Chemical and Microbiological Characterization of Freeze-Dried Superworm (Zophobas morio F.) Larvae Pretreated by Blanching and Ultrasound Treatment

Edible insects may solve the current problem of the greater demand for food for the world's growing human population. This work aimed to examine the impact of blanching (BL) and ultrasound (US) at 20 and 50 °C as a pretreatment method on the chemical composition, mineral composition, FTIR spectra, presence of allergens and microorganisms, and properties of the isolated oil of freeze-dried superworm larvae. The US treatment resulted in significantly lower protein content (31.65-33.34 g/100 g d.m.) compared to untreated (36.38 g/100 g d.m.) and BL (37.72 g/100 g d.m.) samples. The study demonstrated that the US-treated insects exhibited a lower content of crustacean and mollusk allergens than the BL insects, and the lowest content of tested allergens was found in the US_50°C superworm larvae. Furthermore, oil isolated from US_50°C insects exhibited the lowest SFA and the highest PUFA content and the best prospective nutritional properties expressed through theoretical health indices. The presence of Enterobacteriaceae and anaerobic spore-forming bacteria was not detected in the tested insects, proving suitable microbiological quality. It appears that using US treatment is a promising alternative to traditional blanching of insects before drying.