3.3. Colour, clarity, NEBI, and HMF content Significant differences in colour of juice samples were observed after both treatments (UV-C and thermal) when compared to the control (Table 3). According to Cserhalmi et al. (2006), the differences in colour parameters (E) can be classified as not noticeable (0 < E < 0.5), slightly notice-able (0.5 < E < 1.5), noticeable (1.5 < E < 3.0), well visible(3.0 < E < 6.0) and greatly visible (6.0 < E < 12). The U15 sample showed the least variation from the control, therefore falling within the ‘slightly noticeable’ range. This is consistent with the study conducted by Caminiti et al. (2012) on UV-C treated orange and carrot juice blend, where ‘slightly noticeable’ colour changes were observed. In addition, an increase in E corresponding to increased UV-C treatment time was observed, as previously reported by Bhat et al.(2011) and Zhang et al. (2011). With regard to thermal pasteurized samples, ‘well visible’ colour changes were observed. Similarly, significant colour degradation in thermal treated pineapple juice was reported by Rattanathanalerk et al. (2005).