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Effect of cold plasma treatment on the functional properties of MPC 85.

S. Raghunath

Abstract:

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Effect of cold plasma treatment on the functional properties of MPC 85.
S. Raghunath*, T. Schoenfuss, K. Mallikarjunan, G. Annor. University of Minnesota-Twin Cities Saint Paul, MN.

Milk protein concentrate (MPC) is a high-quality protein found in milk and a complete protein consisting of both casein and whey. MPC is known to have poor solubility and flowability due to physicochemical interactions. The cold plasma (CP) treatment is known to modify protein and thereby alter its functionality. The scope of this study is to improve functional characteristics of MPC after cold plasma treatment and understand mechanisms involved. In this study, MPC 85 powder was directly subjected to various treatment duration (15 min to 60 min) with cold plasma at 25�C, 120 W radio frequency (RF) power, and flowrates of 10 and 25 cm3/min of argon and CO2. The samples (treated and untreated) were then subjected to various physiochemical tests including flowability, water activity, solubility, moisture content, dry mass, foaming capacity, stability, pH, wettability, zeta potential, water binding capacity and solubility (at 50, 22 and 5�C) in triplicates. The statistical analysis was done using ANOVA, and the significant differences were calculated (P < 0.05) using Tukey HSD. Flow index significantly increased by 50% at 45 min. Foaming capacity and stability had a 63% (157.33 to 257.33 mL/g) and 64% (52.54 to 86.11%) increase till 30 min and then had a drop to 22% (192.00 mL/g) at 60 min whereas the stability remained constant. The pH remained constant in the range of 6.8 — 7.00. There was an 80% decrease (93s to 18.67s) in wettability and 38% (45.16 to 62%) increase in water binding capacity after 45 min. Zeta potential did not follow a particular trend. The dry mass remained constant, but the moisture content decreased to 77% (9 to 2). The solubility increased significantly after CP treatment but the maximum increase was observed at different time points for each temperature. The solubility at 50 and 5�C had an increase of 16% and 97%, respectively. The flowability, wettability, foaming capacity and stability, water binding capacity improved following the CP treatment due to the change in protein structure. Results proved that the samples showed better functionality in comparison to untreated samples. RF cold plasma could provide an alternative non-thermal processing approach to modify functional properties of MPC 85 and can be tailored for specific applications.

Keywords: cold plasma, functionality, milk protein concentrate.

Biography: Sonali Raghunath is a PhD student at the University of Minnesota - Twin Cities, USA, working on the application of pulsed electric field and cold plasma as a treatment for milk proteins. She has a Master's degree in Food Science from the University of Minnesota (2019) and a Bachelor's degree in Food Technology (2017) from Anna University, India. Sonali has been working in non-thermal processing techniques and have explored the use of ultrasound for cold brewing of tea for her Master's and is continuing to explore the opportunities in non-thermal processing for her PhD in Schoenfuss dairy lab.