Novel Online Sensor Technology for Continuous Monitoring of Milk Coagulation and Whey Separation in Cheesemaking

Abstract

The cheese industry has continually sought a robust method to monitor milk coagulation. Measurement of whey separation is also critical to control cheese moisture content, which affects quality. The objective of this study was to demonstrate that an online optical sensor detecting light backscatter in a vat could be applied to monitor both coagulation and syneresis during cheesemaking. A prototype sensor having a large field of view (LFV) relative to curd particle size was constructed. Temperature, cutting time, and calcium chloride addition were varied to evaluate the response of the sensor over a wide range of coagulation and syneresis rates. The LFV sensor response was related to casein micelle aggregation and curd firming during coagulation and to changes in curd moisture and whey fat contents during syneresis. The LFV sensor has potential as an online, continuous sensor technology for monitoring both coagulation and syneresis during cheesemaking.

Visible-near infrared spectroscopy sensor for predicting curd and whey composition during cheese processing

“…It was shown by Fagan et al [13] that at 40.4°C whey fat concentration increased during syneresis and that this increase in whey fat globules resulted in an increase in light backscatter. This increase in whey fat concentration during syneresis at 40.4°C is due to higher mobility of fat globules at this temperature as they have reached their general melting point of 37°C, allowing them to be expelled throughout syneresis and not just upon cutting of the gel.…”

“…Milk was prepared and coagulated according to the procedure employed by Fagan et al [13]. Coagulation temperature was controlled using a cheese vat connected to a water bath (Lauda, RM 20, Brinkman Instrument Inc., Westbury, NY, USA).…”

“…Light is conducted through another quartz rod, a SMA connector and a *800 lm diameter fibre optic cable (Spectran Specialty Optics, Avon, CN, USA) to the master unit of a miniature fibre optic spectrometer (model SD2000, Ocean Optics, Inc., Dunedin, FL, USA). Light emerging from the fibre optic cable is processed in the spectrometer and the data transferred to a computer through an A/D converter as described by Fagan [13]. Spectra were collected over the range 300-1,100 nm with a resolution of 0.7 nm.…”

Dynamic visualization and microstructure of syneresis of cheese curd during mechanical treatment

“…Syneresis is highly dependent on temperature (Castillo, Payne, Lopez, Ferrandini, & Laencina, 2005;Fagan et al, 2007;Hansen et al, 2010;Lawrence, 1959a;Marshall, 1982), but the rate of whey expulsion is influenced by several other factors such as pH, amount of added CaCl 2 (Marshall, 1982), curd firmness (Hansen et al, 2010;Johnson, Chen, & Jaeggi, 2001;Payne, Hicks, Madangopal, & Shearer, 1993), size of curd grains, composition of milk, and the mechanical treatment generated by the stirring tool in the cheese vat (Lawrence, 1959b). External pressure generated by stirring has been reported to be 10 Pa on average, though collision of curd particles with each other or with the agitation tools can cause brief pressure bursts of 100 Pa or above (Dejmek & Walstra, 2004).…”

“…Lowresolution NMR was introduced by Tellier, Mariette, Guillement, and Marchal (1993) and has been applied in many studies on modelling of whey expulsion and water mobility in rennet curd (Hinrichs, Bulca, & Kulozik, 2007;Özilgen & Kauten, 1994;Tijskens & De Baerdemaeker, 2004) and the effect of gel firmness, pH and temperature on syneresis (Hansen et al, 2010). More recent methods include applying an optical sensor with a large field of view and measuring the backscatter of near infrared light (Castillo et al, 2005;Fagan, Castillo, O'Donnell, O'Callaghan, & Payne, 2008;Fagan et al, 2007;Mateo et al, 2009b). In most studies, however, syneresis has been measured either in the cheese vat or by using a one-dimensional system at constant conditions.…”