Effect of Roasting, Soaking and Alkaline Treatment on Chemical properties of Neem Seed (Azadirachta indica A. juss)

Neem (Azadirachta indica) products, particularly its seeds, have considerable scientific and economic importance because they contain bioactive compounds such as azadirachtin, a triterpenoid that is also present in other parts of the plant. Azadirachtin is widely recognised for its insecticidal properties, particularly its ability to suppress feeding and interfere with insect growth and reproduction. Despite these benefits, information concerning the suitability of neem seeds for safe human consumption remains limited. This study therefore evaluated the effects of selected processing methods, namely water soaking, alkaline treatment, and roasting, on the chemical composition of neem seeds. Based on preliminary investigations, the seeds were subjected to water soaking and alkaline treatment using NaOH for 24 h, while roasting was performed at 160°C for 10 min. For each treatment, 200 g of neem seeds was processed separately, with an untreated sample maintained as the control. The proximate composition, including crude protein, crude fat, crude fibre, ash, moisture, and carbohydrate contents, together with selected mineral elements (Ca, Na, Mg, P, K, Cu, Zn, Fe, Mn, and Se), was determined using standard AOAC procedures. The results showed that roasting increased the crude fat content of the seeds, while processing treatments produced measurable changes in their mineral composition. In particular, alkaline treatment increased the concentrations of sodium (40.20 mg/100 g), magnesium (49.10 mg/100 g), and phosphorus (39.30 mg/100 g). Water soaking also altered the proportional distribution of the proximate constituents, whereas alkaline processing enhanced the levels of several of the evaluated minerals. Overall, the findings demonstrate that processing conditions influence the nutritional and mineral characteristics of neem seeds, with different treatments producing distinct changes in their chemical composition.