Effects of lactoperoxidase on gelation properties of yogurt

Effects of lactoperoxidase and hydrogen peroxide on rheological properties of yoghurt

“…b-Lg possesses free SH groups, which are exposed as the molecule is denatured (Bjö rck et al 1979). OSCN -not only oxidises the SH groups, but also increases protein hydrophobicity leading to the enhanced gelation (Hirano et al 1998a). Nevertheless, Hirano et al (1998a) found that in parallel with the increase in hydrophobicity in LPO activated yoghurts, the degree of hardness was reduced.…”

Properties of set-style skim milk yoghurt as affected by an enzymatic or Maillard reaction induced milk protein oligomerisation

“…Hirano, Hirano, Ooka, and Hatanaka (1998) and Hirano and Kudo (1998) observed that lactoperoxidase treated milk formed smooth, but solid yoghurt gels of lower elasticity than yoghurt from untreated milk. According to Dickinson (1997), less elastic yoghurt gels result from non-covalent protein bonding upon an enzymatic treatment of yoghurt milk.…”

“…According to Dickinson (1997), less elastic yoghurt gels result from non-covalent protein bonding upon an enzymatic treatment of yoghurt milk. Furthermore, the formation of characteristic yoghurt gel structures upon thiol/disulfide interchange reactions as well as b-lactoglobulin/k-casein interactions (Ozer et al, 2003;Vasbinder et al, 2003) may be impaired by an enzymatic or spontaneous oxidation of protein sulfhydryls (Hirano, Hirano, Ooka, & Hatanaka, 1998, 1997Ozer & Atamer, 1999;Ozer et al, 2003) as well as diminutions of hydrophobic protein interactions (Hirano, Hirano, Ooka, Dosako, et al, 1998;Khalid & Masud, 2004).…”

Functional properties of milk proteins as affected by enzymatic oligomerisation

“…This increase in surface hydrophobicity corresponds to an unfolding of protein structure upon enzymatic oxidation (Davies & Delsignore, 1987;Dean et al, 1997) and thus an exposure of hydrophobic amino acid residues which were buried within the tertiary structure of untreated protein molecules. Hirano, Hirano, Oooka, and Hatanaka (1998) and Khalid and Masud (2004) hypothesised that an increase in protein hydrophobicity was related to the formation of soft, weak yoghurt gels made from lactoperoxidase-treated milk. Rawel et al (2002) also obtained increased surface hydrophobicity of serum albumin/chlorogenic acid adducts.…”