Extraction and physicochemical characterization of chitin and chitosan from Zophobas morio larvae in varying sodium hydroxide concentration

Biomass-based mineralized chitin microsheets for high-efficiency radiative cooling

The increasing frequency of extreme heat events under global climate change, combined with high energy consumption and CO2 emissions from conventional cooling systems, threatens both ecological sustainability and human health. While traditional passive radiative cooling materials offer a potential solution, they often lead to pollution and have complex designs with high costs. To address these limitations, we developed Mineralized Chitin-based Composite Microsheets (MCCM), a low-cost, eco-friendly radiative cooling material derived from shrimp shells. By leveraging the natural mineralized multiscale Bouligand structure of shrimp shells, we designed a simple chemical treatment to remove proteins, lipids, and pigments while preserving its multiscale structure. Under solar irradiation, MCCM enables sub-ambient radiative cooling, achieving an average temperature reduction of 4.5 °C, attributed to its high solar reflectance (90.0 %) and mid-infrared emissivity (96.0 %). When applied to building exteriors and rooftops, MCCM significantly enhances annual energy-saving performance (>80 GJ) and effectively reduces CO2 emissions. Additionally, it exhibits excellent thermal stability and flame retardancy and can be recycled as agricultural fertilizer, further enhancing its sustainability. This simple processing method for high-value utilization of waste shrimp shells offers a novel approach to developing low-cost functional materials and recycling biomass waste, demonstrating significant potential for building temperature management.

Extraction and characterization of chitin and chitosan from molts and Eupolyphaga sinensis Walker: Influence of chemical and ultrasound-assisted enzymatic processing

Chitin was extracted from molts and different life-stages of Eupolyphaga sinensis Walker (ESW) using both chemical and ultrasound-assisted enzymolysis (UAE) methods, followed by deacetylation to produce chitosan. The physicochemical and structural properties of extracted chitosan were characterized and compared with commercially available chitosan (CAC), to validate the methods used. Results illustrated changes in chitosan structure, referencing the growth-stages of ESW, with more significant differences observed between UAE and chemical approaches. UAE method remarkably increased the chitin and chitosan yields, particularly in male nymphs (66.42 %-increase in chitin) and adult males (56.42 %-increase in chitosan), with molts showing the highest chitin (30.49 %) and chitosan (17.16 %). FTIR and XRD spectra indicated that the transmission peaks of the extracted chitosan were consistent with CAC, but the UAE-prepared chitosan (UMC) exhibited higher acetylation (81.00 %-81.82 %) and lower viscosity-average molecular weight compared to chemical method. Scanning electron microscopy showed the surface of ESW chitosan had several pores, whereas the CAC had no voids, implying ESW chitosan possessed higher water- and fat-binding capacity. Furthermore, differential scanning calorimetry analysis showed better homogeneity and thermal stability in UMC. This study suggests that ESW could be used as an alternative source for chitosan production, especially following the application of UAE method.

siRNA self-assembled carboxymethyl chitosan and pymetrozine nucleic pesticides for enhanced control of Sogatella furcifera: Bidirectional transduction and detoxification inhibition

Sogatella furcifera (Horváth) is a significant migratory pest in southeast Asia and northern Australia, exhibiting a notable resistance to the conventional insecticides, and RNAi pesticide is a promising approach for managing resistance. However, the poor stability and difficulty in delivery hinders its wide application. Here, we present a self-assembled siRNAs, carboxymethyl chitosan (CMCS) and pymetrozine complex (abbreviated as PM-CMCS/siRNAs micro-complex) to facilitate the control of S. furcifera in rice. When the transcription factors USP and KrH1 were interfered with dsUSP or dsKr-H1, a mortality of 84.4 % ~ 88.9 % was observed at a concentration of 150 μg/mL of pymetrozine, indicating a potential strategy for managing pymetrozine resistance. With the envelope of CMCS, the micro-complex effectively enhances the siRNA stability >96 h, downregulates the expression of USP, KrH1, and CYP6FJ3, leading to a mortality of 100 % at 100 μg/mL pymetrozine. Moreover, the time-dependent disintegration of micro-complex induces the release of lesser PM-CMCS/siRNAs, allowing that more fluorescently labeled complexes were enriched in the phloem of rice via the apoplastic pathway. The integration of PM-CMCS/siRNAs enable precise enrichment in phloem and effective management of pest resistance by silencing their detoxification genes, and promises an environmental-friendly strategy for controlling devastating pest.

Synthesis, Characterization, and Preliminary Analysis of Squid Pen Trypsin Hydrolysates and Chitosan Microcapsules

Squid pen (SP) was found to contain 64.41% protein and 26.03% chitin. The amino acid composition revealed that Met was the most abundant amino acid in SP, with a concentration of 13.67 g/100 g. To enhance the stability and bioavailability of SP hydrolysates, microcapsules were developed using ultrasonic emulsification techniques with SP trypsin hydrolysates (SPTH) and SP β-chitosan (SPC). The optimal preparation conditions involved using a 2% concentration of SPC, a 4 mg/mL concentration of SPTH, a core-to-wall ratio (v/v) of 1:3 for SPTH/SPC, and subjecting them to ultrasonic treatment for 20 min. These microcapsules had a loading capacity of 58.95% for SPTH under these conditions. The successful encapsulation of SPTH in the SPC complex to form SPC-SPTH microcapsules was confirmed by FTIR, XRD, DSC, and SEM, exhibiting good thermal stability, small particle size, and high encapsulation efficiency. In vitro digestion studies demonstrated a release of 15.61% in simulated gastric fluid and 69.32% in intestinal fluid, achieving targeted release in the intestines. The digested products exhibited superior antioxidant activity compared to free SPTH digests, suggesting that microencapsulation effectively preserves SPTH bioactivity. This study enhances the bioavailability of SPTH and offers a promising delivery system for natural compounds with low bioavailability and stability.

Chitin and chitosan from North Pacific krill (Euphausia Pacifica): Comparative study of conventional and microwave-assisted extraction methods and the potential use in chitosan film production

The characteristics and prospective applications of North Pacific krill chitin and chitosan are currently unexplored, and their conventional isolation method is time- and energy-consuming. In this study, chitin and chitosan were extracted from North Pacific krill using conventional and microwave-assisted methods, followed by comprehensive characterisation and evaluation of chitosan film potential. The extracted chitin was identified as an α-polymorph, and chitosan exhibited a remarkable degree of deacetylation (90 %) in both methods. Microwave-assisted extraction provided comparable chitin and chitosan yields without adversely affecting their properties, and the resulting products also exhibited enhanced crystallinity and thermal stability. Moreover, microwave-assisted-extracted chitosan (MCS) had a significantly lower molecular weight (Mw). Krill chitosan films demonstrated superior performance as food packaging materials compared to films prepared from commercial chitosan, due to their greater extensibility and transparency. Notably, the MCS film exhibited exceptional antioxidant activity and solubility. These findings suggest that North Pacific krill holds promise as a viable source of α-chitin and chitosan, and microwave-assisted extraction is effective in producing low Mw chitosan that has the potential to be used for preparing functional biodegradable film, with a fivefold reduction in treatment time.

Bioactive compounds in edible insects: Aspects of cultivation, processing and nutrition

The increasing interest in edible insects, driven by projected global population growth and environmental concerns, has led to the exploration of their potential in the food sector. Edible insects are abundant in macronutrients, such as proteins, lipids and chitin, as well as micronutrients, such as minerals, vitamins and phenolic compounds. Considering their content of bioactive compounds, they offer a sustainable solution to meet future food demands while providing potential health benefits. This review identifies bioactive peptides, phenolic compounds, chitosan, and vitamins as major bioactive ingredients derived from insects. It discusses their presence in various edible insect species, their primary bioactive properties, and methods for production and isolation. Bioactive compounds sourced from edible insects exhibit antioxidant, antimicrobial, and disease-preventing properties. Insects also serve as rich sources of vitamins A, B2, B6, B12, D, and E, albeit with variations in content among species and life stages. However, the consumption of insects poses risks related to their biological and chemical contaminants, as well as their allergenicity. Managed diets in farm-bred insects ensure controlled nutrient levels, highlighting their potential as sustainable sources of bioactive compounds for human health. Adequate processing and labeling of insect-derived products can reduce the risk of insect consumption. In conclusion, the bioactive compound profile of edible insects complements their nutritional richness and highlights their potential to address future nutrition and food security.

Characterization of extracellular chitin deacetylase from Aneurinibacillus aneurinilyticus isolated from marine crustacean shell

Chitosan is a promising biopolymer with wide range of applications. It is the deacetylated product of chitin. Commercially, it is produced from chitin via a harsh thermochemical process that has several shortcomings and heterogenous deacetylation product. Chitin can be transformed into chitosan through enzymatic deacetylation using chitin deacetylase (CDA), enabling the production of chitosan with a specific degree of deacetylation. CDA is primarily extracted from fungi followed by bacteria and insects. The extraction of CDA from fungus is more complex, possess several health risks for human including skin lesions. Therefore, screening of potent bacterial CDA is the need of the hour. In this study, for the first time we have isolated a bacterial strain Aneurinibacillus aneurinilyticus from the rinsed water of marine crab shell, and it was found to be a potent CDA producer. The extracellular CDA from A. aneurinilyticus has been partially purified and the specific activity of the enzyme was found to be 569.73 U/ mg protein. SDS-PAGE profiling of the purified sample depicts two isomers of CDA with molecular weights of 27 kD and 45 kD. The pH and temperature optima of the purified CDA were found to be 7.4 and 37 °C, respectively. The partially purified enzyme has Km and Vmax values of 98.455 µM and 909.09 µmole/min, for non-chitinous substrate such as p-nitroacetanilide. For chitinous substrates like glycol chitin, N-acetyl glucosamine hexamer and colloidal chitin, the enzyme exhibited Km of 96.96, 111.75 and 127.86 µM, respectively, Vmax for these substrates were 23.31, 10.12 and 10.772 µmole/min, respectively. Metal ions like Mn and Mg considerably boost the production and activity of CDA, whereas Cd and Co strongly inhibit its activity. Insights from this study further substantiate that this enzyme follows Michaelis-Menten equation and has potential for industrial applications.

Extraction, characterization and evaluation of antimicrobial activity of chitosan from adult Zophobas morio (Fabricius, 1776) (Coleoptera: Tenebrionidae)

The increasing demand for chitosan has led to the exploration of alternative sources, including insects. In this study, chitosan was extracted from Zophobas morio beetles with 19.17 % yield. FTIR and Raman Spectroscopy showed similar peaks in Z. morio chitosan (ZC) and commercial chitosan (CC). ZC showed low crystallinity (40.96 %) and high thermal residual mass (42.7 %) than CC. SEM imaging of ZC displayed pores ranging from 10 μm to 0.3 μm. EDX mapping revealed the homogenous presence of C, N and O elements. ZC exhibited low molecular weight (435.95 kDa) and low intrinsic viscosity (317.95 cm3/g) than CC (680.20 kDa and 480.87 cm3/g, respectively). Degree of deacetylation of ZC and CC was 96.24 % and 78.26 %, respectively. ZC showed antimicrobial activity against Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13883), Proteus mirabilis (ATCC 29906), Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212) and Candida albicans (ATCC 90028) with zones of inhibition ranging from 5 mm to 11 mm. The minimum bactericidal concentration of ZC against K. pneumoniae and P. mirabilis was lower than CC. This study suggests the applicability of insect chitosan as an antimicrobial agent in the food and pharmaceutical industries.

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.

Investigation of 9 True Weevil (Curculionidae Latreille, 1802) Species for Chitin Extraction

Chitin, the second most abundant biopolymer after cellulose, is an important resource for biosourced materials. The global demand for chitin is rapidly increasing, however, the majority of industrial chitin is sourced from crustacean shells, which may be less accessible in regions without seafood waste. Therefore, it is crucial to explore alternative chitin sources, such as those derived from beetles and other arthropods. This study investigated chitin extraction from nine species of Curculionidae (true weevils), which are recognized as crop pests. The extraction process and yields were described, and the isolated chitin was characterized by SEM, IR spectroscopy, elemental analysis, XRD, and ash and water content measurements. This work highlights the potential of Curculionidae as an alternative chitin source.

Extraction of Fungal Chitosan by Leveraging Pineapple Peel Substrate for Sustainable Biopolymer Production

The cost-effective production of commercially important biopolymers, such as chitosan, has gained momentum in recent decades owing to its versatile material properties. The seasonal variability in the availability of crustacean waste and fish waste, routinely used for chitosan extraction, has triggered a focus on fungal chitosan as a sustainable alternative. This study demonstrates a cost-effective strategy for cultivating an endophytic fungus isolated from Pichavaram mangrove soil in a pineapple peel-based medium for harvesting fungal biomass. Chitosan was extracted using alkali and acid treatment methods from various combinations of media. The highest chitosan yield (139 ± 0.25 mg/L) was obtained from the pineapple peel waste-derived medium supplemented with peptone. The extracted polymer was characterized by FTIR, XRD, DSC, and TGA analysis. The antioxidant activity of the fungal chitosan was evaluated using DPPH assay and showed an IC50 value of 0.22 mg/L. Subsequently, a transparent chitosan film was fabricated using the extracted fungal chitosan, and its biodegradability was assessed using a soil burial test for 50 days. Biodegradation tests revealed that, after 50 days, a degradation rate of 28.92 ± 0.75% (w/w) was recorded. Thus, this study emphasizes a cost-effective strategy for the production of biopolymers with significant antioxidant activity, which may have promising applications in food packaging if additional investigations are carried out in the future.

Insect meal in aquafeeds: A sustainable path to enhanced mucosal immunity in fish

The mucosal surfaces of fish, including their intestines, gills, and skin, are constantly exposed to various environmental threats, such as water quality fluctuations, pollutants, and pathogens. However, various cells and microbiota closely associated with these surfaces work in tandem to create a functional protective barrier against these conditions. Recent research has shown that incorporating specific feed ingredients into fish diets can significantly boost their mucosal and general immune response. Among the various ingredients being investigated, insect meal has emerged as one of the most promising options, owing to its high protein content and immunomodulatory properties. By positively influencing the structure and function of mucosal surfaces, insect meal (IM) has the potential to enhance the overall immune status of fish. This review provides a comprehensive overview of the potential benefits of incorporating IM into aquafeed as a feed ingredient for augmenting the mucosal immune response of fish.

Properties of Chitin and Its Regenerated Hydrogels from the Insect Zophobas morio Fed Citrus Biomass or Polystyrene

The potential of insects as a recycling tool has recently attracted attention. In this study, chitin was extracted with 1 M HCl for 24 h at 20 °C, followed by 1 M NaOH for 5 h at 90 °C, and bleached with 2.5% v/v NaOCl for 2 h at 20 °C from Zophobas morio (ZM) insects fed citrus waste biomass (OP) or polystyrene foam (PS). The highest survival rate was found in the OP group. The properties of the resulting chitin material are reported, as well as the preparation of hydrogels using a DMAc/LiCl solvent. All chitins obtained were α-chitin. The degrees of deacetylation, crystallinity, molecular weight, and solubility in DMAc/LiCl were similar between the PS and biomass feeds, and they showed similar viscosities in the DMAc/LiCl solution. All hydrogels obtained had similar properties and viscoelastic behavior, indicating that the resultant chitins and their hydrogels from ZM were similar between those fed with citrus biomass and those fed with PS.

Chitosan-Cement Composite Mortars: Exploring Interactions, Structural Evolution, Environmental Footprint and Mechanical Performance

The increasing environmental concerns about synthetic polymers as reinforcement in the construction industry have highlighted the need for eco-friendly, biodegradable fibers as potential alternative materials for cementitious composites. This study examines the influence of chitosan particle concentrations on the midterm compressive strength of mortars. Chitosan particles, derived from shrimp shells, were mixed with high early strength hydraulic cement at various percentages (0, 0.05, 0.25, 0.5, 1, and 2 wt %) and silica sand to prepare the mortar samples. The findings indicate that chitosan affects the hydration process through the distribution of chitosan particles within the mortar matrix and slightly improved midterm mechanical properties. A life cycle assessment (LCA) revealed a slight increase in greenhouse gas emissions and embodied energy for chitosan-modified mortars, likely due to the use of chemicals in the chitosan synthesis and purification process. In fact, the addition of 0.25 wt % of chitosan into the mortar only added 1.3% of the global warming potential of the sample when compared to the control sample. Incorporating chitosan into a mortar matrix does not significantly affect the resistance-mechanical properties of the composite. The hydration of the cement mortar appears to be slowed by the inclusion of chitosan particles in the cementitious matrix. This research lays the groundwork as one of the first studies for the development of high-performance, early strength cement using chitosan, contributing to a more sustainable construction industry.

A comprehensive characterization of Hermetia illucens derived chitosan produced through homogeneous deacetylation

The increasing demand for chitin and chitosan is driving research to explore alternative sources to crustaceans. Insects, particularly bioconverters as Hermetia illucens, are promising substitutes as they process food industry waste into valuable molecules, including chitin. Chitosan can be produced by chitin deacetylation: hot deacetylation to obtain a heterogeneous chitosan, the commonly produced, and cold deacetylation to obtain a homogeneous chitosan, not widely available. The two different treatments lead to a different arrangement of the amine and acetyl groups in the chitosan structure, affecting its molecular weight, deacetylation degree, and biological activity. This is the first report on the production and chemical-physical and biological characterization of homogenous chitosan derived from H. illucens larvae, pupal exuviae, and adults. This work, in addition to the report on heterogeneous chitosan by our research group, completes the overview of H. illucens chitosan. The yield values obtained for homogeneous chitosan from pupal exuviae (3 and 7 %) are in the range of insect (2-8 %) and crustaceans (4-15 %) chitosan. The evaluation of the antioxidant activity and antimicrobial properties against Gram-negative (Escherichia coli) and Gram-positive (Micrococcus flavus) bacteria confirmed the great versatility of H. illucens chitosan for biomedical and industrial applications and its suitability as an alternative source to crustaceans.

Plasma-activated water improves the accessibility of chitinase to chitin by decreasing molecular weight and breaking crystal structure

Chitooligosaccharides, the hydrolysis products of chitin, have superior biological activities and application value to those of chitin itself; however, the ordered and highly crystalline structure of chitin renders its degradation by chitinase difficult. Herein, the effects of plasma-activated water (PAW) pre-treatment on the physicochemical properties, crystal structure, and enzymatic hydrolysis of chitin were investigated. The hydrolysis of PAW-pre-treated chitin (PAW activation time of 5 min) using chitinase from Vibrio harveyi (VhChit2) yielded 71 % more reducing sugar, compared with that from untreated chitin, with the degree of chitin hydrolysis increasing from 13 % without pre-treatment to 23 % post-treatment. Moreover, the amount of VhChit2 adsorbed by chitin increased from 41.7 to 58.2 mg/g. Fourier transform infrared spectrometry revealed that PAW could break the β-1,4-glycosidic bonds of chitin (but had no effects on the hydrogen and amido bonds), thereby decreasing the molecular weight and crystallinity of the polysaccharide, which caused its structural damage and enhanced its enzymatic hydrolysis by chitinase. Consequently, PAW pre-treatment can be considered a simple, effective, and environmentally-friendly method for the biotransformation of chitin as its easier hydrolysis yields high-value products.

Update on Chitin and Chitosan from Insects: Sources, Production, Characterization, and Biomedical Applications

Insects, renowned for their abundant and renewable biomass, stand at the forefront of biomimicry-inspired research and offer promising alternatives for chitin and chitosan production considering mounting environmental concerns and the inherent limitations of conventional sources. This comprehensive review provides a meticulous exploration of the current state of insect-derived chitin and chitosan, focusing on their sources, production methods, characterization, physical and chemical properties, and emerging biomedical applications. Abundant insect sources of chitin and chitosan, from the Lepidoptera, Coleoptera, Orthoptera, Hymenoptera, Diptera, Hemiptera, Dictyoptera, Odonata, and Ephemeroptera orders, were comprehensively summarized. A variety of characterization techniques, including spectroscopy, chromatography, and microscopy, were used to reveal their physical and chemical properties like molecular weight, degree of deacetylation, and crystallinity, laying a solid foundation for their wide application, especially for the biomimetic design process. The examination of insect-derived chitin and chitosan extends into a wide realm of biomedical applications, highlighting their unique advantages in wound healing, tissue engineering, drug delivery, and antimicrobial therapies. Their intrinsic biocompatibility and antimicrobial properties position them as promising candidates for innovative solutions in diverse medical interventions.

Sourcing chitin from exoskeleton of Tenebrio molitor fed with polystyrene or plastic kitchen wrap

In this work we have characterized and compared chitin sourced from exoskeleton of Tenebrio molitor larvae fed with polystyrene or plastic kitchen wrap combined with bran in the ratio 1: 1 with chitin sourced from larvae exoskeleton fed only with bran. Analysis of the frass by ATR-FTIR showed very similar spectra and confirmed degradation of the plastic feed components, while ATR-FTIR analysis of the exoskeleton verified the absence of any plastic residue. Deproteinization followed by demineralization produced 6.78-5.29 % chitin, showing that plastic (polystyrene or plastic kitchen wrap) in the larvae diet resulted in heavier insect exoskeleton, but yielded slightly less chitin, with the lowest value obtained for plastic kitchen wrap in the insect diet. The deacetylation degree of 98.17-98.61 % was determined from measured ATR-FTIR spectra. XRD analysis confirmed the presence of α-chitin with a crystallinity index of 66.5-62 % and crystallite size 4-5 nm. Thermogravimetric analysis showed similar degradation curves for all chitin samples, with two degradation steps. These results show that chitin sourced from exoskeleton of T. molitor larvae fed with plastic (polystyrene or plastic kitchen wrap) and contributing to significant biodegradation of major polluting materials can be a feasible and alternative source of chitin, further promoting a bio-circular economy.

Study of the degradation in an ultisol of alginate-chitosan complex and its stability and applicability as a soil conditioner

The present work describes the process of degradation of a polyelectrolytic complex (PEC) based on sodium alginate (ALG) and chitosan (CHI), buried for different time intervals, in a clayey soil (ultisol) collected from the municipality of Campos dos Goytacazes, in the northern region of the state of Rio de Janeiro, Brazil. The influence of PEC on soil moisture was also investigated. The results showed that soil moisture increased with the presence of PEC after 7 days of testing, and remained high until the end of the study. FTIR and Raman spectra showed that the breaking of the glycosidic bond (C-O-C) was responsible for the PEC degradation. Thermogravimetry results revealed that alginate was possibly degraded faster than chitosan. Microscopic analysis of the PEC revealed a fragile and fragmented surface of the samples that were buried, in comparison with those not buried. The microbiological assays of the soil confirmed the biodegradation of the polysaccharides. Chemical analysis of soil indicated that PEC did not significantly influence soil fertility. Therefore, we conclude that the PEC (ALG: CHI), formed only by electrostatic interaction, buried in clayey soil, even being biodegraded, can be a promising soil conditioner for agricultural applications.

Physicochemical comparison of chitin characteristics in three major stored-product beetle pests: Implications for biofumigant toxicity

The present study investigates the chitin properties of stored-product insect pests and their association with the fumigant toxicity of garlic essential oil. Chitin isolates of Callosobruchus maculatus, Sitophilus oryzae, and Tribolium castaneum adults were characterized using FT-IR, XRD, EA, SEM-EDS, and NMR techniques. Fumigant toxicity assay was performed under airtight condition in glass vial. The S. oryzae contains highest chitin content (19 %), followed by T. castaneum (10 %) and C. maculatus (8 %). The degree of crystallinity was lower in C. maculatus (67.13 %) than in S. oryzae (77.05 %) and T. castaneum (76.56 %). Morphologically, C. maculatus chitin displayed a flat lamellar surface with pores, while S. oryzae and T. castaneum exhibited densely arranged microfibrils based surfaces. Fumigant toxicity assays revealed varied susceptibility levels, C. maculatus exhibited higher susceptibility (0.27 μL/L air of LC50) compared to S. oryzae and T. castaneum (14.35 and 3.74 μL/L air of LC50, respectively) to garlic essential oil. The higher chitin content, greater crystallinity, and densely arranged structures in S. oryzae might contribute to its tolerance towards fumigant. Additionally, physico-chemical properties and penetration potentiality of the bioactive constituents might be linked to the toxicity in insects. Understanding these relations can enrich knowledge of chitin's role in fumigant toxicity mechanism.

An analysis of emerging food safety and fraud risks of novel insect proteins within complex supply chains

Food consumption play a crucial role in human life, yet conventional food production and consumption patterns can be detrimental to the environment. Thus, research and development has been directed towards alternative proteins, with edible insects being promising sources. Edible insects have been recognised for their sustainable benefits providing protein, with less emission of greenhouse gas, land and water usage compared to sources, such as beef, chicken, and dairy products. Among the over 2000 known edible insect species, only four, namely yellow mealworm (Tenebrio molitor), migratory locust/grasshopper (Locusta migratoria), grain mould beetle, also known as lesser mealworm which is a larval form of Alphitobius diaperinus (from the family of Tenebrionidae of darkling beetles) and house cricket (Acheta domesticus), are currently authorised in specific products through specific producers in the EU. The expansion of such foods into Western diets face challenges such as consumer barriers, gaps in microbiological and chemical safety hazard data during production and processing, and the potential for fraudulent supply chain activity. The main aim of this study was to map the supply chain, through interviews with personnel along the supply chain, coupled with searches for relevant publications and governmental documents. Thus, the main potential points of food safety and fraud along the edible insect supply chain were identified. Feed substrate was identified as the main area of concern regarding microbiological and chemical food safety and novel processing techniques were forecast to be of most concern for future fraudulent activity. Despite the on-going authorisation of insect species in many countries there are substantial food safety and authenticity information gaps in this industry that need to be addressed before edible insects can be viewed as a safe and sustainable protein sources by Western consumers.

An overview of the potential application of chitosan in meat and meat products

Chitosan is considered the second most ubiquitous polysaccharide next to cellulose. It has gained prominence in various industries including biomedicine, textile, pharmaceutical, cosmetic, and notably, the food industry over the last few decades. The polymer's continual attention within the food industry can be attributed to the increasing popularity of greener means of packaging and demand for foods incorporated with natural alternatives instead of synthetic additives. Its antioxidant, antimicrobial, and film-forming abilities reinforced by the polymer's biocompatible, biodegradable, and nontoxic nature have fostered its usage in food packaging and preservation. Microbial activity and lipid oxidation significantly influence the shelf-life of meat, resulting in unfavorable changes in nutritional and sensory properties during storage. In this review, the scientific studies published in recent years regarding potential applications of chitosan in meat products; and their effects on shelf-life extension and sensory properties are discussed. The utilization of chitosan in the form of films, coatings, and additives in meat products has supported the extension of shelf-life while inducing a positive impact on their organoleptic properties. The nature of chitosan and its compatibility with various materials make it an ideal biopolymer to be used in novel arenas of food technology.

Insect residues as an alternative and promising source for the extraction of chitin and chitosan

This work aimed to obtain and characterize chitin and chitosan extracted from the rearing residues of Tenebrio molitor, Zophobas morio, and Blaptica dubia insects in different growth stages in the same rearing cycles chitin and chitosan yielded 11.21 %-20.89 % and 6.26 %-7.07 %, respectively. The deacetylation degrees of chitosan ranged from 75.75 %-89.21 %, and the solubilities from 69.88 %-94.39 %. Infrared spectroscopy corroborated the acquisition of chitin and chitosan and can be used as a semi-quantitative technique for determining the degree of chitosan deacetylation. The X-ray diffraction profiles revealed the presence of α-chitin, and the relative crystalline indices ranged from 65.9 %-89.2 %. Typical TG profiles with two thermal events are observed for chitin and chitosan samples with different residue contents from the extraction procedure. The chitosan solutions exhibited pseudoplastic behavior, with apparent viscosities ranging from 195.96 to 249.86 mPa.s. The characterization results of the biopolymers extracted from insect residues were similar to those obtained from conventional sources. The growth stage influenced the chitin yield and crystallinity index. The results of this study reinforce the feasibility of using alternative sources of chitin and chitosan, providing the use of waste from insect farms and contributing to sustainability and a circular economy.

Sustainable valorization approaches on crustacean wastes for the extraction of chitin, bioactive compounds and their applications - A review

The unscientific disposal of the most abundant crustacean wastes, especially those derived from marine sources, affects both the economy and the environment. Strategic waste collection and management is the need of the hour. Sustainable valorization approaches have played a crucial role in solving those issues as well as generating wealth from waste. The shellfishery wastes are rich in valuable bioactive compounds such as chitin, chitosan, minerals, carotenoids, lipids, and other amino acid derivatives. These value-added components possessed pleiotropic applications in different sectors viz., food, nutraceutical, cosmeceutical, agro-industrial, healthcare, and pharmaceutical sectors. The manuscript covers the recent status, scope of shellfishery management, and different bioactive compounds obtained from crustacean wastes. In addition, both sustainable and conventional routes of valorization approaches were discussed with their merits and demerits along with their combinations. The utilization of nano and microtechnology was also included in the discussion, as they have become prominent research areas in recent years. More importantly, the future perspectives of crustacean waste management and other potential valorization approaches that can be implemented on a large scale.

Hermetia illucens, an innovative and sustainable source of chitosan-based coating for postharvest preservation of strawberries

The ability of chitosan produced from pupal exuviae of Hermetia illucens to retard the decay of the local strawberry (Fragaria x ananassa) cultivar Melissa was investigated for the first time in this paper. The results demonstrated the effectiveness of insect chitosan compared to the commercial polymer in preserving and enhancing, at the same time, some physicochemical parameters (weight loss, pH and soluble solids content) and nutraceutical properties (total polyphenol content, total flavonoid content and total antioxidant activity) of strawberries stored at RT, 4°C and at mixed storage conditions (4°C + RT). Moreover, chitosan from H. illucens was also effective in reducing fungal decay and improving fruit shelf life. The obtained results confirm that insect chitosan, particularly deriving from H. illucens pupal exuviae, can be a viable alternative to crustacean one in safeguarding postharvest fruits.

Edible Insects: A New Sustainable Nutritional Resource Worth Promoting

Edible insects are a highly nutritious source of protein and are enjoyed by people all over the world. Insects contain various other nutrients and beneficial compounds, such as lipids, vitamins and minerals, chitin, phenolic compounds, and antimicrobial peptides, which contribute to good health. The practice of insect farming is far more resource-efficient compared to traditional agriculture and animal husbandry, requiring less land, energy, and water, and resulting in a significantly lower carbon footprint. In fact, insects are 12 to 25 times more efficient than animals in converting low-protein feed into protein. When it comes to protein production per unit area, insect farming only requires about one-eighth of the land needed for beef production. Moreover, insect farming generates minimal waste, as insects can consume food and biomass that would otherwise go to waste, contributing to a circular economy that promotes resource recycling and reuse. Insects can be fed with agricultural waste, such as unused plant stems and food scraps. Additionally, the excrement produced by insects can be used as fertilizer for crops, completing the circular chain. Despite the undeniable sustainability and nutritional benefits of consuming insects, widespread acceptance of incorporating insects into our daily diets still has a long way to go. This paper provides a comprehensive overview of the nutritional value of edible insects, the development of farming and processing technologies, and the problems faced in the marketing of edible insect products and insect foods to improve the reference for how people choose edible insects.

Dual-Pulsed Laser Ablation of Oyster Shell Producing Novel Thin Layers Deposed to Saccharomyces cerevisiae

Dual-pulsed (DPL) laser deposition using oyster shells as targets was studied in order to find out if this method can replace the use of high-power pulsed lasers. Aspects related to changes in the morphological structure of the thin layer but also to the chemical composition of the obtained thin layer were analyzed and compared with the target as well as with the thin layers obtained with a higher power pulsed laser in a single-pulsed (SPL) regime. Orthorhombic structures were noticed with Scanning Electron Microscopy for the thin film obtained in DPL mode compared to the irregular particles obtained in SPL mode. The deacetylation process during ablation was evidenced by Fourier Transform Infrared spectroscopy, resulting in chitosan-based thin films. The effect of the obtained thin films of chitosan on the cells of baker's yeast (Saccharomyces cerevisiae) was studied. Restoration of the yeast paste into initial yeast was noticed mainly when the hemp fabric was used as support for the coating with yeas which was after that coated with chitosan thin film produced by DPL method.

Synthesis and physicochemical properties of an aromatic chitosan derivative: In vitro antibacterial, antioxidant, and anticancer evaluations, and in silico studies

This study was designed to synthesize a functionalized chitosan by coupling the amine groups of chitosan with 2,4,6-Trimethoxybenzaldehyde, producing a chitosan Schiff base (Cs-TMB). The development of Cs-TMB was verified employing FT-IR, 1H NMR, the electronic spectrum, and elemental analysis. Antioxidant assays exhibited significant ameliorations of Cs-TMB, reporting scavenging activities of 69.67 ± 3.48 % and 39.65 ± 1.98 % for ABTS•+ and DPPH, respectively, while native chitosan showed scavenging ratios of 22.69 ± 1.13 % and 8.24 ± 0.4.1 % toward ABTS•+ and DPPH, respectively. Besides, Cs-TMB exerted significant antibacterial activity up to 90 % with remarkable bactericidal capacity against virulent gram-negative and gram-positive bacteria compared to the original chitosan. Furthermore, Cs-TMB exhibited a safe profile against normal fibroblast cells (HFB4). Interestingly, flow cytometric analysis showed that Cs-TMB demonstrated prominent anticancer properties of 52.35 ± 2.99 % against human skin cancer cells (A375), compared to 10.66 ± 0.55 % for Cs-treated cells. Moreover, Python and PyMOL in-house scripts were used to predict the interaction of Cs-TMB with the adenosine A1 receptor and visualized as a protein-ligand system submerged in a lipid membrane. Overall, these findings accentuate that Cs-TMB could be a favorable representative for wound dressing formulations and skin cancer treatment.

Insights into the relationships of modifying methods, structure, functional properties and applications of chitin: A review

Chitin as the second plentiful polysaccharide has arouse widely attention due to its remarkable availability and biocompatibility. While the strong inter/intra molecular hydrogen bonds and crystallinity severely restrict its applications. Recently, multiple emerging technologies are increasingly used to modify chitin structure for the sake of obtaining excellent functional properties, as well as broadening the corresponding applications. Firstly, this review systematically outlines the features of single and combined methods for chitin modification. Then, the impacts of various modifying methods on the structural characteristics of chitin, including molecular weight, degree of acetylation and functional groups, are further summarized. In addition, the effects of these structural characteristics on the functional properties as well as its potential related applications are illustrated. The conclusion of this review provides better understanding of the relationships among the modifying methods, structure, properties and applications, contributing to chitin modification for the targeted purpose in the future study.

Chitin/deacetylated chitin nanocomposite film for effective adsorption of organic pollutant from aqueous solution

Cross-linked chitin/deacetylated chitin nanocomposite films can be considered as a potential industrial adsorbent for the removal of organic pollutants for water purification. Chitin (C) and deacetylated chitin (dC) nanofibers were extracted from raw chitin and characterized using FTIR, XRD and TGA techniques. The TEM image confirmed the formation of chitin nanofibers with a diameter range of 10-45 nm. The deacetylated chitin nanofibers (DDA-46 %) having 30 nm diameter was evidenced using FESEM. Further, the C/dC nanofibers were prepared at different ratios (80/20, 70/30, 60/40 & 50/50 ratios) and cross-linked. The highest tensile strength of 40 MPa and Young's modulus of 3872 MPa was exhibited by 50/50C/dC. The DMA studies revealed that the storage modulus enhanced by 86 % for 50/50C/dC (9.06 GPa) in comparison to 80/20C/dC nanocomposite. Further, the 50/50C/dC exhibited a maximum adsorption capacity of 30.8 mg/g at pH = 4 in 30 mg/L of Methyl Orange (MO) dye within 120 min. The experimental data agreed with pseudo-second-order model indicating chemisorption process. The adsorption isotherm data was best described by Freundlich model. The nanocomposite film is an effective adsorbent can be regenerated and recycled for five adsorption-desorption cycle.

The Preparation and Physiochemical Characterization of Tenebrio molitor Chitin Using Alcalase

Chitin is mostly produced from crustaceans, but it is difficult to supply raw materials due to marine pollution, and the commonly used chemical chitin extraction method is not environmentally friendly. Therefore, this study aims to establish a chitin extraction process using enzymes and to develop edible insect-derived chitin as an eco-friendly new material. The response surface methodology (RSM) was used to determine the optimal conditions for enzymatic hydrolysis. The optimal conditions for enzymatic hydrolysis by RSM were determined to be the substrate concentration (7.5%), enzyme concentration (80 μL/g), and reaction time (24 h). The solubility and DDA of the mealworm chitosan were 45% and 37%, respectively, and those of the commercial chitosan were 61% and 57%, respectively. In regard to the thermodynamic properties, the exothermic peak of mealworm chitin was similar to that of commercial chitin. In the FT-IR spectrum, a band was observed in mealworm chitin corresponding to the C=O of the NHCOCH3 group at 1645 cm-1, but this band showed low-intensity C=O in the mealworm chitosan due to deacetylation. Collectively, mealworm chitosan shows almost similar physical and chemical properties to commercial chitosan. Therefore, it is shown that an eco-friendly process can be introduced into chitosan production by using enzyme-extracted mealworms for chitin/chitosan production.

A novel chitinous nanoparticles prepared and characterized with black soldier fly (Hermetia illucens L.) using steam flash explosion treatment

This is the first report of the use of steam flash explosion (SFE) to prepare chitinous nanoparticles from black soldier fly (BSF). SFE treatment was performed at a steam pressure of 0.45 to 1.60 MPa with a holding time of 60 s. As the pressure increased, the particle size of the chitinous particles decreased. Under SFE at 1.60 MPa, chitinous nanoparticles with sizes ranging from 59 to 162 nm were produced. SEM, AFM, Raman spectroscopy, FT-IR spectroscopy, ¹H NMR, TGA, and DSC were used to characterize the BSF chitin materials. It was demonstrated that SFE treatment deacetylated chitin to obtain chitosan with 91.24 % deacetylation. In addition, the polymer backbone was maintained, and the degree of polymerization of chitosan nanoparticles was reduced. The activity of the cationic groups of chitosan nanoparticles was improved, thereby enhancing the temperature sensitivity of the polymeric material. It can be concluded that the SFE one-step processing method is a simple and efficient way to prepare homogeneous biomaterial nanoparticles. This study has implications for the development of chitosan nanomaterials for biomedical applications.

Extraction and characterization of chitosan from Eupolyphaga sinensis Walker and its application in the preparation of electrospinning nanofiber membranes

Due to its capabilities for wound healing, antimicrobial defense, hemostasis, and biodegradation, chitosan has seen increased use in biomedical disciplines in recent years. In the meantime, efforts have been made to develop and use insect chitosan as a source to address the seasonal, irritating, and regional shortcomings of traditional shrimp and crab chitosan. In this study, a new type of insect chitosan (DCS) was first extracted from Eupolyphaga sinensis Walker by a low-temperature intermittent method and was compared with commercially available pharmaceutical chitosan (CS). Firstly, the degree of deacetylation and molecular weight of DCS were determined, and DCS was characterized by FT-IR, ¹H NMR, XRD, and TGA-DTG. On this basis, DCS was mixed with PVA and PEO to create a novel electrospun nanofiber membrane. The air permeability, antibacterial properties, and biocompatibility of the nanofiber membrane were evaluated, as well as the membrane's shape, structure, and mechanical characteristics. Finally, the activity of nanofiber membranes in promoting wound healing was verified with a rat full-thickness skin defect model, hoping to provide a reference for the development of new drug delivery carriers and wound dressings.

A Self-Healing Gel Polymer Electrolyte, Based on a Macromolecule Cross-Linked Chitosan for Flexible Supercapacitors

Gel polymer electrolytes with a satisfied ionic conductivity have attracted interest in flexible energy storage technologies, such as supercapacitors and rechargeable batteries. However, the poor mechanical strength inhibits its widespread application. One of the most significant ways to avoid the drawbacks of the gel polymer electrolytes without compromising their ion transportation capabilities is to create a self-healing structure with the cross-linking segment. Herein, a new kind of macromolecule chemical cross-linked network ionic gel polymer electrolyte (MCIGPE) with superior electrochemical characteristics, a high flexibility, and an excellent self-healing ability were designed, based on chitosan and dibenzaldehyde-terminated poly (ethylene glycol) (PEGDA) via dynamic imine bonds. The ionic conductivity of the MCIGPE-65 can achieve 2.75 × 10^-2 S cm^-1. A symmetric all-solid-state supercapacitor employing carbon cloth as current collectors, activated a carbon film as electrodes, and MCIGPE-65 as a gel polymer electrolyte exhibits a high specific capacitance of 51.1 F g^-1 at 1 A g^-1, and the energy density of 7.1 Wh kg^-1 at a power density of 500.2 W kg^-1. This research proves the enormous potential of incorporating, environmentally and economically, chitosan into gel polymer electrolytes for supercapacitors.

Physicochemical Properties and Functional Characteristics of Ecologically Extracted Shrimp Chitosans with Different Organic Acids during Demineralization Step

The current study aims to develop eco-friendly and economical chitosans with a wide range of applications using organic acids for shrimp shells demineralization. Chitosan samples were extracted from shrimp (Parapenaeus longirostris) shells and the demineralization step was performed with three organic acids (citric, acetic, and lactic) and two mineral acids (hydrochloric and sulfuric). The chitosans were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The chitosans’ physicochemical properties were also determined. The characteristic bands and functional groups of the chitosans were identified by FTIR spectra. The chitosans’ crystallinity order was as follows: ChHCl > ChCitric > ChH2SO4 > ChLactic > ChAcetic. The chitosans’ morphological characteristics revealed a smooth surface and fibrous structures with pores. Chitosans extracted by organic acids showed the highest extraction yields. ChHCl and ChCitric had higher degrees of deacetylation values; 83.67% and 81.47%, respectively. The solubility was proportional to the degree of deacetylation. Furthermore, ChH2SO4 and ChCitric had lower molecular weight values; 149 kDa and 183 kDa, respectively. Organic acids are as effective as mineral acids for shrimp shells demineralization. The developed process opens up possibilities to produce chitin and chitosan in a more eco-friendly way and at a lower cost in many industrial sectors.

Preparation, physicochemical properties and antimicrobial activity of chitosan from fly pupae

As an alternative chitosan source, edible insects have been proposed as an unconventional but viable option. Taking fly pupae as an example, this work performed chitosan extraction through a traditional chemical method with some modifications, and investigated its physicochemical properties and antimicrobial activity. The results showed that adding 0.5% sodium sulfite (Na2SO3, w/w, Na2SO3/fly pupae) synergized with sodium hydroxide (NaOH) for deproteinization was more effective than lye alone. Acid leaching was applied for desalination, and the optimal concentration of hydrochloric acid (HCl) was determined as 2 mol/L by ash content. For decoloration, the optimal decolorization oxidant was sodium hypochlorite (NaClO) with a concentration of 1.0%. For the deacetylation of chitin to chitosan, both the yield and degree of deacetylation (DD) using segmented treatment with alkali-NaOH were higher than those of traditional one-time deacetylation. The established physicochemical properties corresponded with the typical characteristics of chitosan. The determination of antimicrobial activity of chitosan by the turbidimetric method showed that chitosan exhibited notable activity in the order of Staphylococcus aureus > Escherichia coli > Saccharomyces cerevisiae, and this effect decreased with the increase in viscosity-average molecular weight (Mη). These results proved the viability of our improved method for the preparation of chitosan, a valuable antimicrobial agent, using an alternative natural source.

Chitin Isolation and Chitosan Production from House Crickets (Acheta domesticus) by Environmentally Friendly Methods

Alternative methods were evaluated for chitin isolation from Acheta domesticus. Chemical demineralization was compared to fermentation with Lactococcus lactis, citric acid treatment, and microwave treatment, leading to a degree of demineralization of 91.1 ± 0.3, 97.3 ± 0.8, 70.5 ± 3.5, and 85.8 ± 1.3%, respectively. Fermentation with Bacillus subtilis, a deep eutectic solvent, and enzymatic digestion were tested for chitin isolation, generating materials with less than half the chitin content when compared to alkaline deproteinization. Chitosan was produced on a large scale by deacetylation of the chitinous material obtained from two selected processes: the chemical treatment and an alternative process combining L. lactis fermentation with bromelain deproteinization. The chemical and alternative processes resulted in similar chitosan content (81.9 and 88.0%), antioxidant activity (59 and 49%), and degree of deacetylation (66.6 and 62.9%), respectively. The chitosan products had comparable physical properties. Therefore, the alternative process is appropriate to replace the chemical process of chitin isolation for industrial applications.

The first insight into black soldier fly meal in brown trout nutrition as an environmentally sustainable fish meal replacement

Insect meals are considered among the most promising feed materials in fish nutrition due to their sustainability and possibility of fish meal replacement. The present study is the first application of full-fat black soldier fly larvae (BSFL) meal in brown trout (Salmo trutta m. fario) diets. Two experiments were performed on 240 brown trout fingerlings (average body mass 4.85 g) distributed into four groups (12 tanks for the growth performance experiment, 10 fish/tank; and 12 metabolic tanks for the digestibility test, 10 fish/tank). The experimental group design was conducted as follows: control diet, with no BSFL and 35% fish meal, and experimental diets: BSFL5 - with 5% BSFL full-fat meal and 32.5% fish meal; BSFL10 - with 10% BSFL full-fat meal and 30% fish meal; and BSFL20 - with 20% BSFL full-fat meal and 25% fish meal. No effects were recorded in the case of growth performance and feed utilization parameters. The environmental sustainability of the usage of insect meals in fish diets was proven - due to the lower fish meal inclusion, the fish-in-fish-out ratio decreased by 31% in BSFL20. In the case of the viscerosomatic index, increases in BSFL5 and BSFL20 were reported. In all experimental groups, decreases in hepatosomatic index values were observed. Crude protein digestibility decreased in BSFL5 and BSFL20, while crude fat digestibility decreased only in the BSFL20 group. The effect of including BSFL full-fat meal in a brown trout diet on serum biochemical parameters was reported. The aspartate transaminase concentration increased in BSFL10 and BSFL20, while the gamma-glutamyl transpeptidase values decreased in BSFL20. In the case of total cholesterol, higher values were observed in BSFL10 and BSFL20. The albumin content decreased in the BSFL20 group, while globulin showed the highest values in the control group. The microbiota composition was not affected by insect meal inclusion. In conclusion, the results of the present study showed the high potential of BSFL full-fat meal application of up to 20% in a brown trout diet.

Characterization of chitin and chitosan derived from Hermetia illucens, a further step in a circular economy process

Due to their properties and applications, the growing demand for chitin and chitosan has stimulated the market to find more sustainable alternatives to the current commercial source (crustaceans). Bioconverter insects, such as Hermetia illucens, are the appropriate candidates, as chitin is a side stream of insect farms for feed applications. This is the first report on production and characterization of chitin and chitosan from different biomasses derived from H. illucens, valorizing the overproduced larvae in feed applications, the pupal exuviae and the dead adults. Pupal exuviae are the best biomass, both for chitin and chitosan yields and for their abundance and easy supply from insect farms. Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscope analysis revealed the similarity of insect-derived polymers to commercial ones in terms of purity and structural morphology, and therefore their suitability for industrial and biomedical applications. Its fibrillary nature makes H. illucens chitin suitable for producing fibrous manufacts after conversion to chitin nanofibrils, particularly adults-derived chitin, because of its high crystallinity. A great versatility emerged from the evaluation of the physicochemical properties of chitosan obtained from H. illucens, which presented a lower viscosity-average molecular weight and a high deacetylation degree, fostering its putative antimicrobial properties.

Characteristics of chitosan fiber and their effects towards improvement of antibacterial activity

We selected eight kinds of chitosan fibers to characterize and analyze their composition, surface morphology, and mechanical properties. Crucially, we investigated their antibacterial activity against Escherichia coli, Staphylococcus aureus and Candida albicans and the dependence on the molecular weight (Mw) and the degree of deacetylation (DD). On that basis, the relationship between antibacterial activity and Mw and DD can be established. Finally, the antibacterial mechanism of chitosan fiber was obtained. The results show that the inhibition rate of samples I, K, L, and M against Staphylococcus aureus first increased and then decreased with the increase of Mw, and their bactericidal activity against Escherichia coli decreased with the increase of Mw when the DD was similar. This study provides an effective strategy for characterizing the chitosan fiber and the resultant relationship between antibacterial property and structural parameters that may benefit the enhancement of antibacterial activity and application in antibacterial textiles.

Investigation on dung beetle's (Heliocopris Hope, 1838) chitosan valorisation for hydrogel 3D printing

Biopolymers and their derivatives are materials with increasing interest for industry and especially for sustainable engineering development. Among such kind of materials, carbohydrate polymer like highly deacetylated chitin (chitosan) is widely used for a wide range of applications, including material and biomedical developments. The majority of industrially produced chitosan is based on chitin extracted from crustacean exoskeleton. However, with increase of interest on this material, chitosan's production will rapidly become insufficient and other species should be investigated as new sources of chitosan. In the present work, we focus on the preparation of chitosan from giant dung beetles (Genus Heliocopris, Hope, 1838). This genus was chosen to show the possibility to take animals that develop and leave near dejection and valuate them for material applications. This work includes all the chitosan extraction procedures, chitosan characterisation IR, SEM, NMR, ash content, and deacetylation degree. Finally, the prepared carbohydrate polymer is used to form hydrogel. The prepared gel has been characterised and used for 3D printing, to show the compatibility of extracted chitosan with biomaterial application.

Edible Aquatic Insects: Diversities, Nutrition, and Safety

Edible insects have great potential to be human food; among them, aquatic insects have unique characteristics and deserve special attention. Before consuming these insects, the nutrition and food safety should always be considered. In this review, we summarized the species diversity, nutrition composition, and food safety of edible aquatic insects, and also compared their distinguished characteristics with those of terrestrial insects. Generally, in contrast with the role of plant feeders that most terrestrial edible insect species play, most aquatic edible insects are carnivorous animals. Besides the differences in physiology and metabolism, there are differences in fat, fatty acid, limiting/flavor amino acid, and mineral element contents between terrestrial and aquatic insects. Furthermore, heavy metal, pesticide residue, and uric acid composition, concerning food safety, are also discussed. Combined with the nutritional characteristics of aquatic insects, it is not recommended to eat the wild resources on a large scale. For the aquatic insects with large consumption, it is better to realize the standardized cultivation before they can be safely eaten.

Chitin Determination in Residual Streams Derived From Insect Production by LC-ECD and LC-MS/MS Methods

Chitin, a biopolymer present in fungi and arthropods, is a compound of interest for various applications, such as in the agricultural and medical fields. With the recently growing interest in the development of insect farming, the availability of chitin-containing residual streams, particularly the molting skins (exuviae), is expected to increase in the near future. For application purposes, accurate quantification of chitin in these insect sources is essential. Previous studies on chitin extraction and quantification often overlooked the purity of the extracted chitin, making the outcomes inconsistent and prone to overestimation. The present study aims to determine chitin content in the exuviae of three insect species mass-reared worldwide: black soldier fly (BSF), mealworm, and house cricket. Chitin was chemically extracted using acid and alkali treatments to remove minerals and proteins. The purity of extracted chitin was evaluated by hydrolyzing the chitin into glucosamine, followed by quantitative determination of the latter using two liquid chromatography methods: electrochemical detection (ECD) and tandem mass spectrometry (MS/MS). Both methods proved accurate and precise, without the need for labor-intensive derivatization steps. Pearson's correlation and Bland-Altman plots showed that the glucosamine determination results obtained by the two methods were comparable, and there is no consistent bias of one approach vs. the other. The chitin content in extracted residues ranged between 7.9 and 18.5%, with the highest amount found in BSF puparium. In summary, the study demonstrated that (1) the residual streams of the insect farming industry have a great potential for utilization as an alternative chitin source, and (2) both LC-ECD and LC-MS/MS are reliable for the quantitative determination of glucosamine in insect chitin.

Tenebrio molitor as a source of interesting natural compounds, their recovery processes, biological effects, and safety aspects

Nowadays, it is urgent to produce in larger quantities and more sustainably to reduce the gap between food supply and demand. In a circular bioeconomy vision, insects receive great attention as a sustainable alternative to satisfy food and nutritional needs. Among all insects, Tenebrio molitor (TM) is the first insect approved by the European Food Safety Authority as a novel food in specific conditions and uses, testifying its growing relevance and potential. This review holistically presents the possible role of TM in the sustainable and circular solution to the growing needs for food and nutrients. We analyze all high value-added products obtained from TM (powders and extracts, oils and fatty acids, proteins and peptides, and chitin and chitosan), their recovery processes (evaluating the best ones in technical and environmental terms), their nutritional and economical values, and their biological effects. Safety aspects are also mentioned. TM potential is undoubted, but some aspects still need to be discussed, including the health effects of substances and microorganisms in its body, the optimal production conditions (that affect product quality and safety), and TM capacity to convert by-products into new products. Environmental, economic, social, and market feasibility studies are also required to analyze the new value chains. Finally, to unlock the enormous potential of edible insects as a source of nutritious and sustainable food, it will be necessary to overcome the cultural, psychological, and regulatory barriers still present in Western countries.

Terrestrial insects as a promising source of chitosan and recent developments in its application for various industries

Chitosan is a deacetylated form of chitin and increasingly important amino-polysaccharide used in many various sectors including agriculture, food, and biomedicine. However, chitosan from marine sources has several adverse effects, including allergenic components harmful to human health. Furthermore, marine resources are seasonal, and availability is limited due to dependency on environmental conditions and climate change. In addition, shell infection in crustaceans and environmental contamination make the harvesting of chitin and chitosan problematic. In recent years, chitosan from terrestrial insects has attracted considerable interest. The discoveries show insect chitosan is more advantageous compared to crustacean chitosan. In addition, we were unable to find any literature about the adverse effects of insect chitosan thus far. This review aims to reveal information regarding crustacean and terrestrial insect chitosan and recent advances in chitosan sources. Applications from specific insect orders and perspectives for further study will also be highlighted, including medical and sensing applications.

Biopolymer-based flocculants: a review of recent technologies

Biopolymer-based flocculants have become a potential substitute for inorganic coagulants and synthetic organic flocculants due to their wide natural reserves, environmental friendliness, easy natural degradation, and high material safety. In recent years, with more and more attention to clean technologies, a lot of researches on the modification and application of biopolymer-based flocculants have been carried out. The present paper reviews the latest important information about the base materials of biopolymer-based flocculants, including chitosan, starch, cellulose, and lignin etc. This review also highlights the various modification methods of these base materials according to reaction types in detail. Via the recent researches, the flocculation mechanisms of biopolymer-based flocculants, such as adsorption, bridging, charge neutralization, net trapping, and sweeping, as well as, some other special mechanisms are comprehensively summarized. This paper also focuses on the water treatment conditions, the removal efficiency, and advantages of biopolymer-based flocculants in applications. Further, this review sheds light on the future perspectives of biopolymer-based flocculants, which may make progress in the sources of base materials, modification processes, multi-function, and deepening application researches. We believe that this review can guide the further researches and developments of biopolymer-based flocculants in the future, to develop them with a higher efficiency, a lower cost, more safety, and multi-function for more diversified applications. Graphical abstract.

Method for Zero-Waste Circular Economy Using Worms for Plastic Agriculture: Augmenting Polystyrene Consumption and Plant Growth

Polystyrene (PS) is one of the major plastics contributing to environmental pollution with its durability and resistance to natural biodegradation. Recent research showed that mealworms (Tenebrio molitor) and superworms (Zophobas morio) are naturally able to consume PS as a carbon food source and degrade them without observable toxic effects. In this study, we explored the effects of possible food additives and use of worm frass as potential plant fertilizers. We found that small amounts of sucrose and bran increased PS consumption and that the worm frass alone could support dragon fruit cacti (Hylocereus undatus) growth, with superworm frass in particular, supporting better growth and rooting than mealworm frass and control media over a fortnight. As known fish and poultry feed, these findings present worms as a natural solution to simultaneously tackle both the global plastic problem and urban farming issue in a zero-waste sustainable bioremediation cycle.