Nutritional values of edible Coleoptera (Tenebrio molitor, Zophobas morio and Alphitobius diaperinus) reared in the Czech Republic

Edible insects have gained the status of highly nutritious food with high protein and fat content. However, nutritional value of insects is not constant. It could be affected by species, developmental stage, rearing technology, nutrition or sex. This study's goal is to determine the protein and fat contents of three edible beetle species (giant mealworm - larvae of Zophobas morio, mealworm - larvae of Tenebrio molitor and, lesser mealworm - larvae of Alphitobius diaperinus) bred in the Czech Republic. Based on the obtained results, all investigated species could be considered as a reasonable source of lipids and two of them (mealworm and lesser mealworm) are also an excellent source of protein. Crude protein content of mealworm (630 g. kg-1 DM) was found to be higher than in other studies. The investigated species of lesser mealworm contained 600 g of crude protein/kg DM, which was equal to the results of other authors. Most authors report a higher content of nitrogen in the giant mealworm than were the values measured by this experiment (390 g.kg-1 DM). The lipid content in the tested samples was found in a range of 170 - 390 g.kg-1 DM. The highest lipid content was found in the larvae of giant mealworm and the lowest lipid content was found in the larvae of mealworm. The determined fat content of lesser mealworms was 290 g.kg-1. The fatty acid profiles of all samples were also determined. © 2016 Potravinarstvo. All rights reserved

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. © 2017 Potravinarstvo Slovak Journal of Food Sciences, License

Fat from Tenebrionidae bugs – Sterols content, fatty acid profiles, and cardiovascular risk indexes

This work focused on analysing the content of selected sterols and profile of fatty acids of edible insect species – mealworm (Tenebrio molitor) and superworm (Zophobas morio), which are expected to increase their usability in human nutrition. Sterols content was determined using capillary gas chromatography method. Cholesterol content was determined at 1335 mg/kg in dry matter (DM) for the mealworm, which was less than for superworm (3224 mg/kg DM). Other sterols analysed were stigmasterol and β-sitosterol, which were once again higher in superworm (stigmasterol – 44 mg/kg DM and β-sitosterol – 414 mg/kg DM) than in mealworm (stigmasterol – 18 mg/kg DM and β-sitosterol – 171 mg/kg DM). From the nutritional point of view, the amount of cholecalciferol is also not negligible, which was 190 μg/kg DM in mealworm and 199 μg/kg DM in superworm. Atherogenic index (AI), thrombogenic index (TI), and cholesterol index (CSI) were calculated for both species and compared with the results of other authors. These indexes are often considered predictors of cardiovascular diseases. A potential benefit of both species could be the balanced proportion of sterols of animal and plant origin that could be nutritionally well-accessible and lower weight of dry matter necessary to consume to cover the daily dose of linoleic acid compared to dried beef. © Copyright by Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences.TBU in Zlin [IGA/FT/2019/004]; project BUT in Brno; FEKT [S-17-3934

A comprehensive look at the possibilities of edible insects as food in Europe - A Review

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

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). © 2017 Potravinarstvo Slovak Journal of Food Sciences

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. © 2017 by the authors. Licensee MDPI, Basel, Switzerland

Is edible insect as a novel food digestible?

This work deals with the digestibility of a selected species of edible insect - mealworm (larvae) as novel food in dependency on its culinary treatment. The aim of this work was to find suitable thermic culinary treatment of mealworm larvae considering its optimum digestibility by human. The digestibility of materials from whole insect and extracted nitrogenous substances was determined using three different culinary treatments - without culinary treatment (freshly killed), dried insect and roasted insect. The digestibility was determined by gravimetric in vitro method using pepsin and pancreatin enzymes and their combination. The total nitrogen content of the insect samples was determined by the Kjeldahl method. The digestibility of the whole homogenized larvae using the combination of pepsin and pancreatin enzymes, thus simulating human digestion in-vitro, ranged from 81% for roasted specimens to 91.5% for culinary unprocessed insect. Similarly, the digestibility of nitrogenous substances of homogenized insect samples using this combination of enzymes ranged from 24.2% for roasted specimens to 80.2% for culinary unprocessed samples. The work showed the dependence of the digestibility of the mealworm larvae on the culinary treatment - the increasing heat load of the sample reduced the digestibility. Furthermore, it proved the effect of the digestive enzyme on the digestibility of the insect sample. © 2019 Potravinarstvo Slovak Journal of Food Sciences

Effect of temperature and feed on the mineral content and the content of selected heavy metals in mealworm

Minerals are important components of thousands of enzymes and other compounds in the body. Although the content of minerals in the human body is small, their importance is immense. Edible insects can provide many of these minerals in abundance, and are therefore thought to be a good source of micronutrients. This study dealt with the effect of a rearing temperature and feed on the mineral content and on the content of selected heavy metals in mealworm (Tenebrio molitor). Mealworm larvae were kept at temperatures of 15, 20 and 25°C, and fed with wheat bran, lentil flour and a mixture of both. The types of feed for the experimental groups were chosen purposefully, considering the availability on site, price and especially the impact on the nutrition composition suitable for human. The concentrations of the most significant elements in terms of human nutrition concerns, that is zinc and copper, were determined with inductively coupled plasma mass spectrometry. The results showed that the normality condition was not achieved for Ca, Fe, P and Pb (p<0.05). Therefore, these data were compared using the Kruskal-Wallis method, while ANOVA test was performed for the other elements. There was a statistically significant dependence of the Cd concentration on feed at a constant rearing temperature of 15°C and 25°C over the entire feed change range. The results included a change in Mg over the whole range of monitored values with a change of the rearing temperature and constant feed of lentils-bran,and with a change of feed and constant rearing temperature of 15°C. In contrast, concentrations of Na, P, Ca and Cu over the whole observed range of feed or rearing temperature changes were independent from the variables. With an appro-priately chosen rearing temperature and feed, it is possible to obtain mealworm with specific nutritional properties for a target group of consumers. © 2020, Polish Society Magnesium Research. All rights reserved.TBU in Zlin [IGA/FT/2020/010]; project BUT in Brno [FEKT-S-20-6215

Welfare of the mealworm (Tenebrio molitor) breeding with regard to nutrition value and food safety

Livestock welfare is an important condition for obtaining high-quality and safe food. According to the legislation edible insects are classified as livestock; and for this reason it is necessary to comply with the edible insect welfare conditions. This article focuses on selected welfare conditions for mealworm (Tenebrio molitor) breeding, with special focus on the fat content influenced by different breeding temperature (17 °C, 23 °C and 28 °C). Maximum fat content 24.56% was observed at 23 °C. To obtain maximum fat content this appears to be the optimal breeding temperature. Another evaluated aspect was the nutritional stress and a way of killing, and their impact on fat content, which showed to decrease with the nutrient stress. The most decline was detected towards the end of the observation period. The analysis showed that in terms of preservation of the fat content, the best way is killing by freezing, due to the metabolism slowdown. We also analysed the content of heavy metals in a mealworm larvae using cyclic voltammetry with subsequent evaluation. In the measured sample concentrations of heavy metals did not exceed the maximum allowable concentration of heavy metals in this commodity. From this point of view mealworm appears to be a safe food. © 2017 Potravinarstvo Slovak Journal of Food Sciences

Calcium in edible insects and its use in human nutrition

Calcium is one of the most problematic substances in human nutrition. Nutrition in the present population is not optimal, because of insufficient consumption of milk and dairy products. Due to the expanding interest of specialists and the general public about entomophagy, as well as increase of the EU interest in this type of food, there is a need to consider the use of edible insects as an alternative source of nutrition. From the perspective of edible insects as a source of calcium, edible insects could be considered as a possible source of calcium for enriching the diet and also as a substitute for people with lactose intolerance and allergies to other categories of foods rich in calcium. Of the six analysed species of edible insect, Bombyx mori had the highest calcium content, almost comparable to semi-skimmed cow's milk. Gryllus assimillis can also be a rich source of calcium as well as other analysed species. The lowest content of calcium was detected in Zophobas morio. Common meat (chicken, beef, pork) has lower calcium content comparing with all analysed species of edible insect (Apis mellifera, Bombyx mori, Gryllus assimillis, Locusta migratoria, Tenebrio molitor, Zophobas morio). Therefore, the selected species of edible insect could serve as an alternative source of calcium for people with lactose intolerance and allergies to soy. Phosphorus level in human body is closely related to calcium in the calcium-phosphate metabolism, therefore phosphorus level was detected in these samples too. Bombyx mori had the highest phosphorus content and the lowest content of phosphorus was measured in Zophobas morio samples. © 2014 Potravinarstvo. All rights reserved