Physicochemical characterisation of oil palm (Elaeis guineensis) trunk syrup from the sap of different storage period as potential sweetener

Sap from the trunk of oil palm (Elaeis guineensis) was processed into syrup in this study. Physicochemical properties of syrups produced from the sap of freshly cut oil palm trunks (OPT0syrup) and sap of trunks stored for 60 days (OPT60syrup) at ambient temperature were compared to nipa palm syrup (Nsyrup), maple syrup (Msyrup), and two commercial glucose syrups (G1syrup and G2syrup). The total soluble solids for the syrups (OPT0sy, OPT60sy, Nsy, Msy, G1sy and G2sy) were in the range of 66 to 82 ˚Brix. The sugar analysis indicated that glucose was the main sugar for OPT0sy and OPT60sy as 367 and 300 mg/g, respectively, whereby sucrose was the foremost sugar for Nsy and Msy. The colour of the syrups was ranked from the darkest to the lightest; OPT60syrup > OPT0syrup > Msyrup > Nsyrup > G1syrup > G2syrup. OPT0syrup and OPT60syrup achieved reducing capacity of 825 and 886 mg GAE/100 g, respectively, significantly higher than other syrups. The free radical scavenging activities of OPT0syrup and OPT60syrup were 74% and 70%, respectively. In conclusion, the oil palm trunk syrup has similar physicochemical properties with the commercial syrups, and it has the potential to be an alternative to the commercial sweeteners with added nutritional benefits.