The antioxidant power of grasshoppers and silkworms

A study published in Frontiers in Nutrition measuring the antioxidant levels in commercially available edible insects reveals grasshoppers and silkworms have an antioxidant capacity similar to fresh orange juice. The antioxidant benefits of consuming scorpions, spiders and centipedes were also studied, with crickets containing 75% of the antioxidant power of fresh orange juice and silkworm fat twice that of olive oil.

“At least 2 billion people — a quarter of the world’s population — regularly eat insects,” said Professor Mauro Serafini, lead author of the study.

Edible insects are a valuable source of protein, polyunsaturated fatty acids, minerals, vitamins and fibre. The antioxidant capacity of insects was tested on a range of commercially available edible insects and invertebrates, with inedible parts like wings and stings removed. The insects were then ground up and two parts extracted for each species: the fat, and whatever would dissolve in water.

Each extract was then tested for its antioxidant content and activity. The antioxidant capacities of orange juice and olive oil were tested using a similar set-up.

“Fat from giant cicadas and silkworms showed twice the antioxidant activity of olive oil, while black tarantula, palm worm and black ants are placed in the bottom of the ranking,” said Prof Serafini.

Water-soluble extracts of grasshoppers, silkworms and crickets displayed the highest values of antioxidant capacity while giant cicada, giant water bugs, black tarantula and black scorpions showed negligible values.

Diluting the dry, fat-free insect dust in water would have about 75% of the antioxidant activity of orange juice. The total content of polyphenols — the major source of plant-derived antioxidant activity — followed a similar pattern across species but was lower in insects compared to orange juice, suggested that the antioxidant capacity of insects depends on other, as-yet-unknown compounds.

A high antioxidant content is a primary requisite for screening the antioxidant potentiality of novel foods to determine if they are meant for human consumption.

“The in vivo efficiency of antioxidant-rich food is highly dependent on bioavailability and the presence of an ongoing oxidative stress. So as well as identifying other antioxidant compounds in insects, we need tailored intervention studies to clarify their antioxidant effects in humans,” concluded Prof Serafini.

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