Optimising mopane worm (Gonimbrasia belina) processing for improved nutritional and microbial quality.

Area of Science:

• Food Science
• Entomophagy
• Nutritional Biochemistry

Background:

• Mopane worms (Gonimbrasia belina) are a vital food source, but traditional processing can degrade nutritional quality and microbial safety.
• Optimizing processing is crucial for maximizing the nutritional benefits and ensuring the safety of mopane worms for consumption.

Purpose of the Study:

• To investigate the impact of different boiling times and drying temperatures on the nutritional composition and microbial quality of mopane worms.
• To determine the optimal processing conditions for mopane worms using response surface methodology.

Main Methods:

• Mopane worms were processed under varying boiling times (0-20 min) and drying temperatures (40-60 °C).
• Nutritional composition (protein, crude fiber, fat) and microbial quality (coliforms, E. coli, yeasts, molds) were analyzed.
• Response surface methodology was employed to optimize processing parameters.

Main Results:

• Increased boiling time (20 min) at lower drying temperatures (40 °C) significantly increased protein content to 49.4% DW.
• Optimal conditions yielded low coliform counts (<1.5 log cfu/g) and reduced overall microbial load.
• High levels of crude fiber (13.6% DW), fat (20.2% DW), iron (19.0 mg/100 g), and zinc (17.9 mg/100 g) were recorded.

Conclusions:

• Boiling for 20 minutes and drying at 40 °C are recommended optimal conditions for mopane worm processing.
• These conditions enhance protein content and ensure microbial safety, making mopane worms a more valuable food product.
• Reduced moisture content (<7%) through drying further inhibits microbial growth, extending shelf life.