Ferreira, João Paulo

Gomes, Ana Maria

Vilela, Tatiana Paula

English

Repositório Institucional da Universidade Católica Portuguesa

The Effect of Dissociating Agents on the Dispersion of a Grated CheeseConclusions for its Structure-Holding InteractionsJune 17th 2019Tatiana Paula VilelaSummary Introduction Material and Methods Results and Discussion Conclusions References17/06/19Tariana Paula Vilela 2IntroductionCheese Microstructure[1]17/06/19Tatiana Paula Vilela 3Figure 1 - Cheese Microstructure. Image from https://pt.slideshare.net/MarkFink/the-microstructure-of-australian-cheddar-cheese-and-other-dairy-products Cheese microstructure affects:[2]o Flavouro Textureo Meltingo QualityIntroductionEmmental Cheese[3]17/06/19Tatiana Paula Vilela 4Swiss-typeSemi-hard curdMatrix acidification after pressing of curdColloidal calcium concentration increases with casein concentration at drainageFormation of para--casein matrix with Ca-casein ratio close to that of milk casein micellesIntroductionCheese Interactions[4] [5]17/06/19Tatiana Paula Vilela 5Main  Interactions in CheeseHydrophobicHydrogen bondsIonicDisulphide bondsIntroductionDissociating Agents[6]17/06/19Tatiana Paula Vilela 6UreaSDSEDTAContribution that each type of interaction had in cheese structureNaClNaOHIntroductionDissociating Agents17/06/19Tatiana Paula Vilela 7NaClNaOHConcentrationsCombinationsModify protein solubility and stabilityIntroductionDissociating Agents[7] [8] [9]17/06/19Tatiana Paula Vilela 8Hydrogen BondsHydrophobic InteractionsIonic bondsDisulphide bondsUreaSDSEDTANaClNaOHMaterial and MethodsDetermination of Total Protein in Cheese[10]17/06/19Tatiana Paula Vilela 9Cheese +NaOH 0.1M70ºCFat layerPelletSupernatant -% total proteinUV 280 nmMaterial and MethodsDetermination of Soluble Protein in Cheese Dispersions[10]17/06/19Tatiana Paula Vilela 10Cheese +Dissociating Agent70ºCFat layerPelletSupernatant -% soluble proteinUV 280 nmMaterial and MethodsExperimental Design17/06/19Tatiana Paula Vilela 11Dissociating Agent ConcentrationNaCl 0.05 and 0.6 MUrea 1.5 and 6 MSDS 2.5 %EDTA 4 and 50 mMUrea + SDS 6 M + 2.5 %Urea + EDTA 6 M + 4 mMUrea + SDS + EDTA 6 M + 2.5 % + 4 mMNaOH 0.1 MTable 1 – Dissociating agents and combinations used in the study, and respective concentrations.Results and DiscussionDetermination of Total Protein in Cheese17/06/19Tatiana Paula Vilela 12New Method Kjeldahl Method0.315 ± 0.010 g 0.297 ± 0.030 g Difference of 5.7%Results and DiscussionDetermination of Soluble Protein in Cheese Dispersions17/06/19Tatiana Paula Vilela 13Dispersing mediumSoluble Protein (g solubilized protein / g added cheese)Soluble Protein (%)Deionized Water 0.0319  0.006 9.97  1.90NaCl 50 mM 0.0439  0.003 13.70  0.95NaCl 0.6 M 0.0746  0.011 23.33  3.52Urea 1.5 M 0.167  0.018 52.10  5.47Urea 6 M 0.269  0.025 85.30  6.13EDTA 4 mM 0.0905  0.0079 28.67  2.02EDTA 50 mM 0.0730  0.0063 22.83  1.96SDS 2.5 % 0.213  0.007 67.37  1.40Urea 1.5 M + SDS 2.5% 0.282  0.012 88.20  3.60Urea 6 M + SDS 2.5 % 0.270  0.016 85.40  2.40Urea 6 M + EDTA 4 mM 0.275  0.008 87.27  3.56Urea 6 M + SDS 2.5 % + EDTA 4 mM 0.279  0.022 92.13  10.61Table 2 – Dissociating agents and combinations used in the study, and respective quantity ofsoluble cheese protein, as well as percentage of soluble cheese protein obtained.Conclusions17/06/19Tatiana Paula Vilela 14 The new protein quantification method introduced is validfor cheese and probably other lactic matrices (ongoingwork). Cooperation between hydrophobic interactions, hydrogenbonds and ionic interactions are involved in the proteinstructure of Emmental cheese. The main interactions responsible for protein structure inthis cheese matrix are electrostatic, in particular hydrogenbonds, and hydrophobic interactions, since urea (6M)alone can solubilize up to 85% of cheese proteins.References 1. S. J. Vogt, J. R. Smith, J. D. Seymour, A. J. Carr, M. D. Golding, and S. L. Codd,“Assessment of the changes in the structure and component mobility of Mozzarellaand Cheddar cheese during heating,” J. Food Eng., vol. 150, pp. 35–43, 2015 2. El-Bakry M, Sheehan J. Analysing cheese microstructure: A review of recentdevelopments. J Food Eng [Internet]. 2014;125(1):84–96. Available from:http://dx.doi.org/10.1016/j.jfoodeng.2013.10.030 3. V. Gagnaire, E. Trotel, Y. Le Graët, and J. Léonil, “Role of electrostaticinteractions in the curd of Emmental cheese,” Int. Dairy J., vol. 12, pp. 601–608,2002 4. Horne, D. S. (1998). Casein Interactions: Casting Light on the Black Boxes, theStructure in Dairy Products. International Dairy Journal, 8, 171–177 5. Marchesseau, S., Gastaldi, E., & Lagaude, A. (1997). Influence of pH on ProteinInteractions and Microstructure of Process Cheese. Journal of Dairy Science,80(8), 1483–1489. https://doi.org/10.3168/jds.S0022-0302(97)76076-417/06/19Tatiana Paula Vilela 15References 6. D. Shukla and B. L. Trout, “Interaction of arginine with proteins and themechanism by which it inhibits aggregation,” J. Phys. Chem. B, vol. 114, pp.13426–13438, 2010 7. von Hagen, J. (2008). Electrophoresis. In Proteomics Sample Preparation(pp. 135–142). Wiley-VCH 8. Gaucheron, F. (2005). The minerals of milk. Reproduction NutritionDevelopment, 45, 473–483. https://doi.org/10.1051/rnd 9. Florence, T. M. (1980). Degradation of protein disulphide bonds in dilutealkali. Biochemical Journal, 189, 507–520. https://doi.org/10.1042/bj1890507 10. Reichardt, W., & Eckert, B. (1991). Zur Betimmung des Proteingehaltesvon Milch, Kase und Fleisch mit Hilfe der Biuret-Reaktion. Die Nahrung, 35(7),731–73817/06/19Tatiana Paula Vilela 16Thanks for the attention!Tatiana Paula Vilela 1717/06/19

The effect of dissociating agents on the dispersion of a grated cheese: conclusions for its structure-holding interactions

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The effect of dissociating agents on the dispersion of a grated cheese: conclusions for its structure-holding interactions

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