Potential of High Methoxyl and Low Methoxyl Pectin Blend from Nigerian Citrus Sinensis Peels as an Emulsifier in Oil in Water Emulsion

The potential of pectin as an emulsifier in oil in water emulsions has increasingly attracted the interest of researchers especially in the food and beverage industry. This is partially because of its interesting diverse molecular structure and chemical properties which can be tailored and/or modified to achieve emulsification and in part because it is natural, safe and sustainable. This study sets out to evaluate the potential of High Methoxyl and Low Methoxyl Pectin Blend from Nigerian Citrus sinensis Peels as an Emulsifier in an Oil in Water emulsion. High Methoxyl(HM) and Low Methoxyl (LM) Pectin were extracted from Nigerian Citrus sinensis peels at different extraction conditions; Temperature 90⁰C, pH 4, Time 120mins, Extract to Ethanol Ratio 2 and Temperature 90⁰C, pH 1, time 120mins and Extract to Ethanol Ratio 0.5 respectively. These pectin were characterized for their solubility in oil, glycerine, hot and cold water, hot and cold alkali including their chemical properties such as moisture content, ash content, degrees of esterification, anhydrouronic acid content, methoxyl content, acetyl content, protein content, molecular weight and intrinsic viscosity. Oil in water emulsions were prepared with different HM-LM blend ratios (80:20, 50:50 and 20:80) and concentration (1%, 1.5% and 3%) respectively. These pectin formulated emulsions were evaluated for their emulsifying properties (creaming index, particle size, emulsion stability) and activity. HM and LM pectin were soluble in hot water and hot alkali, moderately soluble in cold water, formed precipitate in cold alkali and insoluble in oil and glycerine. Chemical characterization results of HM and LM pectin revealed moisture content, ash content, degrees of esterification, anhydrouronic acid content, methoxyl content, acetyl content, protein content, molecular weight and intrinsic viscosity; (12 and 8%), (1.014 and 1.124%), (78.164 and 28.256%), (70.928 and 51.92%), (9.765 and 2.584%), (1.236 and 1.344%), (3.323 and 1.619%), (405.627 and 61.697Kg/mol) and (146.47 and 9.913ml/g) respectively. It was observed that all HM-LM OPP (orange peels pectin) blends possessed effective oil in water emulsifying activity between 30-77%, emulsion stability index of between 40-77%, creaming index between 16-66% at storage conditions of 10 and 27⁰C for 28 days. These evaluation results portray pectin from Nigerian citrus sinensis peels as a natural, sustainable and potential emulsifier in oil in water emulsion.