Changes in volatile compounds of palm sap (Arenga pinnata) during the heating process for production of palm sugar

This study was carried out to determine the changes of volatile compounds composition during palm sugar production. The samples were collected at every 30 min interval for 4 h of heating process at 150 °C from a local traditional manufacturer in Kuala Pilah, Malaysia. The analyses were performed by gas chromatography–mass spectrometry after headspace solid phase micro extraction. The results showed that N-heterocyclic chemical class possessed the highest relative percentage area (RPA) 83.69%, followed by O-heterocyclic group with RPA of 14.5%. Main volatile compounds the determined were 5-methyl-6,7-dihydro-5H-cyclopenta pyrazine and 4-hydroxy-2,5-dimethyl-3(2H) furanone which were responsible for roasty and sweet caramel-like aroma notes, respectively. The pyrazine compounds increase exponentially with heating time but furan derivatives compounds were formed at a later stage, i.e. at 180 min of heating time and above 105 °C.