Plasmin activity, β-lactoglobulin denaturation and proteolysis in high pressure treated milk

Scollard, Patrick G.; Beresford, Thomas P.; Needs, Eric C.; Murphy, Patrick M.; Kelly, Alan L.

doi:10.1016/s0958-6946(01)00028-0

Cited by 79 publications

(74 citation statements)

References 23 publications

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“…In this study, treatment of milk at ≥400 MPa reduced plasmin activity therein considerably (Tab. I), as previously reported by Scollard et al [26,27], and denatured ≥95% of β-Lg (data not shown), again consistent with previous studies [10,14,20,27], supporting the possibility that HPinduced inactivation of plasmin in milk may be linked to denaturation of β-Lg. However, it remains unclear whether there is a direct causal relationship between the two phenomena.…”

Section: Discussionsupporting

confidence: 91%

“…In milk treated at ≥200 MPa, however, plasmin activity did not increase on storage at 37°C (Tab. I), possibly through inactivation either of plasminogen or of its activators; Scollard et al [27] showed that treatment at <500 MPa inactivated < 20% of plasminogen, with more extensive inactivation at higher pressures.…”

Section: Discussionmentioning

confidence: 99%

“…The majority of plasmin in milk is in the form of the inactive precursor, plasminogen, which is converted to plasmin through a complex system of plasminogen activators [3,18]. Plasmin is not affected by treatment at pressures <400 MPa, but treatment at a higher pressure causes considerable inactivation [8,26,27].…”

Section: Introductionmentioning

confidence: 99%

“…Scollard et al [27] reported that proteolysis in milk was not affected by HP treatment at 50 MPa, was increased in milk treated at 300-500 MPa, but was reduced in milk treated at higher pressures. According to Garcia-Risco et al [9], increased proteolysis in milk treated at such pressures is probably related to HP-induced disruption of casein micelles.…”

Section: Introductionmentioning

confidence: 99%

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Plasmin activity and proteolysis in high pressure-treated bovine milk

Huppertz

Fox

Kelly

2004

Lait

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-In this study, proteolysis resulting from the action of the indigenous milk proteinase, plasmin, in high pressure (HP)-treated raw skim bovine milk during storage was examined. Plasmin activity was reduced by treatment at pressures ≥400 MPa and decreased further throughout 28 d of storage at 5°C. In untreated milk or milk treated at 100 MPa plasmin activity increased during the first 3 d of storage at 37°C, indicating activation of plasminogen; considerably less activation occurred in milk treated at 200-600 MPa. However, considerable decreases in plasmin activity, probably due to autolysis, were apparent in all samples on storage at 37°C for >3 d. Proteolysis, as measured by increases in the level of pH 4.6-soluble N and decreases in the level of β-casein, was very limited on storage of milk at 5°C, with little difference between untreated and HP-treated samples. Proteolysis on storage of milk at 37°C was influenced only slightly by treatment of milk at a pressure ≤250 MPa and was reduced considerably in milk treated at 600 MPa for 30 min, but in milk treated at 300-400 MPa, proteolysis was more extensive than in untreated milk, possibly as a result of HP-induced disruption of casein micelles. Overall, HP can either induce or reduce proteolysis in milk, and may therefore have implications for products made from such milk.High pressure / milk / proteolysis / plasmin / casein micelle Résumé -Activité de la plasmine et protéolyse dans un lait de bovin traité par hautes pressions. Dans cette étude, nous nous sommes intéressés à la protéolyse résultant de l'activité d'une protéinase indigène du lait, la plasmine, au cours de l'incubation d'un lait de bovin frais écrémé et traité par hautes pressions. L'activité de la plasmine était réduite par un traitement à des pressions ≥400 MPa et diminuait progressivement au cours des 28 j de stockage à 5°C. Pour un lait non traité ou traité à 100 MPa, l'activité de la plasmine augmentait pendant les trois premiers jours d'incubation à 37°C, indiquant l'activation du plasminogène ; l'activation était bien moins importante pour un lait traité à des pressions comprises entre 200 et 600 MPa. Cependant, des diminutions considé-rables de l'activité de la plasmine, probablement due à une autolyse, étaient observées pour tous les échantillons incubés à 37 °C pour des durées de stockage >3 j. La protéolyse, mesurée par les augmentations du taux d'azote soluble à pH 4,6 et par les diminutions du taux de caséine β résiduelle, était très limitée pour un stockage du lait à 5°C, avec une petite différence entre les échantillons non traités et ceux traités aux hautes pressions. La protéolyse durant l'incubation du lait à 37°C était seulement légèrement influencée par le traitement du lait à des pressions ≤250 MPa et était considérablement réduite pour un lait traité à 600 MPa pour 30 min, mais pour un lait traité à 300-400 MPa, la protéolyse était plus importante que dans un lait non traité, cela étant probablement dû à la désintégration des micelles de caséine induite par les haut...

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Plasmin activity and proteolysis in high pressure-treated bovine milk

Huppertz

Fox

Kelly

2004

Lait

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show abstract

“…The proteolysis was correlated to the drop in pH due to the action of Lactobacillus curvatus, what favoured the action of indigenous proteolytic enzymes of the meat. The milk contains the indigenous plasmin that works best at pH between 6.5 and 8.0 (SCOLLARD et al, 2000;MARTINS, 2006;CORTELLINO et al, 2006). This enzyme plays an important role in aroma and flavour development in Emmenthal and Gouda cheese production, due to its ability to induce proteolysis (VARNAM & SUTHERLAND, 1995).…”

Section: Resultsmentioning

confidence: 99%