Effects of combined high pressure and enzymatic treatments on the hydrolysis and immunoreactivity of dairy whey proteins

Abstract

The effect of high-pressure (HP) treatment on the hydrolysis of dairy whey proteins by trypsin, chymotrypsin and pepsin was analysed. Isostatic pressure (100-300 MPa for 15 min at 37 1C) was applied to the protein substrate prior to its enzymatic hydrolysis. Digestion was also conducted at atmospheric pressure (0.1 MPa) and under high pressure. The extent of hydrolysis was measured by the o-phthaldialdehyde method, the peptide profile was analysed by reverse-phase high performance liquid chromatography (RP-HPLC) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and the residual immunochemical reactivity was assessed by an ELISA test using a pool of seven sera from children allergic to bovine milk, an individual serum also positive (positive control) and two sera from non-allergic children (negative controls). The high pressure increased the degree of hydrolysis by the three enzymes used. Chymotrypsin and trypsin showed the highest proteolysis at 100 and 200 MPa followed by pepsin at 300 MPa. The b-lactoglobulin was hydrolysed by trypsin and chymotrypsin at atmospheric and at high pressures, whereas the pepsin only hydrolysed this protein under high pressure. Pepsin and trypsin hydrolysed a-lactalbumin in all cases. In contrast, this protein was not digested by chymotrypsin, irrespective of the pressure applied. An important decrease of immunochemical reactivity was found for pepsin and trypsin hydrolysates obtained under high pressure. The pool of seven sera detected immunoreactivity in the products of chymotrypsin hydrolysis under high pressure, which was not detected when the serum of one patient was used. The results suggest that dairy whey hydrolysates obtained by pepsin and trypsin in combination with HP treatment could be used as a source of peptides in hypo-allergenic infant formulae. r

Hemoglobin hydrolysates from porcine blood obtained through enzymatic hydrolysis assisted by high hydrostatic pressure processing

“…HHP treatment favours the activity of trypsin on the Hb molecule because pressurized samples showed higher intensity of hydrolysis than control ones. These results were in agreement with Peñas et al (2004;2006a), who reported an increase in hydrolysis by trypsin and chymotrypsin for bovine whey and soybean whey proteins treated by high pressure before or during the hydrolysis reaction, as a result of denaturation of the proteins induced by HHP and dissociation into monomers. According to these authors, the increase in proteolysis when HHP was applied during the hydrolysis could be related to protein denaturation allowing the exposure of the susceptible peptide bonds to the active protease.…”

“…Quirós et al (2007) proposed a method for the commercial production of bioactive peptides from ovalbumin, consisting on HHP treatment of egg white proteins followed by hydrolysis with proteases. Moreover, according to Peñas et al (2004;2006a;2006b), increased yields of hydrolysates from bovine whey and soybean proteins can also be obtained when combining enzymatic and HHP treatments.…”

Proteolytic action of Lactobacillus delbrueckii subsp. bulgaricus CRL 656 reduces antigenic response to bovine β-lactoglobulin

“…The major whey proteins are b-lactoglobulin (BLG, 55-60%) and a-lactalbumin (ALA,(15)(16)(17)(18)(19)(20); other minor proteins are bovine serum albumin, immunoglobulins, lactoferrin and phospholipoproteins (Peñas, Préstamo, Baeza, Martínez-Molero, & Gomez, 2006). BLG is absent in human milk and may induce allergies in infants because of the underdevelopment of their gastrointestinal tract and immune system (Pintado, Pintado, & Malcata, 1999).…”

Effects of combined microwave and enzymatic treatments on the hydrolysis and immunoreactivity of dairy whey proteins

“…Peñ as, Pré stamo, Baeza,Martínez-Molero, & Gó mez, 2006;Peñ as et al, 2006b;Peñ as, Snel, Floris, Pré stamo, & Gó mez, 2006) and soybean WP(Peñ as et al, 2004(Peñ as et al, , 2006aPeñ as, Pré stamo, Polo, & Gó mez, 2006) performed under high pressure. The unfolded proteins formed under MWI could represent an ideal substrate for the action of proteases, making some epitopes more accessible to enzymatic hydrolysis.4.…”