## 4 Discussion  
The final heating temperature used during the evaporation process considerably impacts the flavor quality of NCS. Higher temperatures may accelerate Maillard reaction and other thermal degradation processes, resulting in higher volatile compound concentrations [2; 11; 14]. This outcome is consistent with that of a previous study on modifying the heating temperature, which affected not only the physical properties of NCS, such as color and moisture content, but also its volatile Maillard reaction products [2]. In this study, the relative increases in concentrations of furans (2-acetylfuran, 5-methyl-2-furanaldehyde, furfural, 5-methyl-2-furanmethanol, and 2-furanmethanol), furanones (dihydro-2-methyl-3(2H)-furanone), a pyranone (2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one), a pyrazine (2,3,5-trimethylpyrazine), and a pyrrole (2-acetylpyrrole) were greater than 90% in the NCS obtained at the evaporation temperature of 140 \({}^{\circ}\)C compared to that in the NCS obtained at the lowest applied evaporation temperature. Increased levels of furans in the NCS may enhance desirable aromas, such as the nutty-sweet odor (2-acetylfuran), brown caramel-sweet odor (5-methyl-2-furanaldehyde and furfural), fruits-sweet odor (5-methyl-2-furanmethanol), and nutty-roasted odor (2-furanmethanol) [15] (the aroma descriptions were also retrieved from [[http://www.thegoodscentscompany.com/](http://www.thegoodscentscompany.com/)]([http://www.thegoodscentscompany.com/](http://www.thegoodscentscompany.com/)), accessed on 20 October 2024). Augmented buttery-toasted, sweet-map-like, nutty-earthy-roasted, and herbaceous-metallic scents in this NCS may also be attributed to dihydro-2-methyl-3(2H)-furanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 2,3,5-trimethylpyrazine, and 2-acetylpyrrole, respectively [15]. Among the individual compounds, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, furfural, and 2-furanmethanol were predominant in the NCS produced at 140 \({}^{\circ}\)C, emphasizing the temperature dependence of their formations. These compounds provide distinct aroma qualities to various brown sugars of different origins that greatly contribute to their overall flavor quality [15; 16]. Thus, manufacturers can enhance flavor substances in NCS, particularly Maillard reaction products, by optimizing the thermal processing conditions, which are also responsible for forming darker colors in NCS and other foods [15; 17]. However, the decline in certain aldehydes, such as hexanal and heptanal, suggests thermal instability as they decompose or react further at higher temperatures [18]. Similarly, the decrease in 2-pentylfuran and [R-(R*,R*)]-2,3-butanediol indicates that some of these molecules may either volatileize or break down during heating. PTR-TOF-MS retronasal monitoring analysis revealed the real-time detection of volatiles during tasting, providing detailed insight into how aroma compounds from NCS evolve in an in vivo consumption environment. The aroma release plots indicated that different evaporation temperatures during NCS production greatly affected the progression of volatile compounds toward the olfactory receptors in the nasal cavity, which is consistent  
Figure 4: Sensory characteristics of non-centrifugal cane sugar (NCS) obtained at different evaporation temperatures. Significant differences between groups were observed at \(p<0.05\) as represented with different letters as follows: *1 120 \({}^{\circ}\)C (b), 130 \({}^{\circ}\)C (ab), 140 \({}^{\circ}\)C (a); *2 120 \({}^{\circ}\)C (b), 130 \({}^{\circ}\)C (b), 140 \({}^{\circ}\)C (a). with the SPME-GC-MS results (Figures 2 and 3b vs. Table 1). Thus, the volatile compounds from NCS produced at higher temperatures were more prominently perceived in both the mouth and nose retronasal pathways. Similar studies have also reported that higher roasting temperatures enhance the release of desirable volatile compounds in food products, such as bread and tea, leading to more intense aroma perceptions [17; 19].