Influence of Freeze-Drying and Oven-Drying Post Blanching on the Nutrient Composition of the Edible Insect Ruspolia differens

The contribution of commonly consumed edible insects to nutrition security in the Eastern D.R. Congo

Edible insects are perceived as an incredible opportunity to mitigate the major challenge of sustainably producing healthy foods for a growing world population in the face of climate change uncertainties over the coming decade. In this study, we assessed the nutrient composition and sensory properties of Acheta domesticus, Apis mellifera, Gnathocera trivittata, Gryllotalpa africana, Imbrasia epimethea, Imbrasia oyemensis, Locusta migratoria, Macrotermes subhylanus, Nomadacris septemfasciata, Rhyncophorus phoenicis, Ruspolia differens and Rhynchophorus ferrugineus consumed in Eastern D. R. Congo. The investigated edible insects are highly appreciated and nutritious, with proteins (20.67-43.93 g/100 g) and fats (14.53-36.02 g/100 g) being the major macro-nutrients, proving their potential to improve diets through food enrichment. The high potassium (24-386.67 mg/100 g), sodium (152-257.82 mg/100 g), magnesium (32-64 mg/100 g), iron (5.3-16.13 mg/100 g), calcium (25-156.67 mg/100 g) and zinc (11-19.67 mg/100 g) content make the assessed edible insects a useful mineral-containing ingredient for preventing undernutrition in countries which are plagued by micronutrient deficiencies. A scatter plot of matrices and Pearson's correlations between sensory attributes and nutritional composition showed a negative correlation (r = - 0.45) between protein and appearance. While no strong correlation was observed between nutritional attributes and sensory acceptance, a positive correlation was observed between potassium and aroma (r = 0.50), after-taste (r = 0.50) and acceptability (r = 0.52). Principal component analysis results indicated that the two axes accounted for up to 97.4% of the observed variability in the nutrient composition and sensory attributes of commonly consumed edible insects in the Eastern D. R. Congo. Given the significant delicacy and nutritional potential of edible insects highlighted in this paper, households can rely on the latter to meet their nutritional needs rather than conventional livestock, thus contributing to environmental and financial security through local business opportunities.

Effect of fortifying sorghum and wheat with Longhorn grasshopper (Ruspolia differens) powder on nutritional composition and consumer acceptability of biscuits

This study aimed at improving the nutrient composition and protein quality of biscuits made from sorghum and wheat through fortification with Longhorn Ruspolia differens powder (RDP) for use as a supplementary food targeting children vulnerable to protein-energy malnutrition (PEM). Ten biscuit formulations were prepared by replacing a part of wheat and sorghum-wheat flours with 5, 15, 20, and 40% RDP. To establish the nutrient content of biscuits, proximate and mineral compositions were determined. The amino acid composition, reactive lysine and in vitro protein digestibility were determined for protein quality. Compositing wheat or wheat-sorghum biscuits with RDP increased the protein, fat, ash, and crude fiber by percentages as high as 118, 37, 133, and 573%, respectively. Mineral content increased with, iron, zinc, and potassium as high as 161, 219, and 169%, respectively. The lysine, reactive lysine and in vitro protein digestibility of the fortified biscuits increased significantly, relative to the 100% cereal biscuits. Fortification with RDP significantly improved the amino acid content of the biscuits but had a marginal effect on improvement of the lysine score and did not meet the reference pattern for children aged 3-10 years. The Protein Digestibility Corrected Amino Acid Score (PDCAAS) of wheat-sorghum and wheat biscuits improved by 6% to 47% and 2% to 33%, respectively, compared to the control biscuits. The fortified biscuits were liked by the consumers. The RDP-fortified biscuits have the potential to alleviate PME in developing countries.

Recent advances in edible insect processing technologies

Alternative foods have emerged as one of the hot research topics aiming at alleviating food shortage. Insects are one of the alternative foods due to their rich nutrients. Processing is a critical step to develop insect foods, while there is a lack of comprehensive reviews to summarize the main studies. This review aims to demonstrate different processing methods in terms of their impact on insect nutrition and their potential risks. Heat treatments such as boiling and blanching show a negative effect on insect nutrition, but essential to assure food safety. Insects treated by high-pressure hydrostatic technology (HPP) and cold atmospheric pressure plasma (CAPP) can achieve a similar sterilization effect but retain the nutritional and sensory properties. Drying is a practical processing method for industrial insect production, where oven drying serves as a cost-effective method yielding products comparable in quality to freeze-dried ones. In terms of extraction technology, supercritical carbon dioxide and ultrasound-assisted technology can improve the extraction efficiency of proteins and lipids from insects, enhance the production of composite insect-fortified foods, and thus facilitate the development of the insect food industry. To address the widespread negative perceptions and low acceptance towards insect foods among consumers, the primary development direction of the insect food industry may involve creating composite fortified foods and extracting insect-based food components.

Optimising mopane worm (Gonimbrasia belina) processing for improved nutritional and microbial quality

Mopane worms (Gonimbrasia belina) is an important source of food and contribute to the nutrition of people who consume them. However, the traditional processing methods may have detrimental effects on the nutritional value and should also guarantee microbial quality. In this study, the nutritional composition and microbial quality of mopane worms processed under different boiling time (0-20 min) and drying temperature (40-60 °C) conditions were investigated and optimised using response surface methodology. An increase in the boiling time at the lowest drying temperature resulted in an increase in protein content and reduction in coliform counts. The optimum conditions of boiling for 20 min and drying at 40 °C resulted in mopane worms with a protein content of 49.4% DW and coliform counts <1.5 log cfu/g. In addition, high concentrations of crude fibre (13.6% DW) and fat (20.2% DW), as well as Fe (19.0 mg/100 g) and Zn (17.9 mg/100 g) were also recorded. A decrease in the total bacterial count, Escherichia coli and yeasts and moulds at the boiling time ≥20 min irrespective of the drying temperature suggested that exposure to heat reduced the microbial growth and contamination. Reduction of the mopane worms' moisture content (<7%) due to drying further slowed down the rate of microbial growth. The optimal processing conditions (boiling for 20 min and drying at 40 °C) are recommended for pretreatment of mopane worms prior to further processing into various products.

The current state of research and potential applications of insects for resource recovery and aquaculture feed

Concerns about fishmeal use and its ecological footprints must be addressed for the aquaculture industry to move on as a sustainable food production sector. Through recent research outcomes, the insect-based meals in fish diets have promise and harnessed promises for commercial applications. In this midst, the efficiency of the selected insects in valorizing biological waste, as well as the nutritional profile of the harvested insects for use in fish diets, will be the driving forces behind such an approach. More extensive research has been published on the suitability of the waste substrate, the nutritional profiling of the meals, the level of substitution, the effects on growth, the immune physiology, and the flesh quality of the animals. Previously, there are only a few reviews available in insect protein applications in aqua feed that focused particularly on the nutritional quality and substitution levels. Considering the dearth of available work, the goal of this review is to provide a more comprehensive account of the resource recovery potential of insects and its derivatives, with a special emphasis on quality as determined by substrate used and processing techniques. Suggestions and policy implications for a sustainable approach to achieving a circular bio-economy of insect farming and its application in aquaculture are discussed for progression and advancement of the existing state of the art.

Effects of drying on the nutritional, sensory and microbiological quality of edible stinkbug (Encosternumdelgorguei)

Entomophagy has recently gained attention as a potential solution to the problems of food and nutritional security. One example is the consumption of edible stinkbug. Different drying techniques may affect the nutritional, microbiological and sensory properties of the edible stinkbugs. Thus, the study assessed the effects of toasting, microwave, oven and sun drying on the nutritional composition, microbiological quality and sensory attributes of processed edible stinkbugs. Drying significantly (p < 0.05) increased the crude protein and fat content of the edible stink bugs with the highest values being recorded for the toasted samples (66.65 & 37.17% respectively). Highest Ca, K, Zn, Mg, Fe and P values were recorded after microwave drying. Reduction of 2.94 and 2.99 log cycles of the total viable count (TVC) was observed in oven and microwave dried edible stinkbugs. Toasting and microwave drying eliminated the yeasts and moulds, Enterobacteriaceae and lactic acid bacteria (LAB) in edible stinkbugs. The appearance, aroma, taste, texture and overall acceptability scores were in the same order for toasted > oven dried > microwave dried > sun dried edible stinkbugs. Toasting, oven and microwave drying can be used for processing of edible stinkbugs.

Variability in nutrient composition of the edible long-horned grasshopper (Ruspolia differens) in Uganda and its potential in alleviating food insecurity

Ruspolia differens Serville (Orthoptera: Tettigonidae) is a highly nutritious and luxurious insect delicacy that is consumed as a food source in many African countries. However, the nutrient profile of R. differens in different geographical regions have received limited research interest. Here, we provide comprehensive evidence of geographical impact on the nutrient profile of R. differens and its potential to meet the recommended dietary intake of the population. Our results demonstrated that proximate composition, fatty acids, amino acids, minerals, vitamins, and flavonoid contents of R. differens collected from five districts in Uganda varied considerably. The crude protein (28-45%), crude fat (41-54%), and energy (582-644 Kj/100 g) contents of R. differens exceed that reported from animal origins. The highest crude protein, crude fat, and carbohydrate contents of R. differens were recorded in Kabale, Masaka, and Kampala, respectively. A total of 37 fatty acids were identified with linoleic acid (omega-6 fatty acid) being the most abundant polyunsaturated fatty acid in R. differens from Kabale, Masaka, and Mbarara. All essential amino acids were recorded in R. differens, particularly histidine with values exceeding the daily requirement for adults. Mineral and vitamin content differed significantly across the five districts. The highest quantity of flavonoids was recorded in R. differens from Hoima (484 mg/100 g). Our findings revealed that R. differens could be considered as functional food ingredients capable of supplying essential macro- and micronutrients that are critical in curbing the rising food insecurity and malnutrition in the regions.

The Review of Cooking, Drying, and Green Extraction Methods on General Nutritional Properties of Mealworms and Locusts

The processing of edible insects as an alternative source of nutrition may be a key driver in the development of a sustainable food and feed system. This review will study two industrial types of insects-mealworms and locusts-and summarize evidence related to the impact of processing on their micro- and macronutritional characteristics. The focus will be on their potential use as food for human consumption as opposed to animal feed. Literature has indicated that these two insects have the potential to provide protein and fat qualities comparable to or better than traditional mammalian sources. For example, mealworms-the larval form of the yellow mealworm beetlepossess a higher fat content, while adult locusts are rich in fibers, especially chitin. However, due to the different matrix and nutrient compositions, the processing of mealworms or locusts at a commercial scale needs to be tailored to minimize nutritional loss and maximize cost efficiency. The stages of preprocessing, cooking, drying, and extraction are the most critical control points for nutritional preservation. Thermal cooking applications such as microwave technology have demonstrated promising results, but the generation of heat may contribute to a certain nutritional loss. In an industrial context, drying using freeze dry is the preferred choice due to its uniformity, but it can be costly while increasing lipid peroxidation. During the extraction of nutrients, the use of green emerging technologies such as high hydrostatic pressure, pulsed electric field, and ultrasound may provide an alternative method to enhance nutrient preservation.

Graphical Abstract

Quality of Tenebrio molitor Powders: Effects of Four Processes on Microbiological Quality and Physicochemical Factors

Tenebrio molitor, the first edible insect approved as a novel food in the EU, is a promising candidate for alternative protein sources, implementing circular and sustainable production systems. This study aims to determine the microbiological quality and physicochemical properties of mealworm powders obtained by four different processing pathways. Contents of dry matter, protein, fat, ash, water activity (aw) and a range of microbial counts were measured and analyzed by one-way ANOVA with Tukey's test. Results showed small differences in the proximate composition of the powder samples (protein 55.62-57.90% and fat 23.63-28.21% of dry matter, DM), except for the one that underwent a defatting step (protein 70.04% and fat 16.84%), p < 0.05. A level of water activity of less than 0.2 was reached for all pathways. Fresh mealworm samples had high total aerobic counts (8.4 log CFU/g) but were free of foodborne pathogens. Heat treatments applied during transformation were sufficient to kill vegetative cells (reduction of 2.8-5.1 log CFU/g) rather than bacterial endospores (reduction of 0.3-1.8 log CFU/g). Results were confirmed by predictive microbiology. This study validated the efficacy of a boiling step as critical control points (CCPs) of insect powder processing, providing primary data for the implementation of HACCP plans.

Beyond Human Nutrition of Edible Insects: Health Benefits and Safety Aspects

Nowadays, edible insects are considered an outstanding source of nutrients, primarily because they contain high-quality protein, amino acids, and vitamins. Insects are considered a promising alternative protein source towards alleviating future global food shortage problems due to their production considered as being more sustainable by using less agricultural land and water, as well as releasing a smaller amount of greenhouse gas emissions. However, other important aspects to consider about the consumption of edible insects include their health benefits and some safety aspects, which has been relatively overlooked. In this sense, edible insects contain bioactive compounds that can provide diverse bioactivities, such as antioxidant, antihypertensive, anti-inflammatory, antimicrobial, and immunomodulatory with a positive impact on human health. On the other hand, edible insects are a nutrient-rich food that can provide a perfect growth medium for diverse microorganisms, as well as possess some anti-nutritive factors. These two main aspects could represent food safety concerns for consumers. In this context, recent scientific evidence indicates that preservation methods, mainly thermal treatments, utilized in the cooking or processing of edible insects decreased the microbial levels and anti-nutritive factors, which suggests that edible insects do not represent a critical biological risk to humans. Besides, edible insects could have a positive effect on gut microbiota, either by their pre-biotic effect or their antimicrobial activity towards pathogens. Thus, this review is focused on studies related to the health benefits of edible insects and their isolated components, as well as discussion about potential issues related to their microbial content and anti-nutritive factors; this review will provide a synopsis on whether edible insects may be considered safe for human consumption.

The Characteristic of Insect Oil for a Potential Component of Oleogel and Its Application as a Solid Fat Replacer in Cookies

The larvae of Tenebrio molitor, an edible insect, have recently attracted attention in the food industry as a protein supplement or future food material. However, despite more than 30% of the total weight being fat content, few studies have been conducted on the fat (oil) derived from Tenebrio molitor larvae (TM oil) and its food utilization. In this study, TM oil was extracted and its fatty acid composition and antioxidant activity were investigated. Then, the oleogels were prepared with TM oil and oleogelators (candelilla wax, carnauba wax, and beeswax) and their rheological and thermal properties were evaluated to elucidate their utilization as a solid fat replacer in cookies. In the results, TM oil contained 73.6% unsaturated fatty acids and showed a lower antioxidant activity than olive oil. Although the highest hardness was shown in oleogel with candelilla wax, the highest viscoelasticity above 50 °C was observed for oleogel with carnauba wax. The highest melting point was observed in carnauba oleogel. Lower peroxide values were observed in the oleogel samples than for TM oil, indicating that oleogelation of structuring oil improved the oxidative stability of TM oil. In addition, the shortening replacement with carnauba wax oleogel showed a desirable cookie quality in terms of spreadability and texture properties.

Nutritional Quality of Four Novel Porridge Products Blended with Edible Cricket (Scapsipedus icipe) Meal for Food

Currently, no data exist on the utilization of the newly described cricket species (Scapsipedus icipe) meal as additive in food products, though they have high protein (57%) with 88% total digestibility as well as a variety of essential amino acids. This article presents the first report on the effects of processing techniques and the inclusion of cricket meal (CM) on the nutrient and antinutrient properties of four porridge products compared to a popularly consumed commercial porridge flour (CPF). Porridge enriched with CM had significantly higher protein (2-folds), crude fat (3.4–4-folds), and energy (1.1–1.2-folds) levels than the CPF. Fermented cereal porridge fortified with CM had all three types of omega-3 fatty acids compared to the others. The vitamin content across the different porridge products varied considerably. Germinated cereal porridge with CM had significantly higher iron content (19.5 mg/100 g). Zinc levels ranged from 3.1–3.7 mg/100 g across the various treatments. Total flavonoid content varied significantly in the different porridge products. The phytic acid degradation in germinated and fermented porridge products with CM was 67% and 33%, respectively. Thus, the fortification of porridge products with cricket and indigenous vegetable grain powder could be considered an appropriate preventive approach against malnutrition and to reduce incidences in many low-and middle-income countries.

Edible insects, a valuable protein source from ancient to modern times

The current COVID-19 pandemic has demonstrated that we are not prepared to deal with food security amid unexpected situations; the FAO (Food and Agriculture Organization) has stipulated that the future of our food & agriculture looks challenging toward the year 2050; primarily in response to the fact that global population is expected to increase by 9 billion people by 2050. Although entomophagy has been practiced by humans for thousands of years, until recently, edible insects have gained special attention due to their high nutritional value (particularly their high protein and essential amino acid content) and lower environmental impact that could help alleviate the global food demand. Edible insects are classified into eight main orders belonging to Blattodea (cockroaches and termites), Coleoptera (beetles), Diptera (flies), Hemiptera (cicadas, stink bugs), Hymenoptera (bees, wasps, ants), Lepidoptera (butterflies, moths), Odonata (dragonflies), and Orthoptera (crickets, grasshoppers, locusts). Several traditional cooking (e.g., boiling, roasting, sun-drying) and processing technologies (e.g., pasteurization, enzymatic proteolysis, high pressure processing) have shown that it is feasible to prepare safe and nutritious insects and/or foods with insects. Nevertheless, challenges associated with consumers acceptance to eat insects, as well as potential presence of anti-nutritive factors and allergens, need to be carefully evaluated as the industry grows in the coming years. Foreseeing such food shortages during pandemics and future food security concerns, consumers, scientists, and the food industry need to consider the value of farming insects as promising protein sources.

Potential of Fermentation and Vacuum Packaging Followed by Chilling to Preserve Black Soldier Fly Larvae (Hermetia illucens)

Simple Summary

Insects are being produced at an industrial scale, mainly as feed ingredient to replace less sustainable protein sources in feed. Larvae of the black soldier fly (Hermetia illucens) are currently the most important species reared for this purpose. After production, it is necessary that the larvae be stored and transported in a stable way, i.e., without deterioration. In this study, we investigated fermentation and vacuum packaging technology as potential stabilisation techniques. Fermentation appears to be possible when the larvae are first blanched and pulverised, but bacterial endospores remain present and can potentially be dangerous if the conditions are not acidic enough. Vacuum packaging was tested as storage technique for living larvae, but their survival was lower than for living larvae packaged in air. Additionally, for killed larvae, vacuum packaging before chilling did not bring benefits over chilled storage alone. That was concluded from the fact that microbial counts were similar for larvae that were packaged in air or under vacuum during storage.

Abstract

Black soldier fly larvae (Hermetia illucens) are currently reared at an industrial scale, mainly as a feed ingredient. The logistic chain not only involves the production of larvae, but also stabilisation, storage, and transport. The aim of this work was to study fermentation and vacuum packaging of larvae as potential preservation technologies. For fermentation, blanched larvae were pulverised into a paste, and a starter culture, NaCl, and glucose were added. The mixture was fermented for 7 days at 35 °C and then stored for 14 days at 4 °C and pH and microbial counts were monitored. Vacuum packaging was applied to living, blanched and frozen larvae. After packaging, they were stored for 6–10 days at several temperatures and gas composition, survival (living larvae) and microbial counts (killed larvae) were recorded. Fermentation allows storage of pulverised larvae, but points to consider are a rapid pH reduction and the presence of bacterial endospores. Vacuum packaging did not bring added value over cooling alone. This was the case for all types of larvae investigated. Vacuum packaging is not considered as a valuable preservation technology to pursue for storage and transport of black soldier fly larvae.

Nutritional Qualities and Enhancement of Edible Insects

Over the last decade, the urgency to find alternative and sustainable protein sources has prompted an exponential increase in the interest in insects as a human food source. Edible insects contribute suitable amounts of energy and protein, fatty acids, and micronutrients to the human diet. Nutritional values of insects can be manipulated to meet specific needs. Edible insects in food-insecure countries can contribute to improving diets and preventing undernutrition. Bioactive compounds in insects may reduce health risks. Food safety risks are low and mainly relate to those of allergenicity. Strategies to overcome barriers to the consumption of insect products include emphasizing their sustainability, increasing their tastiness, and developing the ability to disguise insects in familiar products. A new sector of insects as food and feed is emerging. Major challenges include legislation, lowering prices by automation and cheap substrates, developing insect products that appeal to consumers, and exploring the health benefits. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Chemical Composition, Nutrient Quality and Acceptability of Edible Insects Are Affected by Species, Developmental Stage, Gender, Diet, and Processing Method

Edible insects have been considered as either nutritious food itemsper se, or as wholesome ingredients to various dishes and components of traditional subsistence. Protein, fat, mineral and vitamin contents in insects generally satisfy the requirements of healthy food, although there is considerable variation associated with insect species, collection site, processing method, insect life stage, rearing technology and insect feed. A comparison of available data(based on dry weight) showed that processing can improve the nutrient content, taste, flavour, appearance and palatability of insects, but that there are additional factors, which can impact the content and composition of insect species that have been recommended for consumption by humans. This review focuses on factors that have received little attention in connection with the task to improve acceptability or choice of edible insects and suggests ways to guarantee food security in countries where deficiencies in protein and minerals are an acute and perpetual problem. This review is meant to assist the food industry to select the most suitable species as well as processing methods for insect-based food products.

Enhancing the specificity of chitin determinations through glucosamine analysis via ultra-performance LC-MS

As chitin is gaining an increased attention as feedstock for industry, quantification thereof is becoming increasingly important. While gravimetric procedures are long, not specific and highly labour-intensive, acidic hydrolysis of chitin into glucosamine followed by quantification of the latter is more performant. Even though several quantification procedures for the determination of chitin can be found in the literature, they give inconsistent results and their accuracy was not assessed due to the lack of certified analytical standards. Therefore, in the present study, commercially available chitin from practical grade was characterised in detail, allowing the assessment of method accuracy. The procedure for the hydrolysis of chitin into glucosamine and subsequent quantification via UPLC-MS was investigated in detail as well. Using 9-fluorenylmethyl chloroformate (FMOC-Cl) as derivatisation reagent, glucosamine was quantified using reversed-phase chromatography. For the chitin hydrolysis, the highest glucosamine recovery was obtained with 8.0 M HCl for 2 h at 100 °C. The entire procedure for chitin quantification, including the hydrolysis, was characterised by high interday and intraday precision and accuracy. The specificity of the procedure was assessed as well by analysing different mixtures of cellulose and chitin. Chitin recoveries from these analyses ranged from 98.8 to 105.8% while no signal was observed for 100% cellulose, indicating the high specificity of the procedure. It was also concluded that the procedure is much faster and less labour-intensive compared to the gravimetric procedure.

Potential Development of Sustainable 3D-Printed Meat Analogues: A Review

To mitigate the threat of climate change driven by livestock meat production, a multifaceted approach that incorporates dietary changes, innovative product development, advances in technologies, and reductions in food wastes/losses is proposed. The emerging technology of 3D printing (3DP) has been recognized for its unprecedented capacity to fabricate food products with intricate structures and reduced material cost and energy. For sustainable 3DP of meat substitutes, the possible materials discussed are derived from in vitro cell culture, meat byproducts/waste, insects, and plants. These material-based approaches are analyzed from their potential environmental effects, technological viability, and consumer acceptance standpoints. Although skeletal muscles and skin are bioprinted for medical applications, they could be utilized as meat without the additional printing of vascular networks. The impediments to bioprinting of meat are lack of food-safe substrates/materials, cost-effectiveness, and scalability. The sustainability of bioprinting could be enhanced by the utilization of generic/universal components or scaffolds and optimization of cell sourcing and fabrication logistics. Despite the availability of several plants and their byproducts and some start-up ventures attempting to fabricate food products, 3D printing of meat analogues remains a challenge. From various insects, powders, proteins (soluble/insoluble), lipids, and fibers are produced, which—in different combinations and at optimal concentrations—can potentially result in superior meat substitutes. Valuable materials derived from meat byproducts/wastes using low energy methods could reduce waste production and offset some greenhouse gas (GHG) emissions. Apart from printer innovations (speed, precision, and productivity), rational structure of supply chain and optimization of material flow and logistic costs can improve the sustainability of 3D printing. Irrespective of the materials used, perception-related challenges exist for 3D-printed food products. Consumer acceptance could be a significant challenge that could hinder the success of 3D-printed meat analogs.

Affordable Processing of Edible Orthopterans Provides a Highly Nutritive Source of Food Ingredients

Edible orthopterans (grasshoppers, crickets, and locusts) are major delicacies, especially across sub-Saharan Africa. Their promotion as food ingredients is increasingly gaining momentum. This study evaluates the nutritional profiles of three widely consumed orthopterans: Gryllus bimaculatus, Locusta migratoria, and Schistocerca gregaria after blanching and oven-drying. All three species had high protein (65.3, 54.2, and 61.4% on a dry matter (DM) basis for G. bimaculatus, L. migratoria, and S. gregaria, respectively) and fat contents. Oleic (22.9-40.8%) and palmitic (26.1-43.0%) were the two most abundant fatty acids. All essential amino acids (in mg/100 g protein) were present, with glutamic acid (120-131), alanine (90.2-123), and leucine (82.3-84.6) being the most abundant. The minerals (in mg/100 g dry matter) potassium (796-1309) and phosphorus (697-968) were moderately high, and iron (4.60-7.31), zinc (12.7-24.9), manganese (0.40-7.15), and copper (1.20-4.86) were also observed in the samples. Vitamin B12 contents were high (0.22-1.35 µg/100 g dry matter). Our findings demonstrate that the excellent nutritional profile of the three processed insects could serve as promising alternative ingredients for improving food and nutritional security.

Food waste valorisation and circular economy concepts in insect production and processing

Food loss and waste are serious threats to the sustainability of our food systems. Innovative and multi-faced solutions are continuously being proposed, tested and implemented by researchers, government authorities, non-government bodies and food industries to tackle this problem of food waste. Insect-based bioconversions have been reported as a marketable solution for reducing food waste. This rather novel approach can efficiently convert several tonnes of food waste into valuable products including human food, animal feed, fertiliser and other secondary industrial compounds. This paper couples the production of edible insects with the valorisation of food waste, providing an attractive key for closing the loop of food value chain. Current status of insect processing and their importance in circular economy is also discussed in detail.

Functionality of Cricket and Mealworm Hydrolysates Generated after Pretreatment of Meals with High Hydrostatic Pressures

The low consumer acceptance to entomophagy in Western society remains the strongest barrier of this practice, despite these numerous advantages. More positively, it was demonstrated that the attractiveness of edible insects can be enhanced by the use of insect ingredients. Currently, insect ingredients are mainly used as filler agents due to their poor functional properties. Nevertheless, new research on insect ingredient functionalities is emerging to overcome these issues. Recently, high hydrostatic pressure processing has been used to improve the functional properties of proteins. The study described here evaluates the functional properties of two commercial insect meals (Gryllodes sigillatus and Tenebrio molitor) and their respective hydrolysates generated by Alcalase®, conventionally and after pressurization pretreatment of the insect meals. Regardless of the insect species and treatments, water binding capacity, foaming and gelation properties did not improve after enzymatic hydrolysis. The low emulsion properties after enzymatic hydrolysis were due to rapid instability of emulsion. The pretreatment of mealworm meal with pressurization probably induced protein denaturation and aggregation phenomena which lowered the degree of hydrolysis. As expected, enzymatic digestion (with and without pressurization) increased the solubility, reaching values close to 100%. The pretreatment of mealworm meal with pressure further improved its solubility compared to control hydrolysate, while pressurization pretreatment decreased the solubility of cricket meal. These results may be related to the impact of pressurization on protein structure and therefore to the generation of different peptide compositions and profiles. The oil binding capacity also improved after enzymatic hydrolysis, but further for pressure-treated mealworm hydrolysate. Despite the moderate effect of pretreatment by high hydrostatic pressures, insect protein hydrolysates demonstrated interesting functional properties which could potentially facilitate their use in the food industry.

Strategies for Sustainable Substitution of Livestock Meat

The consequences of climate change are becoming increasingly discernible everywhere, and initiatives have been taken worldwide to mitigate climate change. In agriculture, particularly meat production from the livestock sector is known to contribute to greenhouse gas emissions (GHG) that drive climate change. Thus, to mitigate climate impact, strategies that include a shift in consumption patterns, technological advancements and reduction in food wastes/losses have been discussed. In this review, strategies that focus on meat consumption patterns are evaluated from the technological feasibility, environmental impact and consumer acceptance viewpoints. While plant-based substitutes have efficient nutrient conversion and lower GHG emissions, consumer perception, cost, and other trade-offs exist. Although cultured meat precludes the need of any animals and large land areas, its environmental impact is not clear and is contingent upon production systems and the achievement of decarbonization. Reducing wastes and the re-use of meat processing by-products have the potential to lower the environmental impact. Valuable proteins, heat, electricity and biofuels extracted from wastes and by-products not only reduce the disposal of wastes but also offset some GHG emissions. Perception related challenges that exist for all substitution strategies require specific consumer target marketing strategies. Policy measures such as taxation of meat products and subsidies for alternatives are also met with challenges, thereby requiring reforms or new policies.

What Is Required for Edible Insects to Become Medical Food? From a Health Professionals and Caregivers' Perspective

The challenge in the edible insect industry is to reverse consumers' aversion to insects, which is a barrier to their consumption. This requires innovation by users rather than producers. This study aimed to present how edible insects could be promoted as medical foods from the health professionals and caregivers' perspective. By analyzing the characteristics of the medical foods market, this study found a niche market and plan to develop medical foods using edible insects as an alternative to meet the needs of consumers. The survey participants were caregivers, nurses, and doctors as providers of medical foods. Based on the survey results, this study proposed strategies to reduce consumers' aversion to edible insects and increase their consumption. To promote insect medical foods, it is required to hold frequent insect-related events and use clean raw materials.

Thermal Impact on the Culturable Microbial Diversity Along the Processing Chain of Flour From Crickets (Acheta domesticus)

The role of insects for human consumption has lately increased in interest and in order to deliver safe and high-quality raw materials and ingredients for food and feed applications, processing of insects is a major pre-requisite. For edible insects a thermal treatment and appropriate storage conditions are recommended to minimize the microbiological risk and the impact of processing methods on the microbial contamination needs to be considered and determined. Based on standard process conditions for the production of Acheta domesticus flour, different heating treatments were used to reduce the microbial load of A. domesticus. In addition, the drying temperature and drying time were varied to determine whether the required residual moisture of <5% can be achieved more quickly with consistent microbial quality. The influence of the process conditions on the microbial community of A. domesticus along the processing chain was finally investigated under optimized process conditions. The total viable count was reduced from 9.24 log10 CFU/gDM to 1.98 log10 CFU/gDM along the entire processing chain. While Bacillaceae, Enterobacteriaceae, Enterococcaceae, and yeast and molds were no longer detectable in the A. domesticus flour, Staphylococcaceae and mesophilic spore forming bacteria were still found in the flour. The results indicate that the steaming process is essential for effectively increasing microbial safety since this processing step showed the highest inactivation. It is recommended to not only evaluate the total viable count but also to monitor changes in microbial diversity during processing to ensure microbial safety of the final product.

Nutrient composition of the long-horned grasshopper Ruspolia differens Serville: Effect of swarming season and sourcing geographical area

This research investigates the effect of swarming season and sourcing geographical area on the nutrient composition of R. differens. On a dry matter basis, protein (34.2-45.8%) and fat (42.2-54.3%) are the major macro-nutrients. Leucine (80. 9-88.5), lysine (54.0-69.8) and valine (59.2-61.8) are the most abundant essential amino acids (EAA) (mg/g protein). Tryptophan is the most limiting EAA. Its EAA composition is like the children and adults' reference protein. Its fat is highly unsaturated (63.5-64.7). Oleic (38.4-42.7), linoleic (19.0-23.0) and palmitic (26.6-27.8) fatty acids (FA) (g/100 g total FA) are the most abundant. Geographical area significantly influences its mineral content within seasons. Season significantly influences its fat, protein, ash and mineral content but not its AAs' and FAs' content. Both factors significantly influence its vitamin B12 content (0.73-1.35 µg/100 g).

Effect of Different Drying Methods on Nutrient Quality of the Yellow Mealworm (Tenebrio molitor L.)

Yellow mealworm (Tenebrio molitor L.) represents a sustainable source of proteins and fatty acids for feed and food. Industrial production of mealworms necessitates optimized processing techniques, where drying as the first postharvest procedure is of utmost importance for the quality of the final product. This study examines the nutritional quality of mealworm larvae processed by rack oven drying, vacuum drying or freeze drying, respectively. Proximate composition and fatty acid profile were comparable between the dried larvae. In contrast, larvae color impressions and volatile compound profiles were very much dependent on processing procedure. High-temperature rack oven drying caused pronounced darkening with rather low content of volatiles, pointing toward the progress of Maillard reaction. On the other hand, vacuum drying or freeze drying led to enrichment of volatile Maillard reaction and lipid oxidation intermediates, whose actual sensory relevance needs to be clarified in the future. Beyond sensory and visual importance drying intermediates have to be considered with regard to their metal ion chelating ability; in particular for essential trace elements such as Zn²⁺. This study found comparable total zinc contents for the differently dried mealworm samples. However, dried larvae, in particular after rack oven drying, had only low zinc accessibility, which was between 20% and 40%. Therefore, bioaccessibility rather than total zinc has to be considered when their contribution to meeting the nutritional requirements for zinc in humans and animals is evaluated.

Fatty acid content and composition in edible Ruspolia differens feeding on mixtures of natural food plants

Objectives

To develop successful mass-rearing programs of edible insects, knowledge of the feeds and their influence on nutritional content is critical. We assessed the influence of natural food plants (grass inflorescences) and their mixtures on fatty acid profiles of edible Ruspolia differens. We reared neonate nymphs to adult on six dietary treatments consisting of one, and mixtures of two, three, five, six and eight plants.

Results

The contents of saturated, monounsaturated and polyunsaturated fatty acids, omega-6/omega-3 ratio, and adult body weight did not differ among dietary treatments. However, the composition of fatty acids differed significantly among insects fed on six dietary treatments, but only for the rare fatty acids. Our results demonstrate that even if natural diets (grass inflorescences) do not strongly modify fatty acid contents or compositions of R. differens, when reared from neonate nymphs to adults, their n − 6/n − 3 fatty acid ratio is generally low and thus good for a healthy human diet.

Microbial Dynamics during Industrial Rearing, Processing, and Storage of Tropical House Crickets (Gryllodes sigillatus) for Human Consumption

In this study, the microbiota during industrial rearing, processing, and storage of the edible tropical house cricket, Gryllodes sigillatus, was investigated. To this end, we analyzed samples from the cricket feed, obtained before feeding as well as from the cages, and from the crickets during rearing, after harvest, and after processing into frozen, oven-dried, and smoked and oven-dried (smoked/dried) end products. Although the feed contained lower microbial numbers than the crickets, both were dominated by the same species-level operational taxonomic units, as determined by Illumina MiSeq sequencing. They corresponded, among others, to members of Porphyromonadaceae, Fusobacterium, Parabacteroides, and Erwinia The harvested crickets contained high microbial numbers, but none of the investigated food pathogens Salmonella spp., Listeria monocytogenes, Bacillus cereus, or coagulase-positive staphylococci. However, some possible mycotoxin-producing fungi were isolated from the crickets. A postharvest heat treatment, shortly boiling the crickets, reduced microbial numbers, but an endospore load of 2.4 log CFU/g remained. After processing, an increase in microbial counts was observed for the dried and smoked/dried crickets. Additionally, in the smoked/dried crickets, a high abundance of a Bacillus sp. was observed. Considering the possible occurrence of food-pathogenic species from this genus, it is advised to apply a heat treatment which is sufficient to eliminate spores. Nevertheless, the microbial numbers remained constant over a 6-month storage period, whether frozen (frozen end product) or at ambient temperature (oven-dried and smoked/dried end products).IMPORTANCE The need for sustainable protein sources has led to the emergence of a new food sector, producing and processing edible insects into foods. However, insight into the microbial quality of this new food and into the microbial dynamics during rearing, processing, and storage of edible insects is still limited. Samples monitored for their microbiota were obtained in this study from an industrial rearing and processing cycle. The results lead first to the identification of process steps which are critical for microbial food safety. Second, they can be used in the construction of a Hazard Analysis and Critical Control Points (HACCP) plan and of a Novel Food dossier, which is required in Europe for edible insects. Finally, they confirm the shelf-life period which was determined by the rearer.