Extraction, Characterization, and Antimicrobial Ability of Chitosan and Edible Oil From Ugandan Winged Termites

Edible oil and chitosan were extracted from the flour of four edible winged termite species (Macrotermes subhylanus, Macrotermes bellicosus, Pseudocanthotermes spriniger, and Odontotermes lateritius), characterized for physico-chemical properties, and the antimicrobial activity of extracted chitosan was assessed against Staphylococcus aureus, Escherichia coli, and Candida albicans. Mechanical pressing yielded the significantly highest oil quantity (37.42%-38.50%) throughout all the species, followed by microwave-assisted oil extraction. Overall, the significantly lowest oil yield was observed in the conventional soxhlet extraction method (8.05%-18.92%). Generally, the extracted termite oils appeared as clear, golden-to-light yellow liquids. Oil solidification temperature ranged from 10.1°C to 12.9°C, whereas the refractive index ranged from 1.23 to 1.46. Mechanically pressed oil produced the highest iodine (111-121 g iodine/100 g oil) and saponification value (110.41-113.92 mg KOH/g). The total cholesterol content of termite oils ranged from 24.98 to 39.00 mg/100 mL, and ultrasound-assisted oil extraction yielded the lowest total cholesterol content. M. bellicosus oil had the highest total cholesterol content. Fermentation yielded the highest demineralization percentage (93.8%-96.0%), whereas the chemical method produced the highest deproteinization percentage (42.59%-49.71%) and chitosan yield (6.05%-7.00%). M. subhyalinus and M. bellicosus produced higher chitosan yields than other termite species. Termite chitosan showed the highest antimicrobial activity against E. coli, followed by S. aureus. Chemically-extracted chitosan exhibited higher antimicrobial activity than enzymatically extracted chitosan. From the present study, edible winged termites can be utilized as an unconventional source of chitosan for antimicrobial activity and low cholesterol edible cooking oil.