Use of the Foodtexture Puff Device to Monitor Milk Coagulation
Lab for Agromachinery and Processing, Katholieke Universiteit Leuven, Faculty of Agricultural Sciences, Kasteelpark Arenberg 30, B-3001 Heverlee, Belgium. Journal of Dairy Science
(Impact Factor: 2.57).
02/2006; 89(1):29-36. DOI: 10.3168/jds.S0022-0302(06)72066-5
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.
Available from: Marta I S Veríssimo
- "Gelation temperature is usually optimized based on cheese making experience, and cutting is performed at previous defined times. However, there are a list of devices available to evaluate coagulum firmness   , some of them suitable for on-line usage. Among them, hot wire probes proved to be capable of detecting the gel point, but are incapable of monitoring the rate of curd firming, which varies with milk composition. "
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ABSTRACT: Abstract Optimum coagulation temperature and cutting time are usually empirically defined. The use of inexpensive acoustic wave sensors to monitor milk coagulation allows monitoring the process in real time, since its early stages. Besides, data are collected with minimum disturbance, which is an advantage over other methodologies, namely rheology. Coagulation of milk was followed by measuring both the frequency and equivalent circuit resistance of a piezoelectric quartz crystal. Three types of milk, ewe, goat and cow, were coagulated using different rennets at three different temperatures. Maximum observed coagulation rate, either with plant or animal rennet, increased with temperature both for ewe and goat milk. Maximum coagulation rate was higher with plant rennet than with animal rennet at 25 °C and 32 °C, while the opposite was found at 50 °C. The time needed to attain maximum coagulation rate was always smaller with ewe's milk than with goat's milk, and maximum coagulation rate was higher with the former. Cow's milk was much more difficult to coagulate and needed twice the rennet quantity used for ewe and goat milk. Cheese obtained with the mentioned types of milk and different rennets shows different flavours, usually perceived by experts and connoisseurs, and that an electronic nose built in our laboratory was also able to distinguish. One sensor was enough to separate cheeses made from cow, ewe and goat milk. Besides, the addition of a second sensor allowed to separate the cheeses by rennet among the ones produced with the same milk.
Available from: cabi.org
Available from: Stefan Karastojanov
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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, firmness
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