Lightness ab Ratio and Hue angle

4.1.5. Sepal color

4.1.5.1. Lightness

Sepal colo r is the most important criterion and strongly affects consumers‟ acceptance when purchasing mangosteen fruit. The lightness of mangosteen fruit sepal gradually decreased over storage time Figure 12, 13. CPPU had no effect on sepal lightness among observed days, except day 14 Appendix table 9. At day 14 CPPU 30 ppm could better maintain lightness higher L value. Application of CoSO 4 at applied concentrations could reduce sepal lightness of mangosteen fruit during prolonged storage with statistical significance at day 2, day 14, day 24, and day 30. CoSO 4 2000 ppm tended to substantially accelerate sepal darkening during storage, especially at the end of storage Appendix table 9. Figure 12. Changes in sepal color L of mangosteen fruit treated with CPPU during storage. 10 20 30 40 50 60 4 8 10 12 14 16 18 24 30 S ep al color L Storage time days 0 ppm 10 ppm 20 ppm 30 ppm Figure 13. Changes in sepal color L of mangosteen fruit treated with CoSO 4 during storage.

4.1.5.2. ab Ratio and Hue angle

ab ratio of mangosteen fruit sepal at the initial storage was negative, implying that the sepal was very fresh and green. However, sepal turned brown over prolonged storage with an increase in ab ratio Figure 14 and Figure 15, and decreased hue value as shown in Figure 16, and Figure 17. The brown color was due to the degradation of chlorophyll, synthesis of other pigments and loss of water. Figure 14. Changes in sepal color ab of mangosteen fruit treated with CPPU during storage. 10 20 30 40 50 60 4 8 10 12 14 16 18 24 30 S ep al color L Storage time days 0 ppm 500 ppm 1000 ppm 2000 ppm -0,05 0,00 0,05 0,10 0,15 0,20 0,25 0,30 0,35 4 8 10 12 14 16 18 24 30 S ep al color ab Storage time days 0 ppm 10 ppm 20 ppm 30 ppm Figure 15. Changes in sepal color ab of mangosteen fruit treated with CoSO 4 during storage. Figure 16. Changes in sepal color h o of mangosteen fruit treated with CPPU during storage. -0,05 0,00 0,05 0,10 0,15 0,20 0,25 0,30 0,35 4 8 10 12 14 16 18 24 30 S ep al color ab Storage time days 0 ppm 500 ppm 1000 ppm 2000 ppm 10 20 30 40 50 60 70 80 90 100 4 8 10 12 14 16 18 24 30 S ep al col or h o Storage time days 0 ppm 10 ppm 20 ppm 30 ppm Figure 17. Changes in sepal color h o of mangosteen fruit treated with CoSO 4 during storage. Table 3 showed that there were significant interactions between CPPU and CoSO 4 on ab ratio of mangosteen fruit sepal at day 22 and day 26. The ab was significantly higher in fruit treated with CPPU 0 pmm + CoSO 4 2000 ppm 0.37 than control 0.27 at day 22. At day 26, CPPU 30 ppm and CoSO 4 2000 ppm gave higher ab 0.41 and statistically significant compared to control fruit with ab only 0.27. The result showed that application of Cobalt Sulphate was likely to accelerate redness of the sepal increase a value as seen in appendix table 10. Table 3. Effects of CPPU and CoSO 4 interaction on ab ratio of sepal of mangosteen fruit during storage at d22 and d26 Day CPPU ppm CoSO 4 ppm 500 1000 2000 22 0.27 c 0.30 bc 0.27 c 0.37 a 10 0.33 ab 0.30 bc 0.30 bc 0.30 bc 20 0.34 ab 0.29 bc 0.31 bc 0.34 ab 30 0.29 bc 0.30 bc 0.33 ab 0.33 ab 26 0.34 bc 0.31 bcd 0.27 d 0.35 ab 10 0.36 ab 0.31 bcd 0.31 bcd 0.33 bc 20 0.35 bc 0.30 bcd 0.35 bc 0.36 ab 30 0.30 bcd 0.29 cd 0.32 bcd 0.41 a Note: Different letters indicate significant differences among treatment means P 0.05 by Duncan‟s ultiple range test DMRT 10 20 30 40 50 60 70 80 90 100 4 8 10 12 14 16 18 24 30 S ep al color h o Storage time days 0 ppm 500 ppm 1000 ppm 2000 ppm As shown in Table 4 control fruit had higher hue angle and significantly different from fruit treated with CPPU 0 ppm + CoSO 4 2000 ppm, CPPU 20 ppm + CoSO 4 2000 ppm, and CPPU 30 ppm + CoSO 4 2000 ppm at day 22. Hue angle of fruit treated with CPPU 0 ppm + CoSO 4 1000 ppm was significantly higher from the combination of CPPU 30 ppm + CoSO 4 2000 ppm, and control fruit at day 26. Table 4. Effects of CPPU and CoSO 4 interaction on hue angle of sepal of mangosteen fruit during storage at day 22 and 26 Day CPPU ppm CoSO 4 ppm 500 1000 2000 22 75.13 a 73.03 abc 74.81 ab 69.90 d 10 71.88 bcd 73.20 abc 73.20 abc 73.53 abc 20 71.52 bc 73.66 abc 72.80 abc 70.99 cd 30 73.91 abc 73.24 abc 71.56 cd 71.51 cd 26 71.33 bc 72.94 abc 75.01 a 70.43 cd 10 70.22 cd 72.56 abc 72.80 abc 71.54 cd 20 70.83 cd 73.18 abc 70.96 bc 70.32 cd 30 73.18 abc 73.69 ab 72.17 abc 67.64 d Note: Different letters indicate significant differences among treatment means P 0.05 by Duncan‟s multiple range test DMRT.

4.1.6. Visual Observation