Extraction, physicochemical characterization, and morphological properties of chitin and chitosan from cuticles of edible insects

Anti-inflammatory and anti-hyperglycemia effects of mealworm (Tenebrio molitor larvae) protein extracted by four methods: alkali, salt, enzyme, and screw press

The use of edible insect protein in food products is contingent on their biological effects. Conventional protein extraction methods are not only time-consuming and costly but also energy-intensive. There is a need for alternative techniques that maintain the bioactivities of insect proteins and are environmentally sustainable. This study compares the health functionality of mealworm (Tenebrio molitor larvae) concentrates obtained by conventional methods-alkali and salt (MS) extraction-and nonconventional methods-enzyme (ME) and screw press (MP)-to enhance their applicability despite lower protein concentration. Overall, MP exhibited the highest essential amino acids content, whereas ME showed the highest in vitro digestibility, total phenolic contents, and antioxidant capacities among all the concentrates. ME also had a significant cell proliferative capacity at concentrations ≥500 µg/mL. MS significantly inhibited tumor necrosis factor-alpha and interleukin-1beta secretion in lipopolysaccharide-treated Hep3B cells compared to other samples. As for anti-hyperglycemia effects, treatment with MS and ME for 2 and 5 min significantly increased the p-Akt/Akt ratio (MS, 1.34- and 1.61-fold; ME, 2.26- and 2.70-fold, respectively). In conclusion, enzyme treatment enhanced nutritional value and antioxidant capacity, whereas salt treatment potentially contributed to anti-inflammatory and anti-hyperglycemia activities. Hybrid extraction techniques combining conventional and nonconventional methods are suggested based on target applications, considering health benefits, environmental impact, costs, and efficiencies. PRACTICAL APPLICATION: Four mealworm protein extraction methods (alkali/salt/enzyme/screw press) were compared for their nutritional and biological properties. Alkali extraction enhanced protein content, enzyme treatment improved nutritional value and antioxidant capacity, and salt-assisted extraction exhibited immunomodulatory effects in vitro. Notably, enzyme and salt treatments produced protein concentrates with significant antidiabetic and anti-hyperglycemic properties.

Crucial roles of specialized chitinases in elytral and hindwing cuticles construction in Leptinotarsa decemlineata

BACKGROUND

The Colorado potato beetle (CPB), Leptinotarsa decemlineata, is a major potato (Solanum tuberosum) pest, infesting over 16 million km2 and causing substantial economic losses. The insect cuticle forms an apical extracellular matrix (ECM) envelope covering exposed organs to direct morphogenesis and confer structural protection. While select chitinase (Cht) genes have proven essential for larval development, their potential activities directing ECM remodeling underlying adult wing maturation remain undefined.

RESULTS

We investigated the expression patterns and performed an oral RNA interference (RNAi) screen targeting 19 LdChts in late-instar L. decemlineata larvae. Subsequently, we assessed their effects on adult eclosion and wing characteristics. Knockdown of LdCht5, LdCht7, LdCht10, LdIDGF2, and LdIDGF4, as well as others from Group IV (LdCht15, LdCht12, LdCht17, and LdCht13) and Groups VII-X (LdCht2, LdCht11, LdCht1, and LdCht3), resulting in shrunken, misshapen elytra with reduced areal density, as well as transverse wrinkling and impaired wing-tip folding in hindwings. Scanning electron micrographs revealed eroded elytral ridges alongside thinned, ruptured hindwing veins, indicative of mechanical fragility post-LdCht suppression. Spectroscopic analysis uncovered biomolecular alterations underlying the elytral anomalies, including decreases in peaks representing chitin, proteins, and lipids. This loss of essential ECM components provides evidence for the fragility, wrinkling, and shrinkage observed in the RNAi groups.

CONCLUSION

Our findings elucidate the crucial role of chitinases in the turnover of chitinous cuticles on beetle wings, offering insights into RNAi-based control strategies against this invasive pest. © 2024 Society of Chemical Industry.

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.

Chitosan from the base of Flammulina velutipes stipe alleviates oral Candida albicans infection via modulating Th-17 cell differentiation and Streptococcus mutans

The base of Flammulina velutipes (F. velutipes) stipe are agricultural wastes generated during the cultivation of edible fungus F. velutipes with high amount of chitin. Herein, this study firstly prepared chitosan from the base of F. velutipes stipe (FVC) and its structure was identified. It was confirmed that FVC acted as an antigenic substance to activate the immune system in vivo and in vitro, drive T cells to differentiate into Th-17 cells, and establish an effective mucosal immune barrier in the oral cavity, thus inhibited C. albicans infection; On the other hand, FVC maintained the oral flora stability and significantly reduced the abundance of Streptococcus spp., which was closely related to C. albicans infection. On this basis, the inhibitory effects of FVC on oral pathogens Streptococcus mutans and Lactobacillus casei associated with C. albicans infection were further verified, and it was demonstrated that FVC effectively interfered with the growth of pathogenic bacteria by inducing the production of intracellular ROS to damage bacterial cells. Therefore, FVC may be potentially exploited as a novel approach to the prevention and treatment of oral C. albicans infection.

Development of Chitosan Polysaccharide-Based Magnetic Gel for Direct Red 83:1 Removal from Water

Water pollution caused by dyes is a significant environmental issue, necessitating the development of effective, cost-efficient decolorization methods suitable for industrial use. In this study, a Chitosan-Fe polymeric gel was synthesized, characterized, and tested for removing the azo dye Direct Red 83:1 from water. The polymeric magnetic chitosan was analyzed using various techniques: Field Emission Scanning Electron Microscopy (FE-SEM) revealed a porous structure, Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) demonstrated the thermal stability, Infrared Spectrophotometry (IR) indicated the successful coordination of iron at the C3 position, and X-ray Powder Diffraction (XRD) confirmed the crystalline nature of the polymeric structure. Optimal conditions for kinetic and isotherm models were found at 1 g and pH 7.0. Adsorption behavior of Direct Red 83:1 onto magnetic chitosan gel beads was studied through kinetic tests and isotherm curves. The maximum adsorption capacity was 17.46 mg/g (qmax). The adsorption process followed pseudo-second-order kinetics (R2 = 0.999) and fit the Temkin isotherm (R2 = 0.946), suggesting heterogeneous surface adsorption. The newly synthesized Chitosan-Fe polymeric gel demonstrated good adsorption properties and facilitated easy separation of purified water.

Moving towards fully circular insect production: A focus on insect-derived biowastes

Over the last decade, commercialization of insects for food and feed has been exponentially increasing. Insect protein is emerging as a sustainable livestock feed and human food alternative due to its low land and carbon footprint. The principles of insect industry are deeply embedded in the core values of sustainability and circular economy. Black soldier fly (BSF) is the crown jewel of insect industry and is one of the most commercially farmed insects. However, this steadfast growth is accompanied by generation of insect based biowaste such as dead flies and pupae exuviae. This will be a major waste fraction from this industry. This study discusses the valorization potential of this waste into chitin (which finds application in cosmetics, bioplastics, and pesticides, among other industries), biogas, fertilizer, and biochar. There is need to conduct more explorative research on value proposition of insect based biowaste to ensure that this industry can comply fully with circular economy and sustainability principles.

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.

Injecting hope: chitosan hydrogels as bone regeneration innovators

Spontaneous bone regeneration encounters substantial restrictions in cases of bone defects, demanding external intervention to improve the repair and regeneration procedure. The field of bone tissue engineering (BTE), which embraces a range of disciplines, offers compelling replacements for conventional strategies like autografts, allografts, and xenografts. Among the diverse scaffolding materials utilized in BTE applications, hydrogels have demonstrated great promise as templates for the regeneration of bone owing to their resemblance to the innate extracellular matrix. In spite of the advancement of several biomaterials, chitosan (CS), a natural biopolymer, has garnered significant attention in recent years as a beneficial graft material for producing injectable hydrogels. Injectable hydrogels based on CS formulations provide numerous advantages, including their capacity to absorb and preserve a significant amount of water, their minimally invasive character, the existence of porous structures, and their capability to adapt accurately to irregular defects. Moreover, combining CS with other naturally derived or synthetic polymers and bioactive materials has displayed its effectiveness as a feasible substitute for traditional grafts. We aim to spotlight the composition, production, and physicochemical characteristics and practical utilization of CS-based injectable hydrogels, explicitly focusing on their potential implementations in bone regeneration. We consider this review a fundamental resource and a source of inspiration for future research attempts to pioneer the next era of tissue-engineering scaffold materials.

From Food Waste to Functional Biopolymers: Characterization of Chitin and Chitosan Produced from Prepupae of Black Soldier Fly Reared with Different Food Waste-Based Diets

The use of food waste as a rearing substrate to grow insects is an ecofriendly and sustainable alternative to food waste disposal. In the present research, Hermetia illucens prepupae were reared with a standard diet, different food waste-based diets based on vegetables, fruits, and meat, and a mixed one, where the previous three components were present equally. The demineralization and deproteination of the prepupae allowed for the obtainment of chitin that was then deacetylated to produce chitosan. Also, the bleaching of chitosan was attempted for further purification. The yield of the different reactions was investigated, and the infrared spectra of the obtained materials were analyzed to obtain information on the quantity and acetylation degree trend of the chitin and chitosan as a function of the diet. The possibility to slightly modulate the yield and acetylation degree of both biopolymers thanks to the specific diet was enlightened. Interestingly, the standard diet resulted in the highest fraction of chitin having the highest acetylation degree, and in the highest fraction of chitosan having the lowest acetylation degree.

Valorization of biological waste from insect-based food industry: Assessment of chitin and chitosan potential

Edible mealworms can be farmed to produce high-quality nutrients and proteins, useful as ingredients in human and animal foods. During this process biological waste is produced. This work explores the usage of the biological waste as source to produce chitin and chitosan with different potential applications. Different waste fractions were processed, and the feasibility of chitin isolation was assessed. Chitosan was derived, and films were fabricated and tested for intended uses. Data indicate that biopolymers with different properties can be obtained from multiple biological waste fractions. All samples show antibacterial activity, while chitosan films derived from molt show interesting properties for packaging purposes. Films also trigger the expression of anti-inflammatory phenotype markers in macrophage cells, which may be useful for tissue engineering implantation purposes. Altogether, biological waste from insect farming can be used to extract chitin and chitosan with different properties, and therefore, suitable for different applications.

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.

Chemical extraction, characterization, and inspection of the antimicrobial and antibiofilm activities of shrimp chitosan against foodborne fungi and bacteria

Nowadays, the exploitation of biopolymers in the industrial sector has become a trend. Chitosan is considered one of the most investigated biopolymers due to its abundance and antibacterial, antifungal, and antibiofilm activities. In this work, chitosan was chemically extracted from shrimp shells. Solutions of HCl 1 M, NaOH 4 M, and NaOH 15 M were used for the demineralization, deproteinization, and deacetylation process, respectively. The utilized methods of characterization (FTIR, 1 H NMR, 13 C NMR, and SEC-MALS) revealed that the obtained chitosan has a moderate degree of deacetylation and low molecular weight (DDA = 74% and Mw = 72.14 kDa). The microdilution method and inoculation of solid medium were carried out to assess the antibiofilm action of chitosan against Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus hirae, Escherichia coli, Rhizopus sp., and Aspergillus sp. which are known as foodborne microorganisms. Results showed that the produced chitosan at 1 g/L inhibits between 63.44 and 99.75% of the microbial biofilm depending on the tested strains. These promising results confirm the potential deployment of the obtained chitosan in the food industry as a replacement for synthetic antimicrobial agents.

Edible insects as emerging food products-processing and product development perspective

Edible insects (EI) are also becoming as a part of the diet due to their nutritional value and health benefits in many regions of the world. These EI are inexhaustible sources accessible by garnering from the wild with high feed conversion efficiency. Appreciating the budding of EI in justifiable food production, enlightening food security and biodiversity conversion, is promising a sufficient supply of the insect resource for future food to the world. These insects are processed to develop new products, improve organoleptic and nutritional parameters as well as the extension of shelf life. In this review, we discuss the edible insect characteristics, the potential application of EI in food industry, processing, pretreatments, drying, extraction of edible compounds like protein, lipid and chitin various food products formulation, safety regulation. Availability of broad nutritional spectrum of EI includes protein, mono and poly unsaturaturated fatty acids, amino acids, vitamins, amino aids and minerals has been used as an ingredient in development of various forms of food products such as flours in the form of whole insect powder, protein isolate, canned products, extruded products, hard candies, spreads, liquor infusion, cookies and other products.

Physicochemical Properties of Chitosan from Green Mussel Shells (Perna viridis): A Comparative Study

Green mussel shells (Perna viridis) are generated in huge amounts and discarded as waste materials. Such waste may be used to produce biopolymer materials such as chitosan. The physicochemical properties of chitosan prepared from different sizes of green mussel shells (small size (CHS): ≤5.00 cm in length and big size (CHB): >5.01 cm in length) were characterized and compared with commercial chitosan (CH). Furthermore, the mechanical and physicochemical properties of the blended films were also investigated. The results of the physicochemical properties showed that CHS and CHB were quite different from CH. The degree of deacetylation of CHS, CHB, and CH was found to be 32.71%, 52.56%, and 70.42%, respectively (p < 0.05). The water- and fat-binding capacities of CH were higher than those of CHS and CHB. Structural differences between CHS, CHB, and CH were studied using Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). Significant increases in thickness, water vapor permeability, and strength of the blended films were found when the extracted chitosan was added (p < 0.05). However, further study is needed to improve the chitosan extraction process, which can enhance the physicochemical properties of the obtained chitosan and be widely used in many industries.

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.

Recent Advances in Chitosan-Based Applications-A Review

Chitosan derived from chitin gas gathered much interest as a biopolymer due to its known and possible broad applications. Chitin is a nitrogen-enriched polymer abundantly present in the exoskeletons of arthropods, cell walls of fungi, green algae, and microorganisms, radulae and beaks of molluscs and cephalopods, etc. Chitosan is a promising candidate for a wide variety of applications due to its macromolecular structure and its unique biological and physiological properties, including solubility, biocompatibility, biodegradability, and reactivity. Chitosan and its derivatives have been known to be applicable in medicine, pharmaceuticals, food, cosmetics, agriculture, the textile and paper industries, the energy industry, and industrial sustainability. More specifically, their use in drug delivery, dentistry, ophthalmology, wound dressing, cell encapsulation, bioimaging, tissue engineering, food packaging, gelling and coating, food additives and preservatives, active biopolymeric nanofilms, nutraceuticals, skin and hair care, preventing abiotic stress in flora, increasing water availability in plants, controlled release fertilizers, dye-sensitised solar cells, wastewater and sludge treatment, and metal extraction. The merits and demerits associated with the use of chitosan derivatives in the above applications are elucidated, and finally, the key challenges and future perspectives are discussed in detail.

Response Surface Methodology (RSM) Approach to Optimization of Coagulation-Flocculation of Aquaculture Wastewater Treatment Using Chitosan from Carapace of Giant Freshwater Prawn Macrobrachium rosenbergii

The major sources of waste from aquaculture operations emanates from fish or shellfish processing and wastewater generation. A simple technique called coagulation/flocculation utilizes biowaste from aquaculture to produce chitosan coagulant for wastewater treatment. A chemical method was applied in the present study for chitin and chitosan extraction from carapace of Macrobrachium rosenbergii and subsequent application for removal of turbidity and salinity from shrimp aquaculture wastewater. Box-Behnken in RSM was used to determine the optimum operating conditions of chitosan dosage, pH, and settling time, after which quadratic models were developed and validated. Results show that 80 g of raw powder carapace yielded chitin and chitosan of 23.79% and 20.21%, respectively. The low moisture (0.38%) and ash (12.58%) content were an indication of good quality chitosan, while other properties such as water-binding capacity (WBC), fat-binding capacity (FBC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM) confirmed the structure and the α-group, as well as the rough morphology of chitosan. In addition, the high solubility (71.23%) and DDA (85.20%) suggested good coagulant potentials. It was recorded in this study that 87.67% turbidity was successfully removed at 20 mg/L of chitosan dosage and 6.25 pH after 30 min settling time, while 21.43% salinity was removed at 5 mg/L of chitosan dosage, 7.5 pH, and 30 min settling time. Therefore, the process conditions adopted in this study yielded chitosan of good quality, suitable as biopolymer coagulant for aquaculture wastewater treatment.

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

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

Graphical Abstract

Chitosan Based Materials in Cosmetic Applications: A Review

This review provides a report on the properties and recent advances in the application of chitosan and chitosan-based materials in cosmetics. Chitosan is a polysaccharide that can be obtained from chitin via the deacetylation process. Chitin most commonly is extracted from cell walls in fungi and the exoskeletons of arthropods, such as crustaceans and insects. Chitosan has attracted significant academic interest, as well as the attention of the cosmetic industry, due to its interesting properties, which include being a natural humectant and moisturizer for the skin and a rheology modifier. This review paper covers the structure of chitosan, the sources of chitosan used in the cosmetic industry, and the role played by this polysaccharide in cosmetics. Future aspects regarding applications of chitosan-based materials in cosmetics are also mentioned.

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.

Nutritional Composition, Phenolic Compounds and Antioxidant Activity of Different Samples of Water Boatmen Eggs (Hemiptera: Corixidae)

The group of aquatic insects collectively called "water boatmen" or "Axayacatl" (Hemiptera: Corixidae) and their eggs, called "Ahuahutle", have been consumed and cultivated since the pre-Hispanic era in Mexico. Nevertheless, food composition databases contain limited information on the nutritional composition of these eggs. This work evaluates the macronutrients and bioactive compounds of water boatmen eggs obtained from three different locations in Mexico. The primary analyses to be determined for the first time were some bioactive compounds in the eggs, such as phenolic compounds, total flavonoids, condensed tannins content, antioxidant activity (DPPH and ABTS), and, additionally, fatty acids and proximal composition. The results showed that the sample from Hidalgo (AMC) presented the highest number of phenolic compounds (855.12 ± 0.52), followed by ALT (125.52 ± 0.05) and, with the lowest amount, AMT (99.92 ± 0.13), all expressed in an mg GAE/g sample. ALT indicated the highest mol TE/g sample concentration for ABTS (25.34 ± 0.472) and DPPH (39.76 ± 0.054), showing a significant difference in the DPPH method with the AMT samples. The three Corixidae egg samples had between 15 to 18 different fatty acid profiles, and there were statistically significant differences (Student's t-test ≤ 0.05) between the means using MSD. The total fats of the three samples were between 12.5 and 15.5 g/100 g dry basis. In addition, Corixidae eggs are excellent protein sources. Thus, water boatmen's eggs can be considered to be a food rich in bioactive compounds.

A New Mediterranean Flour Moth-Derived Chitosan: Characterization and Co-electrospun Hybrid Fabrication

In this study, the chitin of adult Mediterranean flour moth (Ephestia kuheniella) (Cht) was extracted and then converted to chitosan by deacetylation process to achieve the chitosan derived from E. kuheniella (Chs_fm). The new chitosan-based scaffold was produced using the polyvinyl alcohol (PVA) co-electrospinning technique. The degree of deacetylation was obtained using the distillation-titration and Fourier transform infrared spectroscopy. The surface morphology and crystallinity index of Chs_fm were observed using scanning electron microscopy and X-ray diffraction analysis, respectively, and compared with the commercial chitosan (Chs_c). Thermogravimetric analysis was used to estimate two chitosans' water content and thermal stability. The average molecular mass analysis was performed using viscometry. Moreover, the minimum inhibitory concentration and DPPH assay were used to study the antimicrobial activity and antioxidant potential of the Chs_fm, respectively. Accordingly, Chs_fm was smoother with fewer pores and flakes than Chs_c, and its crystallinity index was higher than Chs_c. The water content and thermal stability were lower and similar for Chs_fm compared to Chs_c. The average molecular mass of Chs_fm was ~ 5.8 kDa, making it classified as low molecular weight chitosan. The antimicrobial activity of Chs_fm against a representative Gram-negative bacteria; E. coli resulted to be the same as Chs_c. However, less effective than Chs_c against a representative Gram-positive bacteria is S. aureus. The Chs_fm/PVA ratio scaffold was optimized at 30:70 to fabricate a uniform nanofiber scaffold.

Nutritional Composition, Health Benefits, and Application Value of Edible Insects: A Review

For thousands of years, edible insects have been used as food to alleviate hunger and improve malnutrition. Some insects have also been used as medicines because of their therapeutic properties. This is not only due to the high nutritional value of edible insects, but more importantly, the active substances from edible insects have a variety of biofunctional activities. In this paper, we described and summarized the nutritional composition of edible insects and discussed the biological functions of edible insects and their potential benefits for human health. A summary analysis of the findings for each active function confirms that edible insects have the potential to develop functional foods and medicines that are beneficial to humans. In addition, we analyzed the issues that need to be considered in the application of edible insects and the current status of edible insects in food and pharmaceutical applications. We concluded with a discussion of regulations related to edible insects and an outlook on future research and applications of edible insects. By analyzing the current state of research on edible insects, we aim to raise awareness of the use of edible insects to improve human health and thus promote their better use and development.

Enhanced bioenergy and nutrients recovery from wastewater using hybrid anodes in microbial nutrient recovery system

Background

The combined microbial fuel cell–microbial nutrient recovery system has lately been thoroughly explored from an engineering standpoint. The relevance of microbial communities in this process, on the other hand, has been widely underestimated.

Results

A lab-scale microbial nutrients recovery system was created in this work, and the microbial community structure was further defined, to give a thorough insight into the important microbial groups in the present system. We reported for the first-time different hybrid anodes of activated carbon and chitosan that were used in the microbial nutrient recovery system for bioenergy production, and, for the removal of COD and recovery of nutrients present in the wastewater. The hybrid anodic materials were studied to adapt electrochemically active bacteria for the recovery of nutrients and energy generation from wastewater without the need for an external source of electricity. The potential of the created hybrid anodes in terms of nutrients recovery, chemical oxygen demand elimination, and energy generation from municipal wastewater was thoroughly examined and compared with each other under similar operating conditions. When the COD loading was 718 mg/L, a total COD removal of ~ 79.2% was achieved with a hybrid activated carbon and chitosan anode having an equal ratio after 10 days of the operation cycle. The maximum power density estimated for hybrid anode (~ 870 mWm⁻²) was found.

Conclusion

Overall, this work reveals a schematic self-driven way for the collection and enrichment of nutrients (~ 72.9% phosphorus recovery and ~ 73% ammonium recovery) from municipal wastewater, as well as consistent voltage production throughout the operation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13068-022-02116-y.

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 exploration and utilization of functional substances in edible insects: a review

Edible insects as food have been considered as a core future protein source. Not only are edible insects abundant in nutrient value, but also have numbers of functional substances, which could provide a multiple valuable benefits for humans. This review examines and summarizes the functional substances in edible insects and their special effects for people, as well as the use and prospects for these functional substances. There are many functional substances in edible insects, such as antimicrobial peptides, interferon, sex attractant hormones, cordycepin, active polysaccharides, microelement, chitin/chitosan, steroidal material, vitamin, lecithin, etc., which could provide multiple benefits for human beings. These special functional substances could help people enhance immunity, inhibit tumor, regulate intestinal function, relieve fatigue, anti oxidation, protect against colds, improve sleeping, promote the growth and development, as well as reducing blood sugar and blood pressure, among others. According to these valuable efficacies, the functional substances extracted from edible insects can be exploited mainly in three ways: edible insects are used to discover new medicines or health care products for people; and edible insects are applied in chemical, agricultural, food technology, pollutant treatment and textile sectors; as well as being consumed as animal feedstuff for livestock and other animals, which indirectly meet the different requirements for humans. Currently, edible insects have generated global interest to be developed as different forms of products and has promoted more research and development. However, pupae and larvae are still the main consumption ways in the market, which is unacceptable to most people. It is expected that the edible insect industry would be prosperous and sustainable by integrating the power of beneficial policies and regulations, huge consumer demand and proper strategies of promotion and production.

Graphical Abstract

Repurposing of Marine Raw Materials in the Formulation of Innovative Plant Protection Products

Over the years, the growth of the world population has caused a huge agricultural production to support the population's needs. Since plant protection products are essential to preserve agricultural crops and to optimize vital plant processes, it is crucial to use more sustainable, biodegradable, and biocompatible raw materials, without harming the environment and human health. Although the development of new plant protection products is a costly process, the environmental benefits should be considered. In this context, marine raw materials obtained as byproducts of fishing industries, possessing a wide variety of physicochemical and biological properties, can serve as a promising source of such materials. They have a high potential for developing alternative and safe formulations for agricultural applications, not only as biocompatible excipients but also as effective and selective, or even both. It is also possible to promote a synergistic effect between an active substance and the biological activity of the marine polymer used in the formulation, enabling plant protection products with lower concentrations of the active substances. Thus, this review addresses the repurposing of marine raw materials for the development of innovative plant protection products, focusing on micro- and nanoparticulate formulations, to protect the environment through more ecological and sustainable strategies.

Applications of infrared spectroscopy in polysaccharide structural analysis: Progress, challenge and perspective

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Functional properties of polysaccharides depend on their structural features.

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IR spectroscopy is widely used in polysaccharide structural analysis.

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Classical applications of IR spectroscopy in polysaccharide are reviewed.

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IR integrating techniques can considerably expand its application scope.

Polysaccharides are important biomacromolecules with numerous beneficial functions and a wide range of industrial applications. Functions and properties of polysaccharides are closely related to their structural features. Infrared (IR) spectroscopy is a well-established technique which has been widely applied in polysaccharide structural analysis. In this paper, the principle of IR and interpretation of polysaccharide IR spectrum are briefly introduced. Classical applications of IR spectroscopy in polysaccharide structural elucidation are reviewed from qualitative and quantitative aspects. Some advanced IR techniques including integrating with mass spectrometry (MS), microscopy and computational chemistry are introduced and their applications are emphasized. These emerging techniques can considerably expand application scope of IR, thus exert a more important effect on carbohydrate characterization. Overall, this review seeks to provide a comprehensive insight to applications of IR spectroscopy in polysaccharide structural analysis and highlights the importance of advanced IR-integrating techniques.

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.

Possibilities of the Development of Edible Insect-Based Foods in Europe

All over the world, a large proportion of the population consume insects as part of their diet. In Western countries, however, the consumption of insects is perceived as a negative phenomenon. The consumption of insects worldwide can be considered in two ways: on the one hand, as a source of protein in countries affected by hunger, while, on the other, as an alternative protein in highly-developed regions, in response to the need for implementing policies of sustainable development. This review focused on both the regulations concerning the production and marketing of insects in Europe and the characteristics of edible insects that are most likely to establish a presence on the European market. The paper indicates numerous advantages of the consumption of insects, not only as a valuable source of protein but also as a raw material rich in valuable fatty acids, vitamins, and mineral salts. Attention was paid to the functional properties of proteins derived from insects, and to the possibility for using them in the production of functional food. The study also addresses the hazards which undoubtedly contribute to the mistrust and lowered acceptance of European consumers and points to the potential gaps in the knowledge concerning the breeding conditions, raw material processing and health safety. This set of analyzed data allows us to look optimistically at the possibilities for the development of edible insect-based foods, particularly in Europe.

Evaluation of α-Chitosan from Crab Shell and β-Chitosan from Squid Gladius Based on Biochemistry Performance

The objective of this study is to innovatively evaluate the biochemistry performance of α-chitosan from Portunus trituberculatus shell and β-chitosan from Illex argentinus squid gladius by using the weighted composite index method, and provide a theoretical basis for better development and utilization of chitosan biomedical materials. To build a composite evaluation system, seven key indicators, including molecular weight (Mw), deacetylation degree (DD), water binding capacity (WBC), fat binding capacity (FBC), thermal stability (TS), primary structure and secondary structure, which significantly affect chitosan biochemical characteristics, were determined and analyzed. The viscosity average Mw of chitosan was in the range of 22.5–377.1 kDa, and the DD was 83.4–97.8%. Thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses of commercial chitosan (CS), crab chitosan (CSC) and squid chitosan (CSS) showed a downward trend in TS, while WBC and FBC showed an obvious upward trend. FT-IR had a similar profile in peak shape, but the peak position slightly shifted. CD indicated that chitosan maintained the double helix structure and multiple secondary structural elements. The composite weighted index values of CS, CSC and CSS were 0.85, 0.94 and 1.31 respectively, which indicated that the CSS biochemistry performance was significantly better than CSC, and β-chitosan has great potential in biomedical materials.