Effect of thermal processings on physical, chemical properties and volatile compounds of coconut (Cocos nucifera L.) sugar

The objectives of this research were to study the physical, chemical properties and volatile compounds of both coconut sap and sugar and changes in the physical, chemical properties and volatile compounds of coconut sugar during heating processes. The physical, chemical properties including moisture content (MC), water activity (aw), total soluble solids (TSS), color parameters, intimidated browning product (IBP) and browning index (BI) values and volatile compounds were determined. The coconut sap was heated at 110 and 120oC for 6 and 4.5 hours, respectively. The physical, chemical properties and volatile compounds of coconut sugar were investigated. The results found that the MC and aw decreased with increasing heating times while TSS increased with the times for both of heating temperatures of 110 and 120ฐC. The color parameters for both heating temperatures of 110 and 120ฐC fell in the same trend showing that the L* decreased, a*, b*, IBP and BI values increased with the heating times. The major volatile compounds found in coconut sugar for both temperatures were 2, 3-dimethyl pyrazine, 2, 5-dimethyl pyrazine, 2-methyl pyrazine and 5-methyl furfural. Most of volatile compounds increased with the heating times. Thus, along heating time could be applied to develop the aroma of coconut sugar.