title: Evaluation of milk compositional variables on coagulation properties using partial least squares.
abstract: The aim of this study was to investigate the effects of numerous milk compositional factors on milk coagulation properties using Partial Least Squares (PLS). Milk from herds of Jersey and Holstein-Friesian cattle was collected across the year and blended (n=55), to maximise variation in composition and coagulation. The milk was analysed for casein, protein, fat, titratable acidity, lactose, Ca2+, urea content, micelles size, fat globule size, somatic cell count and pH. Milk coagulation properties were defined as coagulation time, curd firmness and curd firmness rate measured by a controlled strain rheometer. The models derived from PLS had higher predictive power than previous models demonstrating the value of measuring more milk components. In addition to the well-established relationships with casein and protein levels, CMS and fat globule size were found to have as strong impact on all of the three models. The study also found a positive impact of fat on milk coagulation properties and a strong relationship between lactose and curd firmness, and urea and curd firmness rate, all of which warrant further investigation due to current lack of knowledge of the underlying mechanism. These findings demonstrate the importance of using a wider range of milk compositional variables for the prediction of the milk coagulation properties, and hence as indicators of milk suitability for cheese making.
authors.affiliation: Department of Food and Nutritional Sciences,University of Reading,Whiteknights, PO Box 226,Reading, RG6 6AP,UK.
authors.forename: Julie H
authors.initials: JH
authors.lastname: Bland
authors.affiliation: Department of Food and Nutritional Sciences,University of Reading,Whiteknights, PO Box 226,Reading, RG6 6AP,UK.
authors.forename: Alistair S
authors.initials: AS
authors.lastname: Grandison
authors.affiliation: Department of Food and Nutritional Sciences,University of Reading,Whiteknights, PO Box 226,Reading, RG6 6AP,UK.
authors.forename: Colette C
authors.initials: CC
authors.lastname: Fagan
mesh_terms: D000818:Animals; D002364:Caseins / Q000032:analysis; D002417:Cattle; D002452:Cell Count; D055598:Chemical Phenomena; D012085:Chymosin / Q000378:metabolism; D005223:Fats / Q000032:analysis; D006017:Glycolipids; D006023:Glycoproteins; D006863:Hydrogen-Ion Concentration; D007785:Lactose / Q000032:analysis; D016018:Least-Squares Analysis; D066292:Lipid Droplets; D008892:Milk / Q000737:chemistry* / Q000166:cytology; D008894:Milk Proteins / Q000032:analysis / Q000378:metabolism; D014508:Urea / Q000032:analysis
chemical_list: D002364:Caseins; D005223:Fats; D006017:Glycolipids; D006023:Glycoproteins; D008894:Milk Proteins; C110367:milk fat globule; D014508:Urea; C025350:rennet; D012085:Chymosin; D007785:Lactose
keywords: Milk coagulation properties; milk composition; partial least squares