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Ahmadi E, Markoska T, Huppertz T, Vasiljevic T. Structural Properties of Casein Micelles with Adjusted Micellar Calcium Phosphate Content. Foods 2024; 13:322. [PMID: 38275688 PMCID: PMC10815582 DOI: 10.3390/foods13020322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/18/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
Micellar calcium phosphate (MCP) content of skim milk was modified by pH adjustment followed by dialysis. Turbidity, casein micelle size and partitioning of Ca and caseins between the colloidal and soluble phases of milk were determined. Protein structure was characterised by Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (1H NMR), whereas organic and inorganic phosphorus were studied by phosphorus-31 nuclear magnetic resonance (31P NMR). The sample with the lowest MCP content (MCP7) exhibited the smallest particle size and turbidity, measuring 83 ± 8 nm and 0.08 ± 0.01 cm-1, respectively. Concentrations of soluble caseins increased with decreasing MCP levels. At ~60% MCP removal, FTIR analysis indicated a critical stage of structural rearrangement and 31P NMR analysis showed an increase in signal intensity for Ca-free Ser-P, which further increased as MCP concentration was further reduced. In conclusion, this study highlighted the importance of MCP in maintaining micellar structure and its impact on the integrity of casein micelle.
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Affiliation(s)
- Elaheh Ahmadi
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Sport, Health and Engineering, Victoria University, Melbourne, VIC 3001, Australia; (E.A.); (T.M.); (T.H.)
| | - Tatijana Markoska
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Sport, Health and Engineering, Victoria University, Melbourne, VIC 3001, Australia; (E.A.); (T.M.); (T.H.)
| | - Thom Huppertz
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Sport, Health and Engineering, Victoria University, Melbourne, VIC 3001, Australia; (E.A.); (T.M.); (T.H.)
- FrieslandCampina, 3818 LE Amersfoort, The Netherlands
- Food Quality and Design Group, Wageningen University and Research, 6708 WG Wageningen, The Netherlands
| | - Todor Vasiljevic
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Sport, Health and Engineering, Victoria University, Melbourne, VIC 3001, Australia; (E.A.); (T.M.); (T.H.)
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Cai H, Bijl E, Scholten E, Sala G. Effect of plasmin on casein hydrolysis and textural properties of rennet-induced model cheeses. Food Res Int 2023; 165:112421. [PMID: 36869466 DOI: 10.1016/j.foodres.2022.112421] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 12/28/2022]
Abstract
Plasmin plays an important role in casein hydrolysis during cheese ripening, which may influence the properties of the casein network and the texture of the final product. In view of this, the relation between plasmin-induced casein hydrolysis and textural changes of cheese during ripening was investigated in this study. Four batches of model cheese with different concentrations of added plasmin (0, 0.4, 0.6 and 1.0 μL/g milk) were prepared, and were stored for 12 weeks at 16 °C. During this period, plasmin activity, casein hydrolysis, textural properties and other compositional characteristics (pH, dry matter) were determined. Our results show that the addition of plasmin had significant effect on both the degree and the pattern of proteolysis. As a result, cheeses with different plasmin content showed different textural properties. With increased plasmin concentration, Young's modulus, hardness, resilience and cohesion decreased, while brittleness increased. All textural properties showed linear relations with the degree of casein hydrolysis, and logarithmic relations with the percentage of intact casein fractions. At the beginning of ripening, only slight changes in textural properties were found, although a substantial part (40-60 %) of the casein fractions was already been broken down. When ripening progressed, ongoing proteolysis significantly weakened the protein network and consequently led to noticeable textural changes. Model cheeses became softer, more brittle and less elastic. The knowledge gained from this study provide new insights in the changes of different textural parameters of model cheese. This will help to optimize the existing products and create new ones.
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Affiliation(s)
- Huifang Cai
- Physics and Physical Chemistry of Foods Group, Wageningen University, The Netherlands; Dairy Science and Technology, Food Quality and Design Group, Wageningen University, The Netherlands
| | - Etske Bijl
- Dairy Science and Technology, Food Quality and Design Group, Wageningen University, The Netherlands.
| | - Elke Scholten
- Physics and Physical Chemistry of Foods Group, Wageningen University, The Netherlands
| | - Guido Sala
- Physics and Physical Chemistry of Foods Group, Wageningen University, The Netherlands
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Yildirim-Elikoglu S, Vural H. Binding characteristics of polyphenols as milk plasmin inhibitors. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2019; 99:6922-6930. [PMID: 31393601 DOI: 10.1002/jsfa.9978] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 07/31/2019] [Accepted: 08/05/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND The potential use of polyphenols to improve the functional characteristics of dairy products has gained much attention. However, the effects of the polyphenols on naturally occurring enzymes in milk have not been studied extensively. Excess plasmin activity in dairy products might result in several quality defects. The objective of this study was to assess the ability of polyphenols to inhibit plasmin in milk using a molecular and kinetic approach. RESULTS Epicatechin gallate (ECG), epigallocatechin gallate (EGCG), quercetin (QUER), and myricetin (MYR) caused a significant decrease in plasmin activity by 60, 86, 65, and 90%, respectively. The inhibition rates were alleviated in the presence of milk proteins. EGCG, QUER, and MYR, exhibited noncompetitive inhibition against plasmin, whereas ECG caused a mixed-type inhibition. A decrease in the random structure of plasmin upon the complex formation with ECG, EGCG, QUER, and MYR was found. The other phenolics that were evaluated did not cause any significant changes in plasmin conformation. The observed inhibitory phenolic-plasmin interactions were dominated by H-bonds and electrostatic attractions. Green tea extract (GTE) rich in catechins also inhibited plasmin activity in the milk. CONCLUSION Significant changes in the secondary structure of plasmin upon binding of ECG, EGCG, QUER, and MYR led to diminished plasmin activity both in the absence and presence of milk proteins. These flavonoids with promising plasmin inhibitory potential could be used in new dairy formulations leading to controlled undesired consequences of plasmin activity. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Seda Yildirim-Elikoglu
- Department of Food Engineering, Faculty of Engineering, Hacettepe University, Ankara, Turkey
| | - Halil Vural
- Department of Food Engineering, Faculty of Engineering, Hacettepe University, Ankara, Turkey
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Leitner G, Rovai M, Merin U. Clinical and subclinical intrammamay infection caused by coagulase negative staphylococci negatively affect milk yield and its quality in dairy sheep. Small Rumin Res 2019. [DOI: 10.1016/j.smallrumres.2019.07.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hogenboom J, Pellegrino L, Sandrucci A, Rosi V, D'Incecco P. Invited review: Hygienic quality, composition, and technological performance of raw milk obtained by robotic milking of cows. J Dairy Sci 2019; 102:7640-7654. [DOI: 10.3168/jds.2018-16013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 04/07/2019] [Indexed: 01/09/2023]
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Caballero-Villalobos J, Garzón A, Martínez Marín A, Arias R, Ciocia F, McSweeney P. Plasmin activity in Manchega ewe milk: The effect of lactation, parity and health of the udder, and its influence on milk composition and rennet coagulation. Small Rumin Res 2018. [DOI: 10.1016/j.smallrumres.2017.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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de Vries R, Brandt M, Lundh Å, Holtenius K, Hettinga K, Johansson M. Short communication: Influence of shortening the dry period of Swedish dairy cows on plasmin activity in milk. J Dairy Sci 2016; 99:9300-9306. [DOI: 10.3168/jds.2016-11502] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/16/2016] [Indexed: 11/19/2022]
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Abdelgawad AR, Rovai M, Caja G, Leitner G, Castillo M. Evaluating coagulation properties of milk from dairy sheep with subclinical intramammary infection using near infrared light scatter. A preliminary study. J FOOD ENG 2016. [DOI: 10.1016/j.jfoodeng.2015.07.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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The effect of health status of the udder on plasminogen activator activity of milk somatic cells in ovine milk. Small Rumin Res 2015. [DOI: 10.1016/j.smallrumres.2015.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Choi J, Horne D, Lucey J. Effect of insoluble calcium concentration on endogenous syneresis rate in rennet-coagulated bovine milk. J Dairy Sci 2015; 98:5955-66. [DOI: 10.3168/jds.2015-9527] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/29/2015] [Indexed: 11/19/2022]
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11
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Maristela R, Natalia R, Gerardo C, Jordi S, Gabriel L. Effect of subclinical intrammamay infection on milk quality in dairy sheep: I. Fresh-soft cheese produced from milk of uninfected and infected glands and from their blends. Small Rumin Res 2015. [DOI: 10.1016/j.smallrumres.2015.02.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Shima H, Tanimoto M. Quantifying Thermally Induced Flowability of Rennet Cheese Curds. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2015. [DOI: 10.1080/10942912.2014.978009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Beigomi M, Mohammadifar MA, Hashemi M, rohani MG, Senthil K, Valizadeh M. Biochemical and rheological characterization of a protease from fruits of Withania coagulans with a milk-clotting activity. Food Sci Biotechnol 2014. [DOI: 10.1007/s10068-014-0247-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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14
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Zhou L, Bi X, Xu Z, Yang Y, Liao X. Effects of High-Pressure CO2Processing on Flavor, Texture, and Color of Foods. Crit Rev Food Sci Nutr 2014; 55:750-68. [DOI: 10.1080/10408398.2012.677871] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Vásquez JA, Novoa CF, Carulla JE. EFECTO DEL RECUENTO DE CÉLULAS SOMÁTICAS SOBRE LA APTITUD QUESERA DE LA LECHE Y EN LA CALIDAD FISICOQUÍMICA Y SENSORIAL DEL QUESO CAMPESINO. REVISTA DE LA FACULTAD DE MEDICINA VETERINARIA Y DE ZOOTECNIA 2014. [DOI: 10.15446/rfmvz.v61n2.44680] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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The influence of alkaline earth metal equilibria on the rheological properties of rennet-induced skim milk gels. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s13594-014-0166-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wang F, Liu X, Hu Y, Luo J, Lv X, Guo H, Ren F. Effect of carrageenan on the formation of rennet-induced casein micelle gels. Food Hydrocoll 2014. [DOI: 10.1016/j.foodhyd.2013.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Cecchinato A. Survival analysis as a statistical methodology for analyzing factors that affect milk coagulation time in Holstein-Friesian and Brown Swiss cows. J Dairy Sci 2013; 96:5556-64. [DOI: 10.3168/jds.2013-6720] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 05/23/2013] [Indexed: 11/19/2022]
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20
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Corassin CH, Rosim RE, Kobashigawa E, Fernandes AM, Oliveira CAFD. Relação entre atividade de plasmina e frações de caseína durante o armazenamento do leite longa vida. BRAZILIAN JOURNAL OF FOOD TECHNOLOGY 2013. [DOI: 10.1590/s1981-67232013005000008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Este estudo teve como objetivo correlacionar a atividade da plasmina e as concentrações de frações de caseína no leite longa vida (UAT) produzido em usina de beneficiamento do Estado de São Paulo. O leite cru foi submetido à pasteurização (72-76 ºC, 15-20 segundos), seguida da esterilização por processo de injeção direta de vapor (132-136 ºC, 34 segundos), sendo homogeneizado e envasado assepticamente em embalagens cartonadas. Quatro lotes de UAT foram analisados para atividade de plasmina e frações de caseína após 10, 30, 60, 90 e 120 dias de armazenamento. A atividade de plasmina no leite longa vida aumentou durante o armazenamento, correlacionando-se negativamente com a concentração de αs1-caseína. A atividade da plasmina apresenta resistência à esterilização do leite pelo processo UAT e aumenta a proteólise do leite longa vida como consequência da degradação da αs1-caseína.
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LU XIAOMING, ZUO FANGLEI, ZHAO JIANYUN, GUO HUIYUAN, REN FAZHENG, CHEN SHANGWU. EFFECT OF VARYING LEVELS OF ADDED CALCIUM ON THE BIOCHEMISTRY, TEXTURE AND MICRO-STRUCTURE OF FRESH CHEESE CONTAINING SESAME PROTEIN ISOLATE. J Food Biochem 2011. [DOI: 10.1111/j.1745-4514.2011.00593.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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DICKOW JONATANA, NIELSEN MARTINT, HAMMERSHØJ MARIANNE. Effect of Lenient Steam Injection (LSI) heat treatment of bovine milk on the activities of some enzymes, the milk fat globule and pH. INT J DAIRY TECHNOL 2011. [DOI: 10.1111/j.1471-0307.2011.00765.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Bonfatti V, Cecchinato A, Gallo L, Blasco A, Carnier P. Genetic analysis of detailed milk protein composition and coagulation properties in Simmental cattle. J Dairy Sci 2011; 94:5183-93. [DOI: 10.3168/jds.2011-4297] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 06/23/2011] [Indexed: 11/19/2022]
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24
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Cecchinato A, Penasa M, De Marchi M, Gallo L, Bittante G, Carnier P. Genetic parameters of coagulation properties, milk yield, quality, and acidity estimated using coagulating and noncoagulating milk information in Brown Swiss and Holstein-Friesian cows. J Dairy Sci 2011; 94:4205-13. [DOI: 10.3168/jds.2010-3913] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 04/15/2011] [Indexed: 11/19/2022]
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Ismail B, Nielsen S. Invited review: Plasmin protease in milk: Current knowledge and relevance to dairy industry. J Dairy Sci 2010; 93:4999-5009. [DOI: 10.3168/jds.2010-3122] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Accepted: 07/18/2010] [Indexed: 11/19/2022]
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27
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Lu X, Schmitt D, Chen S. Effect of sesame protein isolate in partial replacement of milk protein on the rheological, textural and microstructural characteristics of fresh cheese. Int J Food Sci Technol 2010. [DOI: 10.1111/j.1365-2621.2010.02262.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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LURUEÑA-MARTÍNEZ MIGUELA, REVILLA ISABEL, SEVERIANO-PÉREZ PATRICIA, VIVAR-QUINTANA ANAM. The influence of breed on the organoleptic characteristics of Zamorano sheep’s raw milk cheese and its assessment by instrumental analysis. INT J DAIRY TECHNOL 2010. [DOI: 10.1111/j.1471-0307.2010.00565.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Moslehishad M, Ezzatpanah H. Transmission Electron Microscopy Study of Casein Micelle in Raw Milk with Different Somatic Cell Count Levels. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2010. [DOI: 10.1080/10942910802713156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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Yu L, Ngadi M, Raghavan G. Effect of temperature and pulsed electric field treatment on rennet coagulation properties of milk. J FOOD ENG 2009. [DOI: 10.1016/j.jfoodeng.2009.04.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Vianna P, Mazal G, Santos M, Bolini H, Gigante M. Microbial and Sensory Changes Throughout the Ripening of Prato Cheese Made from Milk with Different Levels of Somatic Cells. J Dairy Sci 2008; 91:1743-50. [DOI: 10.3168/jds.2007-0639] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Theodorou G, Kominakis A, Rogdakis E, Politis I. Factors Affecting the Plasmin-Plasminogen System in Milk Obtained from Three Greek Dairy Sheep Breeds with Major Differences in Milk Production Capacity. J Dairy Sci 2007; 90:3263-9. [PMID: 17582110 DOI: 10.3168/jds.2006-780] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The purpose of this study was to evaluate the effect of breed, stage of lactation, and health status of the udder on the plasmin-plasminogen system in ovine milk. A total of 38 ewes were used from 3 breeds [Boutsiko (n = 12), Chios (n = 12), and a synthetic breed (50% Boutsiko, 25% Arta, and 25% Chios, n = 14)] with major differences in their genetic potential with respect to milk yield. Milk samples were collected every 2 wk throughout the lactation period and were analyzed for fat, protein, lactose, and somatic cell count (SCC). In addition, milk plasmin (PL), plasminogen (PG), and plasminogen activator (PA) activities were determined. The Chios breed had the greatest average daily milk yield, the synthetic breed had an intermediate milk yield, and ewes of the Boutsiko breed had the lowest milk yield. Milk samples obtained from the Boutsiko breed had similar PL and PA activities, compared with those obtained from the other 2 breeds. The ratio of PG:PL was less in milk samples from the Boutsiko breed compared with the other 2 breeds, indicative of an increased rate of conversion of PG to PL for this breed. There was no correlation between PL activity and daily milk yield in ewes from all 3 breeds. Activities of PL, PG, and PA were greater in ovine milk with elevated SCC (>300,000/mL) compared with activities in milk with low SCC (<300,000/mL). The ratio of PG:PL was less in the high-SCC group compared with the low-SCC group, which indicates an increased rate of conversion of PG to PL for the high-SCC group. There was a decrease in PG and PA activities as well as in the PG:PL ratio in late lactation milk (mo 5 to 6) when compared with early or mid lactation milk (mo 1 to 4). Thus, the PL-PG system is affected by breed, stage of lactation, and the health status of the udder. No relationship was found between PL activity and daily milk yield in the 3 Greek dairy sheep breeds. Plasmin is not a marker for gradual involution in the Greek sheep breeds studied.
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Affiliation(s)
- G Theodorou
- Department of Animal Science, Agricultural University of Athens, 11855 Athens, Greece
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Choi J, Horne DS, Lucey JA. Effect of Insoluble Calcium Concentration on Rennet Coagulation Properties of Milk. J Dairy Sci 2007; 90:2612-23. [PMID: 17517701 DOI: 10.3168/jds.2006-814] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Rennet-induced gels were made from milk acidified to various pH values or milk at pH 6.0 that had added EDTA. The objective was to examine the effect of removing insoluble Ca (INS Ca) from casein micelles (CM) on rennet gelation properties. For the pH trial, diluted lactic acid was added to reconstituted skim milk to decrease the pH to 6.4, 6.0, 5.8, 5.6, and 5.4. For the EDTA trial, EDTA was slowly added (0, 2, 4, and 6 mM) to reconstituted skim milk, and the final pH values were subsequently adjusted to pH 6.0. Dynamic low amplitude oscillatory rheology was used to monitor gel development. The Ca content of CM and rennet wheys made from these milks was measured using inductively coupled plasma spectroscopy. The INS Ca content of milk was altered by the acidification pH values or level of EDTA added. In all samples, the storage modulus (G' ) exhibited a maximum (GM), with a decrease in G' during longer aging times. Gels made at pH 6.4 had higher GM compared with gels made at pH 6.7 probably due to the reduction in electrostatic repulsion, whereas the INS Ca content only slightly decreased. The highest GM value of gels was observed at pH 6.4 and the GM value decreased with decreasing pH from 6.4 to 5.4. This was due to an excessive loss of INS Ca from CM. There was a decrease in GM with the increase in the concentration of added EDTA, which was probably due to the loss of colloidal calcium phosphate, which weakens the integrity of CM. Loss tangent (LT) values at GM increased with a reduction in milk pH and the addition of EDTA to milk. Rennet gels at the point of the GM were subjected to constant low shearing to fracture the gels. With a reduction in INS Ca content, the yield stress decreased, whereas LT values increased indicating a weaker, more flexible casein network. Microstructure of rennet-induced gels near the GM point and 2 to 10 h after this point was studied using fluorescence microscopy. At GM, gels made from milk acidified to pH 6.4 exhibited more branched, interconnected networks, whereas strands and clusters became larger with a reduction in milk pH to 5.4. Gels made from milk with EDTA added had more finely dispersed protein clusters compared with gels made from milk with no EDTA added. These microscopic observations supported the effect of loss of INS Ca on GM and LT. There was a decrease in apparent interconnectivity between strands in gel microstructure during aging, which agreed with the decrease in G' after GM. It can be concluded that low levels of solubilization of INS Ca and the decrease in milk pH resulted in an increase in GM. With greater losses of INS Ca there was excessive reduction in cross-linking within CM, which resulted in weaker, more flexible rennet gels. This complex behavior cannot be explained by adhesive hard sphere models for CM or rennet gels made from these CM.
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Affiliation(s)
- J Choi
- Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison 53706, USA
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A comparison of low-intensity ultrasound and oscillating rheology to assess the renneting properties of casein solutions after UHT heat pre-treatment. Int Dairy J 2007. [DOI: 10.1016/j.idairyj.2005.12.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ismail B, Choi LH, Were LM, Nielsen SS. Activity and Nature of Plasminogen Activators Associated with the Casein Micelle. J Dairy Sci 2006; 89:3285-95. [PMID: 16899661 DOI: 10.3168/jds.s0022-0302(06)72365-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In fresh milk, plasminogen, the zymogen form of plasmin (PL), is the predominant form. Therefore, plasminogen activators (PA) can contribute significantly to PL activity in milk. Both tissue-type PA (tPA) and urokinase-type PA (uPA) exist in milk; however, contradictory findings have been reported for which type of PA is most closely associated with the casein micelles. Little is known about the factors that might lead to variations in the individual activities of the PA. The objective of this work was therefore to investigate possible factors that might affect the association of tPA and uPA with the casein micelle and their activities thereafter. Plasminogen activators were isolated from milk samples with different somatic cell counts following 2 different isolation protocols. Determination of uPA, tPA, and PL activities was carried out quantitatively following chromogenic assays using 2 different substrates, and qualitatively using specialized sodium dodecyl sulfate-PAGE. Different isolation methods and conditions led to differences in uPA, tPA, and PL activities. Urokinase-type PA activity was significantly higher in PA fractions isolated from milk with high somatic cell counts than from milk with low somatic cell counts. Activity results indicated that in pasteurized milk uPA could dissociate from the somatic cells and bind to casein. Moreover, a high level of PL in isolated PA fractions contributed to significantly enhanced PA activities. Overall, results confirmed the association of both uPA and tPA with the casein micelle; however, their amounts, activities, and molecular weights varied based on the nature of the milk and methods of separation, with uPA being the PA with greater potential to affect plasminogen activation in milk.
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Affiliation(s)
- B Ismail
- Purdue University, Department of Food Science, 745 Agricultural Mall Drive, West Lafayette, IN 47907, USA
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Leiber F, Kreuzer M, Leuenberger H, Wettstein HR. Contribution of diet type and pasture conditions to the influence of high altitude grazing on intake, performance and composition and renneting properties of the milk of cows. ACTA ACUST UNITED AC 2006. [DOI: 10.1051/animres:2005041] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Frohbieter KA, Ismail B, Nielsen SS, Hayes KD. Effects of Pseudomonas fluorescens M3/6 Bacterial Protease on Plasmin System and Plasminogen Activation. J Dairy Sci 2005; 88:3392-401. [PMID: 16162512 DOI: 10.3168/jds.s0022-0302(05)73023-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Heat-stable proteases produced by the psychrotroph Pseudomonas fluorescens M3/6 have been shown to affect the plasmin system in milk, which in turn will affect the quality of processed milk. The M3/6 proteases cause dissociation of plasmin from casein in minimally processed milk. The objective of this work was to study the effect of M3/6 protease on the plasmin system, as well as its role in plasminogen activation, under commonly applied cheese-making conditions. Isolated M3/6 protease was added to raw milk, which then was pasteurized, and subjected to pH adjustments and CaCl2 addition. Casein and whey fractions were separated by chymosin treatment then analyzed for plasmin activity. Individual and interaction effects of M3/6 protease addition, pH treatment, and CaCl2 addition on plasmin activity were studied. Enzyme activity assays were carried out to study individually the effect of M3/6 protease on plasmin system components. Kinetic parameters were calculated to characterize the effect of M3/6 protease on plasminogen activation. Plasmin activity increased in the curd fractions of the protease-treated milk that was subjected to conditions most resembling cheese-making conditions, indicating that M3/6 protease triggered plasminogen activation rather than dissociation of plasmin from casein micelles. Results from the studies on plasminogen activation confirmed that the observed activation of plasminogen in protease-treated samples subjected to cheese making conditions was attributed to the stimulatory effect M3/6 protease had on plasminogen activators (PA). The M3/6 protease stimulated human and bovine PA by increasing their activity 4.5- and 2.5-fold, respectively. Similarly, the catalytic efficiencies of human urokinase-type PA and bovine PA were increased in the presence of M3/6 protease by 12- and 4-fold, respectively. Our research presented a basic step toward fully understanding the effect of bacterial proteases under different processing conditions, where the gathered information can aid in better control of processing conditions based on the desired outcome.
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Affiliation(s)
- K A Frohbieter
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA
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Leitner G, Merin U, Silanikove N. Changes in milk composition as affected by subclinical mastitis in goats. J Dairy Sci 2005; 87:1719-26. [PMID: 15453484 DOI: 10.3168/jds.s0022-0302(04)73325-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The mechanism of the effects of subclinical mastitis (SM) at the glandular level in dairy goats on milk yield and its composition as expressed in curd yield (Yc) was studied. Twenty-five Israeli goats of various crossbreeds were chosen; one udder half was naturally infected with identified coagulase-negative staphylococci, and the contralateral gland was free of bacteria. The milk yield of the infected halves was significantly lower than that of the uninfected ones. Somatic cell count and N-acetyl-beta-D-glucosaminidase activity were significantly higher in the infected halves. The lactose concentration in the infected glands was significantly lower than that in the uninfected ones, casein concentrations did not differ, and the whey protein and albumin concentrations were significantly higher in the infected glands. Plasmin activity was significantly higher in the infected glands, whereas plasminogen activity was undetectable. Concentrations of Ca2+ did not differ, whereas Ca2+ activity was significantly lower in the infected glands. The proteose peptone concentration was 1.5 times as great in the infected glands as in the uninfected ones. The Yc was significantly lower in the infected halves, and clotting time was significantly longer. The mechanisms of the effects of SM on milk yield and Yc in goats and sheep are discussed and compared.
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Affiliation(s)
- G Leitner
- National Mastitis Reference Center, Kimron Veterinary Institute, Bet Dagan 50250, Israel.
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Bianchi L, Bolla A, Budelli E, Caroli A, Casoli C, Pauselli M, Duranti E. Effect of Udder Health Status and Lactation Phase on the Characteristics of Sardinian Ewe Milk. J Dairy Sci 2004; 87:2401-8. [PMID: 15328261 DOI: 10.3168/jds.s0022-0302(04)73362-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mammary involution and inflammation are known to negatively affect milk quality. A trial was carried out to elucidate the mechanism by which udder health status and lactational phase determine compositional modifications in ovine milk. A total of 60 individual milk samples was collected from a group of 20 pluriparous Sardinian ewes from mid to late lactation. Each sample was assessed for its chemical characteristics, quantitative distribution of casein fractions, lactodynamographic characteristics, and enzymatic activity. Udders were classed as healthy, doubtful, or infected on the basis of repeated somatic cell counts, and samples were grouped in 3 classes of days in milk. Results indicated that both udder inflammation and mammary involution can increase plasmin (PL) activity (15.6 vs. 18.4 U/mL in healthy vs. infected udders; 14.0 vs. 20.2 U/mL in phase 1 vs. 3), which is responsible for an evident protein breakdown in milk. Significant differences between groups were observed for several characteristics. With regard to udder heath status, casein index was lower in the infected vs. healthy udders (74.8 vs. 76.6%), and beta(tot)-casein showed a similar trend (43.9 vs. 46.6%). As a consequence of protein degradation, gamma-casein (5.78 vs. 2.82%) and proteolysis index (7.60 vs. 3.82) increased in the infected group with respect to the healthy group. Udder health status also affected milk technological traits. Udder inflammation resulted in longer clotting time (20.7 vs. 16.5 min for infected vs. healthy, respectively) and in poorer curd firmness (35.6 vs. 47.6 mm for infected vs. healthy, respectively). Frequency of samples reactive to rennet was 100, 93, and 67%, respectively, for healthy, doubtful, and infected groups. With regard to lactational phase, a decrease in alpha(s1)-casein (39.13 vs. 29.36%) and beta(1)-casein (23.41 vs. 19.36%) occurred during phase 1 vs. 3, whereas kappa + alpha(s2)-casein increased (12.30 vs. 21.56%, phase 1 vs. 3). Correlation coefficients confirmed the role of PL in protein degradation. It was concluded that PL activity was strongly affected by both lactational phase and udder health status and, in turn, could be an important agent enhancing milk quality detriment.
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Affiliation(s)
- L Bianchi
- Dipartimento di Scienze Zootecniche, Università degli Studi di Perugia, 06121 Perugia, Italy
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Albenzio M, Caroprese M, Santillo A, Marino R, Taibi L, Sevi A. Effects of Somatic Cell Count and Stage of Lactation on the Plasmin Activity and Cheese-Making Properties of Ewe Milk. J Dairy Sci 2004; 87:533-42. [PMID: 15202636 DOI: 10.3168/jds.s0022-0302(04)73194-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The experiment was conducted from March to July 2002 using 5 intensively managed flocks of Southern Italy. In each flock, 2 groups of 50 ewes were created. The groups were designated LSCC (low somatic cell count [SCC]) when their milk SCC was lower than 500,000/mL and HSCC (high SCC) when their milk SCC was higher than 1,000,000/mL. Bulk milk and whey samples were analyzed for fat, total protein, lactose, casein, and whey protein contents. Renneting properties of milk were also determined. Moisture, NaCl, and nitrogen fractions were determined in fresh cheese curds. In addition, plasmin (PL) and plasminogen (PG) activities in milk and cheese were monitored. The proteolytic activity of plasmin by urea-polyacrylamide gel electrophoresis and the white blood cell (WBC) differentials were determined. The HSCC resulted in higher pH values in milk and in higher moisture and lower fat contents in fresh cheese curds. Moreover, a lower recovery of fat and whey proteins was obtained from the HSCC than from the LSCC raw milk. The crude protein and casein contents were higher in the HSCC than in the LSCC curds during early and midlactation; an opposite trend was observed in late lactation. Plasmin and PG activities underwent more marked fluctuations in the LSCC than in the HSCC curds through lactation. The results of this experiment demonstrate that the PL activity in ewe milk is markedly influenced by the SCC, although SCC is not the only parameter for predicting PL and PG evolution in ewe milk. The LSCC milk resulted in a higher proteolytic potential of Canestrato pugliese cheese curds.
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Affiliation(s)
- M Albenzio
- Dipartimento PRIME, Università di Foggia, Italy.
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Lucey JA, Johnson ME, Horne DS. Invited Review: Perspectives on the Basis of the Rheology and Texture Properties of Cheese. J Dairy Sci 2003; 86:2725-43. [PMID: 14507008 DOI: 10.3168/jds.s0022-0302(03)73869-7] [Citation(s) in RCA: 398] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Physical and chemical properties of cheese, such as texture, color, melt, and stretch, are primarily determined by the interaction of casein (CN) molecules. This review will discuss CN chemistry, how it is influenced by the cheese-making process, and how it impinges on the final product, cheese. We attempt to demonstrate that the application of principles governing the molecular interactions of CN can be useful in understanding the many physical and chemical properties of cheese and, in turn, how this can be used by the cheesemaker to produce the desired cheese. The physical properties of cheese (as well as flavor) are influenced by a number of factors including: milk composition; milk quality; temperature; the rate and extent of acidification by the starter bacteria; the pH history of cheese; the concentration of Ca salts (proportions of soluble and insoluble forms); extent and type of proteolysis, and other ripening reactions. Our hypothesis is that these factors also control and modify the nature and strength of CN interactions. The approach behind the recently proposed dual-binding model for the structure and stability of CN micelles is used as a framework to understand the physical and chemical properties of cheese.
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Affiliation(s)
- J A Lucey
- Department of Food Science, University of Wisconsin-Madison, 53706, USA.
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Esteves CLC, Lucey JA, Wang T, Pires EMV. Effect of pH on the gelation properties of skim milk gels made from plant coagulants and chymosin. J Dairy Sci 2003; 86:2558-67. [PMID: 12939079 DOI: 10.3168/jds.s0022-0302(03)73850-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The effect of three milk pH values, 6.0, 6.3 and 6.7, on gelation properties was monitored by small amplitude oscillatory rheology as well as a large deformation (yield) test for gels induced by the plant coagulants, Cynara cardunculus L. and Cynara humilis L., and chymosin. Gel microstructure was studied using confocal scanning laser microscopy. For each coagulant, a decrease in pH of milk resulted in a decrease in gelation time (tg), and an increase in the rate of increase in storage modulus (G'). At pH 6.0 and 6.3, plant coagulant-induced gels reached a maximum value in G' (G'max) followed by a decrease in G' values during the rest of the experiment, reflecting higher proteolytic activity of plant coagulants towards caseins as determined by SDS-PAGE. Gels produced at pH 6.0 and 6.3, exhibited a minimum in loss tangent (tan delta) followed by slight increase in tan delta during gel aging, that may have been associated with faster rearrangements of the gel network structure. In gels aged for approximately 6 h, the values for G', tan delta at low frequency (0.006 Hz) and yield stress were higher for chymosin than for plant-induced gels. For gels with the same pH value, no major differences were observed in microstructure between coagulants. Gels made at low pH values (6.3 and 6.0) appeared to have a denser or more interconnected structure than gels made at pH 6.7. Our results suggest that, at a low pH, the type of coagulant used in gelation is likely to have a considerably impact on gel/cheese structure.
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Affiliation(s)
- C L C Esteves
- Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison WI 53706, USA
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