• Atlantic salmon (Salmo salar) co-product-derived protein hydrolysates: A source of antidiabetic peptides

      Harnedy, Pàdraigín A.; Parthsarathy, Vadivel; McLaughlin, Chris M.; O'Keeffe, Martina B.; Allsopp, Philip J.; McSorley, Emeir M.; O'Harte, Finbarr P. M.; FitzGerald, Richard J. (Elsevier, 2018-02-06)
      Large quantities of low-value protein rich co-products, such as salmon skin and trimmings, are generated annually. These co-products can be upgraded to high-value functional ingredients. The aim of this study was to assess the antidiabetic potential of salmon skin gelatin and trimmingderived protein hydrolysates in vitro. The gelatin hydrolysate generated with Alcalase 2.4L and Flavourzyme 500L exhibited significantly higher (p<0.001) insulin and GLP-1 secretory activity from pancreatic BRIN-BD11 and enteroendocrine GLUTag cells, respectively, when tested at 2.5 mg/mL compared to hydrolysates generated with Alcalase 2.4L or Promod 144MG. The gelatin hydrolysate generated with Alcalase 2.4L and Flavourzyme 500L showed significantly more potent (p<0.01) DPP-IV inhibitory activity than those generated with Alcalase 2.4L or Promod 144MG. No significant difference was observed in the insulinotropic activity mediated by any of the trimming-derived hydrolysates when tested at 2.5 mg/mL. However, the trimmings hydrolysate generated with Alcalase 2.4L and Flavourzyme 500L exhibited significantly higher DPP-IV inhibitory (p<0.05:Alcalase 2.4L and p<0.01:Promod 144MG) and GLP-1 (p<0.001, 2.5 mg/mL) secretory activity than those generated with Alcalase 2.4L or Promod 144MG. The salmon trimmings hydrolysate generated with Alcalase 2.4L and Flavourzyme 500L when subjected to simulated gastrointestinal digestion (SGID) was shown to retain its GLP-1 secretory and DPP-IV inhibitory activities, in addition to improving its insulin secretory activity. However, the gelatin hydrolysate generated with Alcalase 2.4L and Flavourzyme 500L was shown to lose GLP-1 secretory activity following SGID. A significant increase in membrane potential (p<0.001) and intracellular calcium (p<0.001) by both co-product hydrolysates generated with Alcalase 2.4L and Flavourzyme 500L suggest that both hydrolysates mediate their insulinotropic activity through the KATP channel-dependent pathway. Additionally, by stimulating a significant increase in intracellular cAMP release (p<0.05) it is likely that the trimming-derived hydrolysate may also mediate insulin secretion through the protein kinase A pathway. The results presented herein demonstrate that salmon co-product hydrolysates exhibit promising in vitro antidiabetic activity.
    • Blue whiting (Micromesistius poutassou) muscle protein hydrolysate with in vitro and in vivo antidiabetic properties

      Harnedy, Pàdraigín A.; Parthsarathy, Vadivel; McLaughlin, Chris M.; O'Keeffe, Martina B.; Allsopp, Philip J.; McSorley, Emeir M.; O'Harte, Finbarr P. M.; Fitzgerald, Richard J. (Elsevier, 2017-10-29)
      A blue whiting (Micromesistius poutassou) protein hydrolysate generated using Alcalase 2.4L and Flavourzyme 500L and its simulated gastrointestinal digestion (SGID) sample was assessed for antidiabetic potential in vitro and in vivo. In addition to inhibiting dipeptidyl peptidase-IV (DPP–IV), the hydrolysates mediated insulin and glucagon-like peptide-1 (GLP-1) release from BRIN-BD11 and GLUTag cells, respectively. No significant difference was observed in insulinotropic and DPP-IV inhibitory activity following SGID, while GLP-1 secretion increased significantly (p < 0.01). SGID resulted in a significant increase in membrane potential, intracellular calcium and cyclic AMP concentration (p < 0.001) versus a glucose control, indicating that insulin secretion may be mediated by the KATP channel-dependent and the protein kinase A pathways. Additionally, acute (90–120min) and persistent (4h) glucose-lowering effects of the blue whiting hydrolysate were observed in normal healthy mice. These results demonstrate that the blue whiting protein hydrolysate had significant metabolic effects relevant to glucose control in vivo.