title: Application of infrared portable sensor technology for predicting perceived astringency of acidic whey protein beverages.
abstract: Formulating whey protein beverages at acidic pH provides better clarity but the beverages typically develop an unpleasant and astringent flavor. Our aim was to evaluate the application of infrared spectroscopy and chemometrics in predicting astringency of acidic whey protein beverages. Whey protein isolate (WPI), whey protein concentrate (WPC), and whey protein hydrolysate (WPH) from different manufacturers were used to formulate beverages at pH ranging from 2.2 to 3.9. Trained panelists using the spectrum method of descriptive analysis tested the beverages providing astringency scores. A portable Fourier transform infrared spectroscopy attenuated total reflectance spectrometer was used for spectra collection that was analyzed by multivariate regression analysis (partial least squares regression) to build calibration models with the sensory astringency scores. Beverage astringency scores fluctuated from 1.9 to 5.2 units and were explained by pH, protein type (WPC, WPI, or WPH), source (manufacturer), and their interactions, revealing the complexity of astringency development in acidic whey protein beverages. The WPC and WPH beverages showed an increase in astringency as the pH of the solution was lowered, but no relationship was found for WPI beverages. The partial least squares regression analysis showed strong relationship between the reference astringency scores and the infrared predicted values (correlation coefficient >0.94), giving standard error of cross-validation ranging from 0.08 to 0.12 units, depending on whey protein type. Major absorption bands explaining astringency scores were associated with carboxylic groups and amide regions of proteins. The portable infrared technique allowed rapid prediction of astringency of acidic whey protein beverages, providing the industry a novel tool for monitoring sensory characteristics of whey-containing beverages.
authors.affiliation: Department of Food Science and Technology, The Ohio State University, Columbus 43210.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.affiliation: Pepsi-Cola Company, Valhalla, NY 10595.
authors.forename: Siow-Ying
authors.initials: SY
authors.lastname: Tan
authors.affiliation: Pepsi-Cola Company, Valhalla, NY 10595.
authors.forename: William
authors.initials: W
authors.lastname: Mutilangi
authors.affiliation: Department of Food Science and Technology, The Ohio State University, Columbus 43210.
authors.forename: Marcal
authors.initials: M
authors.lastname: Plans
authors.affiliation: Department of Food Science and Technology, The Ohio State University, Columbus 43210. Electronic address: rodriguez-saona.1@osu.edu.
authors.forename: Luis
authors.initials: L
authors.lastname: Rodriguez-Saona
mesh_terms: D000818:Animals; D001628:Beverages; D006863:Hydrogen-Ion Concentration; D008894:Milk Proteins / Q000378:metabolism*; D013649:Taste; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D000067816:Whey Proteins
keywords: acidic beverages; astringency; chemometrics; infrared spectroscopy; whey protein