ABSTRACT
The ability of bioactive peptides to exert biological functions has mainly contributed to their exploitation. The exploitation and utilization of these peptides have grown tremendously over the past two decades. Food-derived peptides from sources such as plant, animal, and marine proteins and their byproducts constitute a more significant portion of the naturally-occurring peptides that have been documented. Due to their high specificity and biocompatibility, these peptides serve as a suitable alternative to pharmacological drugs for treating non-communicable diseases (such as cardiovascular diseases, obesity, and cancer). They are helpful as food preservatives, ingredients in functional foods, and dietary supplements in the food sector. Despite their unique features, the application of these peptides in the clinical and food sector is to some extent hindered by their inherent drawbacks such as toxicity, bitterness, instability, and susceptibility to enzymatic degradation in the gastrointestinal tract. Several strategies have been employed to eliminate or reduce the disadvantages of peptides, thus enhancing the peptide bioactivity and broadening the opportunities for their applications. This review article focuses on the current research status of various bioactive peptides and the strategies that have been implemented to overcome their disadvantages. It will also highlight future perspectives regarding the possible improvements to be made for the development of bioactive peptides with practical uses and their commercialization.
ABSTRACT
Protein content, a vital component determining the nutritional quality of oysters, is unevenly distributed in different parts of oyster. In this study, the spatial distribution (visceral mass, mantle, gill, and adductor) patterns and structural characteristics of proteins, including water-soluble proteins (WSP), salt-soluble proteins (SSP), acid-soluble proteins (ASP) and alkali-soluble proteins (ALSP) of oysters (Crassostrea hongkongensis) were investigated with the amino acid analyzer, circular dichroism spectroscopy (CD), fourier transform infrared spectroscopy (FTIR), and fluorescence spectroscopy. The results showed that oyster proteins were mainly distributed in the visceral mass and mantle. The protein composition was WSP, SSP, ALSP, and ASP in descending order, which conformed to the ideal amino acid pattern. Variations in secondary structure, molecular weight distribution, and thermal denaturation temperatures of the oyster proteins were observed. SSP had wider bands (16-270 kDa) than those of ASP (30-37 kDa) and ALSP (66-270 kDa). Among the four proteins, the SSP of the mantle showed the highest thermal stability (87.4 °C), while ALSP of the adductor muscle had the lowest the lowest the peak denaturation temperature (Tm) (53.8 °C). The proportions of secondary structures in oyster proteins were different, with a higher proportion of solid protein ß-folds, and the exposure of aromatic amino acid residues and disulfide bonds and the microenvironment in which they were located were also different.
ABSTRACT
Essential oils (EOs) and collagen have received recent attention in the seafood industry due to their abilities of antibacterial and seafood preservation individually. However, to the authors' best knowledge, very few publications address the issue of the combined effect of EOs and collagen on seafood preservation. Pacific mackerel is one of the most economically valuable fish species in China and easy to deteriorate during storage. Therefore, present study investigated the effect of combined EOs (cinnamon, oregano, and clove) and collagen on the quality of Pacific mackerel during cold storage. A suite of microbiological, physical, and chemical properties that are indicative of quality was measured. From the results, mackerel fillets treated with an EO-collagen film had a smaller increase in microbial counts compared with control. Furthermore, total volatile basic nitrogen (TVB-N), thiobarbituric acid related substance, and pH of mackerel fillet were lower when treated with an EO-collagen film and somewhat lower when treated with collagen alone. According to texture measurements of muscle, samples treated with EO-collagen film began to deteriorate in 8 d, versus only 4 d for control samples. EOs likely contributed to antibacterial and antioxidative activity, and the collagen film isolated muscle from air, which in turn reduced oxidation and retained the quality. Consequently, combination of EOs and collagen film efficiently extends shelf-life of Pacific mackerel during storage.
