Abstract

Whey Protein Ready-to-Drink (RTD) beverages are popular nutritional products due to their high protein content, complete amino acid profile, convenience, and flavor. However, astringency imparted by whey protein at low pH (pH <4.5) can significantly reduce consumer liking. Astringency is a complex problem, so it may require a multi-faceted solution. Samples were created through Response Surface Methodology (RSM), utilizing parameters determined through literature review and preliminary testing. There is evidence that sucrose may help to reduce astringency in wine. Various natural sweeteners like stevia, monk fruit extract, and sweet proteins: thaumatin and brazzein were evaluated to observe if they may reduce the astringency in acidic whey protein RTD beverages. Samples were assessed by trained quantitative descriptive analysis (QDA), consumer acceptance, and focus group panels. Formulas were instrumentally measured for pH, brix, zeta potential, and particle size. pH and brix were useful measures for monitoring processing consistency, but neither related to level of astringency of samples. Zeta potential instrumental data coincided with results of previous studies finding that a decrease in zeta potential within the range of pH 3-5 correlated with less astringency with whey protein isolates. Particle size relation to astringency is dependent on the zeta potential. A large particle size measurement does not lead to higher astringency if the molecules do not interact due to electrostatic repulsion. Analytical measurements of the samples were statistically compared for differences that may relate to less astringent beverages. The QDA panel determined the combination of 0.20% thaumatin and 0.22% stevia rebaudioside M to most reduce astringency, however this did not correlate with higher acceptability as its acceptability remained as a neither like nor dislike rating. Consumers evaluated thaumatin, brazzein, and monk fruit to be clean-label ingredients after learning about their natural sources and flavor functionalities. More research about thaumatin, monk fruit, and especially brazzein is needed to find the ideal usage levels in AWB formulation. Brazzein was least preferred according to the focus group panel, who felt it did not reduce astringency. Future research could evaluate whether a higher concentration would be more effective. These findings aim to help sensorially improve acidic whey protein beverage formulations and provide the dairy beverage industry insight on creating and marketing more clean-label products.

Degree

College and Department

Life Sciences; Nutrition, Dietetics, and Food Science

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