Extraction of pectin from pistachio hull and its use in emulsion system

The aim of this study is to obtain pectin from pistachio hull and to investigate the emulsifying properties of pectin obtained in the oil-in-water emulsion system. Extraction was carried out by using two different methods, conventional extraction (CE) and ultrasound-assisted extraction (UAE). Two different extraction solvents, water and citric acid solutions were used separately as extraction solvents. While the highest yield (32.3±1.44%) was obtained using citric acid solution in CE method, the lowest yield (5.56±0.25%) was obtained using water in UAE method. The physical and chemical properties of the pectin obtained were determined. The results showed that pectin obtained under optimum conditions was low methoxyl (about 19.29% DE) with moisture content of 4.9±0.062%, ash content of 1.49±0,026%, protein content of 1.85±0.14%, total phenolic content of 6.03±0.08 mg GAE/g, total sugar content of 56.84±2.36 mg sugar/g, and acidity of 38.94±0.17%. The galacturonic acid content had been found as 65.81%. Additionally, the emulsifying property of pectin extracted was investigated in an o/w emulsion system. O/W emulsions were prepared at six different pectin concentration (2, 4, 5, 6, 8 and 10% (w/w)) and at fixed oil ratio (20% (w/w)). Emulsion performance was investigated in terms of emulsion stability, morphological characteristics, droplet size and rheological properties were examined. The best emulsion characteristics were obtained at 6% pectin concentration.