Forest biomass waste as a potential innovative source for rearing edible insects for food and feed – A review

Evaluation of rapeseed cake as a protein substitute in the feed of edible crickets: A case study using Gryllus assimilis

This paper aimed to investigate the optimization of Gryllus assimilis farming production by examining the effects of replacing soybean meal with rapeseed cake (25-100%) and supplementing it with rapeseed oil. The results reveal no adverse effects of soybean meal replacement on the feed conversion ratio and weight of the harvested crickets. However, incorporating larger quantities of rapeseed cake into the diet increased crude protein and decreased fat content. Moreover, the composition of fatty acids varied significantly, with increased levels of oleic acid and decreased levels of palmitic acid, while a high rapeseed cake content led to a decrease in the atherogenic and thrombogenic index values. The amino acid composition remained unaffected. In conclusion, the study demonstrates that rapeseed cake can serve as a viable substitute for soybean meal in the diet of Gryllus assimilis.

Assessing lignocellulosic biomass as a source of emergency foods

Catastrophes such as a nuclear war would generate atmospheric soot and reduce sunlight, making it difficult to grow crops. Under such conditions, people might turn to inedible plant biomass for nutrition, but the convertibility and nutritional content of this biomass have not been rigorously analyzed. We found that if plant biomass were converted into food at 30% efficiency, 6.7 kg of biomass per day would yield adequate carbohydrates, but contain potentially toxic or insufficient levels of other nutrients for a family of four. Therefore, exploiting biomass with low mineral content for carbohydrates and consuming other sources of protein, fat, and vitamins such as edible insects/single-cell proteins and vitamin supplements could provide a balanced diet in a global catastrophic environment.

Multi-elemental consumer-driven nutrient cycling when predators feed on different prey

Predators play a fundamental role in cycling nutrients through ecosystems, by altering the amount and compositions of waste products and uneaten prey parts available to decomposers. Different prey can vary in their elemental content and the deposition of elements in predator waste can vary depending on which elements are preferentially retained versus eliminated as waste products. We tested how feeding on different prey (caterpillars, cockroaches, crickets, and flies) affected the concentrations of 23 elements in excreta deposited by wolf spider across 2 seasons (spring versus fall). Spider excreta had lower concentrations of carbon and higher concentrations of many other elements (Al, B, Ba, K, Li, P, S, Si, and Sr) compared to prey remains and whole prey carcasses. In addition, elemental concentrations in unconsumed whole prey carcasses and prey remains varied between prey species, while spider excreta had the lowest variation among prey species. Finally, the concentrations of elements deposited differed between seasons, with wolf spiders excreting greater concentrations of Fe, Mg, Mn, Mo, S, and V in the fall. However, in the spring, spiders excreted higher concentrations of Al, B, Ba, Ca, Cd, Cu, K, P, Na, Si, Sr, and Zn. These results highlight that prey identity and environmental variation can determine the role that predators play in regulating the cycling of many elements. A better understanding of these convoluted nutritional interactions is critical to disentangle specific consumer-driven effects on ecosystem function.

Unravelling the potential of insects for medicinal purposes - A comprehensive review

Entomotherapy, the use of insects for medicinal purposes, has been practised for centuries in many countries around the world. More than 2100 edible insect species are eaten by humans, but little is known about the possibility of using these insects as a promising alternative to traditional pharmaceuticals for treating diseases. This review offers a fundamental understanding of the therapeutic applications of insects and how they might be used in medicine. In this review, 235 insect species from 15 orders are reported to be used as medicine. Hymenoptera contains the largest medicinal insect species, followed by Coleoptera, Orthoptera, Lepidoptera, and Blattodea. Scientists have examined and validated the potential uses of insects along with their products and by-products in treating various diseases, and records show that they are primarily used to treat digestive and skin disorders. Insects are known to be rich sources of bioactive compounds, explaining their therapeutic features such as anti-inflammatory, antimicrobial, antiviral, and so on. Challenges associated with the consumption of insects (entomophagy) and their therapeutic uses include regulation barriers and consumer acceptance. Moreover, the overexploitation of medicinal insects in their natural habitat has led to a population crisis, thus necessitating the investigation and development of their mass-rearing procedure. Lastly, this review suggests potential directions for developing insects used in medicine and offers advice for scientists interested in entomotherapy. In future, entomotherapy may become a sustainable and cost-effective solution for treating various ailments and has the potential to revolutionize modern medicine.

Biotechnological advances in biomass pretreatment for bio-renewable production through nanotechnological intervention

Globally, the fossil fuel reserves are depleting rapidly and the escalating fuel prices as well as plethora of the pollutants released from the emission of burning fossil fuels cause global warming that massively disturb the ecological balance. Moreover, the unnecessary utilization of non-renewable energy sources is a genuine hazard to nature and economic stability, which demands an alternative renewable source of energy. The lignocellulosic biomass is the pillar of renewable sources of energy. Different conventional pretreatment methods of lignocellulosic feedstocks have employed for biofuel production. However, these pretreatments are associated with disadvantages such as high cost of chemical substances, high load of organic catalysts or mechanical equipment, time consuming, and production of toxic inhibitors causing the environmental pollution. Nanotechnology has shown the promised biorefinery results by overcoming the disadvantages associated with the conventional pretreatments. Recyclability of nanomaterials offers cost effective and economically viable biorefineries processes. Lignolytic and saccharolytic enzymes have immobilized onto/into the nanomaterials for the higher biocatalyst loading due to their inherent properties of high surface area to volume ratios. Nanobiocatalyst enhance the hydrolyzing process of pretreated biomass by their high penetration into the cell wall to disintegrate the complex carbohydrates for the release of high amounts of sugars towards biofuel and various by-products production. Different nanotechnological routes provide cost-effective bioenergy production from the rich repertoires of the forest and agricultural-based lignocellulosic biomass. In this article, a critical survey of diverse biomass pretreatment methods and the nanotechnological interventions for opening up the biomass structure has been carried out.

Towards a Resilient and Resource-Efficient Local Food System Based on Industrial Symbiosis in Härnösand: A Swedish Case Study

The endeavour to align the goals of the Swedish food strategy with the national environmental quality objectives and the 17 global SDGs, presents an extraordinary challenge that calls for systemic innovation. Industrial symbiosis can potentially provide the means for increasing sustainable food production, using locally sub-exploited resources that can reduce the need for land, agrochemicals, transport and energy. This case study of the municipality of Härnösand, aims to assess opportunities and challenges for using waste flows and by-products for local food production, facilitated by industrial symbiosis. A potential symbiotic network was developed during three workshops with the main stakeholders in Härnösand. The potential of the COVID-19 pandemic to instigate policy changes, behavioural changes and formation of new alliances that may catalyse the transition towards food systems based on industrial symbiosis is discussed. The material flow inventory revealed that many underexploited resource flows were present in quantities that rendered them commercially interesting. Resources that can be used for innovative food production include, e.g., lignocellulosic residues, rock dust, and food processing waste. The internalised drive among local companies interested in industrial symbiosis and the emerging symbiotic relations, provide a fertile ground for the establishment of a local network that can process the sub-exploited material flows. Although there are multiple challenges for an industrial symbiosis network to form in Härnösand, this study shows that there is a significant potential to create added value from the region’s many resources while at the same time making the food system more sustainable and resilient, by expanding industrial symbiosis practices.

Food waste bioconversion into new food: A mini-review on nutrients circularity in the production of mushrooms, microalgae and insects

The global challenge of feeding an ever-increasing world population is leading scientists' attention towards nutritious and sustainable foods whose production should have low impacts on environment, economy and society. In case the input feedstock can be waste nutrients, the label of such productions becomes even greener. Nutrients circularity is nowadays an important circular economy practice. This mini-review focuses on the valorisation of food waste as precious biomass to grow new food and feed. In particular, three functional edibles are discussed in the present paper: mushrooms, microalgae and insects. These foods are part of people diets since ages in certain areas of the world and the original aspect of their cultivation and breeding found on waste nutrients recovery is here reviewed. Proofs of such food waste biorefinery viability are already given by several researches featuring the main traits of a suitable growing medium: optimal pool of nutrients and optimal pH. However, lot of work still needs to be done in order to assess the optimal growth and cultivation conditions and the health security of the harvested/bred edibles. A SWOT factors analysis was performed.

Processing insects for use in the food and feed industry

Although insects are becoming more accepted as potential protein sources for food and feed, the appearance of the insect may be off-putting due to associations of disgust. Edible insects are more likely to be eaten if they are processed into non-recognizable forms. Thus, insects require the use of commercial processing methods that will render the protein suitable for food/feed formulation, while maintaining the safety, nutritional and sensory quality of the final product. Common methods that can be used include lipid extraction, enzymatic proteolysis, commercial thermal processing (e.g. blanching, pasteurization, and commercial sterilization), low-temperature processing (refrigeration and freezing), dehydration, and fermentation technology. Each method has advantages and disadvantages that need to be carefully considered as not all processing methods and/or conditions apply to all edible insects or insect flours. This article provides a brief overview of the most commonly used processing methods applicable for insects destined for food and feed.

Pinus Species as Prospective Reserves of Bioactive Compounds with Potential Use in Functional Food-Current State of Knowledge

The pine (Pinus L.) is the largest and most heteromorphic plant genus of the pine family (Pinaceae Lindl.), which grows almost exclusively in the northern hemisphere. The demand for plant-based remedies, supplements and functional food is growing worldwide. Although pine-based products are widely available in many parts of the world, they are almost absent as food ingredients. The literature shows the beneficial effects of pine preparations on human health. Despite the wide geographical distribution of pine trees in the natural environment, there are very few data in the literature on the widespread use of pine in food technology. This study aims to present, characterise and evaluate the content of phytochemicals in pine trees, including shoots, bark and conifer needles, as well as to summarise the available data on their health-promoting and functional properties, and the potential of their use in food and the pharmaceutical industry to support health. Various species of pine tree contain different compositions of bioactive compounds. Regardless of the solvent, method, pine species and plant part used, all pine extracts contain a high number of polyphenols. Pine tree extracts exhibit several described biological activities that may be beneficial to human health. The available examples of the application of pine elements in food are promising. The reuse of residual pine elements is still limited compared to its potential. In this case, it is necessary to conduct more research to find and develop new products and applications of pine residues and by-products.

Enzymatic hydrolysis of black cricket (Gryllus assimilis) proteins positively affects their antioxidant properties

The development of innovative ingredients through biotechnological routes has established insect proteins as an emerging source of bioactive peptides. The current study aimed to evaluate the antioxidant properties of black cricket (Gryllus assimilis) protein hydrolysates produced using the proteases Flavourzyme^TM 500L, Alcalase^TM 2.4L, and Neutrase^TM 0.8L, either individually or in binary/ternary combinations. The enzymatic hydrolysis promoted an increase of approximately 160% in total antioxidant capacity and 93% in the ferric reducing antioxidant power. The isolated use of the enzyme Flavourzyme^TM 500L showed the most prominent positive effect on the antioxidant properties, presenting an IC₅₀ value of 455 and 71 µg/mL for DPPH and ABTS radicals scavenging activities, respectively. This sample was composed mainly of small peptides (MW < 3 kDa), in which the antioxidant properties increased after fractionation by ultrafiltration. Gel electrophoresis analysis showed protein hydrolysates composed mainly of polypeptide chains with a mass of less than 14 kDa. Finally, the enzymatic treatment proved to be an efficient process to improve the antioxidant properties of black cricket proteins, increasing the possibility of applying these hydrolysates as bioactive ingredients in food or nutraceutical products. PRACTICAL APPLICATION: Insects represent an alternative source of proteins. Their modification through hydrolysis allows for the acquisition of compounds with great potential in industrial applications, such as functional ingredients or for nutraceutical purposes. The use of our experimental design proved to be an adequate tool for defining the best process conditions required for increasing the attainment of biologically active compounds.

Insetos comestíveis como potenciais fontes de proteínas para obtenção de peptídeos bioativos

Resumo O consumo de insetos como uma fonte alternativa de proteínas é considerado uma tendência futura e uma estratégia viável, com potencial notório para garantia do fornecimento de alimentos em nível global. Os insetos são uma fonte não convencional de proteínas, seja para consumo humano direto ou indiretamente, como ingredientes em alimentos formulados. Além disso, estudos científicos têm demonstrado que a hidrólise enzimática destas proteínas resulta na produção de peptídeos com atividades biológicas de grande interesse, como atividade antioxidante, antidiabética, anti-hipertensiva e antimicrobiana. O uso desses peptídeos com fim nutracêutico pode substituir ou reduzir o uso de drogas sintéticas, as quais estão associadas a efeitos colaterais indesejáveis. O presente trabalho teve como objetivo abordar o uso de insetos na alimentação humana, destacando sua aplicação como substrato proteico na hidrólise enzimática para produção de peptídeos bioativos. As principais propriedades bioativas dos peptídeos foram relatadas.

An insight to fermented edible insects: A global perspective and prospective

The practice of eating insects is not a new phenomenon; however, the interest for their consumption has increased in recent years due to their recognized nutritional value (high content of micro- and macronutrient), potential health benefits (presence of bioactive substances), and low-environmental impact (use of less resources and reduced pollution levels). Currently, research on insects has focused on the promotion of various processing technologies for their use as either ingredients (in a non-recognizable form) to the development of innovative products, or as sources of novel bioactive compounds. In this context, evidence has suggested that alternative technologies, particularly fermentation, could be used the obtain diverse insect-based ingredients/products with unique properties. Therefore, the purpose of this narrative review was to provide an overview of the available literature on fermentation applied to obtain new insect-based products, to summarize the patents and patent-applications to protect fermented edible insect products and processes, as well as to enlist examples of current available products in the market.

Evaluation of Organic Wastes as Substrates for Rearing Zophobas morio, Tenebrio molitor, and Acheta domesticus Larvae as Alternative Feed Supplements

Simple Summary

The yellow mealworm, super worm, and house cricket are among the most widely produced insects, with high feed conversion efficiency. However, their nutritional composition and development rate generally vary with environmental conditions. From an economic point of view, rearing conditions such as diet, temperature, and time, and insect performance such as mortality and nutritional value are the most important factors. During their intensive growth period at room temperature, when fed a diet of vegetable waste, garden waste, cattle manure, or horse manure with 10% chicken feed, the worms performed better in terms of survival, but presented lower weight. Moreover, they showed differences in growth intensity with time. The yellow mealworm and super worm presented a relatively high fat concentration. House cricket is specifically high in protein; however, its nutritional composition is affected by the rearing substrate, and it was more sensitive to the low-value substrates. Feeding nutrient-poor diets resulted in a low protein concentration and high fat concentration in the larvae of all three species.

Abstract

Studies have focused on identifying combinations of insects and organic waste to optimise bio-conversion. Here, the effects of different diets (10% chicken feed complemented with 90% vegetable waste, garden waste, cattle manure, or horse manure) on growth and survival rates, and nutritional value of Zophobas morio and Tenebrio molitor larvae, and Acheta domesticus were investigated. Compared with chicken feed, organic waste decreased the individual larval weight, although green waste showed fewer negative effects than the manure. The macronutrient concentrations in garden waste were moderate compared with chicken feed, and vegetable waste was the poorest diet in terms of nutrient concentration, as revealed by the principal component analysis (PCA). There was no difference in weight between larvae reared on garden waste and those reared on vegetable waste. Tenebrio molitor and A. domesticus showed the maximum growth rates at 71–101 and 36–66 days of age at 22.5 ± 2.5 °C, respectively. The PCA showed that the protein and fibre concentrations were inversely proportional to fat concentration in the larvae. Acheta domesticus was rich in proteins, whereas Z. morio and T. molitor were rich in fat. Feeding nutrient-poor diets resulted in a lower protein and a higher fat concentration in the larvae.

Identification of Polyphenols from Coniferous Shoots as Natural Antioxidants and Antimicrobial Compounds

Currently, coniferous shoots are almost absent as a food ingredient despite their wide availability in many parts of the world. The aim of the study was to assess and compare the composition of selected plant metabolites, evaluate the antioxidant and antimicrobial properties of selected shoots collected in 2019 from the arboretum in Zielonka (Poland), including individual samples from Picea abies L. (PA), Larix decidua Mill (LD), Pinus sylvestris L. (PS), Pseudotsuga menziesii (PM) and Juniperus communis L. (JC). The present work has shown that aqueous extracts obtained from tested shoots are a rich source of phenols such as caffeic acid, ferulic acid, chlorogenic acid, 4-hydroxybenzoic acid and many others. Obtained extracts exhibit antioxidant and antimicrobial properties in vitro. The highest sum of the studied phenolic compounds was found in the PA sample (13,947.80 µg/g dw), while the lowest in PS (6123.57 µg/g dw). The samples were particularly rich in ferulic acid, chlorogenic acid and 4-hydroxybenzoic acid. The highest values regarding the Folin-Ciocâlteu reagent (FCR) and ferric reducing ability of plasma (FRAP) reducing ability tests, as well as the total flavonoid content assay, were obtained for the LD sample, although the LD (14.83 mg GAE/g dw) and PM (14.53 mg GAE/g dw) samples did not differ statistically in the FCR assay. With respect to free radical quenching measurements (DPPH), the PA (404.18-μM Trolox/g dw) and JC (384.30-μM Trolox/g dw) samples had the highest radical quenching ability and did not differ statistically. Generally, extracts obtained from PA and PS showed the highest antimicrobial activity against tested Gram-negative bacteria, Gram-positive bacteria and fungi.

Potential use of mealworm frass as a fertilizer: Impact on crop growth and soil properties

Rearing insects is expected to dramatically increase during the next few years, and this will be associated with generating high quantities of frass (insect excreta). It is necessary to find solutions allowing the efficient valorization of these by-products before a major upscaling of the industry takes place. Therefore, this study aims at investigating the fertilizer potential of frass. A pot experiment was established and soil was amended either with mealworm (Tenebrio molitor L.) frass (10 Mg ha⁻¹), with mineral fertilizer (NPK) at equivalent nutrient level to frass or with a mixture of 50% NPK and 50% frass. Changes of soil properties and growth and nutrient uptake by barley (Hordeum vulgare L.) were then analyzed. Due to its rapid mineralization and the presence of nutrient in a readily-available form, we found that frass is as efficient as mineral NPK fertilizer to improve biomass and N, P and K uptake by barley. Compared to mineral fertilizer, water soluble P concentration is five times lower in the presence of frass, which prevents P from loss and sorption onto soil constituents. More importantly, BIOLOG EcoPlate reveals that addition of frass stimulates soil microbial activity, especially when it is mixed with mineral fertilizer, suggesting a synergistic effect between both amendments. Taken together, our results indicate that frass has a great potential to be used as a partial or a complete substitute for mineral NPK fertilizer. This is especially relevant in the context of a reduced availability of mineral fertilizers while being consistent with circular economy’s principles.

Quality Aspects of Insects as Food-Nutritional, Sensory, and Related Concepts

In the search for another appealing source of future food to cover the increasing need for nutrients of a growing global population, this study reviewed the potential of insects as human food. Most previous reviews have dealt with insects as a group, making it difficult to evaluate each individual insect species as food because of the generalized data. This study assessed some common edible insects, but concentrated on mealworms. Insects, especially mealworms, have a similar or higher nutritional value than many conventional food sources. For example, the protein content of mealworm larvae is reported to be almost 50% of dry weight, while the fat content is about 30% of larval dry weight. Mealworms can be cooked by different methods, such as hot air drying, oven broiling, roasting, pan frying, deep frying, boiling, steaming, and microwaving. Oven broiling in particular gives a desirable aroma of steamed corn for consumers. Changes in the flavor, taste, and texture of mealworm products during storage have not been studied, but must be determined before mealworms can be used as a commercial food source. Factors controlling the shelf-life of mealworms, such as their packaging and storage, should be identified and considered with respect to the feasibility of using mealworms on a commercial scale.

Approaching Ecological Sustainability in the Emerging Insects-as-Food Industry

The emerging insects-as-food industry is increasingly promoted as a sustainable alternative to other animal protein production systems. However, the exact nature of its environmental benefits are uncertain because of the overwhelming lack of knowledge concerning almost every aspect of production: from suitable species, their housing and feed requirements, and potential for accidental release. If ecological sustainability is to be a hallmark of mass insect rearing for consumption, ecologists need to engage in research related to sustainability criteria that are directly linked to key elements of the development of the industry. There is more to this subject than simply comparing feed-conversion ratios (FCRs) of insects to traditional livestock production, and we highlight areas where research needs to be immediately focused.