Effect of heat treatment on the activity of inhibitors of plasmin and plasminogen activators in milk

Prado, B.M.; Sombers, S.E.; Ismail, Baraem; Hayes, K.D.

doi:10.1016/j.idairyj.2005.09.018

Cited by 55 publications

(44 citation statements)

References 23 publications

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“…This implies that milk with higher somatic cell counts has a greater propensity for PL-induced proteolysis, even after pasteurization. Even though milk does contain PL inhibitors, which have recently been shown to be more heat stable than previously thought, PG activation into greater quantities of PL can overcome the competitive inhibition afforded by PL inhibitors [23].…”

Section: Study 2: Storage Study Of Reconstituted Non-fat Dry Milkmentioning

confidence: 98%

Effects of cysteine addition and heat treatment during non-fat dry milk processing on the plasmin enzyme system

Durkee

Hayes

2008

Dairy Sci. Technol.

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-The objective of this study was to measure the effects of cysteine addition and heat treatment on plasmin (PL) activity and plasminogen (PG) activation in reconstituted non-fat dry milk (NFDM). Cysteine was added to a final concentration of 0.16 mg·mL −1 to raw, defatted milk and pasteurized at 72 • C for 15 s (low heat, LH) or 100 • C for 30 s (medium heat, MH) prior to spray drying. Both MH fluid milk and NFDM had no PL activity or PG activation, regardless of cysteine addition. For both LH fluid milk and NFDM, there was a significant decrease in PL activity upon cysteine addition (P < 0.0001 for both), as well as in PG activation (P = 0.0003 for fluid milk, P < 0.0001 for NFDM), likely due to the polymerization of PG or binding of PL and PG with other milk proteins. Upon storage of reconstituted powders at 21 • C and 4 • C, PL activity increased with a complimentary decrease in PG-derived PL activity in LH samples, though these changes slowed in samples with added cysteine. Urea-PAGE showed proteolysis of β-casein consistent with PL activities in LH samples. No PL or PG-derived PL activities or proteolysis were observed in stored MH samples. These results suggest that the addition of cysteine prior to the pasteurization and manufacture of LH-NFDM significantly decreases the potential for proteolysis during storage of reconstituted powder caused by the PL enzyme system. plasmin / plasminogen / cysteine / heat treatment / non-fat dry milk

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Section: Study 2: Storage Study Of Reconstituted Non-fat Dry Milkmentioning

confidence: 98%

Effects of cysteine addition and heat treatment during non-fat dry milk processing on the plasmin enzyme system

Durkee

Hayes

2008

Dairy Sci. Technol.

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“…In fact, a high proportion of proteolytic activity in milk may be associated with SCC (Saeman et al, 1988;Ballou et al, 1995), which leads to the corresponding reduction of αs1-and β-casein fractions in milk (Randolph et al, 1974;. As some SCC-related proteases are heat-resistant (Prado et al, 2006), such effects are expected to occur in ultra-high-temperature (UHT) milk during storage. Proteolysis of UHT milk during storage at room temperature decreases its shelf life and might cause undesirable precipitation or gelation (Topçu et al, 2006).…”

Section: Effect Of Somatic Cell On Ultra-high Temperature (Uht) Productmentioning

confidence: 99%

“…Proteolysis of UHT milk during storage at room temperature decreases its shelf life and might cause undesirable precipitation or gelation (Topçu et al, 2006). The enzymatic hydrolysis of casein, associated with SCC, may also lead to detrimental sensory changes in milk, mainly a bitter taste due to the release of bitter peptides (Prado et al, 2006). Mastitic milk (i.e.…”

Section: Effect Of Somatic Cell On Ultra-high Temperature (Uht) Productmentioning

confidence: 99%

Effect of somatic cell count on dairy products: a review

Talukder

Ahmed²

2017

Asian J. Med. Biol. Res

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Somatic cells are the most essential factors naturally present in milk, and somatic cell count (SCC) is used as an indicator of monitoring mastitis incidence in the herd and also to assess the quality of milk. In addition, SCC is frequently used to determine quality payments to dairy producers. The SCC is directly related to get maximum milk production from individual cow and a lower SCC indicates better animal health, as somatic cells originate only from inside the animal's udder. SCC monitoring is important because as the number of somatic cells increases, milk yield is likely to fall, primarily due to the damage to milk-producing tissue in the udder caused by mastitis pathogens and the toxins they produce, particularly when epithelial cells are lost. Keeping low SSC will allow good quality more raw milk and provide a better product to milk processors whether used as fluid milk or converted to milk based products. Somatic cells containing lipolytic and proteolytic enzymes lead to degrade major nutrients fats and proteins, respectively. Elevated SCC is related to udder inflammation, which leads to alter the normal microbial count and physicochemical parameters of milk, as well as the quality of heat treated fluid milk and milk based product. The objective of this review is to discuss on the SSC and endogenous enzymes released from somatic cells in raw milk as well as effect of somatic cells count and their endogenous enzymes in processed milk and milk based products.

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“…About 81.1 and 35.8% of plasminogen activator inhibitors and plasmin inhibitors respectively were inactivated at 75°C for 15 s (Prado et al, 2006). This in turn increases plasmin activity as more plasminogen is also converted to plasmin (Richardson, 1983) and hence higher proteolysis.…”

Section: Effect Of Storage Time (Days) On Proteolysis Of Milk Heated mentioning

confidence: 99%

Proteolysis of milk heated at high temperatures by native enzymes analysed by trinitrobenzene sulphonic acid (TNBS) method

CHOVE¹

2013

Afr. J. Food Sci.

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Native enzymes play a significant role in proteolysis of milk during storage. This is significant for heat resistant native enzymes. Plasmin is one of the most heat resistant enzymes found in milk. It has been reported to survive several heat treatments, causing spoilage during storage. The aim of this study was to assess susceptibility of high temperature heated milk to proteolysis by native enzymes. The trinitrobenzene sulphonic acid (TNBS) method was used for this purpose. Raw milk was heated at 110, 120, 130,142°C for 2 s and 85°C for 15 s and milk processed at low temperature (85°C /15s) was selected to mimic pasteurisation. TNBS method confirmed that raw milk and milk processed at 85°C /15s were the most proteolysed, whereas treatment of milk at high temperatures (110, 120, 130 and 142°C for 2 s) inactivated the native enzymes. It may thus be concluded that high temperature processing positively affects proteolysis by lowering its susceptibility to spoilage during storage.

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Effect of heat treatment on the activity of inhibitors of plasmin and plasminogen activators in milk

Cited by 55 publications

References 23 publications

Effects of cysteine addition and heat treatment during non-fat dry milk processing on the plasmin enzyme system

Effects of cysteine addition and heat treatment during non-fat dry milk processing on the plasmin enzyme system

Effect of somatic cell count on dairy products: a review

Proteolysis of milk heated at high temperatures by native enzymes analysed by trinitrobenzene sulphonic acid (TNBS) method

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