3.6.1. Fruit Peel Colour

Fruit peel colour is an important contributor to visual appeal and acceptance of pomegranate fruit by consumers. Generally, there was a progressive decline in the lightness (*L*\*) values with storage time (Table 5). Fruit skin lightness was 51.7 ± 2.4 before storage, after 84 d of storage; fruit packed with no-liner lost 30.0% of the lightness. This can be attributed to excessive moisture loss causing the peel to become pale. The darkening (*L*\*→ 0) of the peel is expected as the fruit ages during storage. However, packing fruit with non-perforated 'Decco' and 'Zoe' liners significantly (*p* < 0.05) minimised the loss in skin colour lightness to 5.7% and 3.6%, respectively. Fruit packed with micro-perforated Xtend® lost 14.1% compared to 15.0% and 15.7% for fruit packed with 2 mm macro-perforated and 4 mm macro-perforated HDPE liners, respectively. The difference in results can be attributed to differences in the ability of liners to minimise moisture loss and respiration rate. Similarly, Selcuk and Erkan [22] reported higher skin colour lightness for pomegranate (cv. Hicrannar) fruit stored under MAP liners with the fruit looking brighter and fresher compared to the no liner control fruit at the end of 4 months of cold storage and additional 3 d of shelf life.


**Table 5.** Impact of liners on pomegranate fruit peel colour parameters. Fruit were stored at 5 ◦C and 90% relative humidity (RH).

<sup>1</sup> Lightnesss index describes surface color in the range from 0 (black) to 100 (white). <sup>2</sup> Redness index describes surface color in the range from green (−*a*\*) to red (+*a*\*). <sup>3</sup> Chroma. Mean values with different letters are significantly different (*p* < 0.05) according to Duncan's multiple range test. HDPE: high density polyethylene.

There was no difference in peel redness colour (*a*\*) among treatments throughout the study; however at 84 d, fruit packed with micro-perforated Xtend® and non-perforated 'Decco' and 'Zoe' liners retained the initial skin redness colour (*a*\*) before storage. However, Drake [52] reported that packing pears in MAP liners preserved more of the green colour at 90 d of cold storage than did the pears under regular atmosphere at 30 d of storage. This could be attributed to the ability of liners modifying the atmosphere around the fruit, thereby minimising break down of colour pigments.

The effect of storage time on chroma (*C*\*) was only significant on fruit packed with no-liner and macro-perforated HDPE liners. At 84 d of cold storage, fruit packed with nonperforated 'Decco', non-perforated 'Zoe', and micro-perforated Xtend® liners significantly retained the initial skin *C*\* (colour saturation) compared with fruit in other treatments. Furthermore, fruit packed with macro-perforated HDPE liners significantly retained higher

*C*\* than fruit packed with no-liner. Selcuk and Erkan [22] reported a no significant impact of liner packaging on the chroma (*C*\*) for 'Hicrannar' pomegranate stored for 120 d at 6 ◦C. A decrease in skin colour parameters *L*\* and *C*\* was observed with minimal changes for wrapped fruit compared to un-wrapped pomegranate (cv. Primosole) stored at 8 ◦C for 84 d storage [17].
