Evaluation of Water Vapour Permeability of Some Food Grain Packaging Materials

The properties of any packaging material are essential parameters to know before storage of any kind of food materials. Physical properties are prerequisites for selecting proper packaging materials to obtain the desired shelf-life during the storage and distribution chain of food commodity. At the village/household level for packaging of food grains and other Non-Timber Forest Produce (NTFP) commodities, generally used packaging materials namely, low-density polyethylene (LDPE), polypropylene (PP), earthen pot (EP), polypropylene woven sack (PPWS), and gunny sack (GS) were evaluated for their physical properties such as strengths (grammage and thickness) and water vapour permeability using the standard gravimetric method. The thickness was determined to be 0.065 mm, 0.056 mm, 0.168 mm, 3.530 mm, and 0.849 mm for LDPE, PP, PPWS, EP, and GS respectively. Similarly, grammage was found to be 6.03 x 10-5 g m-2, 4.94 x 10-5 g m-2, 9.59 x 10-5 g m-2, and 3.70 x 10-4 g m-2 for LDPE, PP, PPWS, and GS respectively. Results revealed a significant difference between the permeability of packing materials. The highest water vapour permeability of 7.26 x 10-5 kg m-2 day-1 Pa-1 was obtained for GS, whereas the lowest 1.81 x 10-5 kg m-2 day-1 Pa-1 was for LDPE at 40 ± 1°C temperature and 90 ± 1% relative humidity. The water vapour permeability of other packaging materials viz., PP, PPWS, and EP was 2.18 x 10-5 kg m-2 day-1 Pa-1, 3.63 x 10-5 kg m-2 day-1 Pa-1, and 5.03 x 10-5 kg m-2 day-1 Pa-1 respectively.