Investigation into the potential of commercially available lesser mealworm (A. diaperinus) protein to serve as sources of peptides with DPP-IV inhibitory activity

Food-derived peptides are known to possess inhibitory activity against the dipeptidyl-peptidase IV (DPP-IV) enzyme, a target in the management of type 2 diabetes. While proteins from commonly consumed food commodities have been investigated as precursors of DPP-IV-inhibiting peptides, studies on novel protein sources, such as those from insects, are sparse. This research aimed to determine if DPP-IV inhibitors can be generated upon in vitro digestion or enzymatic hydrolysis of lesser mealworm protein isolate and concentrate. Treatment of the proteins with digestive enzymes and proteases generated hydrolysates with varying potency, thermolysin being the most effective at releasing active peptides (IC₅₀ = 0.63 and 0.60 mg mL⁻¹ for the isolate and concentrate). Ultrafiltration of the thermolysin-treated hydrolysates did not significantly improve the potency. This study shows that DPP-IV inhibitors can be generated from lesser mealworm protein and provides insight on the potential of insects to serve as functional food ingredients.     

Chlorella viruses as a source of novel enzymes

A special advantage has been conferred upon Chlorella cells as tools in biotechnology when viruses (Phycodnaviridae) infecting Chlorella cells were discovered and isolated. The viruses are large icosahedral particles (150-200 nm in diameter), containing a giant, 330-380 kbp long, linear dsDNA genome. Recently, the nucleotide sequence of the 330,740-bp genome of PBCV-1, the prototype virus of Phycodnaviridae, was determined, and up to 702 open reading frames (ORFs) were identified along the genome. The possible genes present include those encoding a variety of enzymes involved in the modification of DNA, RNA, protein and polysaccharides as well as those involved in the metabolism of sugars, amino acids, lipids, nucleotides and nucleosides. Many of these genes are actually expressed during viral infection, with functional enzymes detected in the host cytoplasm or incorporated into the virion. The successful utilization of these viral enzymes as various DNA restriction and modification enzymes (Cvi enzymes) that are now commercially available is well documented. Also noteworthy are virion-associated chitinase and chitosanase activities that have potentially important applications in the recycling of natural resources. The virions of Chlorella viruses contain more than 50 different structural proteins, ranging in size from 10 to 200 kDa. Some of these proteins may be replaced with useful foreign proteins using recombinant DNA technology. The proteins of interest can be recovered easily from the viral particles, and collected by centrifugation after complete lysis of the host Chlorella cells.     

利用发酵废弃物制备大麦虫饲养饵料的研究

大麦虫是一种新的蛋白源昆虫,作为昆虫养殖新秀,其幼虫营养价值比黄粉虫更高,可用作水产动物饵料。本研究以提高大麦虫的营养价值、降低养殖成本,实现循环经济、再生资源利用为目的,利用酶制剂生产过程中产生的废料作为大麦虫的饲料进行饲养及成分检测。结果表明,与普通以麦麸为饲料的大麦虫相比,以麦麸、发酵废料1∶1为饲料的大麦虫在饲养过程、个体质量、灰分、粗蛋白、粗脂肪、粗纤维的含量等方面均没有显著性差异。     

再生动物蛋白纤维的生产工艺与设备

根据我国羊毛、蚕丝等动物蛋白纤维远远不能满足人们需求的实际，提出采用皮革工业下脚料、毛纺工业下脚料、畜禽毛发、奶渣、蚕蛹、昆虫等动物蛋白质原料，开发生产再生动物蛋白纤维，并对生产再生动物蛋白纤维的工艺流程、关键技术、设备改造及配置比选方案进行了讨论。     

Eat or not eat: an analysis of the status of entomophagy in Botswana

In Botswana, mopane worm Imbrasia belina Westwood is culturally accepted as food by people of different age groups from different regions and districts. However, there are several other insect that are anecdotally known to be edible in Botswana. To verify this, a study was conducted by means of a questionnaire and discussions among Batswana of different age groups from six districts in the country to obtain the names of insects that are known to be edible. A total of 27 insect species was identified. The study also investigated methods of collection, processing, precooking preparation, cooking methods, storage and recipes. Chi-square analysis showed that people’s knowledge of edible insects differed with districts and age groups. Older people were more familiar with uncommon edible insect compared to the younger generation. With the exception of mopane worm, the majority of the people interviewed, especially the young, had not eaten any of the species, despite knowing that they were edible. This shows that, apart from the use of mopane worm, entomophagy (the eating of insect by humans) as practiced among Batswana is declining. However, in the light of current decline in food production in Africa, especially in the arid regions of Botswana, insects may make a valuable contribution to the protein and calories of many peoples’ diets. A shift from traditional harvesting to mass production of insects has the potential to provide animal protein to humans through direct consumption or indirectly when used as livestock feed, and could reduce malnutrition.     

Edible Insects Processing: Traditional and Innovative Technologies

Insects are part of the human diet in many parts of the world. Their nutritional value is widely recognized. Currently, most edible insects are harvested from the wild, although semi‐domestication and indoor farming have increased insect availability and the sustainability of production. In traditional cultures, insects are processed in a number of ways (steaming, roasting, smoking, frying, stewing, and curing, among others) to improve their sensory and nutritional qualities as well as their shelf‐life. In order to increase consumer interest in the West, various technologies have been developed that are aimed primarily at using insects as ingredients in a non‐recognizable form, such as powders or flour. These technologies include drying (sun‐drying, freeze‐drying, oven‐drying, fluidized bed drying, and microwave‐drying) and new processing methods (ultrasound‐assisted extraction, cold atmospheric pressure plasma, and dry fractionation) designed mainly for protein, fat, and/or chitin extraction. Insect‐based ingredients are sold for the production of cookies, chocolates, tortilla‐style chips, and other snacks. This review focuses on edible insect production, processing technologies, and commercialization using strategies ranging from traditional to novel as a sustainable approach for improving food security worldwide.     

Food Safety Issues Related to Uses of Insects for Feeds and Foods

Edible insects are expected to become an important nutrient source for animals and humans in the Western world in the near future. However, before insects can be put on the market, the safety of their use for feed and food is warranted. This literature study was prepared to provide an overview of the actual knowledge of possible food safety hazards, including chemical, microbiological, and allergenic agents and prions, to human and animal health upon the use of insects for food and feed, and to highlight data gaps and suggest the way forward. From the data available, heavy metals of concern are cadmium in black soldier fly and arsenic in yellow mealworm larvae. Investigated mycotoxins do not seem to accumulate. Residues of pesticides, veterinary drugs, and hormones, as well as dioxins and PCBs, are sometimes found in insects. Contamination of insects with pathogens to human health is a consequence of a combination of the substrates used and the farming and processing steps applied. Insects harbor a wide variety of microorganisms, and some human pathogenic bacteria may be present. In addition, insects may harbor and transmit parasites. There is no evidence so far insects may harbor pathogenic viruses or prions, but they may act as vectors. Insects and insect‐derived products may have allergenic potential. In this review, evidence on some safety aspects is displayed, and data gaps are identified. Recommendations are given for future research to fill the most relevant data gaps.     

Overview of antibacterial, antitoxin, antiviral, and antifungal activities of tea flavonoids and teas

Tea leaves produce organic compounds that may be involved in the defense of the plants against invading pathogens including insects, bacteria, fungi, and viruses. These metabolites include polyphenolic compounds, the six so-called catechins, and the methyl-xanthine alkaloids caffeine, theobromine, and theophylline. Postharvest inactivation of phenol oxidases in green tea leaves prevents oxidation of the catechins, whereas postharvest enzyme-catalyzed oxidation (fermentation) of catechins in tea leaves results in the formation of four theaflavins as well as polymeric thearubigins. These substances impart the black color to black teas. Black and partly fermented oolong teas contain both classes of phenolic compounds. A need exists to develop a better understanding of the roles of polyphenolic tea compounds in food and medical microbiology. This overview surveys and interprets our present knowledge of activities of tea flavonoids and teas against foodborne and other pathogenic bacteria, virulent protein toxins produced by some of the bacteria, virulent bacteriophages, pathogenic viruses and fungi. Also covered are synergistic, mechanistic, and bioavailability aspects of the antimicrobial effects. Further research is suggested for each of these categories. The herein described findings are not only of fundamental interest, but also have practical implications for nutrition, food safety, and animal and human health.     

The use of edible insect proteins in food: Challenges and issues related to their functional properties

Over the past decade, the potential of edible insects as a novel ingredient in high value-added products has been investigated to find alternatives to conventional protein sources that are expensive, over-exploited and harmful to the environment. This review assesses the state of insects as an alternative protein source from production to consumption. More specifically, this review details the conventional procedures related to the production of insect flours as well as insect-derived ingredients such as protein concentrates and isolates. As a source of alternative protein in food ingredient formulations, the available data on the functionalities of edible insect ingredients is also examined and compared to conventional animal- and plant-based protein sources. Finally, the major challenges facing entomophagy in the mainstream food industry are explored. This review highlights the fact that insect proteins can serve as functional ingredients in food preparation. However, additional comparative studies are required to assess the functionality of various insect proteins compared to conventional proteins, regardless of processing method. To be incorporated into large scale industries, more research is needed to optimize processing methods to obtain the best compromise between cost-effectiveness, functionality, tastiness and sustainability, while ensuring consumer safety.     

Sono-activation of food enzymes: From principles to practice

Over the last decade, sono-activation of enzymes as an emerging research area has received considerable attention from food researchers. This kind of relatively new application of ultrasound has demonstrated promising potential in facilitating the modern food industry by broadening the application of various food enzymes, improving relevant industrial unit operation and productivity, as well as increasing the yield of target products. This review aims to provide insight into the fundamental principles and possible industrialization strategies of the sono-activation of food enzymes to facilitate its commercialization. This review first provides an overview of ultrasound application in the activation of food protease, carbohydrase, and lipase. Then, the recent development on ultrasound activation of food enzymes is discussed on aspects including mechanisms, influencing factors, modification effects, and its applications in real food systems for free and immobilized enzymes. Despite the far fewer studies on sono-activation of immobilized enzymes compared with those on free enzymes, we endeavored to summarize the relevant aspects in three stages: ultrasound pretreatment of free enzyme/carrier, assistance in immobilization process, and modification of the already immobilized enzyme. Lastly, challenges for the scalability of ultrasound in these target areas are discussed and future research prospects are proposed.     

Ecological aspects of digestive enzyme covariation in almond moth larvae, Ephestia cautella (Walker) (Lepidoptera, Phyticidae)

In this paper we examine the correlations between activity levels of several digestive enzymes measured simultaneously in larvae of the almond moth, Ephestia (=Cadra) cautella (Walker). This study is unique in that we measured enzyme activity in each individual larva, not in samples pooled from several individuals as is the usual procedure in physiological studies of insects. This enabled us to take individual variation in size and enzyme activity into consideration and to calculate the correlation between different enzymes. We demonstrate that inter-enzyme correlations are affected by the diet on which the larvae feed.

In most of the research on insect digestive physiology, investigators have concentrated on a single enzyme. But in the insect alimentary canal, different enzymes do not work in isolation. We demonstrate some patterns of activity correlations of different enzymes measured in extracts from the same individual larva which may suggest possible mechanisms of enzyme activity regulation.     

Nutritional,functional and biological properties of insect proteins: Processes for obtaining,consumption and future challenges

BackgroundConsuming insects as an alternative protein source is considered a future trend and a viable strategy that could potentially contribute to global food security. Insects are a non-conventional source of protein, either for human consumption directly or indirectly as a component in recomposed foods or added to feedstock mixtures. Moreover, these proteins have demonstrated a broad range of applications as peptides with antihypertensive, antimicrobial and antioxidant properties. However, aspects such as food safety and processing of these proteins need further studies for their elucidation and optimization.Scope and approachIn this review, aspects of nutritional value and risks of insect consumption are reported. Additionally, conventional processing techniques and recent advances in insect protein extraction and production are presented. The application of bioactive peptides obtained from insect protein hydrolysates is reported, focusing on their potential antihypertensive, antimicrobial and antioxidant properties.Key findings and conclusionsInsect proteins have great advantages in terms of nutritional value, total protein level and amino acid profile. However, some safety concerns must be taken into consideration in large-scale production. The conventional processing of insects proteins is very particular, depending on several aspects such as species, larval stage, and cultivation, among others. Nonetheless, recent advances in insect protein production via enzymatic hydrolysis and heterologous expression have shown a promising technology for the study and exploitation of their bioactive properties, such as the antimicrobial, antioxidant and antihypertensive (inhibition of ACE) activity of insect peptides.     

Safety of Novel Protein Sources (Insects,Microalgae, Seaweed,Duckweed, and Rapeseed) and Legislative Aspects for Their Application in Food and Feed Production

Novel protein sources (like insects, algae, duckweed, and rapeseed) are expected to enter the European feed and food market as replacers for animal‐derived proteins. However, food safety aspects of these novel protein sources are not well‐known. The aim of this article is to review the state of the art on the safety of major novel protein sources for feed and food production, in particular insects, algae (microalgae and seaweed), duckweed, and rapeseed. Potential hazards for these protein sources are described and EU legislative requirements as regard to food and feed safety are explained. Potential hazards may include a range of contaminants, like heavy metals, mycotoxins, pesticide residues, as well as pathogens. Some safety aspects of novel protein sources are intrinsic to the product, but many potential hazards can also be due to production methods and processing conditions. These aspects should be considered in advance during product development. European law is unclear on several issues regarding the use of novel protein sources in food and feed products. For food product applications, the most important question for food producers is whether or not the product is considered a novel food. One of the major unclarities for feed applications is whether or not products with insects are considered animal‐derived products or not. Due to the unclarities in European law, it is not always clear which Regulation and maximum levels for contaminants apply. For market introduction, European legislation should be adjusted and clarified.     

Polymers and Biopolymers with Antiviral Activity: Potential Applications for Improving Food Safety

Gastroenteritis and hepatitis, caused by human noroviruses (HuNoVs) and hepatitis A virus (HAV), respectively, are the most common illnesses resulting from the consumption of food contaminated with human enteric viruses. Food‐grade polymers can be tailor designed to improve food safety, either as novel food‐packaging materials imparting active antimicrobial properties, applied in food contact surfaces to avoid cross‐contamination, or as edible coatings to increase fresh produce's shelf life. The incorporation of antimicrobial agents into food‐grade polymers can be used to control the food microbiota and even target specific foodborne pathogens to improve microbiological food safety and to enhance food quality. Enteric viruses are responsible for one fifth of acute gastroenteritis cases worldwide and the development of food‐grade polymers and biopolymers with antiviral activity for food applications is a topic of increased interest, both for academia and the food industry, even though developments are still limited. This review compiles existing studies in this widely unexplored area and highlights the potential of these developments to improve viral food safety.     

Influence of different pretreatments on the accessibility of transglutaminase and tyrosinase to wool fibre proteins

Wool fibres are subject to a variety of industrial chemical treatments prior to finishing processes. The influence of such treatments on subsequent enzymatic treatments is still poorly characterised, but its importance is paramount to achieve maximal efficiency of enzymatic action on the fibres. The effect of such treatments on wool fibre structure and their significance on the accessibility of the enzymes transglutaminase and tyrosinase to their target amino acids within wool proteins was investigated. These enzymes are of great interest due to their potential as protein cross‐linkers and their capability to covalently graft beneficial compounds onto proteins. The accessibility of target amino acids was assessed using specific peptides tagged with fluorescent probes, followed by epifluorescence or confocal microscopy. Differences in the action of the different chemical pretreatments were found, with a treatment with permonosulphuric acid resulting in the greatest level accessibility to both enzymes, followed by chlorination and plasma treatments. This was confirmed by the increase in tensile strength of treated wool observed in the enzyme‐treated yarns. This work illustrates that the accessibility of these enzymes to their target aminoacids in solid substrates such as wool is key for their action and to achieve the desired property modifications. The techniques used have the advantage of permitting the visual monitoring of the diffusion of the active enzymes through the wool fibre structure and to relate this to the extent of enzymatic reaction. Crucially, this will allow an informed choice of the best wool processing stage at which to introduce such enzyme treatments.     

Nutritional composition and safety aspects of edible insects

Insects, a traditional food in many parts of the world, are highly nutritious and especially rich in proteins and thus represent a potential food and protein source. A compilation of 236 nutrient compositions in addition to amino acid spectra and fatty acid compositions as well as mineral and vitamin contents of various edible insects as derived from literature is given and the risks and benefits of entomophagy are discussed. Although the data were subject to a large variation, it could be concluded that many edible insects provide satisfactorily with energy and protein, meet amino acid requirements for humans, are high in MUFA and/or PUFA, and rich in several micronutrients such as copper, iron, magnesium, manganese, phosphorous, selenium, and zinc as well as riboflavin, pantothenic acid, biotin, and in some cases folic acid. Liabilities of entomophagy include the possible content of allergenic and toxic substances as well as antinutrients and the presence of pathogens. More data are required for a thorough assessment of the nutritional potential of edible insects and proper processing and decontamination methods have to be developed to ensure food safety.     

High‐Pressure Inactivation of Enzymes: A Review on Its Recent Applications on Fruit Purees and Juices

In the last 2 decades high‐pressure processing (HPP) has established itself as one of the most suitable nonthermal technologies applied to fruit products for the extension of shelf‐life. Several oxidative and pectic enzymes are responsible for deterioration in color, flavor, and texture in fruit purees and juices (FP&J). The effect of HPP on the activities of polyphenoloxidase, peroxidase, β‐glucosidase, pectinmethylesterase, polygalacturonase, lipoxygenase, amylase, and hydroperoxide lyase specific to FP&J have been studied by several researchers. In most of the cases, partial inactivation of the target enzymes was possible under the experimental domain, although their pressure sensitivity largely depended on the origin and their microenvironmental condition. The variable sensitivity of different enzymes also reflects on their kinetics. Several empirical models have been established to describe the kinetics of an enzyme specific to a FP&J. The scientific literature in the last decade illustrating the effects of HPP on enzymes in FP&J, enzymatic action on those products, mechanism of enzyme inactivation during high pressure, their inactivation kinetics, and several intrinsic and extrinsic factors influencing the efficacy of HPP is critically reviewed in this article. In addition, process optimization of HPP targeting specific enzymes is of great interest from an industrial approach. This review will give a fair idea about the target enzymes specific to FP&J and the optimum conditions needed to achieve sufficient inactivation during HPP treatment.     

一种基于聚类特征的Faster R-CNN粮仓害虫检测方法

本文基于Faster R-CNN模型提出复杂背景下粮仓害虫的检测识别方法。将六种常见的储粮害虫(豆象、谷蠹、米象、锯谷盗、赤拟谷盗、锈赤扁谷盗)分别以大米、小米为背景,建立了真实背景下粮仓害虫图像数据集SGI-6。SGI-6中包括网络获取图像、显微镜采集图像和单反拍摄图像三种多目标尺度的数据集。根据粮仓害虫的小目标特性,使用聚类算法改进Faster R-CNN模型的区域提案网络,来提取这些图像中含有害虫的区域,并对这些区域中的害虫进行分类。实验结果表明,该方法能够在储粮条件下检测和识别粮仓害虫,且其平均准确率(mAP)达到96.63%。     

Which insect species can best be proposed for human consumption?

Edible insects have become popular in the past few years not only in the scientific literature but in other media as well. One of the major advantages of entomophagy (eating insects) is said to be the great nutritional composition. Many sources report that insects (generally) have better nutritional characteristics than traditional protein sources. In our research, we aim to give a complete picture of the nutritional profile of insects using a multicriteria optimization method, sum of ranking differences. The materials we used are published results of different authors from the past few years. The proximate analysis tells that insects generally have a better nutritional profile than other meats. The situation is a bit different in the case of mineral content; hence some vegetables have excellent mineral sources but waxworm larvae were ranked in the first three. Additionally, waxworm larvae have the most similar amino acid pattern to the FAO recommendation for adults. Earthworm, house cricket, and mealworm larvae showed the most promising vitamin content; however, huge differences were observed between the developmental stages of insects. A detailed analysis of these differences on the example of mealworms showed that adults may present a better option from the nutritional point of view. Same measurements conducted by different authors on the same species show considerable differences; hence the comparison of the results of different publications is dubious and should be handled with care. Based on our results, insects have a promising nutritional profile and may become part of many food products in the future. Present status of knowledge allows to conclude; which insect is best suitable for human consumption.     

Homology modeling of milk enzymes using on-line resources: Insights to structure-function and evolutionary relationships

Only 1251 three-dimensional structures for bovine proteins are currently in the protein data bank (PDB), compared with over 60,000 protein sequences, demonstrating a large gap between knowledge of sequences and three-dimensional structures. An alternative approach to obtaining protein structures experimentally is to use homology modelling. In this paper, online homology modelling with Geno3D was used to create structural models for selected milk enzymes, i.e., lysozyme, alkaline phosphatase, lactoperoxidase, lipoprotein lipase, and cathepsin D. Models were also generated for the N-terminal and catalytic domains of plasmin. The models generated were assessed in terms of their geometry, Ramachandran diagrams and root mean-square deviation from targets. Generally, models were plausible and provided a first approach to protein structure for enzymes for which an experimentally determined three-dimensional structure is as yet unavailable. As a positive control, bovine chymosin (which is in the PDB) was modelled on the 38% homologous human protein and the resulting structure shown to be very similar to the experimentally determined crystal structure.