Monitoring Viscosity and Total Solids Content of Milk Protein Concentrate Using an Inline Acoustic Flowmeter at Laboratory Scale

Abstract

Control of milk concentrate viscosity and total solids (TS) content prior to spray drying can improve dairy ingredient manufacture. However, the availability of hygienic and appropriately pressure rated process viscometers for inline monitoring of viscosity is limited. An acoustic flowmeter (FLOWave) is an inline process analytical technology (PAT) tool that measures changes in acoustic signals in response to changes in liquid properties (i.e., acoustic transmission (AT), acoustic impedance (AI), temperature and volume flowrate). In this study, an acoustic flowmeter is evaluated as an inline PAT tool for monitoring viscosity of milk protein concentrate (MPC85), protein and TS content of (MPC85), and standardised MPC (sMPC). Laboratory scale experiments were carried out at 45 °C for five different concentrations (4–21%) of MPC85 and sMPC. Results showed that AT decreased with an increase in MPC85 viscosity (e.g., AT was 98.79 ± 0.04% and 86.65 ± 0.17% for 4% and 21% TS content, respectively). Non-linear regression was carried out to develop a relationship between AT and offline viscosity (R2 (coefficient of determination) value = 0.97 and standard error of prediction = 1.86 mPa·s). AI was observed to increase at higher protein and TS content which was dependent on protein to total solid ratio (P_TSR). Multiple linear regression was carried out to develop the relationship between AI, protein content, TS content and P_TSR. Results demonstrated that AI could be used to monitor the protein and TS content of milk protein concentrate (R2 > 0.96). Overall this study demonstrated the potential of an inline acoustic flowmeter for monitoring process viscosity, protein and TS during dairy concentrate processing.

A Potentially Ecosustainable Hazelnut/Carob-Based Spread

“…Previous work [ 47 ] highlighted a strong effect of total soluble solid (TSS) concentration on the apparent viscosity of oat milk, thus showing a 145%, 504%, and 1388% increase in viscosity as the TSS increased from 5 to 10, 15, and 20 °Brix, respectively. Similarly, [ 48 ] found a strict direct dependency between total solid content and viscosity in their study on monitoring the total solid content of milk protein concentrate by using acoustic transmission technology.…”

“…Similarly, [48] found a strict direct dependency between total solid content and viscosity in their study on monitoring the total solid content of milk protein concentrate by using acoustic transmission technology.…”

Principles of lactose crystallization and rheology of milk protein concentrate

“…The viscosity of MPC increases exponentially with increasing total solids (TS), in the range of 44 to 50% TS (Hayashi & Kudo, 1989;Bista et al, 2020). At high concentrations (above 40% TS), even a slight increase in concentration results in a significant increase in viscosity (Bienvenue et al, 2003).…”

"Survey of Integrated Viscosity Sensing Methods for the Augmentation of Mobile Food Scanner and In-line Sensing"

“…These viscometers can measure the viscosity in macroscopic materials but are insufficient for microscopic materials[26]. Researchers have exploited other techniques and sensing methods for viscosity detection for food quality control, listed in Table 2[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Most of those techniques are laboratory-based measurement, the cost of viscometry measurements becomes very high since they require substantial labor contribution and need a qualified laboratory assistant.…”