title: Contributions to ultrasound monitoring of the process of milk curdling.
abstract: Ultrasound evaluation permits the state of milk being curdled to be determined quickly and cheaply, thus satisfying the demands faced by today's dairy product producers. This paper describes the non-invasive ultrasonic method of in situ monitoring the changing physical properties of milk during the renneting process. The basic objectives of the study were, on the one hand, to confirm the usefulness of conventional non-destructive ultrasonic testing (time-of-flight and attenuation of the ultrasound waves) in monitoring the process in the case of ewe's milk, and, on the other, to include other ultrasound parameters which have not previously been considered in studies on this topic, in particular, parameters provided by the Fast Fourier Transform technique. The experimental study was carried out in a dairy industry environment on four 52-l samples of raw milk in which were immersed 500kHz ultrasound transducers. Other physicochemical parameters of the raw milk (pH, dry matter, protein, Gerber fat test, and lactose) were measured, as also were the pH and temperature of the curdled samples simultaneously with the ultrasound tests. Another contribution of this study is the linear correlation analysis of the aforementioned ultrasound parameters and the physicochemical properties of the curdled milk.
authors.affiliation: Department of Applied Physics, School of Technology, University of Extremadura, Avenida de la Universidad, s/n, 10003 Cáceres, Spain. Electronic address: ajimenez@unex.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Jiménez
authors.affiliation: Department of Applied Physics, School of Technology, University of Extremadura, Avenida de la Universidad, s/n, 10003 Cáceres, Spain.
authors.forename: Montaña
authors.initials: M
authors.lastname: Rufo
authors.affiliation: Department of Applied Physics, School of Technology, University of Extremadura, Avenida de la Universidad, s/n, 10003 Cáceres, Spain.
authors.forename: Jesús M
authors.initials: JM
authors.lastname: Paniagua
authors.affiliation: Department of Food Technology, Centro Tecnológico Agroalimentario Extremadura (CTAEX), Apdo. Correos 435, 06080 Badajoz, Spain.
authors.forename: Abel T
authors.initials: AT
authors.lastname: Crespo
authors.affiliation: Department of Food Technology, Centro Tecnológico Agroalimentario Extremadura (CTAEX), Apdo. Correos 435, 06080 Badajoz, Spain.
authors.forename: M Patricia
authors.initials: MP
authors.lastname: Guerrero
authors.affiliation: Department of Food Technology, Centro Tecnológico Agroalimentario Extremadura (CTAEX), Apdo. Correos 435, 06080 Badajoz, Spain.
authors.forename: M José
authors.initials: MJ
authors.lastname: Riballo
mesh_terms: D000818:Animals; D003612:Dairying; D005583:Fourier Analysis; D008892:Milk; D008894:Milk Proteins / Q000378:metabolism*; D034561:Sheep, Domestic; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*
chemical_list: D008894:Milk Proteins
keywords: A-scan; Correlation study; Fast Fourier Transform; Milk coagulation process monitoring; Nondestructive ultrasound; Protein content