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Chitin, being the second most abundant biopolymer after cellulose, has been gaining popularity since its initial discovery by Braconot in 1811. However, fundamental knowledge and literature on chitin and its derivatives from insects are difficult to obtain. The most common and sought-after sources of chitin are shellfish (especially crustaceans) and other aquatic invertebrates. The amount of shellfish available is obviously restricted by the amount of food waste that is allowed; hence, it is a limited resource. Therefore, insects are the best choices since, out of 1.3 million species in the world, 900,000 are insects, making them the most abundant species in the world. In this review, a total of 82 samples from shellfish—crustaceans and mollusks (n = 46), insects (n = 23), and others (n = 13)—have been collected and studied for their chemical extraction of chitin and its derivatives. The aim of this paper is to review the extraction method of chitin and chitosan for a comparison of the optimal demineralization and deproteinization processes, with a consideration of insects as alternative sources of chitin. The methods employed in this review are based on comprehensive bibliographic research. Based on previous data, the chitin and chitosan contents of insects in past studies favorably compare and compete with those of commercial chitin and chitosan—for example, 45% in Bombyx eri, 36.6% in Periostracum cicadae (cicada sloughs), and 26.2% in Chyrysomya megacephala. Therefore, according to the data reported by previous researchers, demonstrating comparable yield values to those of crustacean chitin and the great interest in insects as alternative sources, efforts towards comprehensive knowledge in this field are relevant.

The study aimed to develop an effective and eco-friendly enzymatic process to extract carotenoproteins from shrimp waste. The optimization of enzymatic hydrolysis conditions to maximize the degree of deproteinization (DDP) of carotenoprotein from shrimp head waste (SHW) and shrimp shell waste (SSW) was conducted separately using the Box-Behnken design of response surface methodology (RSM). To achieve a maximum DDP of 92.32% for SSW and 96.72% for SHW, the optimal hydrolysis conditions were determined as follows: temperature (SSW: 53.13 °C; SHW: 45.90 °C), pH (SSW: 7.13; SHW: 6.78), time (SSW: 90 min; SHW: 61.18 min), and enzyme/substrate ratio (SSW: 2 g/100 g; SHW: 1.18 g/100 g). The carotenoprotein effluent obtained was subjected to spray drying and subsequently assessed for color, nutritional, and functional characteristics. The carotenoprotein from shrimp shell (CpSS) contained a higher essential amino acid score than carotenoprotein from shrimp head (CpSH). CpSS had a higher whiteness index of 82.05, while CpSH had 64.04. Both CpSS and CpSH showed good functional properties viz solubility, emulsion, and foaming properties. The maximum solubility of CpSH and CpSS was determined to be 92.94% and 96.48% at pH 10.0, respectively. The highest emulsion capacity (CpSH: 81.33%, CpSS: 70.13%) and stability (CpSH: 57.06%, CpSS: 63.05%) were observed at 3% carotenoprotein concentration. Similarly, the highest values of foaming capacity (CpSH: 27.66%, CpSS: 105.5%) and stability (CpSH: 23.83%, CpSS: 105.33%) were also found at the same 3% carotenoprotein concentration. In conclusion, the carotenoproteins obtained from shrimp waste showed favorable attributes in terms of color, amino acid composition, and functional properties. These findings strongly suggest the potential applicability of CpSS and CpSH as valuable resources in various domains. CpSS, with its higher whiteness index, greater amino acid content, and superior functional characteristics, may find suitability as functional ingredients in human food products. Conversely, CpSH could be considered for incorporation into animal feed formulations.

Chitosan is a versatile biopolymer due to its biocompatibility, biodegradability, antimicrobial, non-toxic, mucoadhesive, and highly adsorptive properties. Chitosan and its derivatives have been used for many biomedical applications. Currently, crustacean shells and other marine organisms are the significant sources of chitin/chitosan production worldwide. However, extraction from marine sources presents several challenges, including an unstable supply of raw materials. Large-scale chitosan extraction from crustacean sources harms the environment by involving harsh processing steps such as alkali deproteinization. Recently many studies have been carried out focusing on alternative sources or eco-friendlier routes for production of chitosan. This paper briefly overviews recent studies on fungi and insect cuticles as alternative chitosan sources. Milder extraction processes for fungal chitosan and the superior quality of the resultant polymer make it highly desirable for biological applications. Biological techniques involving fermentation and enzymatic processing of the raw materials are looked at in detail. In the concluding remarks, the paper highlights the potential of using a combination of “green” technologies and briefly looks at potential biological/biomedical applications of extracted chitinous materials.

Huge amounts of chitin and chitosans can be found in the biosphere as important constituents of the exoskeleton of many organisms and as waste by worldwide seafood companies. Presently, politicians, environmentalists, and industrialists encourage the use of these marine polysaccharides as a renewable source developed by alternative eco-friendly processes, especially in the production of regular cosmetics. The aim of this review is to outline the physicochemical and biological properties and the different bioextraction methods of chitin and chitosan sources, focusing on enzymatic deproteinization, bacteria fermentation, and enzymatic deacetylation methods. Thanks to their biodegradability, non-toxicity, biocompatibility, and bioactivity, the applications of these marine polymers are widely used in the contemporary manufacturing of biomedical and pharmaceutical products. In the end, advanced cosmetics based on chitin and chitosans are presented, analyzing different therapeutic aspects regarding skin, hair, nail, and oral care. The innovative formulations described can be considered excellent candidates for the prevention and treatment of several diseases associated with different body anatomical sectors.

The main source of commercial chitosan is the extensive deacetylation of its parent polymer chitin. It is present in green algae, the cell walls or fungi and in the exoskeleton of crustaceans. A novel procedure for preparing chitosan from shrimp shells was developed. The procedure involves two 10-minutes bleaching steps with ethanol after the usual demineralization and deproteinization processes. Before deacetylation, chitin was immersed in 12.5 M NaOH, cooled down and kept frozen for 24 h. The obtained chitosan was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV, X-ray diffraction (XRD) and viscosimetry. Samples of white chitosan with acetylation degrees below 9 % were obtained, as determined by FTIR and UV-first derivative spectroscopy. The change in the morphology of samples was followed by SEM. The ash content of chitosan samples were all below 0.063 % . Chitosan was soluble in 1 % acetic acid with insoluble contents of 0.62 % or less. XRD patterns exhibited the characteristic peaks of chitosan centered at 10 and 20 degrees in 2 θ . The molecular weight of chitosan was between 2.3 and 2.8 × 10 5 g/mol. It is concluded that the procedure developed in the present work allowed obtaining chitosans with physical and chemical properties suitable for pharmaceutical applications.

There are two viable options to produce shrimp shells as by-product waste, either within the shrimp production phases or when the shrimp are peeled before cooking by the end user. This waste is considered a double-edged sword, as it is possible to be either a source of environmental pollution, through dumping and burning, or a promising source from which to produce chitosan as a biodegradable, biocompatible biopolymer which has a variety of agricultural, industrial, and biomedical applications. Chitosan is a deacetylated form of chitin that can be chemically recovered from shrimp shells through the three sequential stages of demineralization, deproteinization, and deacetylation. The main aim of this review paper is to summarize the recent literature on the chemical extraction of chitosan from shrimp shells and to represent the physicochemical properties of chitosan extracted from shrimp shells in different articles, such as chitosan yield, moisture content, solubility, ash content, and degree of deacetylation. Another aim is to analyze the influence of the main predictors of the chemical extraction stages (demineralization, deproteinization, and deacetylation) on the chitosan yield percentage by using a multilayer perceptron artificial neural network. This study showed that the deacetylation alkali concentration is the most crucial parameter, followed by the concentrations of acid and alkali of demineralization and deproteinization, respectively. The current review was conducted to be used in prospective studies for optimizing the chemical extraction of chitosan from shrimp wastes.

Chitin is the second-most abundant bioresource and widely used in the food, agricultural, biomedicine, and other industries. However, under the mutual restriction of extraction cost and environmental protection, it is relatively difficult to prepare chitin from natural sources by pure separation. The aim of this study is to extract chitin from fresh crab shell waste by decalcification (DC) and deproteinization (DP) using glutamic acid and alkaline protease. The optimum technological conditions for DC and DP were as follows: (1) 5% (w/v) glutamic acid solution was used as decalcifying agent, the ratio of material to liquid was 1:10 (m/v), and the ash content in chitin was 0.83 ± 0.027% after decalcification at 75° C for 12 h. (2) Using alkaline protease as enzymatic hydrolyzer, 1500 U of alkaline protease was added per gram of crab shell. Under the conditions of material-liquid ratio of 1:10 (m/v) and pH value of hydrolysate of 9.0, N content in chitin was 6.63 ± 0.10% after 6 h of enzymatic hydrolysis at 55° C. And the extraction rate of chitin was 92.25 ± 0.51%. As a decalcifying agent, glutamic acid could be recycled with a recovery rate of 77.42 ± 2.16%. Calcium carbonate in crab shell was converted into calcium hydrogen phosphate by calcium glutamate, and protein into amino acids and polypeptides, which could be used as feed additives. The “glutamic acid-enzymolysis” for extracting chitin from crab shell is a relatively closed process, which has the advantages of mild reaction, greatly reducing the discharge of three wastes and high comprehensive utilization rate of raw materials.

This study investigated the possibility of using yeast fermentation to transform shrimp waste to chitin for further application. The white leg shrimp head was incubated with three yeast strains Yarrowia lipolytica, Candida tropicalis and Pichia kudriavzevii , in comparison with bacteria Bacillus subtilis and commercial protease Alcalase. The efficacy of fermentation was evaluated through deproteinization and demineralization levels after 2 days. A deproteinization of 80.9% was obtained when incubation with Y. lipolytica which was significantly higher than 76.9% and 65.6% obtained with Alcalase hydrolysis and B. subtilis incubation respectively. Besides, C. tropicalis and P. kudriavzevii expressed a similar low level on deproteinization (31.3-31.7%.) All three yeast showed a good demineralization in range 38.2-49.4% on shrimp head while B. subtilis could demineralize only 16.0%. This primary research shows a potential application of yeast fermentation in chitin recovery from shrimp waste.

The effect of methods to remove protein content on the properties of glucosamine hydrochloride from the shells of white leg shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeus monodon) was investigated. Chitin from shrimp shells was obtained by demineralization in 6% HCl for 12h, deproteinization by two different methods (first group soaked in 8% NaOH for 36h and second group treated in Alcalase enzyme at the concentration of 0.2% for 36h). Two group samples were converted to glucosamine hydrochloride by soaking in 36.76% HCl solution for 5h at 85 °C. The results of fourier transform infrared spectroscopy (FTIR), solubility and recovery yield analysis showed that deproteinization methods did not significantly affect the properties of glucosamine hydrochloride. However, glucosamine hydrochloride from white leg shrimp shells contained higher recovery yield and solubility than black tiger shrimp shells. RESUMO: Investigou-se o efeito de métodos para remover o conteúdo de proteínas nas propriedades do cloridrato de glucosamina das conchas de camarão de pernas brancas (Litopenaeus vannamei) e camarão de tigre preto (Penaeus monodon). A quitina das cascas de camarão foi obtida por desmineralização em HCl a 6% por 12 h, desproteinização por dois métodos diferentes (primeiro grupo embebido em NaOH a 8% por 36 h e segundo grupo tratado na enzima Alcalase na concentração de 0,2% por 36 h). Duas amostras de grupo foram convertidas em cloridrato de glucosamina por imersão em solução de 12M HCl por 5 h a 85 °C. Os resultados das análises de FTIR, solubilidade e rendimento de recuperação mostraram que os métodos de desproteinização não afetaram significativamente as propriedades do cloridrato de glucosamina. No entanto, o cloridrato de glucosamina de cascas de camarão de pernas brancas continha maior rendimento e solubilidade de recuperação do que as cascas de camarão tigre preto.

Natural polysaccharides derived from plants have demonstrated significant antidiabetic properties by effectively alleviating hyperglycemia, improving insulin resistance, and preventing diabetes-associated complications. In this study, polysaccharides were extracted from Centella asiatica (L.) leaves via hot water extraction, followed by 50% (v/v) alcohol precipitation and Sevag deproteinization. Using DEAE-52 cellulose chromatography, the crude Centella asiatica polysaccharide (CAP) was separated into three fractions: P50-1, P50-2, and P50-3. P50-2 showed the greatest inhibition of α-amylase and α-glucosidase. Consequently, P50-2 was further purified using Sephacryl S-400 high-resolution (HR) gel chromatography to yield a single fraction, designated P50-2 A. An evaluation of the composition demonstrated that the compound P50-2 A, characterized as an acidic heteropolysaccharide, possesses a molecular mass of 3014 kDa. Its structure comprises fucose, rhamnose, mannose, arabinose, galactose, glucose, glucuronic acid, and galacturonic acid, arranged in a molar proportion of 0.83:1.21:6.32:24.36:37.16:19.29:5.48:5.35. Fourier transform infrared spectroscopy (FT-IR) and methylation analysis confirmed that P50-2 A is an arabinogalactan with a pyranose ring structure and 14 methylated sugar residues. Scanning electron microscopy (SEM) revealed an irregular, spongy morphology, while X-ray diffraction (XRD) analysis indicated a semi-crystalline structure comprising both amorphous and crystalline phases. In conclusion, this investigation offers the first thorough structural characterisation of CAP, providing a strong basis for further research into the links between its structure and activity as well as its uses in a variety of domains.