Effect of selected retail packaging materials, storage temperature and time on the quality of dried mopane worm (Imbrasia belina)

Abstract

This study assessed the effects of selected retail packaging materials, storage temperature and duration on the quality and shelf life of traditionally processed and sun-dried mopane worms (Imbrasia belina). Changes in the quality of dried mopane worms (MW) were evaluated in a 2 x 2 x 5 factorial experiment comprising packaging materials (low-density polyethylene (LDPE) and high-density polyethylene (HDPE)), storage temperature (ambient and accelerated), and storage time (0, 30, 60, 90 and 120 days) with three replications. Dried MW samples were analysed for changes in physicochemical (ash, moisture, fat, protein content and colour, microbiological (yeast, mould and coliform count), and sensory (colour, taste, texture and overall acceptability) qualities. The results of the experiment were subjected to ANOVA, and the means were separated using the post hoc Tukey test at 5% level of significance. Packaging material did not significantly (p > 0.05) affect ash, moisture, fat, protein content, yeast and coliform count, and sensory qualities of dried MW. However, the mould count and colour parameters of dried MW were significantly (p < 0.05) affected by packaging material. Storage time significantly affected (p < 0.05) moisture, fat, protein content, colour parameters and sensory qualities of dried MW. The ash content was not significantly (p > 0.05) affected by storage time, but the storage temperature significantly affected (p < 0.05) ash, moisture content and colour parameters of dried MW. The three-way interaction between packaging material, storage temperature and time was not significant (p > 0.05) for all proximate composition and microbial quality parameters, indicating that it is safe to consume dried MW over a period of 120 days post-processing. This study recommended that a further study for storage periods greater than 120 days be done to determine the shelf life of traditionally processed dried MW packaged in retail-sized HDPE and LDPE. The HDPE performed better than LDPE in preserving the quality of dried MW, as evidenced by the better-quality parameters recorded under this packaging material.