Marie Borkovcová

A Comprehensive Look at the Possibilities of Edible Insects as Food in Europe – a Review

Abstract Possibilities of edible insects use in European countries, are now an increasingly debated issue. Insects in Asian, African, Central American and South Central American cultures are mainly nutritional components. This review mainly describes the species of insects that are suitable as food in Europe and other developed countries. This comprehensive work addresses the issue of eating insects, especially considering the nutritionally important factors. Risks are also mentioned, as well as allergies, toxicity, and other aspects of the breeding and use of edible insects. Insects play and will play important roles in the future in various fields of research, exploitation, breeding, etc. This review provides a comprehensive current and future view of insects as a valuable foodstuff.

Thermal profile of rabbits infected with Eimeria intestinalis

In this study, infrared thermography (IRT) was assessed as a means of detecting the changes in body temperature in rabbit coccidiosis, as well as determining IRT used in imaging and measuring the regional changes in skin temperature that occur in the rabbits during this infection. Rabbits were inoculated with 5 x 10(4) or 1 x 10(5) oocysts of Eimeria intestinalis, respectively. The group of control animals remained non-inoculated throughout the study. All measured temperatures (rectal, ocular surface and auricle pavilion temperatures) dropped significantly (P<0.05) in rabbits infected with 1 x 10(5) oocysts. This group of rabbits also showed a medium negative correlation in rectal temperature (r=-0.49), ocular surface temperature (r=-0.49) and auricle pavilion temperature (r=-0.49) and a small negative correlation in live body weight gain (r=-0.22) depending on the number of days elapsed from the time of infection exposure.

Biologically active substances of edible insects and their use in agriculture, veterinary and human medicine – a review

Possibilities of edible insect use in Western countries is now increasingly debated issue. Insects in Asian, African, American and South Central American cultures are mainly nutritional components. In Europe and other developed countries, however, insect is used in different ways, and this issue is viewed from a different angle. Insects are mainly used as feed for animals, in the organic waste recycling systems, in human and veterinary medicine, material production (such as silk) etc. This review summarizes up-to-date knowledge about using edible insects in human, veterinary medicine and agriculture, especially from the viewpoint of the biological and chemical content of active substances and the possibilities of further use in these areas.

Nutritional Potential of Selected Insect Species Reared on the Island of Sumatra

Inhabitants of the Indonesian island of Sumatra are faced with the problem of insufficient food supplies and the consequent risk of undernourishment and health issues. Edible insects as a traditional and readily available food source could be part of the solution. The nutritional value of insects depends on many factors, e.g., species, developmental stage, sex, diet, and climatic conditions. However, edible insects bred in Sumatra for human consumption have never before been assessed with regard to their nutritional value. Our study involved analyses of crude protein, chitin, fat and selected fatty acid contents of giant mealworm larvae (Zophobas morio), larvae of the common mealworm (Tenebrio molitor) and nymphs of the field cricket (Gryllus assimilis). Crude protein content in the samples ranged from 46% to 56%. Highest (35%) and lowest (31%) amounts of fat were recorded in giant mealworm larvae and larvae of the common mealworm, respectively. Chitin amounts ranged from 6% to 13%. Based on these values, which are comparable to those known from other food insects reared in different regions of the world, the edible species bred in Sumatra could become food sources with a potential to help stave off hunger and undernourishment.

To eat or get heat: Behavioral trade-offs between thermoregulation and feeding in gregarious necrophagous larvae: Thermoregulation in gregarious necrophagous larvae

The thermoregulation behavior of Lucilia sericata larvae (Diptera: Calliphoridae), a necrophagous species that feeds on vertebrate cadavers, was investigated. These larvae require high heat incomes to develop, and can elevate temperatures by forming large aggregates. We hypothesized that L. sericata larvae should continue to feed at temperatures up to 38 °C, which can be reached inside larval masses. Thermal regulation behavior such as movement between a hot food spot and colder areas was also postulated. The hypotheses were tested by tracking for 1 h the activity of single, starved third instar larvae in a Petri dish containing 1 food spot (FS) that was heated to a constant temperature of 25 °C, 34 °C or 38 °C with an ambient temperature of 25 °C. The influence of previous conspecific activity in the food on larval behavior was also tested. The crops of larvae were dissected to monitor food content in the digestive systems. Based on relative crop measurements, larvae fed at all food temperatures, but temperature strongly affected larval behavior and kinematics. The total time spent by larvae in FS and the duration of each stay decreased at high FS temperature. Previous activity of conspecifics in the food slightly increased the time spent by larvae in FS and also decreased the average distance to FS. Therefore, necrophagous L. sericata larvae likely thermoregulate during normal feeding activities by adjusting to local fluctuations in temperature, particularly inside maggot masses. By maintaining a steady internal body temperature, larvae likely reduce their development time.

The effect of Syphacia muris on nutrient digestibility in laboratory rats

This study was carried out to investigate how pinworm infection in rats affects nutrient digestibility in the hosts. Twenty-four male outbred Wistar rats were randomly divided into two groups of 12 rats each. The rats from the first group (GI) were kept in cages with bedding containing pinworm eggs, and the second (control) group (GII) were kept in a separate room in clean, uncontaminated filter-top cages. The animals were put into individual metabolic cages later. Metabolic trials lasted five days and records of animal weight, food ingestion, and faecal weight were taken daily. Based on laboratory analysis of the feed and faecal nutrient content, digestibility values were determined. On day 15 of the experiment, the animals were euthanized. Although Syphacia muris were found in all rats from the GI group, animals exhibited no clinical signs. In our experiment, S. muris infection reduced the overall digestibility of all measured nutrients (P < 0.01). The most significant differences in digestibility were observed in the case of crude fibre and mineral matter (P < 0.01).

Effect of different storage conditions on the microbiological characteristics of insect

When introducing a novelty food, its safety needs to be monitored. One of the safety aspects of human health is microbial contamination. In this work, microbiological parameters of long-term stored edible insect material - mealworm ( Tenebrio molitor ), lesser mealworm ( Alphitobius diaperinus ), field cricket ( Gryllus assimilis ), and migratory locust ( Locusta migratoria ) were evaluated. The monitored indicators (colony forming units, enterobacteria, lactic acid bacteria, yeasts and moulds) were evaluated using common microbiological methods. All samples of stored insect were determined as safe for human consumption, except for the lesser mealworm sample from 2016, in which case the limit was exceeded. Sample of adult field cricket seems to be suitable for long-term storage, as it contained the lowest amount of microorganism. Sample of dried Gryllus assimilis from 2014 had the lowest microbial contamination. Further results suggest that, for long-term storage, the most suitable way of preparation is killing with boiling water, drying at 103 °C for 12 hours and subsequent hermetic packaging.

Acceptability and sensory evaluation of energy bars and protein bars enriched with edible insect

For consumers, one of the basic criteria of choosing a foodstuff, apart from nutritional values, is their taste and smell. In edible insect as a novel food, these criteria are not quite decisive. The main criterion in the Western countries is the acceptability of the food. This work deals with sensory evaluation of protein and energy bars, enriched with cricket flour from American and Czech producers, and their acceptability for consumers from the Czech Republic. The sensory evaluation was done using the questionnaire survey and a simple electronic nose. The survey has shown that edible insect bars are acceptable as a new type of food for consumers in the Czech Republic. Best rated by consumers were orange and pineapple flavour bars from the Czech manufacturer. Statistically significant difference was not detected between evaluation of the bars from the American and Czech manufacturers. Also, the difference between the bars of different flavours from the Czech producer was evaluated using a simple machine - a portable electronic nose. There was not a statistically significant difference between bars of different flavours from the American manufacturer. The positive contribution of the survey is that more than 80% of consumers are willing to consume food enriched with edible insect. This fact shows a change in public attitude to these foods.

Electronic nose in edible insects area

Edible insect is appraised by many cultures as delicious and nutritionally beneficial food. In western countries this commodity is not fully appreciated, and the worries about edible insect food safety prevail. Electronic noses can become a simple and cheap way of securing the health safety of food, and they can also become a tool for evaluating the quality of certain commodities. This research is a pilot project of using an electronic nose in edible insect culinary treatment, and this manuscript describes the phases of edible insect culinary treatment and methods of distinguishing mealworm ( Tenebrio molitor ) and giant mealworm ( Zophobas morio ) using simple electronic nose. These species were measured in the live stage, after killing with boiling water, after drying and after inserting into the chocolate.The sensing device was based on the Arduino Mega platform with the ability to store the recorded data on the SD memory card, and with the possibility to communicate via internet. Data analysis shows that even a simple, cheap and portable electronic nose can distinguish between the different steps of culinary treatment (native samples, dried samples, samples enriched with chocolate for cooking) and selected species. Another benefit of the electronic nose could be its future introduction into the control mechanisms of food security systems (e.g. HACCP).

Detection of selected heavy metals and micronutrients in edible insect and their dependency on the feed using XRF spectrometry

Edible insect can be a valuable source of nutrients, but also a potential source of heavy metals. Quick detection of over-limit heavy metals concentration could be a key to processing and quick distribution of edible insect products. The aim of this work was to evaluate the feed-dependent content of heavy metals in the mealworm and superworm using the X-ray fluorescence spectrometry as an easy, cheap and a timeless screening method for evaluating the content of heavy metals and microelements. Using a handheld analyser the content of Cd, Pb, Cu and Zn were detected. Both analysed species proved dependency of metal content on a feed. Detected level of Cu in mealworm was between 571 mg.kg -1 and 1768 mg.kg -1 and in superworm from 571 mg.kg -1 to 1768 mg.kg -1 based on the feed. The content of Zn was similar, between 725 mg.kg -1 and 1437 mg.kg -1 in mealworm and 555-1482 mg.kg -1 in superworm. The level of Pb was below the detection limit in all samples, thus from this point of view this food seems to be safe. On the contrary, the content of Cd in the dry matter samples was above the food limit - 147 mg.kg -1 to 230 mg.kg -1 . From this point of view, the samples were evaluated as unsuitable for consuming.