leafy vegetable that is important items of the diet in many Nigeria homes and they are valuable sources of nutrients especially in rural area where they contribute substantially to protein, minerals, vitamins, fibre and other nutrients which are usually in short supply in the daily diets(Mosha and Gaga 1999). They have the cheapest and most abundant sources of protein (Fasuyi 2006) and add flavour, taste, colour and aesthetic appeal to the diet (Mepha et al., 2007). Consumption of vegetable ensures the intake of various essential vitamins and minerals element thus avoiding the problem of malnutrition (Yamaguchi 1983). However, they contain anti-nutritional which reduce the bioavailability of some nutrients (Akindahunsi 2005).
Solanum macrocapon is the vegetable of interest in this study. It is popularly called African eggplant and locally called gbagba, gboma , anbergine,nyanya e.t.c. Solanum macrocapon is a widespread plant genus of the family solanaceae, which has over 1000 species worldwide with a least 100 indigenous species in Africa and adjacent island (Jaeger and Happer 1986). Solanum macrocarpon leaves represented in Nigeria by some 25 species including those domesticated with their leaves, fruit or both are eaten as vegetables or used in traditional medicine (Gbile and Adeshina 1988; Manoko et al., 2008). Solanum macrocapon is considerably high in calcium, iron, potassium and magnesium. It uses in indigenous medicine range from weight reduction to treatment of several ailments includes asthma, allergic rhinitis, nasal catarrh, skin infections, rheumatics diseases and swollen joint pains, gastro-oesophageal reflux disease, constipation and dyspepsia (Bello et al., 2005).
Solanum macrocarpon leaves are tough and do not readily get soften when heated as in blanching. Most consumers prefer to boil the leaves in order to soften the vegetables. This pre-treatment involves heat treatment at boiling temperature for a relatively longer period than the blanching process. The extra heat treatment has the tendency to cause nutrient loss.
Pre-treating vegetables by blanching in boiling water has been recommended in order to enhance the quality and safety of the dried vegetable. Blanching helps stop the enzyme activity that can cause undesirable changes in flavour and texture during storage. Blanching also relaxes tissues so pieces dry faster, helps protect the products vitamins and colour and reduces the time needed to refresh vegetables before cooking. This project intends to study the impact of these pre-treatments on the minerals and proximate composition of Solanum macrocarpon.
Due to the hardness and toughness of Solanum macrocarpon, its pre-treatment may affects significantly the concentration and availability of minerals, vitamins and other essential compounds in food. Losses of nutrients from the vegetable during the pre-treatment such as it’s done traditionally (boiling or addition of posh) and preservation method such as freezing most likely may affect the nutritional sensory quality of the vegetable. This study therefore is designed to investigate the effects of pre-treatments (boiling or addition of posh) on the nutritive value and sensory characteristics of Solanum macrocarpon (gbagba vegetable).