Colour - Results and Discussion - EVALUATION OF THE EFFECTS OF THE SUPPLY CHAIN ROUTES, MATURTY

4. EVALUATION OF THE EFFECTS OF THE SUPPLY CHAIN ROUTES, MATURTY

4.3 Results and Discussion

4.3.1 Colour

The full layout of all treatment combinations as per experimental design is presented in Appendix F and analysis of variance in Appendix I. Discussed below are typical examples outlining the key findings on tomato colour. The results revealed highly significant difference (P < 0.001) between the hue angle of tomatoes harvested in different seasons, across all different supply routes. Generally, fruit that were harvested in winter had higher hue angle than the ones harvested in summer (Figure 4.3a). Similar results were shown in Figures 4.3, 4.4 and 4.5 for the different maturity stages, storage conditions and across different supply routes. This implies that the rate of tomato fruit ripening was slower in winter than in summer, which resulted in fruit harvested in winter having longer shelf life. The grand mean hue angle for the winter harvest and summer harvest was 45.95 and 44.28, respectively (Figure 4.3a). The results

0 5 10 15 20 25 30

13th June 15th June 17th June 19th June 21st June 23rd June 25th June 27th June 29th June 1st July 3rd July

Temperature (°C)

Time (days)

Winter

Ambient Cold a

0 5 10 15 20 25 30

13-Sep-15 15-Sep-15 17-Sep-15 19-Sep-15 21-Sep-15 23-Sep-15 25-Sep-15 27-Sep-15 29-Sep-15

Temperature (°C)

Time (days)

Summer

Ambient Cold b

revealed a highly significant (P < 0.001) difference between the hue angle of tomatoes from different supply routes, with the average hue angle being highest in fruit from Pontdrift, Letaba Municipality and then Esmè4. The average hue angle of tomatoes was 46.89; 45.83; and 42.62 for tomatoes from Pontdrift, Letaba Municipality and Esmè4, respectively (Figure 4.3d).

The hue angle also varied significantly (P < 0.001) with fruit maturity stages. Green-matured tomatoes had the highest average hue angle (53.78), followed by pink (43.13), then red (38.42) (Figure 4.3c). Similar results were reported by Wang et al. (2011) whereby the tomato hue angle was continuously decreasing with fruit ripening. Viskelis et al. (2008) also reported a significant (P < 0.05) reduction in the hue angle of different tomato cultivars as they turn from green to red-ripe. Cold storage environment significantly (P < 0.001) reduced the rate of ripening, colour change or hue angle reduction. Similar results were reported by Tilahun (2010), whereby cooling system significantly (P < 0.05) reduced the rate of colour change thus ripening in tomatoes of different maturity stages. The average hue angle of cold stored fruit was 54.17 while fruit from ambient storage had 36.06. The hue angle was observed to reduce over time. The highest rate of colour change occurred during the first 8 days of storage. This applied in both storage conditions with the rate of colour change being higher at ambient than at cold room conditions.

The rate of colour change or hue angle reduction significantly (P < 0.001) varied with pre- storage treatments. HWT + GA was a leading treatment in terms of delaying rate of hue angle reduction, followed by anolyte water + GA, GA only, anolyte water only, and then the control (Figure 4.2). Therefore, according to the hue angle results, HWT + GA combination treatment is most effective in delaying the physiological, biochemical and chemical processes associated with tomato colour change (ripening). Contrastingly, the marketability and firmness test revealed anolyte water as the best treatment in delaying tomato ripening process. HWT + GA delayed ripening process especially in green-matured tomatoes. However, it caused irregular ripening (Figure 4.2). On the other hand, green-matured tomatoes treated with anolyte water had fast rate of colour change i.e. quick hue angle reduction (Figure 4.2 a). However, these tomatoes resulted in the longest shelf life of 4 and 7 additional days at ambient and cold storage, respectively. Similar pattern applied to green matured tomatoes stored at cold conditions, however, the rate of colour change was slow.

Figure 4.2 Colour change in tomatoes from Letaba Municipality (EM) with treatments:

a=Anolyte water treatment, b = Gum Arabic Coating, c = Anolyte+ GA, d = HWT+GA and e = Control, during day 8 of sampling at ambient storage

Integrated treatments involving tomatoes harvested at green maturity, pre-storage treatments and cold storage conditions resulted in the rate of hue angle reduction being reduced significantly. These findings were most superior to the effects individual technologies involved. This resulted in an idea that, a holistic approach could be the better approach in sustaining quality and extending shelf life of tomatoes.

(a) (b) (c) (d) (e) E

100 % Red 80% Red 60% Red 20% Red 100% Red

Tomatoes harvested at green matured

Figure 4.3 The effect of harvesting seasons (a), storage condition (b), maturity stage (c), and supply routes (d) on the colour (hue angle) 41

42 43 44 45 46 47 48

Winter Summer

Hue angle (h°)

Seasons

Seasons a

LSD (P < 0.05)= 0.307 CV% = 0.4

0 10 20 30 40 50 60

Ambient Cold

Hue angle (h°)

Storage environment

Storage

LSD (P < 0.05)= 0.308 CV% = 0.4

0 10 20 30 40 50 60

Green Pink Red

Hue angle (h°)

Maturity stages

Maturity c

36 38 40 42 44 46 48 50

PD EM EF

Hue angle (h°)

Supply routes

Routes d

LSD (P < 0.05)= 0.377 CV% = 0.4

b

LSD (P < 0.05) = 0.377 CV% = 0.4

Figure 4.4 The effect of pre-storage treatments and storage conditions on the colour (hue angle) of tomatoes of different maturity stages from Pontdrift region

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Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA

Winter Summer

Hue angle (h°)

Treatments

Ambient Pontdrift (PD)

Green Pink Red LSD (P < 0.05)= 1.192

CV% = 0.4

0 10 20 30 40 50 60 70 80

Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA

Winter Summer

Hue angle (h°)

Treatments

Cold Pontdrift (PD)

Green Pink LSD (P < 0.05) = 1.192 Red

CV% = 0.4

Figure 4.5 The effect of pre-storage treatments and storage conditions on the colour (hue angle) of tomatoes of different maturity stages from Letaba Municipality

0 10 20 30 40 50 60 70 80

Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA

Winter Summer

Hue angle (h°)

Treatments

Ambient Letaba (EM)

Green Pink Red

0 10 20 30 40 50 60 70 80

Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA

Winter Summer

Hue angle (h°)

Treatments

Cold Letaba (EM)

^Green

Pink Red LSD (P < 0.05) = 1.192

CV% = 0.4

LSD (P < 0.05) = 1.192 CV% = 0.4

Figure 4.6 The effect of pre-storage treatments and storage conditions on the colour (hue angle) of tomatoes of different maturity stages from Esmé4 region

0 10 20 30 40 50 60 70 80

Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA

Winter Summer

Hue angle (h°)

Treatments

Ambient Esme4

^Green

Pink Red

0 10 20 30 40 50 60 70 80

Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA Anolyte + GA Anolyte water Control Gum Arabic (GA) HWT + GA

Winter Summer

Hue angle (h°)

Treatments

Cold Esme4

^Green

Pink Red LSD (P < 0.05)= 1.192

CV% = 0.4 LSD (P < 0.05) = 1.192

CV% = 0.4

Dalam dokumen Evaluation of the effects of supply chain routes and pre-storage treatments on the postharvest quality of stored 'Nemo-Netta' tomatoes. (Halaman 81-88)