Protein Isolation and Proximate Evaluation of Sweet and Bitter Cassava Leaves (Manihot esculenta crantz)

Abstract

The need for an alternative source of protein has become pertinent due to the economic situation of developing countries. It has however been revealed by various studies that plant leaves are a good source of protein. Having realized that cassava is a plant that is readily available in tropical Africa, therefore, this project is centered on cassava leaves with the aim of preparing protein isolates and ultimately evaluate the proximate composition of the cassava leaf meal and its protein isolates. Both sweet and bitter cassava leaves were identified and obtained IITA Ibadan, Nigeria, the leaf meal was prepared and the protein isolate was subsequently obtained. Proximate composition analysis was carried out on both the leaf meals and protein isolates according to standard AOAC (2000). Protein digestibility was also carried out on the protein isolates. Sweet Cassava Leaf Protein Isolates possess 87.59% protein digestibility compared to Bitter Cassava Leaf Protein Isolates with protein digestibility of 88.73%. The moisture content was higher in Sweet Cassava Leaf Meal, 78.22% than that of Bitter Cassava Leaf Meal, 77.58%. Crude fibre content in Sweet Cassava Leaf Meal is 10.28% against 9.86% expressed by Bitter Cassava Leaf Meal. The Ash content found in Sweet Cassava Leaf Meal is 7.88% compared to 7.61% present in Bitter Cassava Leaf Meal. Furthermore, Sweet Cassava Leaf Meal contains 3.01% fat compared to 3.00% fat obtained in Bitter Cassava Leaf Meal obtained in Bitter Cassava Leaf Meal. The carbohydrate content is higher in Sweet Cassava Leaf Meal with 46.25% than Bitter Cassava Leaf Meal which contains 44.24%. Sweet Cassava Leaf Meal contains 39.59% protein while Bitter Cassava Leaf Meal contains 39.33% protein. Analysis carried out on the protein isolate revealed that Sweet Cassava Leaf Protein Isolate is higher (57.35%) than that of Bitter Cassava Leaf Protein Isolate (56.49%). The result obtained from this study revealed that cassava leaf is a good source of protein and their chemical supports the probability that they could find their use in food formulation and food supplementation.

Keywords: Sweet and bitter cassava, protein isolates, proximate composition