Valorisation of blood protein from livestock to produce haem iron‐fortified hydrolysates with antioxidant activity

Abstract

Blood is the main by-product from slaughterhouses bearing high levels of suspended solids (18% w/w) and BOD 5 (250 000-375 000 mg O 2 /L), which makes difficult its handling and disposal. This study proposes the valorisation of blood protein to produce enzymatic hydrolysates rich in haemic iron and antioxidant peptides. Haemic iron presents higher bioavailability compared to its inorganic form, but its incorporation into foodstuffs is restrained by its high tendency to oxidation. Six commercial proteases of animal, plant and bacterial origin were employed to produce the enzymatic hydrolysates. Subtilisin and trypsin treatments were able to recover 70% of haem iron as soluble peptides, in contrast with plant enzymes where the proteolysis was reduced. Moreover, some enzymatic treatments led to hydrolysates with high levels of some in vitro antioxidant activities such as radical scavenging (Protamex, IC 50 3.52 mg/mL) or metal chelating activity (trypsin, IC 50 0.27 mg/mL). We conclude the enzymatic valorisation of blood protein increases haemic iron bioavailability and produces antioxidant peptides. Both properties are of interest for their use as iron fortification supplements.

Use of olive and sunflower protein hydrolysates for the physical and oxidative stabilization of fish oil‐in‐water emulsions

“…Subtilisin is a broad‐spectrum endoprotease of bacterial origin that cleaves preferably peptide bonds involving aromatic and methionine amino acids, whereas trypsin is extracted from animals and cleaves only when the carbonyl group is followed to positively charged amino acids arginine and/or lysine. Both enzymes release peptides with hydrophobic or polar residues which exhibit surface active properties 37,57‐59 . When it comes to comparing the enzyme treatment effect on meal solubility and protein recovery at the same DH, no significant differences were found for both olive and sunflower hydrolysates.…”

“…Both enzymes release peptides with hydrophobic or polar residues which exhibit surface active properties. 37,[57][58][59] When it comes to comparing the enzyme treatment effect on meal solubility and protein recovery at the same DH, no significant differences were found for both olive and sunflower hydrolysates. Protein hydrolysates can display different structures and functionalities depending on the enzyme employed.…”

Evaluation of Plant Protein Hydrolysates as Natural Antioxidants in Fish Oil-In-Water Emulsions

“…The cleavage of peptide bonds leads to higher exposure of polar groups, and therefore higher solubility of the hydrolysate compared with the native protein. Similar to alcalase, trypsin cleaves preferably the C-terminus of Arg or Lys residues, releasing positive-charged peptides with improved solubility [ 38 , 39 ]. This is reflected in average values of protein recovery for the hydrolysates, as well as their protein content compared with the plant flours, which suggests that enzymatic reaction was effective to solubilize protein in the reaction medium.…”