Sustainable valorisation of seafood by-products: Recovery of collagen and development of collagen-based novel functional food ingredients

Physicochemical properties of acid- and pepsin-soluble collagens from the cartilage of Siberian sturgeon

To look for the collagen alternatives of mammalian cartilages from aquatics and their by-products, acid-soluble collagen (ASC-SC) and pepsin-soluble collagen (PSC-SC) were extracted from cartilages of Siberian sturgeon (Acipenser baerii) with yields of 27.13 ± 1.15 and 14.69 ± 0.85% on dry weight basis. ASC-SC and PSC-SC had glycine as the major amino acid with the contents of 326.8 and 327.5 residues 1000 residues^-1, and their contents of proline and hydroxyproline were 205.9 and 208.0 residues 1000 residues^-1. ASC-SC and PSC-SC comprised type I collagen ([α1(I)]₂α2(I)) and type II collagen ([α1(II)]₃) on the literatures and results of amino acid composition, SDS-PAGE pattern, UV, and FTIR spectra. Meanwhile, FTIR spectra data indicated that there were more hydrogen bonds in ASC-SC and more intermolecular crosslinks in PSC-SC. The maximum transition temperature (T_max) of the ASC (28.3 °C) and PSC (30.5 °C) was lower than those of collagens from mammalian cartilages (> 37 °C). ASC-SC and PSC-SC showed high solubility in the acidic pH ranges and the solubility decreased in the presence of NaCl at concentrations above 3%. Zeta potential studies indicated that both ASC-SC and PSC-SC exhibited a net zero charge at pH 6.30 and 6.32. SEM results indicated that ASC-SC and PSC-SC presented irregular dense sheet-like film linked by random-coiled filaments. Therefore, collagens from Siberian sturgeon cartilages might be the suitable alternatives of the collagens of mammal cartilages as functional ingredient to treat some diseases.

Physicochemical and Antioxidant Properties of Acid- and Pepsin-Soluble Collagens from the Scales of Miiuy Croaker (Miichthys Miiuy)

In this report, acid-soluble collagen (ASC-MC) and pepsin-soluble collagen (PSC-MC) were extracted from the scales of miiuy croaker (Miichthys miiuy) with yields of 0.64 ± 0.07% and 3.87 ± 0.15% of dry weight basis, respectively. ASC-MC and PSC-MC had glycine as the major amino acid with the contents of 341.8 ± 4.2 and 344.5 ± 3.2 residues/1000 residues, respectively. ASC-MC and PSC-MC had lower denaturation temperatures (32.2 °C and 29.0 °C for ASC-MC and PSC-MC, respectively) compared to mammalian collagen due to their low imino acid content (197.6 and 195.2 residues/1000 residues for ASC-MC and PSC-MC, respectively). ASC-MC and PSC-MC were mainly composed of type I collagen on the literatures and results of amino acid composition, SDS-PAGE pattern, ultraviolet (UV) and Fourier-transform infrared spectroscopy (FTIR) spectra. The maximum solubility of ASC-MC and PSC-MC was appeared at pH 1⁻3 and a sharp decrease in solubility was observed when the NaCl concentration was above 2%. Zeta potential studies indicated that ASC-MC and PSC-MC exhibited a net zero charge at pH 6.66 and 6.81, respectively. Furthermore, the scavenging capabilities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, superoxide anion radical and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical of ASC-MC and PSC-MC were positively correlated with their tested concentration ranged from 0 to 5 mg/mL and PSC-MC showed significantly higher activity than that of ASC-MC at most tested concentrations (p < 0.05). In addition, the scavenging capability of PSC-MC on hydroxyl radical and superoxide anion radical was higher than those of DPPH radical and ABTS radical, which suggested that ASC-SC and PSC-SC might be served as hydroxyl radical and superoxide anion radical scavenger in cosmeceutical products for protecting skins from photoaging and ultraviolet damage.

Effects of chitosan and collagen containing α-tocopherol on the oxidative stability in bulk oil and oil-in-water emulsion

To provide efficient antioxidant capacities, proper carriers are needed to protect antioxidants against oxidative stress. Collagen mesh structure or chitosan gel was loaded with α-tocopherol and their effects were evaluated in bulk corn oil or oil-in-water (O/W) emulsion at 60 °C. Added collagen and chitosan enhanced oxidative stability in corn oil and O/W emulsions at 60 °C compared to corn oils without carriers or with addition of α-tocopherol (p < 0.05). Stability of α-tocopherol in corn oil loaded in collagen or chitosan was significantly enhanced compared to that in oils without carriers (p < 0.05). In O/W emulsions, α-tocopherol loaded collagen showed higher antioxidant properties than α-tocopherol loaded chitosan (p < 0.05). Collagen mesh structure and chitosan gel retarded the rates of lipid oxidation efficiently in both food matrices when α-tocopherol was not loaded. Collagen mesh structure and chitosan gel can be useful carriers for α-tocopherol in bulk oil or O/W emulsion.

Extraction and characterization of collagen hydrolysates from the skin of Rana chensinensis

The production of Hasma generates plentiful non-edible by-products in China and Central Asia. As one of main by-products, the skin of Rana chensinensis is discarded as waste without utilization. In this work, R. chensinensis skin collagen (RCSC) hydrolysates were extracted using pepsin under acidic conditions. The yield of RCSC is 15.1% (w/w). Amino acid analysis revealed that RCSC contained glycine (204.5/1000 residues) and imino acids (182/1000 residues). RCSC exhibited high solubility in acidic pH (1-4) and low NaCl concentrations (< 2%, w/v). Differential scanning calorimetry indicated that the denaturation temperature of RCSC was 33.5 °C. Scanning electron microscopy analysis confirmed their well-defined fibril morphologies. The results indicated that the skin of R. chensinensis is an alternative source of collagen hydrolysates, and RCSC can serve as a potential source applying in foodstuff and medical industry.

Valorisation of Biowastes for the Production of Green Materials Using Chemical Methods

With crude oil reserves dwindling, the hunt for a sustainable alternative feedstock for fuels and materials for our society continues to expand. The biorefinery concept has enjoyed both a surge in popularity and also vocal opposition to the idea of diverting food-grade land and crops for this purpose. The idea of using the inevitable wastes arising from biomass processing, particularly farming and food production, is, therefore, gaining more attention as the feedstock for the biorefinery. For the three main components of biomass-carbohydrates, lipids, and proteins-there are long-established processes for using some of these by-products. However, the recent advances in chemical technologies are expanding both the feedstocks available for processing and the products that be obtained. Herein, this review presents some of the more recent developments in processing these molecules for green materials, as well as case studies that bring these technologies and materials together into final products for applied usage.

Enzymatic extraction and characterisation of a thermostable collagen from swim bladder of rohu (Labeo rohita)

BACKGROUND

The fish swim bladder is considered as a potential source of realistic collagen. Currently, processing of the Indian major carp rohu (Labeo rohita) generates an enormous quantity of non-edible by-products, including swim bladders, which are discarded as waste with no commercial value. In the present study, collagen was prepared from rohu swim bladder and its physicochemical and fibril-forming capacities were assessed.

RESULTS

The collagen isolated from rohu swim bladder was characterised as type I, containing α1 and α2 chains with triple helical structure by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fourier transform infrared spectroscopy and amino acid analysis. The extracted collagen denaturation temperature was found to be 42.16 °C by differential scanning calorimetry analysis and also exhibited a high solubility in the presence of low NaCl concentrations (0-0.6 mol L^-1 ). The extracted collagen exhibited a high fibril-formation capacity at a NaCl concentration of 1.5 mol L^-1 . Examination of the microstructure of collagen by scanning electron microscopy (SEM) showed a porous, sheet-like film and a multilayered structure. The fibril formation capacity of collagen was also confirmed using SEM analysis.

CONCLUSION

The rohu swim bladder type I collagen was successfully extracted using an enzymatic method with a yield of 465.2 g kg^-1 (dry weight basis) and was characterised as a well maintained triple helical structure. The extracted collagen exhibited a high fibril-forming ability. The results of the present study confirm that utilisation of rohu swim bladder will open up a new avenue for the better disposal of by-products and also help to minimise environmental pollution issues. © 2016 Society of Chemical Industry.

Technical note on the isolation and characterization of collagen from fish waste material

The aim of this manuscript was to evaluate the major technical problems on the isolation and characterization of the collagen from fish waste materials that were usually faced by the growing researchers. Although the original research article published by authors contributed new information to the literature, some of them were failed to provide sufficient details in order to reproduce the study as well as could not adequately interpret/compared the results with other publications. Therefore, it is required to research the technical problems during the isolation and characterization of the collagen. This technical note provides the information which is crucial for the reader's and growing researchers for understanding as an essential part of the published research studies about the collagen extraction and characterization. Hence, this technical note may be helpful to those working on the collagen extraction and characterization from fish/marine waste materials.

Enzymes in Fish and Seafood Processing

Enzymes have been used for the production and processing of fish and seafood for several centuries in an empirical manner. In recent decades, a growing trend toward a rational and controlled application of enzymes for such goals has emerged. Underlying such pattern are, among others, the increasingly wider array of enzyme activities and enzyme sources, improved enzyme formulations, and enhanced requirements for cost-effective and environmentally friendly processes. The better use of enzyme action in fish- and seafood-related application has had a significant impact on fish-related industry. Thus, new products have surfaced, product quality has improved, more sustainable processes have been developed, and innovative and reliable analytical techniques have been implemented. Recent development in these fields are presented and discussed, and prospective developments are suggested.