Use of the Foodtexture Puff Device to monitor milk coagulation.
ABSTRACT The further automation of cheese-making on an industrial level requires the development of sensor devices to monitor the gelation process and especially the firming phase. In this paper, the Foodtexture Puff Device (FPD) is tested for its ability to monitor the gelation process by comparing it with classical rheometry (G' and G'') in a series of coagulations at different initial milk pH (6.01 to 6.61). The FPD measures the deformation of the surface of the milk during coagulation after applying an air puff directed on this surface. The maximal and minimal deformation values and the deformation range were calculated. A nonlinear model of the registered characteristics with the time point from adding rennet until the end of the gelation process was fitted on the FPD data and also on the classic rheology parameters. It was concluded that the FPD monitored the coagulation process in the same way as the rheology. Moreover, the start point of the coagulation process as well as the strength of the coagulum could be estimated nondestructively. Therefore, the presented technology together with the nonlinear model may be a basis for the development of an industrial monitoring device.
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ABSTRACT: The Foodtexture Puff Device (FPD) is a new device that yields contactless, fast, easy and non-destructive rheological measurements of food products. The instrument applies a controlled air pulse to the surface of a food product, while a laser distance sensor measures the deformation. This approach can be considered as an alternative method for more fundamental rheological properties like storage and loss module, viscosity, elasticity, … especially for industrial applications. In the present work the FPD was evaluated on O/W emulsions. Eight commercial mayonnaise-type products were analyzed with the FPD, a Texture Analyser (spreadability rig) and the rheometer (storage and loss module from a frequency sweep). It was tested at three different selected temperatures with all instruments. The correlation between the results with the instruments was determined. The FPD was able to determine the firmness with a low standard deviation and good temperature sensitivity. In addition, it was shown that the maximum deformation created by the FPD was strongly correlated to the firmness of the emulsions as determined with the texture analyser, and to the storage module of the frequency sweep, determined with the rheometer. Therefore it was concluded that the FPD is well suited and applicable for measuring the firmness of o/w emulsions. It is a flexible instrument that is applicable in an industrial environment due to its real time analyses of rheological characteristics and its ease of use. Key words: Foodtexture Puff Device, o/w emulsion, rheology, firmnessInternational symposium for agriculture and food; 12/2012
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ABSTRACT: The aim of the work presented in this paper was to determine the rennet clotting time of milk by image sequences (2D + t) processing. A computer vision system (CVS) consisting of a computer coupled with a transmitted light microscope equipped with a digital camera was developed. Each image was decomposed into Red, Green, Blue (RGB) color components and luminance histograms, through algorithms implemented with Matlab 7.7 software. These algorithms computed and analyzed the R, G, B color components and luminance histogram peak in each image. It was shown that during milk coagulation, this histogram peak varies according to sigmoidal law Peak(t) = Peakmin + (Peakmax − Peakmin)/[1 + (t/TC)α], where TC is the rennet coagulation time.Journal of Food Engineering 01/2013; 114(2):235–241. DOI:10.1016/j.jfoodeng.2012.07.024 · 2.58 Impact Factor