Condensation Behaviour over Prolonged Period

Condensate behaviour over time provides insight about water vapor transmission properties of the liners. A lower rate of condensation in the perforated liners suggests a faster moisture transmission rate across the walls of the liners, hence delayed build-up of humidity within the bags compared to non-perforated liner treatments. Severity of condensate within the bags decreased with time (Figure 5). The decrease in observable condensate was slowest in non-perforated liners compared to perforated liners. The rate at which condensate was decreasing was lowest in non-perforated 'Zoe' liners, followed by non-perforated 'Decco' liners. Condensate reduction rate was highest in micro-perforated Xtend® liners, followed by 4 mm macro-perforated HDPE and 2 mm macro-perforated HDPE liners. This can be attributed to a higher water vapor transmission rate across the micro-perforated liner compared to the rest of the liners. After 3 d of monitoring, condensation severity was in traces for micro-perforated Xtend® and 4 mm macro-perforated HDPE liners. By the end of 7 d of condensate monitoring, the micro-perforated Xtend® and macro-perforated 4 mm HDPE liners retained none of the condensate, while macroperforated 2 mm HDPE and non-perforated 'Zoe' and 'Decco' liners retained 10.2, 33.7, and 29.8%, respectively (Figure 6). In another study, a particular MAP liner (Xtend®) was reported to eradicate vapor condensation in pomegranate fruit because of its high water vapor transmission compared to polypropylene bags, which showed progressive moisture accumulation [37].

**Figure 5.** Variation of condensate inside liner bags, as depicted by 0–10 score scale (where 0 = none; 1–2 = trace; 3–4 = slight; 5–6 = moderate; 7–8 = severe; 9–10 = extremely severe). Pomegranate (cv. Wonderful) stored at 5 ◦C and 90% relative humidity (RH). HDPE: high density polyethylene.

**Figure 6.** Condensate within liner bags with respect to weight lost for pomegranate (cv. Wonderful) stored at 5 ◦C and 90% RH for 1 d and condensate retained within plastic bags after a period of 7 d at 5 ◦C and 90% relative humidity (RH). Histograms columns with different letters are significantly different at *p* < 0.05 according to Duncan's multiple range test. Vertical bars represent S.E. HDPE: high density polyethylene.

Condensation and Fruit Mass Loss

The liner treatments with a lower rate of condensate reduction (high condensate retention) had a lower rate of fruit weight loss while treatments with a higher condensate reduction had a higher rate of fruit weight loss. Fruit in non-perforated liner treatments had a lower rate of weight loss than fruit in perforated liners during the 7 d of condensate monitoring (Figure 7). Fruit weight loss is commonly a result of moisture loss, while condensation results from the moisture lost by the fruit. In non-perforated 'Decco' and 'Zoe' liners, 79.6 and 84.4% of fruit moisture loss per day was retained as condensate compared to 42.1, 63.9, and 36.4% for micro-perforated Xtend®, 2 mm macro-perforated HDPE liners, and 4 mm macro-perforated HDPE liners, respectively (Figure 6).

**Figure 7.** Cumulative percentage loss in weight during condensation variation within liner bags. Pomegranate (cv. Wonderful) stored at 5 ◦C and 90% relative humidity (RH). HDPE: high density polyethylene.
