2.6. Packaging treatments

The selection of the packaging materials, LDPE, and biodegradable packaging films, were made based on previous findings, which showed their beneficial effects for avocados (Xiao and Kiyoto, 2001; Aguilar-Mendez et al., 2008).

Soft, flexible, and strong LDPE bags with 20 μm thickness and 250 ✕ 150 mm, high water vapour transmission rate (375–500 g μm m^-2.day⁻¹) and high ratio of CO₂ to O₂ permeability were used (Mangaraj et al., 2009). Micro-perforations (n = 4) at 30 mm intervals were made along the bottom of each bag in two rows, using a 1.13 ✕ 10⁻³ m diameter needle to allow for the movement of gases and moisture between the micro-environment inside the bag and the surroundings.

Transparent biodegradable corn starch cellulose bags (30 μm thickness, 240 ✕ 100 mm and 45 mm gussets) were used. These bags have a high barrier to air and micro-organisms, which is ideal for the packaging of food (Aguilar-Mendez et al., 2008). Two rows containing four micro-perforations (∅ = 1.13 ✕ 10⁻³ m) at 20 mm intervals were made along the bottom of each bag. The interval spacing of the micro-perforations was smaller compared to the LDPE bags, due to the difference in width of the bags. Nine avocados from each of the pre-packaging treatments were each placed in a single LDPE bag and sealed at 164.3 mm from the base, to ensure that the volume within the both the LDPE and biodegradable bags had a similar volume. The individually sealed fruits were then placed in the respective storage temperature environment. Figure 1 represents the LDPE and corn starch packaging treatments.

LDPE and corn starch biodegradable flexible films with micro-perforations.