Effects of Drying Procedures on the Nutritional, Biochemical and Phytochemical Compositions of Cola nitida Seeds

The effects of drying methods on the proximate compositions and phytochemical constituents of Cola nitida seeds were investigated by exposing the kola nuts to different drying procedures. The fresh C. nitida seeds were sorted and divided into four portions with each portion subjected to air-drying (AID), solar drying (SOD), oven-drying (OVD) and sun-drying (SUD) respectively. The results obtained markedly revealed that the proximate property of C. nitida seeds varies from one drying method to the other with OVD retaining the highest moisture and fat contents but has the least ash contents. On the other hand, air-dried C. nitida samples with the maximum carbohydrate composition had the lowest fat, protein and fiber contents. The protein and ash contents of the sun-dried samples were the highest while SOD showed the least moisture and peak fiber contents respectively. Furthermore, it was observed that the phytochemical composition of C. nitida seeds on exposure to these drying procedures differs with the drying methods. Apparently, the air-dried nitida samples had the highest level of total phenols, tannins, alkaloids with good amounts of saponins. However, solar-dried C. nitida seeds which are rich in alkaloids had the least tannins, phenols and saponins composition. The trend of result from this present study revealed that the different drying methods employed in the post-harvest processing of Cola nitida seeds markedly affect the nutrient retention and bioactive constituents of kolanut.