PROXIMATE COMPOSITION, MINERAL CONTENT AND THE EFFECT OF ETHYLENE GLYCOL AND ETHANOL (NON-AQUEOUS SOLVENTS) ON THE FUNCTIONAL PROPERTIES OF PROTEIN CONCENTRATES OF CITRULLUS COLOCYNTHIS L.

Abstract - Determination of proximate composition, mineral content, and the effect of ethylene glycol and ethanol at varied pH on the functional properties using standard methods were carried out on the protein concentrates of two samples of Gourd Melon (Citrullus colocynthis L.), one containing hull and the other without hull. Results for the proximate composition for the sample without hull gave 3.99% Moisture Content, 5% Ash Content, 16.455% Fat Content, 52.875% Crude Protein, 6.855% Crude Fibre and 10.342% for Carbohydrate by Difference. Also the results for the proximate composition of sample containing hull gave 5.09% Moisture Content, 7% Ash Content, 19.835% Fat Content, 45.313% Crude Protein, 20.40% Crude Fibre and 6.842% Carbohydrate by Difference. The Least Gelation Concentrations for both samples were studied at different concentrations of ethylene glycol-water and ethanol-water mixtures. The Solvent Absorption Capacity and the Oil Absorption Capacity of the two samples were also studied in different concentrations of the two different solvent mixtures. Solvent Absorption Capacity was found to be higher in ethanol-water than in ethylene glycol-water, and also higher in sample containing hull than the sample without hull. The Oil Absorption Capacity of sample without hull was found to be less than sample containing hull. It was also found that the Oil Absorption Capacity of the two samples is higher in ethylene glycol-water than in ethanol-water mixtures. Emulsion Capacity, Emulsion Stability, Foaming Capacity, Foaming Stability were investigated in different concentrations of ethylene glycol-water and ethanol-water mixtures for the two different samples under standard conditions. Foaming Capacity (FC) for both samples increased with increasing concentration of ethylene glycol-water and ethanol-water mixtures, while Emulsion Capacity (EC) for the two different samples decreased with increasing solvent concentration. The Emulsion Capacity (ES) for booth samples were nearly constant.

The Protein Solubility of the two different samples (sample containing hull and sample without hull) were investigated at different pH in different concentrations of ethylene glycol-water and ethanol-water mixtures. The results indicated that non-aqueous solvent has effect on the functional properties of the samples.