Functional properties and antioxidative activity of protein hydrolysates from toothed ponyfish muscle treated with viscera extract from hybrid catfish

Porcine placenta hydrolysate as an alternate functional food ingredient: In vitro antioxidant and antibacterial assessments

The production of bioactive peptides from animal-based raw materials highly depends on enzymatic hydrolysis. Porcine placenta is an underutilized biomass in Thailand's pig farms, yet it is still a source of proteins and beneficial compounds. Porcine placenta could be used as a protein substrate for the production of enzymatic hydrolysate, which could be employed as a functional food ingredient in the future. The goal of this study was to enzymatically produce porcine placenta hydrolysates (PPH) using three commercial enzymes (Alcalase, Flavouzyme, and papain) and evaluate their in vitro antioxidant and antibacterial activity. The degree of hydrolysis (DH) increased as the enzyme load and hydrolysis time increased, but the DH was governed by the enzyme class. The maximum DH was found after using 10% enzyme for 20 min of hydrolysis (36.60%, 31.40%, and 29.81% for Alcalase, Flavouzyme, and papain). Depending on the enzyme type and DH, peptides of various sizes (0.40-323.56 kDa) were detected in all PPH. PPH created with Alcalase had an excellent reducing capacity and metal chelating ability (p < 0.05), whereas PPH made with Flavourzyme and Papain had higher DPPH• and ABTS•+ inhibitory activities (p < 0.05). Papain-derived PPH also had a strong antibacterial effect against Staphylococcus aureus and Escherichia coli, with clear zone values of 17.20 mm and 14.00 mm, respectively (p < 0.05). When PPH was transported via a gastrointestinal tract model system, its antioxidative characteristics were altered. PPH's properties and bioactivities were thus influenced by the enzyme type, enzyme concentration, and hydrolysis time used. Therefore, PPH produced from porcine placenta can be categorized as an antioxidant and antibacterial alternative.

Valorisation of smooth hound (Mustelus mustelus) waste biomass through recovery of functional, antioxidative and antihypertensive bioactive peptides

Concerns over the environmental and waste disposal problems created by the large amounts of by-products generated from fish processing industries are increasing worldwide. The bioconversion of those marine waste by-products through the enzymatic hydrolysis of their protein content offers the possibility for the development of bioactive peptides for use in various biotechnological applications. The present study aimed to investigate and evaluate the biological and functional properties of smooth hound (Mustelus mustelus) protein hydrolysates (SHPHs) obtained by treatment with intestinal and gastric enzyme preparations from M. mustelus viscera and porcine pancreatin. The results revealed that the SHPHs exhibited different degrees of hydrolysis and antioxidant activity. The hydrolysate produced by the intestinal crude extract presented the highest rate of antioxidative activity, showing an IC50 value of 1.47 ± 0.07 mg/mL in 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assays. The alkaline protease extract from the intestine of M. mustelus produced hydrolysate with the highest angiotensin I-converting enzyme (ACE) inhibitory activity (82 ± 1.52% at 2 mg/mL). All the protein hydrolysates showed excellent solubility and interfacial properties that were governed by pH. The major amino acids detected in SHPHs were glutamic acid/glutamine, aspartic acid/asparagine, histidine and arginine, followed by methionine, phenylalanine, serine, valine and leucine. Overall, the results indicated that smooth hound by-products can be used to generate high value-added products, thus offering a valuable source of bioactive peptides for application in wide range of biotechnological and functional food applications.

Hydrolyzed fish proteins reduced activation of caspase-3 in H2O2 induced oxidative stressed liver cells isolated from Atlantic salmon (Salmo salar)

Hydrolyzed fish proteins (H-pro) contains high concentrations of free amino acids and low molecular peptides that potentially benefit health. The following study aimed to test whether the water soluble phase of H-pro could reduce apoptosis and inflammation in primary liver cells isolated from Atlantic salmon following H₂O₂ provoked oxidative stress. Cells were grown as monocultures or co-cultured with head kidney cells to assess possible cross talk in inflammation and metabolism during treatments. Cells were grown in media with or without H-pro for 2 days before being stressed with 200 µM H₂O₂ then harvested 24 h post exposure. Both treatments were compared to the respective treatments without H₂O₂ supplementation. Oxidative stressed cells had increased activation of caspase-3, but supplementation with H-pro in the media prior to the oxidative stress reduced caspase-3 activation. In conclusion, free amino acids and low molecular weight peptides from H-pro attenuated oxidative stress, and made cells able to withstand apoptosis after H₂O₂ provoked oxidative stress.