits, ranging between <0.0015 mg/100 g-fw for Cd and 1.27 mg/100 g-fw for Fe. Except for acidity and ascorbic acid contents which were decreasing during storage ripening, the moisture content, total sugar content, reducing sugar content and sucrose were all increasing as the fruit was ripening while in storage. There were no significant changes during storage ripening for levels of crude fat, ash, minerals and heavy metals. The results of this study suggest that these fruits could highly contribute in the improvement of the nutrition of consumers.