Effects of processing methods on nutritional composition and antioxidant activity of mealworm (Tenebrio molitor) larvae

Abstract

We examined the effects of different processing methods on the nutritional composition and antioxidant activity of mealworms. After processing with nine methods, we calculated the contents of protein, fat, ash, carbohydrate, minerals (P, Ca, K, Fe, Na), vitamin B group (B1, B2, B3), moisture, and calories. When processed by freeze drying among freeze drying, hot air drying, oven broiling, roasting, pan frying, deep frying, boiling, steaming, and microwaving, the contents of protein, some minerals, and vitamins were the highest. The content of total minerals was lowest after deep frying, and those of vitamin B1 and B3 were the lowest after microwaving. Antioxidant activity was then evaluated using DPPH and ABTS radical scavenging assays. DPPH assays showed that microwaving, freeze drying, deep frying, steaming, boiling, and oven broiling of mealworms yielded scavenging activities of 20.9–29.0% at 2,000 μg/mL, which was similar to the activity level (22.7–33.2%) of 40–60 μM tocopherol. ABTS assays confirmed that only freeze‐dried mealworms at 2,000 μg/mL exhibited higher activity than 10 μM tocopherol. Interestingly, similar trends were found for antioxidant activity levels and total phenolic contents in mealworms.

Effect of Cooking Techniques on the in vitro Protein Digestibility, Fatty Acid Profile, and Oxidative Status of Mealworms (Tenebrio molitor)

“…Rearing substrate could affect development of mealworms (18,19) as well as partially affect protein concentration and fatty acid (FA) composition (also ratio n6/n3) (4,20,21). Similarly, processing (i.e., cooking methods) of the larvae could affect the chemical composition of the products, both nutritional and quality characteristics (11,22,23).…”

Yellow Mealworm and Black Soldier Fly Larvae for Feed and Food Production in Europe, with Emphasis on Iceland

“…Futhermore, mealworms reared on plant waste have a higher protein content and a lower fat content than mealworms reared on a cereal-based diet [18] and, as mentioned earlier, adding omega-3 fatty acids into insect diets can decrease the omega-6/omega-3 ratio [35]. Additionally, it has been reported that processing methods can affect the nutritional quality of edible insects [27,37]. In a study by Nyangena et al [27], it was reported that heat processing increases the protein content and decreases the fat content of BSF larvae.…”

Tenebrio molitor as a source of interesting natural compounds, their recovery processes, biological effects, and safety aspects

“…It was also noted that some characteristics vary considerably with the cooking method used (Baek et al., 2019). A 2015 Korean study compared the effect of different cooking methods on the sensory characteristics of TML and showed that each process influences some specific sensory aspects making them more perceptible.…”

“…Tests with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) showed that microwaving, freeze-drying, frying, steaming, boiling, and cooking of TML produced scavenging activity similar to the level of activity shown by tocopherol. (Baek et al, 2019).…”