Insect proteins: Researchers investigate methods to overcome extraction challenges

23 Aug 2024 --- Scientists at the Korea University in Seoul have examined four methods of extracting edible insect proteins from mealworms (Tenebrio molitor larvae) to overcome the challenges associated with conventional protein extraction methods, which they say are time-consuming, costly and energy-intensive.

This comes as the F&B industry increasingly explores insect proteins as a more sustainable food source and regulations approving their use in foods. According to the FAO, this is due to the rising cost of animal protein, food insecurity, environmental pressures, population growth and rising demand for protein among the middle classes.

“There is a need for alternative techniques that maintain the bioactivities of insect proteins and are environmentally sustainable,” notes the study.

“This study compares the health functionality of mealworm concentrates obtained by conventional methods — alkali and salt extraction — and nonconventional methods — enzyme and screw press — to enhance their applicability despite lower protein concentration.”

Results revealed that alkali extraction improved protein content, while enzyme treatment enhanced nutritional value and antioxidant capacity. Further, salt-assisted extraction showed health benefit potential, such as anti-inflammatory effects, and enzyme and salt treatments produced protein concentrates with significant anti-hyperglycemic (or anti-diabetic) properties.

Nutrient extraction can be a way to increase insect protein consumption as whole insects have low consumer preference. Another concern the study describes is consumers’ low preference for consuming edible insects directly, despite their nutritional worth and health benefits. This is often due to factors such as neophobia, social norms and familiarity. Nutrient extraction thus emerges as a “more feasible approach” for developing insect-based food products.

Applications beyond mealworms

The EU designated mealworms as the first insect to be used as a novel food source in 2015 and the first novel authorization for insect protein came in 2021 when the EU allowed the commercialization of dried yellow mealworm and derived products across its market.

While the International Platform of Insects for Food and Feed welcomed the move, animal protection groups raised concerns, stating insect meal prices as prohibitive for most farmers. 

Additionally, a recent study in Australia cautioned that edible insects can trigger shellfish allergies that go undetected by testing kits.

The Korean study, published in the Journal of Food Science, primarily focused on mealworms. However, the results suggest that the extraction methods studied could also apply to other types of edible insects, says Yookyung Kim, PhD, of Korea University and corresponding author of the research.

“This broadens the potential for using non-conventional procedures like enzyme and screw press extractions.” The study also describes the role of screw pressers in enhancing rheological properties and textures, along with environmental benefits.

“Despite having lower protein content, less refined ingredients have a lower global warming potential per kg of protein compared to conventional components, highlighting the potential for mass production at an industrial scale and a chemical-free, eco-friendly approach offered by screw pressing as a practical and green technique for protein recovery from insects,” underscores the study.

Scientists view insect proteins as a sustainable food source amid the rising global population and food demand.Non-conventional methods of insect protein extraction such as enzyme, ultrasound, microwave and pulsed electric field-assisted extraction are also considered as environmentally friendly techniques, note the scientists.

Merging traditional and modern methods

The research highlights non-conventional methods, particularly enzymatic-assisted extraction and conventional extraction methods, such as salt-assisted extraction, as having benefits like enhanced health functionality.

“These methods not only preserve a greater amount of bioactive compounds but also offer environmental and health benefits, making them suitable for sustainable protein production despite their lower level of refinement,” says Kim.

The study further details that mealworm contains a variety of proteins with various molecular weights and structural features, and different extraction conditions can affect the type of proteins concentrated and their amino acid profiles. However, “physical extraction may have a lesser impact on protein composition and can help retain native properties.”

In conclusion, the scientists suggest a “hybrid approach, combining both traditional and innovative techniques” to optimize the balance between cost, environmental impact, health benefits and efficacy in food or pharmaceutical applications.

However, the researchers acknowledge that the research's limitations include low protein purity for the concentrates, non-optimized protein extraction methods and the influence of the salt content in the mealworm substrate.

By Insha Naureen