Stability study of honey, black seed oil, and olive oil emulsions with lechitin as the emulsifier

Background: Manufacture of herbal honey (mixture of honey, black seed oil, and olive oil) have a problem to produce stable mixture. The addition of synthetic emulsifier can lead the stable mixture, but it has side effect. Natural emulsifier like lecithin can replace synthetic emulsifier to mix the herbal honey. Objective: The aim of this research is to analyze the influence of adding lecithin emulsifier on the stability of a mixture of herbal honey. Methods: Stability tested herbal honey mixture with 4 kinds of ways, namely centrifugation, cycling test, viscosity test, and the test particle size. Results: Centrifugation test results in a mixture of herbal honey with lecithin below 5% w/w in oil mass not show phase separation. The addition of lecithin after a certain threshold will increase the viscosity of the mixture. The addition of 5% w/w lecithin total mass of oil into the mix with the oil concentration of 7.5% w/w gives a minimum viscosity, cp 4870. Cycling test performed at 4°C refrigerator and oven 40°C for 24 hours each 3 times. Cycling test result does not indicate the availability of crystallization or phase separation. Analysis of PSA (Particle Size Analyzer) showed that the addition of lecithin causes enlargement of the particle size. The average particle diameters of herbal honey mixture without lecithin as big as 6.3 μm while herbal honey with lecithin mixture of 1% of the total oil is at a 4.67 μm. Conclusion: From this study it can be concluded that the use of lecithin 1-5% w/w of the total mass of oil (concentration from 7.5 to 10%) can produce stable mixtures.