Search Results (114)

Due to their nutritional value and sustainability, edible insect-based foods are gaining popularity in Europe. Their use is regulated by EU legislation, which defines authorised species and sets labelling requirements. Molecular tools are being developed to authenticate such products. In this study, yellow mealworm (Tenebrio molitor) larvae authorised for human consumption were fed wheat flour-based diets containing varying proportions of house cricket (Acheta domesticus) flour for 21 days. This was followed by a 48 h starvation period to assess the persistence of insect DNA in the digestive tract. Two novel, species-specific, single-copy markers were designed: ampd gene for the Acheta domesticus and MyD88 gene for the Tenebrio molitor. These were applied using qPCR and ddPCR. Both methods successfully detected cricket DNA in the guts of starved larvae. Linear regression analysis revealed a strong, statistically significant correlation between the proportion of Acheta domesticus flour in the diet and the normalised relative quantity of DNA. ddPCR proved to be more sensitive than qPCR, particularly in the detection of low DNA levels. These results suggest that the presence of DNA from undeclared insect species in edible insects may be indicative of their diet rather than contamination or adulteration. This highlights the importance of contextual interpretation in food authenticity testing. Full article

Yellow mealworm (Tenebrio molitor) meal is a promising sustainable protein for pet food, yet its effect on nutrient balance and granule texture is incompletely defined. Five dry dog food formulas containing 25%, 30%, 35%, 40%, and 45% of T. molitor meal were extruded and analyzed for proximate composition, fatty-acid and amino-acid profiles, and compressive mechanical properties. Crude-protein concentration remained stable, whereas fat and ash increased (p < 0.01) and carbohydrates decreased as the inclusion level rose. Tenebrio molitor meal enriches granules in oleic, linoleic, and α-linolenic acids, improving the ω-6:ω-3 ratio from 8.0 to 5.4. Essential amino acid levels were conserved, although lysine and methionine fell modestly (≤11%). Mechanical testing showed a linear decline in hardness (331 → 300 N) and stiffness (46 → 41 N mm⁻¹), indicating softer, more deformable granules at higher inclusion levels. The inclusion of up to 45% T. molitor meal can be incorporated without compromising protein quality while enhancing unsaturated fat content. Minor lysine/methionine dilution can be offset by targeted supplementation. These data support wider adoption of insect protein in hypoallergenic and eco-friendly canine diets. Full article

The impact of short-term feeding of three distinct diets containing insect meals on the intestinal microbiota of African catfish hybrid (Clarias gariepinus × Heterobranchus longifilis) juveniles was examined. The animals received experimental diets containing 30% insect meals derived from black soldier-fly larvae (BSL) (Hermetia illucens), yellow mealworm (Tenebrio molitor) or blue bottle-fly larvae (Calliphora vicina) for 18 days. The relative abundance of the Bacillaceae, the Planococcaceae and other bacteria significantly increased (p < 0.05) in the intestinal microbiota of the BSL group and also in the pooled group of the three catfish groups that received insect meals. Several strains of the Bacillales cultured from BSL feed had higher (p < 0.05) abundance in the intestinal microbiota of the BSL group compared to those of the control group. Among these Bacillales strains, a single fosB antibiotic resistance gene was identified. In the gut resistomes of both the BSL and the control catfish groups, the tetA(P), tetB(P) and lnu(C) antibiotic-resistance determinants were detected, while fosB was detected only in the BSL group. Overall, the study showed that a short-term shift to diets containing insect meals can induce significant (q < 0.05) changes in the gut microbiota of the African catfish without the development of reduced α-diversity and without the overgrowth of bacteria pathogenic to fish. Full article

Temperature plays a crucial role in shaping the biology of insects. Developmental temperature and acclimation temperatures influence their ability to cope with extreme thermal conditions. This study investigates the effects of developmental temperatures during the pupal stage and adult acclimation temperatures on the thermal tolerance of Tenebrio molitor Linnaeus, 1758. We investigated cold tolerance based on chill-coma recovery time and heat tolerance based on heat knockdown time. Beetles were reared at five developmental temperatures (16, 21, 25, 30 and 35 °C) and later exposed to corresponding adult acclimation temperatures. From developmental temperatures of 21 and 30 °C, the group of beetles was subjected to different temperatures to induce adult acclimation at a different temperature than the developmental temperature. In cold-tolerance tests, beetles reared at lower temperatures showed better recovery from chill coma, while beetles reared at higher temperatures showed greater resistance to heat shock. Adult beetles acclimated to lower temperatures showed better cold tolerance, while those acclimated to higher temperatures performed better in the heat tolerance test. Interestingly, the developmental temperatures during the pupal stage also contributed to resistance, particularly in the heat-tolerance test. However, pupal stage temperatures had no effect on cold-shock resistance, as indicated by chill-coma recovery time. The results could provide insights into the rearing of T. molitor. Full article

The scientific interest in edible insects as an alternative source of high-value protein for the human diet has increased drastically over the last decade. Edible insects harbour enormous potential in terms of planetary health. Their lower water and land use, lower feed conversion ratios, and overall lower global warming potential paired with a high nutritional value compared with conventional livestock are key drivers towards an environmentally sustainable diet. However, low consumer acceptance, as well as regulatory challenges, have slowed down the success of edible insects in Western countries, despite edible insects being consumed regularly all over the world. To date, four edible insect species have been approved as novel foods in the European Union—namely yellow mealworm (Tenebrio molitor), migratory locust (Locusta migratoria), house cricket (Acheta domesticus), and lesser mealworm (Alphitobius diaperinus). Depending on the species, they have a high protein content (48–67%), with a beneficial indispensable amino acid profile, high fat content (21–39%), with a high content of unsaturated fatty acids based on the dry matter, and contain reasonable amounts of minerals and vitamins. Unlike other animal-based foods, edible insects contain dietary fibre. Data on the bioavailability of nutrients in humans are scarce. Although numerous publications have investigated the nutritional profiles, environmental impacts, and future perspectives of edible insects, here, those findings are reviewed critically, as some publications were partially contradictory or related to selected species only. In this narrative review, we emphasise that edible insects could play a key role in a changing world with a steadily increasing demand for nutritionally valuable food and the depletion of natural resources. Full article

Plant–insect interactions mediated by chemical compounds are well documented in roots and above-ground plant parts except seeds. The latter chemoecological interactions remain poorly studied. The chemical composition of seeds, including attractive, repellent, or inhibitory compounds, likely influences oviposition behavior, yet specific studies on this subject are scarce. This study evaluated the oviposition behavior of the yellow mealworm (Tenebrio molitor L. (Coleoptera, Tenebrionidae)) on substrates of common oat (Avena sativa L. (Poales: Poaceae)), common wheat (Triticum aestivum L. (Poales: Poaceae)), rapeseed (Brassica napus L. (Brassicales: Brassicaceae)), and pure sand. Females laid the most eggs on oat and wheat substrates, while oviposition on sand was reduced by 22%. The chemoreceptors located in the antennae of T. molitor were found not to influence oviposition. Hexane extracts of oat flour were found to contain oviposition-inhibiting compounds, identified as fatty acids. Behavioral tests showed that oleic, palmitic, linoleic, and stearic acids inhibited oviposition at concentrations ranging from 5% to 0.5%. A lower concentration (0.05%) did not have this effect. Additionally, linoleic, palmitic, and oleic acids exhibited repellent properties, whereas stearic acid did not. These findings provide valuable insights into optimizing substrate composition to enhance T. molitor reproduction. This has applications for small-scale laboratory research and large-scale industrial production, supporting the use of T. molitor as an alternative protein source for feed and food. Full article

The consumption of edible insects is a promising approach to meet the increasing global demand for food. Commercialization of edible insects in the EU is regulated by the Novel Food regulation. To date, the yellow mealworm (Tenebrio molitor larva), the migratory locust (Locusta migratoria), the house cricket (Acheta domesticus), and the buffalo worm (Alphitobius diaperinus larva) have been authorized in the EU for human consumption. We aimed to develop a method based on DNA barcoding and high-resolution melting (HRM) analysis for the identification and differentiation of these four EU-authorized edible insect species in food. A primer pair previously designed for DNA metabarcoding, targeting a ~200 bp sequence of mitochondrial 16S rDNA, allowed discrimination between the four insect species in highly processed food. However, house cricket and migratory locust could not unambiguously be differentiated from tropical house cricket, desert locust, superworm, cowpea weevil, and sago worm, respectively. This problem could be solved by designing primers specific for house cricket and migratory locust. By combining these primers with the insect primers, additional polymerase chain reaction (PCR) products for house cricket and migratory locust were obtained, resulting in more complex melt curves compared to the unauthorized insect species. The optimized PCR-HRM assay is a very cost-efficient screening tool for authentication of EU-authorized edible insect species in food. Full article

In the context of globalization, cross-cultural studies have become increasingly important for understanding differences in consumer acceptance of various foods. This study examines and compares the acceptance of insect-based foods between consumers in Greece and Ireland, two EU countries where insect-based foods are not widely available. An online survey was distributed in both countries and responses from 489 participants (Greece: n = 283; Ireland: n = 206) were analysed, using non-parametric tests for the quantitative data, and a combination of thematic and content analysis for the qualitative data. Overall, the Mann–Whitney U test showed that participants from Greece were significantly less willing to consume insect-based foods than those in Ireland. Among EU-approved insects, the Friedman test showed that participants in Ireland significantly preferred yellow mealworms over house crickets and migratory locusts, whereas participants in Greece showed no significant preference among these species. Both groups were more willing to consume insect-based foods when the insects were not visible, while they differed in their preference of inclusion percentage of insect protein in foods. However, no differences were found in the willingness to consume different types of non-visible insect products. The Mann–Whitney U test showed that participants in Ireland could be more influenced to consume insect-based foods by external factors, with live demonstrations by chefs being the most influential. However, family members would be the most influencing factor for those from Greece. Nuances in participants’ willingness to buy insect-based foods are presented and discussed. These findings could inform strategies aimed at increasing the acceptance of insects as food among consumers in European countries with limited exposure to such products. Full article

Spodoptera frugiperda (Lepidoptera: Noctuidae) and Tenebrio molitor (Coleoptera: Tenebrionidae) are two prominent pests of maize and its stored grains, respectively. Botanical pesticides have been proposed as an alternative for their management. This study evaluated the insecticidal activity of Salvia connivens (Lamiaceae) methanolic extract and rosmarinic acid against S. frugiperda and T. molitor by adding them to an artificial diet, as well as their ecotoxicological effects on Poecilia reticulata (Cyprinodontiformes: Poeciliidae) and Danio rerio (Cypriniformes: Danionidae) through acute toxicity tests. The methanolic extract showed higher mortality activity against S. frugiperda (LC₅₀ = 874.28 ppm) than against T. molitor (LC₅₀ = 1856.94 ppm) and was non-toxic to fish. Rosmarinic acid, the most abundant compound in the extract (80.45 mg g⁻¹), showed higher activity against S. frugiperda (LC₅₀ = 176.81 ppm). This compound did not cause a toxic effect on adult P. reticulata at the tested concentrations. However, in P. reticulata fingerlings and D. rerio adults, it was non-toxic, except in D. rerio embryos, where it was slightly toxic. These findings suggest that S. connivens methanolic extract has potential as a botanical product for the management of S. frugiperda and T. molitor with low ecotoxicological impact, while rosmarinic acid may be a useful compound for the management of S. frugiperda. Full article

According to the Sustainable Blue Economy Communication, the Farm to Fork Strategy, and the European Green Deal, novel business models supporting the use of resources from oceans and seas are of primary importance. Interestingly, several infesting seaweeds are consumed as foods in Asia and are fundamental ingredients in several traditional dishes. Herein, according to the circular economy approach, we investigate the use of Chaetomorpha linum (CL) as a Tenebrio molitor larvae feed in different percentages: 20%, 50%, and 100%, respectively. We analyzed the effects of CL on the survival and biometric parameters of larvae. The survival rate remained comparable to the control, while the mean weight was inversely proportional to the CL%. The nutrient composition was substantially different from the control, showing increased protein and reduced fat content. Analysis of the secondary metabolites revealed a better fatty acid composition, rich in PUFA, with lipid nutritional indexes comparable to seaweeds and crabs. The simulated gastrointestinal digestion highlights the increased content of essential amino acids, and a two times higher antioxidant activity with respect to the control. Taken together, our results confirm that CL can be used as a TML supplement, with beneficial effects in protein content and fat quality. Full article

The drying of insects is an important step in their processing. This research aimed to investigate the impact of a pulsed electric field (PEF), immersion in ethanol (EtOH), and combined (immersion in EtOH followed by PEF) treatment on the convective drying process, the emission of CO_2, and the quality of the dried insects with regard to such elements as water content and activity, rehydration and hygroscopic properties, optical properties, internal structure, and microbiological quality. In applying a PEF, the drying time was made longer (up to 21%), but the rehydration and hygroscopic properties were improved (about 15–16.5% and 8.3–21.7%, respectively) compared to the untreated sample. Using a PEF prior to EtOH treatment improved the rehydration properties (about 3.9–5.9%), while the hygroscopicity was slightly lower compared to the PEF-treated samples. Furthermore, immersion in ethanol (both alone and after PEF) provided a lighter color of dried insects and more outstanding microbiological quality, e.g., the absence of water-borne and food-borne pathogens and anaerobic spore-forming bacteria. This study revealed that combined pretreatment seems to be the most promising method for insects as regards obtaining better rehydration and comparable hygroscopic properties, as well as an attractive color compared to untreated insects, and, above all, in ensuring suitable microbiological quality. Full article

To investigate the dietary effects of chlorogenic acid (CGA) on the growth performance, lipid metabolism, antioxidant activity, and non-specific immunity of Asian swamp eel (Monopterus albus) during the domestication stage, a 28-day feeding experiment was conducted to supplement with CGA at levels of 0 (Cont.), 250 (CGA 0.50%), 500 (CGA 1.00%), and 750 (CGA 1.50%) mg/kg·bw by feeding with yellow mealworm (Tenebrio molitor). Compared with the control group, the addition of 250–750 mg/kg of CGA significantly increased the weight-gain rate (WG) of M. albus, and the CGA 1.0% group displayed the highest value. The content of hemoglobin and high-density lipoprotein in all CGA groups was markedly elevated (p < 0.05), while the triglyceride, glucose, low-density lipoprotein, and glycosylated serum protein levels were lowered (p < 0.05). Among the antioxidant enzymes, the glutathione peroxidase and catalase activity was significantly higher in all experimental groups than that of the control group, whereas the malondialdehyde activity was significantly reduced (p < 0.05). For a non-specific immune enzyme system, the lysozyme and alkaline phosphatase activity in all treatments and the superoxide dismutase and acid phosphatase activity in the CGA 0.5% group was markedly increased (p < 0.05). In conclusion, supplementation with CGA can enhance the growth performance and improve the lipid metabolism, antioxidant capacity, and non-specific immunity of M. albus during the domestication stage, and the optimal CGA supplementation for T. molitor as biocarrier bait is 500 mg/kg, corresponding to 405 mg/kg. Full article

During defatted Tenebrio molitor (TM) larvae powder production, oil is obtained as a by-product, mainly intended for feed enrichment or as a biofuel component. In 2021, EFSA authorized TM as the first insect to be a novel food. Thus, the study aimed to assess the composition, including fatty acids (FAs), tocopherols, carotenoids, phenolics, volatiles, antioxidant capacity, sensory aroma attributes, physical properties, and oxidative and hydrolytic stability of TM oil. The FAs profile was dominated by oleic—C18:19c (36.8%) and linoleic—C18:29c12c (32,4%) acids, resulting in a PUFA/SFA ratio similar to vegetable oils. Thus, TM oil was characterized by a beneficial Health Promoting Index (HPI) (2.42), which was 10-fold higher than the HPI of common animal fats. TM oil contained bioactive compounds such as carotenoids (13.65 mg/kg), tocopherols (105.8 mg/kg), and phenolic compounds (74 mg GAE/kg). A noticeable amount of apigenin was also noted among nine detected phenolic compounds. The substantial presence of lipophilic and phenolic compounds contributed to antioxidative potential. Sensory estimation revealed the dominance of fried and nutty aromas, probably because of the abundance of Strecker aldehydes and pyrazines in their volatile profile. The results indicated that the technological process needs modification to limit the formation of lipid oxidation volatile compounds such as aldehydes and eliminate some differences between batches. This preliminary study on the composition and properties of TM oil encourages its use as an ingredient for food, pharmaceutical, and cosmetics purposes. Full article

Proteins from insect production represent an interesting (environmentally friendly) option or supplement to commercial livestock farming. At present, however, the larval stages of T. molitor (mealworm) and A. diaperinus (buffalo worm) have been authorized as food for human consumption EU-wide, as have the nymph and adult stages of Locusta (L.) migratoria (Locusta migratoria, Linnaeus, 1758) and Acheta (A.) domesticus (house cricket, Acheta domesticus, Linnaeus, 1758). However, there is the problem that insects that are recognizable as a whole tend to be avoided by consumers, especially in the European region, as they are reminiscent of living things and can cause aversion and disgust in consumers. Against this background, in the present study, five batches of two types of cooked sausages were produced: on the one hand, with turkey, and on the other hand, with pork lean meat as a base. In different formulations, 10% and 20% of the meat contents (turkey or pork) in these meat products were replaced by deep-frozen, pulverized T. molitor and A. diaperinus larvae. The effects of the addition of these insects in the products on the microbiological and physicochemical parameters of these cooked sausages, compared to a product without insect content, directly after heating, were investigated. After production, a storage trial was also carried out to determine whether possible insect ingredients could influence the growth of inoculated bacterial species (Bacillus (B.) cereus, Escherichia (E.) coli, Listeria (L.) monocytogenes, and Campylobacter (C.) jejuni) and how the addition of insect larvae affectsthe sensory and physicochemical properties during storage. The study showed that the products with insects had reduced lightness (turkey p C = 0.025), increased yellowness (pork p S = 0.0009, p C < 0.0001 and turkey p C = 0.0027) and a reduced red color (pork p S < 0.0001, p C = 0.0001) after heating when compared to the cooked sausages without insects. However, no significant differences between the various cooked sausages with or without insects in terms of cooking loss, firmness, and protein, ash, and fat or water contents were found. The microbiological tests showed, on the one hand, that the prior microbial reduction (e.g., in the form of blanching) of the insect larvae was essential in order to guarantee the flawless microbiological quality of the cooked sausages and, on the other hand, that the addition of insects to the cooked sausages did not significantly affect the growth of the inoculated bacterial species and that no sensory differences could be detected during storage. Despite the significant color effects on the product, A. diaperinus and T. molitor larvae would be suitable as protein or meat alternatives in cooked sausages, but they would have to undergo pre-treatment, primarily with regard to microbiological safety. The extent to which a complete replacement of meat is possible has to be investigated in further studies. Full article

Meat delicatessen products, including pâtés, are important for consumers’ daily diets. However, due to the complex recipe composition, pâtés can also contain allergens such as gluten. Simultaneously, powdered edible insects are increasingly used to reformulate food products. Therefore, the paper aimed to investigate the feasibility of replacing wheat flour (total content: 9% w/w) with yellow mealworm powder (3:0, 2:1, 1:2, and 0:3) in chicken and pork pâtés and determine its effect on their quality properties. The rheological properties of pâté batter, as well as texture, color parameters, and microbiological and sensory characteristics of pâtés, were assessed. All prepared pâté batters were identified as weak gels. Furthermore, all the examined pâtés met the microbiological quality requirements. Adding yellow mealworm powder to the formulation weakened the pâté structure, resulting in significantly lower shear force and increased spreadability. In addition, it led to a darker and more gray color of the pâtés. It may be seen as indicating no preservatives or as resembling a typical pork pâté. It has been demonstrated that the complete replacement of wheat flour with insect powder significantly reduced the sensory quality of chicken and pork pâtés. Full article