Recent insights into the extraction, characterization, and bioactivities of chitin and chitosan from insects.

BACKGROUND: Insects are a living resource used for human nutrition, medicine, and industry. Several potential sources of proteins, peptides, and biopolymers, such as silk, chitin, and chitosan are utilized in industry and for biotechnology applications. Chitosan is an amino-polysaccharide derivative of chitin that consists of linear amino polysaccharides with d-glucosamine and N-acetyl-d-glucosamine units. Currently, the chief commercial sources of chitin and chitosan are crustacean shells that accumulate as a major waste product from the marine food industry. Existing chitin resources have some natural challenges, including insufficient supplies, seasonal availability, and environmental pollution. As an alternative, insects could be utilized as unconventional but feasible sources of chitin and chitosan. SCOPE AND APPROACH: This review focuses on the recent sources of insect chitin and chitosan, particularly from the Lepidoptera, Coleoptera, Orthoptera, Hymenoptera, Diptera, Hemiptera, Dictyoptera, and Odonata orders. In addition, the extraction methods and physicochemical characteristics are discussed. Insect chitin and chitosan have numerous biological activities and could be used for food, biomedical, and industrial applications. KEY FINDINGS AND CONCLUSIONS: Recently, the invasive and harmful effects of insect species causing severe damage in agricultural crops has led to great economic losses globally. These dangerous species serve as potential sources of chitin and are underutilized worldwide. The conclusion of the present study provides better insight into the conversion of insect waste-derived chitin into value-added products as an alternative chitin source to address food security related challenges.

Application of marine-derived polysaccharides as immunostimulants in aquaculture: A review of current knowledge and further perspectives.

The use of antibiotics in the feeds of cultivable aquatic animals has been generally practised to reduce infectious diseases as well as to improve the survival and growth. In recent years, many countries ban to aquatic animals due to the use of large amount of antibiotics and chemotherapies, thus alternative novel strategies are need to promote the growth of aquatic animals and control the pathogens. Dietary supplementation of marine-derived polysaccharides (MDPs) is one of the potential substitutes for antibiotics in aquatic animal feeds. Recently, the use of dietary MDPs in the aquaculture animals has been focused with much interest. In aquaculture, MDPs are used as prebiotic substance which is mostly accepted as a nutritional component for improving the growth performance and health conditions. Hence, present review is a comprehensive and an updated collection of available research reports on different MDPs (alginate, fucoidan, carrageenan, laminarin, ulvan, galactan, agar, chitin and chitosan), route of administration, dosage and applications for improving aqua feeds with emphasis on its effects on growth, biochemical indices, immune response, gut microbiota and disease resistance of aquaculture animals. This review describes the sustainability of global aquaculture production by providing a best alternative to harmful antibiotics, thereby meeting the emerging consumer demand for antibiotic-free aquatic food products.

Trends in the extraction, purification, characterisation and biological activities of polysaccharides from tropical and sub-tropical fruits - A comprehensive review.

Tropical and sub-tropical fruits are tremendous sources of polysaccharides (PSs), which are of great interest in the human welfare system as natural medicines, food and cosmetics. This review paper aims to highlight the recent trends in extraction (conventional and non-conventional), purification and analytic techniques of fruit polysaccharides (FPSs). The chemical structure and biological activities, such as immunomodulatory, anti-cancer, anti-oxidant, anti-inflammatory, anti-viral, anti-coagulant and anti-diabetic effects, of PSs extracted from 53 various fruits were compared and discussed. With this wide coverage, a total of 172 scientific articles were reviewed and discussed. This comprehensive survey from previous studies suggests that the FPSs are non-toxic and highly biocompatible. In addition, this review highlights that FPSs might be excellent functional foods as well as effective therapeutic drugs. Finally, the future research advances of FPSs are also described. The content of this review will promote human wellness-based food product development in the future.

Extraction and characterization of chitin from sea snail Conus inscriptus (Reeve, 1843).

The chitin was extracted from C. inscriptus and the structure was elucidated. The yield of the C. inscriptus shell chitin was 21.65% on dry weight basis. The ash and moisture content of the chitin was 1.2 and 6.50%. The result of the molecular analysis of the chitin revealed low molecular weight (25 kDa). The crystalline structure (XRD), functional group (FT-IR), elemental analysis (EDAX), surface morphology (SEM) and thermal stability (TG/DTA) results confirmed conus chitin was in α-crystalline form. The crystalline index value (CrI) of the conus chitin was 82.13%. The FT-IR analysis of the conus chitin displayed two bands at around 1730 and 1628 cm-1. SEM investigation of the commercial chitin and C. inscriptus chitin exposed that it was composed of nanopore and nanofibre structures. Further, the thermal stability of the conus chitin was close to the thermal stability of the commercial chitin. The results show that processing of C. inscriptus shell can lead to a high quality chitin, useful for a broad range of applications.

Biochemical characterization, antimicrobial and hemolytic studies on skin mucus of fresh water spiny eel Mastacembelus armatus

Objective: To characterize the biochemical, antimicrobial and hemolytic activities of Mastacembalus armatus skin mucus. Methods: Antimicrobial and antifungal activities of mucus extractions against human and fish pathogens were tested along with ampicillin as control. Hemolytic activity of the extraction was evaluated against sheep and cow blood cells. Amino acid and fatty acid profiles were analyzed by HPLC and gas chromatography in the mucus of fish. SDS-PAGE analysis of mucus and muscle tissue was done. Oneway-ANOVA was performed against all extraction and pathogens, amino acids and fatty acids. Result: All the mucus extracts exhibited higher inhibitory activity than antibiotic ampicillin against bacterial and fungal pathogens. The hemolytic activity was increased with higher mucus concentrations in both sheep and cow blood cells. The protein content soluble and insoluble fractions of mucus were 63.22 μg/g and 55.79μg/g, respectively. Out of 17 amino acids leucine was higher (8.54 mole %) in soluble gel, and glutamic acid was higher (6.92 mole %) in the insoluble gel, Histidine was very low (i.e. 0.20 mole%) both in soluble and (0.30 mole %) insoluble gel. In SDS-PAGE analysis, 6 bands of mucus and 9 bands of muscle were observed. Conclusions: The soluble and insoluble proteins are responsible for antimicrobial and hemolytic activity, these results indicate that mucus gel was prospective applications in fish and human therapeutics.