Production and quality assessment of mayonnaise from blends of soybean oil and african pear (<i>Dacryodes edulis</i>) pulp oil

Abstract

Mayonnaise is an oil-in-water emulsion rich in calorie, micronutrients and fat-soluble vitamins which is produced from dominantly vegetable oil. African pear oil is a highly unsaturated oil, domestically and commercially underutilize with tonnage of postharvest losses. It presently, has little or no industrial attraction for use as commercial ingredient for food production and formulation. The aim therefore is to improve the commercial value of African pear pulp oil for use as a main ingredient in food applications, hence improving its utilization and reducing postharvest losses. Oil was extracted from African pear through Soxhlet extraction using n-hexane as the solvent and the extracted oil was blended with soybean oil in the following ratios: SO100:APO0 (Control), SO0:APO100, SO85:APO15, SO75:APO25, SO65:APO35, and SO50:APO50 for the production of mayonnaise. Some physicochemical properties of the oil blends were evaluated while proximate and sensory properties were also evaluated in the produced mayonnaise. Blending increased the
iodine, acid and free fatty acid values of the oil blends and decreased significantly (p < 0.05) the peroxide value. The values ranged from 30.65 to 124.00 g iodine 100g^–1, 6.85 to 2.57 mg KOH g^–1, 5.03 to 1.91% and 2.62 to 3.50 meq O₂ kg^–1 for iodine, acid, free fatty acid and peroxide values, respectively. The proximate composition parameters of the mayonnaise samples increased significantly (p < 0.05) after blending. The values ranged from 32.65 to 35.04% for moisture, 1.12 to 1.44% for ash, 30.15 to 37.15% for fat, 1.93 to 2.31% for protein and 25.87 to 34.15% for carbohydrate. Significant improvement was recorded in the values of vitamin E, iodine and viscosity values of the mayonnaise samples after blending compared to the control with values ranging from 4.97 to 22.60 mg 100g^–1 for vitamin E, 28.70 to 88.10 g iodine 100g^–1 for iodine value and 24.70 to 30.13 Pa.s for viscosity. Sensory evaluation showed that the mayonnaise samples were generally acceptable by the panelists. Conclusively, blending soybean oil with African pear oil up to 50:50 could be used in the production of acceptable mayonnaise with higher fat, protein, ash, vitamin E, iodine value and viscosity, thereby reducing its postharvest losses through improved utilization.