Plasmin activity in direct-steam-injection UHT-processed reconstituted milk: Effects of preheat treatment

Newstead, D. F.; Paterson, Geoff R.; Anema, Skelte G.; Coker, C.; Wewala, A.R.

doi:10.1016/j.idairyj.2005.11.011

Cited by 55 publications

(41 citation statements)

References 14 publications

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“…Several studies have been conducted on the effect of heat treatment on PL enzyme system in fluid milk, including the effect of various UHT preheat treatments on PL-like proteolysis in reconstituted LH-NFDM [19]. However, this is the first report of directly measuring PL activity and PG activation in NFDM of different heat classifications.…”

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

confidence: 98%

“…Non-fat dry milk is manufactured by preheating, concentrating, and spray drying pasteurized skim milk [14], which often is reconstituted to produce ultra-high temperature (UHT) milk [19] or utilized for its functional properties in other food formulations. Depending upon the preheat treatment that fluid milk receives during processing, the reconstituted powder exhibits varying degrees of water absorption, emulsion stability, and gelation [22].…”

Section: Introductionmentioning

confidence: 99%

“…Prior research has shown that reconstituted milk powders are capable of undergoing PL-like proteolysis [19]. However, research on PG activation in reconstituted powders has not been reported.…”

Section: Introductionmentioning

confidence: 99%

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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%

Section: Introductionmentioning

confidence: 99%

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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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“…Furthermore, the plasminogen activator inhibitors are inactivated by commercial thermal pasteurization, whereas PL is stable to pasteurization (Fox et al, 2003). Thus, PL and PG survive pasteurization and are somewhat resistant to HTST and UHT treatments (Newstead et al, 2006;Ismail and Nielsen, 2010). Alichanidis et al (1986) reported that at least 30% of the porcine plasmin activity remained in skim milk that was subject to UHT treatment (143°C) and that the D-value (time required for 90% reduction in activity) in skim milk at 143°C was approximately 10 s.…”

Section: Introductionmentioning

confidence: 99%

Quality characteristics and plasmin activity of thermosonicated skim milk and cream

Vijayakumar

Grewell

Annandarajah

et al. 2015

Journal of Dairy Science

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The shelf life of pasteurized milk is limited by heat-stable proteases, which cause gelation and bitter taste upon extended storage of milk. Ultra-high temperature processing inactivates proteases but detrimentally affects milk's sensory quality. An adjunct to pasteurization is desired to extend milk's shelf life while maintaining quality characteristics. In this study, the effects of combined heat and ultrasound (thermosonication) on total plasmin activity and various quality characteristics of skim milk and cream were studied. Thermosonication, at an average power of 115 W (152 µmp-p, where p-p=peak-to-peak amplitude) for 3 min, decreased the total plasmin activity (i.e., plasmin- and plasminogen-derived activity) by nearly 94% in fresh skim milk and cream. Enzyme activity in thermosonicated skim milk samples measured at the end of 30 d was 5- to 10-fold higher than on d 0, but remained stable in thermosonicated cream. Descriptive analysis of odor attributes was conducted for up to 4 wk with 8 trained panelists. No significant differences were observed between the intensities of offensive "eggy" and "rubbery" odor attributes of thermosonicated skim milk and pasteurized commercial skim milk and cream. In addition, lightness (L*) values and viscosity were not adversely affected by thermosonication. Thermosonication decreased the fat globule size in skim milk and cream, and the homogenizing effect increased with treatment time. Thermosonication at average powers of 104 W (133 µmp-p) and 115 W (152 µmp-p) for 1 and 3 min destroyed coliforms and over 99% of the total aerobic bacteria. The total aerobic bacteria counts of thermosonicated skim milk and cream samples were less than 20,000 cfu/mL on d 30. Because thermosonication did not induce off-aromas or viscosity changes but did inactivate microorganisms and protease enzymes, thermosonication may be an appropriate adjunct to pasteurization to extend milk shelf life.

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“…A certain level of proteolysis is required to induce age gelation, the relation between gelation time and extent of proteolysis is controversial (Manji and Kakuda, 1988;Newstead et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Effects of Storage on Some Physico-Chemical Characteristics of UHT Milk Stored at Different Temperature

2014

Alexandria Science Exchange Journal: An International Quarterly

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Raw milk for UHT processing at commercial dairy plant was collected from well managed dairy farms. The milk was processed by direct system and heated at 143-145ºC for 3-5 S , then aseptically packed. Three different batches of UHT milk were used in this study. Samples of UHT milk were analysed after processing and during storage at 4, 22 and 37ºC ± 2°C for 6 months. The changes in pH, acidity as lactic acid, total solids, viscosity, fat content, electrical conductivity, specific gravity nonprotein nitrogen, non-casein nitrogen total and soluble calcium, magnesium, citrate, and phosphorus during storage were studed. The samples were analysed at 0,30,60,90,120,150 and 180 days for the physico-chemical proportes of milk. Values indicate an increase in acidity,viscocity,NCN,NPN, soluble calcium magnesium citrate and phosphate.The results showed after statistically analysis that there is a significant affect of storage period and storage temperature on pH, titratable acidity, nonprotein-nitrogen, non-casein nitrogen, viscosity, soluble and colloidal calcium and phosphate, soluble magnesium and citrate. There are a significant decrease in pH, electrical conductivity, by increasing storage period, with increasing in acidity ratio, non-protein-non-casein nitrogen and viscosity.

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Plasmin activity in direct-steam-injection UHT-processed reconstituted milk: Effects of preheat treatment

Cited by 55 publications

References 14 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

Quality characteristics and plasmin activity of thermosonicated skim milk and cream

Effects of Storage on Some Physico-Chemical Characteristics of UHT Milk Stored at Different Temperature

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