A systematic review of the nutrient composition, microbiological and toxicological profile of Acheta domesticus (house cricket)

Production, characterisation, and biological properties of Tenebrio molitor-derived oligopeptides

Three protein hydrolysates from Tenebrio molitor were obtained by enzymatic hydrolysis employing two food-grade proteases (i.e. Alcalase and Flavourzyme), and a complete characterisation of their composition was done. The digestion-derived products were obtained using the INFOGEST protocol. In vitro antioxidant activity and anti-inflammatory activities were evaluated. Tenebrio molitor flour and the protein hydrolysates showed a high ability to scavenge the DPPH radical (EC50 values from 0.30 to 0.87 mg/mL). The hydrolysate obtained with a combination of the two food-grade proteases could decrease the gene expression of pro-inflammatory genes after being digested. Furthermore, the peptidome was fully determined for the first time for T. molitor hydrolysates and digests, and 40 peptides were selected based on their bioactivity to be evaluated by in silico tools, including prediction tools and molecular docking. These results provide new perspectives on the use of edible insects as sustainable and not nutritionally disadvantageous food for human consumption.

Effect of thermal and defatting treatments on the composition, protein profile and structure of house cricket (Acheta domesticus) protein extracts

This study investigated the impact of blanching (100 °C, 40 s), defatting method (maceration, Soxhlet) and solvent polarity (hexane, ethanol) on the profile, structure and solubility of house cricket protein extracts. Blanching and Soxhlet using ethanol impacted the protein profile, with a lower content of myosin heavy chain and a higher abundance of low molecular weight proteins (<25 kDa). Moreover, ethanol induced aggregation of non-blanched cricket proteins, with a 13-72% reduction in protein recovery yield. The protein secondary structure of non-blanched extracts was also affected by ethanol with 18% more β-sheets. Furthermore, blanching resulted in a lower protein surface hydrophobicity by a factor of 3 to 7, with no impact of solvent polarity. Finally, the solubility of protein extracts remained >75%, regardless of the blanching and defatting methods. These findings, combined with the evaluation of techno-functional properties, could be used for the development of cricket-based protein ingredients for food formulations.

Substituting red meat with insects in burgers: Estimating the public health impact using risk-benefit assessment

In Western societies, reducing red meat consumption gained prominence due to health, environmental, and animal welfare considerations. We estimated the public health impact of substituting beef with house cricket (Acheta domesticus) in European diets (Denmark, France, and Greece) using the risk-benefit assessment (RBA) methodology, building upon the EFSA-funded NovRBA project. The overall health impact of substituting beef patties with insect powder-containing patties was found to be impacted by the amount of cricket powder incorporated in the patties. While using high amounts of cricket powder in meat substitutes may be safe, it does not inherently offer a healthier dietary option compared to beef. Adjustment of cricket powder levels is needed to yield a positive overall health impact. The main driver of the outcome is sodium, naturally present in substantial amounts in crickets. Moreover, the way that cricket powder is hydrated before being used for the production of patties (ratio of powder to water), influences the results. Our study highlighted that any consideration for dietary substitution should be multidimensional, considering nutritional, microbiological and toxicological aspects, and that the design of new food products in the framework of dietary shifts should consider both health risks and benefits associated with the food.

Bioaccessibility of trace elements and Fe and Al endogenic nanoparticles in farmed insects: Pursuing quality sustainable food

This study investigated the in vitro bioaccessibility of aluminum, copper, iron, manganese, lead, selenium, and zinc in three important species of farmed insects: the yellow mealworm (Tenebrio molitor), the house cricket (Acheta domesticus) and the migratory locust (Locusta migratoria). Results show that all three insect species constitute excellent sources of essential elements (Fe, Cu and Zn) for the human diet, contributing to the recommended dietary allowance, i.e., 10%, 50%, and 92%, respectively. A higher accumulation of Se (≥1.4 mg Se/kg) was observed with increasing exposure concentration in A. domesticus, showing the possibility of using insects as a supplements for this element. The presence of Al and Fe nanoparticles was confirmed in all three species using single particle-inductively coupled plasma-mass spectrometry and transmission electron microscopy. The results also indicate that Fe bioaccessibility declines with increasing Fe-nanoparticle concentration. These findings contribute to increase the nutritional and toxicological insights of farmed insects.

Bacteriological Survey of Insect Products in Japan

A microbiological study was conducted on 41 insect product samples (29 raw frozen [21 domestic and 8 imported], 10 powdered, and 2 processed), which were commercially available in Japan. The total aerobic count for raw frozen insects was 5.61 log cfu/g (range: 2.52-8.40), whereas the powdered insect count was 2.89 log cfu/g (range: 1.00-4.57). The bacterial count was significantly higher in raw frozen insects (p < 0.05). The coliform count for the raw frozen insects ranged from <1 to 6.90 log cfu/g, and that for the powdered insects ranged from <1 to 1.00 log cfu/g. The number of samples with values above the detection limit was significantly higher in raw frozen insects (p < 0.05). The detection frequencies of aerobic spores (<1-4.63 log cfu/g), anaerobic spores (<0-4.40 log cfu/g), and Bacillus cereus (<1.7-3.83 log cfu/g) showed no sample type-related significant difference. Listeria spp. was isolated from four samples of raw frozen insects, one of which was Listeria monocytogenes. We did not detect any of the following: Salmonella spp., Shiga toxin-producing E. coli (STEC), Campylobacter jejuni/coli, or pathogenic Yersinia. We isolated insect products retailed in Japan harboring food poisoning bacteria, including L. monocytogenes and B. cereus. In particular, raw frozen products displayed high levels of hygienic indicator bacteria.

Edible insects as a source of biopeptides and their role in immunonutrition

Many edible insect species are attracting the attention of the food industry and consumers in Western societies due to their high content and quality of protein, and consequently, the potential to be used as a more environmentally friendly dietary source could be beneficial for humans. On the other hand, prevention of inflammatory diseases using nutritional interventions is currently being proposed as a sustainable and cost-effective strategy to improve people's health. In this regard, finding bioactive compounds such as peptides with anti-inflammatory properties from sustainable sources (e.g., edible insects) is one area of particular interest, which might have a relevant role in immunonutrition. This review aims to summarize the recent literature on the discovery of immunomodulatory peptides through in vitro studies from edible insects, as well as to describe cell-based assays aiming to prove their bioactivity. On top of that, in vivo studies (i.e., animal and human), although scarce, have been mentioned in relation to the topic. In addition, the challenges and future perspectives related to edible-insect peptides and their role in immunonutrition are discussed. The amount of literature aiming to demonstrate the potential immunomodulatory activity of edible-insect peptides is scarce but promising. Different approaches have been employed, especially cell assays and animal studies employing insect meal as supplementation in the diet. Insects such as Tenebrio molitor or Gryllodes sigillatus are some of the most studied and have demonstrated to contain bioactive peptides. Further investigations, mostly with humans, are needed in order to clearly state that peptides from edible insects may contribute to the modulation of the immune system.

Concentration- and Time-Dependent Dietary Exposure to Graphene Oxide and Silver Nanoparticles: Effects on Food Consumption and Assimilation, Digestive Enzyme Activities, and Body Mass in Acheta domesticus

The advancement of nanotechnology poses a real risk of insect exposure to nanoparticles (NPs) that can enter the digestive system through contaminated food or nanopesticides. This study examines whether the exposure of model insect species-Acheta domesticus-to increasing graphene oxide (GO) and silver nanoparticle (AgNP) concentrations (2, 20, and 200 ppm and 4, 40, and 400 ppm, respectively) could change its digestive functions: enzymes' activities, food consumption, and assimilation. We noticed more pronounced alterations following exposure to AgNPs than to GO. They included increased activity of α-amylase, α-glucosidase, and lipase but inhibited protease activity. Prolonged exposure to higher concentrations of AgNPs resulted in a significantly decreased food consumption and changed assimilation compared with the control in adult crickets. A increase in body weight was observed in the insects from the Ag4 group and a decrease in body weight or no effects were observed in crickets from the Ag40 and Ag400 groups (i.e., 4, 40, or 400 ppm of AgNPs, respectively), suggesting that even a moderate disturbance in nutrient and energy availability may affect the body weight of an organism and its overall condition. This study underscores the intricate interplay between NPs and digestive enzymes, emphasizing the need for further investigation to comprehend the underlying mechanisms and consequences of these interactions.

Potential of Cricket (Acheta domesticus) Flour as a Lean Meat Replacer in the Development of Beef Patties

This study examined the incorporation of cricket (Acheta domesticus) flour (CF) (0, control; 5.0%, CF5.0; 7.5%, CF7.5; and 10.0%, CF10.0) as a lean meat replacer in beef patties and its impact on composition, microbiological, sensory, and technological properties, as well as its influence on the cooking process. The inclusion of CF led to beef patties with significantly higher protein levels than the control group. Additionally, an elevation in total viable (TVC) and lactic acid bacteria (LAB) counts was observed. However, Enterobacteriaceae counts remained at safe levels. CF5.0 demonstrated similar sensory scores and purchase intention to the control treatment. CF7.5 and CF10.0 showed comparable sensory scores to the control except for texture attributes. The inclusion of CF significantly reduced cooking loss and diameter reduction values. Beef patties with CF were notably firmer and had a browner color than the control. In general, the cooking process impacted the technological properties similarly in both the control and beef patties with CF. In all cooked samples, no significant differences in pH, redness (a*), or texture were observed. This study demonstrated that incorporating up to 5.0% CF into beef patties is optimal in terms of composition, technological, sensorial, and cooking properties.

Chemical and Nutritional Fat Profile of Acheta domesticus, Gryllus bimaculatus, Tenebrio molitor and Rhynchophorus ferrugineus

The use of edible insects in the human diet is gaining importance because they are characterized by high nutritional value, and their cultivation is much more environmentally friendly than traditional livestock farming. The objective of this study was to determine the chemical and nutritional fat profile of selected edible insects as follows: house cricket (Acheta domesticus adult), field cricket (Gryllus bimaculatus adult), mealworm (Tenebrio molitor larvae), and palm weevil (Rhynchophorus ferrugineus larvae) which are now commercially available worldwide. Additionally, the degree of implementation of nutrition standards for selected nutrients by these insects was assessed. Freeze-dried insects were studied using infrared-attenuated total reflectance mid-infrared spectroscopy for basic differentiation. The content of fat and fatty acids was determined, and dietary indicators were calculated. The spectroscopic findings align with biochemical data, revealing that Rhynchophorus ferrugineus larvae contain the highest fat content and the least protein. Unsaturated fatty acids (UFAs) predominated in the fat of the assessed insects. The highest content of saturated fatty acids (SFAs), along with the lowest content of polyunsaturated fatty acids (PUFAs), was observed in the larvae of the Rhynchophorus ferrugineus species. From a nutritional standpoint, Tenebrio molitor larvae exhibit the most favorable indicators, characterized by minimal athero- and thrombogenic effects, along with an optimal balance of hypo- and hypercholesterolemic acids. Knowledge of the composition and quantities of fats in different insect species is valuable for planning and preparing meals with accurate nutritional profiles, among other applications.

Hybrid Sausages Using Pork and Cricket Flour: Texture and Oxidative Storage Stability

This study aimed to study the functionalities of cricket flour (CF) and the effects of the addition of CF on the texture and oxidative stability of hybrid sausages made from lean pork and CF. Functional properties of CF, including protein solubility, water-holding capacity, and gelling capacity, were examined at different pHs, NaCl concentrations, and CF contents in laboratory tests. The protein solubility of CF was significantly affected by pH, being at its lowest at pH 5 (within the range 2–10), and the highest protein solubility toward NaCl concentrations was found at 1.0 M (at pH 6.8). A gel was formed when the CF content was ≥10%. A control sausage was made from lean pork, pork fat, salt, phosphate, and ice water. Three different hybrid sausages were formulated by adding CF at 1%, 2.5%, and 5.0% levels on top of the base (control) recipe. In comparison to control sausage, the textural properties of the CF sausages in terms of hardness, springiness, cohesiveness, chewiness, resilience, and fracturability decreased significantly, which corresponded to the rheological results of the raw sausage batter when heated at a higher temperature range (~45–80 °C). The addition of CF to the base recipe accelerated both lipid and protein oxidation during 14 days of storage, as indicated by the changes in TBARS and carbonyls and the loss of free thiols and tryptophan fluorescence intensity. These results suggest that the addition of CF, even at low levels (≤5%), had negative effects on the texture and oxidative stability of the hybrid sausages.

Risk–Benefit assessment of foods: Development of a methodological framework for the harmonized selection of nutritional, microbiological, and toxicological components

Investigating the impact of diet on public health using risk–benefit assessment (RBA) methods that simultaneously consider both beneficial and adverse health outcomes could be useful for shaping dietary policies and guidelines. In the field of food safety and nutrition, RBA is a relatively new approach facing methodological challenges and being subject to further developments. One of the methodological aspects calling for improvement is the selection of components to be considered in the assessment, currently based mainly on non-harmonized unstandardized experts’ judgment. Our aim was to develop a harmonized, transparent, and documented methodological framework for selecting nutritional, microbiological, and toxicological RBA components. The approach was developed under the Novel foods as red meat replacers—an insight using Risk-Benefit Assessment methods (NovRBA) case study, which attempted to estimate the overall health impact of replacing red meat with an edible insect species, Acheta domesticus. Starting from the compositional profiles of both food items, we created a “long list” of food components. By subsequently applying a series of predefined criteria, we proceeded from the “long” to the “short list.” These criteria were established based on the occurrence and severity of health outcomes related to these components. For nutrition and microbiology, the occurrence of health outcomes was evaluated considering the presence of a component in the raw material, as well as the effect of processing on the respective component. Regarding toxicology, the presence and exposure relative to reference doses and the contribution to total exposure were considered. Severity was graded with the potential contribution to the background diet alongside bioavailability aspects (nutrition), the disability-adjusted life years per case of illness of each hazard (microbiology), and disease incidence in the population, potential fatality, and lifelong disability (toxicology). To develop the “final list” of components, the “short list” was refined by considering the availability and quality of data for a feasible inclusion in the RBA model. The methodology developed can be broadly used in food RBA, to guide and reinforce a harmonized selection of nutritional, microbiological, and toxicological components and will contribute to facilitating RBA implementation, enabling the generation of transparent, robust, and comparable outcomes.