PHYSICOCHEMICAL PROPERTIES OF OIL EXTRACTED FROM THE HOT AND COLD EXTRACTED RED PITAYA (HYLOCEREUS POLYRHIZUS) SEEDS

The red pitaya, Hylocereus Polyrhizus, well-known for its tasty pulp attached with sticky and mucilage coated seeds. The seed oils properties are highly influenced by the seed extraction techniques. Therefore, effects of two different seed extraction techniques on some quality characteristics of pitaya seed oil of the red cultivar, Hylocereus Polyrhizus were investigated. The techniques are referred as the hot and cold method applied in extracting clear mucilage free red pitaya seeds. The oil obtained from the seeds were analysed for its free fatty acids, peroxide, p-anisidine and the totox values. The fatty acids and triacylglycerols separated using analytical chromatographic technique. The free fatty acids value and the oxidation products measure of both methods showed no significant differences. The GC analysis for the hot extracted seed oil showed the presence of palmitic (15.712%), oleic (24.889%) and linoleic acid (48.699%) while the cold extracted seed oil exhibited slightly higher content of palmitic (15.778%), oleic (23.566%) and linoleic acid (49.807%). The HPLC analysis triacylglycerols of the pitaya seed oil showed Linoleic: Linoleic: Linoleic (LLL) and Oleic: Linoleic: Linoleic (OLL) dominated the TAG composition of the oil with the average percentage of 14.065% and 13.990% for the cold extracted seed oil and 15.620% and 15.795% for the hot one. The result shows that different seed extraction techniques influence the oil yield and the seed oils properties.