Ingredients and pH are Key to Clear Beverages that Contain Whey Protein

Abstract

A challenge of shelf stable beverages that contain whey protein is that a small portion of protein can be denatured and aggregated during thermal processing, resulting in a turbid solution or white precipitate that consumers perceive as a defect. In this study, 3 approaches were taken to reduce turbidity in heat-treated beverages that contain whey protein: (1) centrifugation to remove insoluble protein aggregates, (2) addition of ingredients, and (3) alteration of pH in the range from 3.0 to 4.0. At pH 3.6 and below, all samples were essentially clear both before and after heating for all ingredients. At a pH of 3.8 and above, ingredient selection was crucial to solution clarity after heat treatment. At a pH of 4.0, addition of salts at both 10 and 50 mM increased the turbidity significantly compared to the control, which contained only whey protein in water. Neither addition of sugars at 25, 50, and 100 g/L, nor addition of sugar alcohols at 25 g/L significantly affected turbidity after heat treatment compared to the control. However, sugar alcohols added at 50 or 100 g/L significantly reduced turbidity after heat treatment compared to the control. Removal of insoluble protein aggregates by centrifugation prior to heat treatment resulted in a statistically significant decrease in turbidity after heat treatment. Understanding these results at the molecular level will assist food scientists in selecting processing treatments, ingredients, and pH in the development of shelf stable clear beverages that contain whey protein.

Ricotta Cheese Whey-Fruit-Based Beverages: Pasteurization Effects on Antioxidant Composition and Color

“…In contrast to what was reported for whey-based fruit juice beverages, after thermal treatments, no formation of precipitate was observed at the bottom of the bottles, whatever the formulation, even if some turbidity, ranging from about 25 NTU (pear-RCW beverage) to about 190 NTU (blueberry-RCW beverage), was found. The values of turbidity found in this research are 10-80 times lower than the range of turbidity reported by Baccouche et al [30] for whey-based prickly pear beverages, suggesting that replacing whey with RCW in fruit-based functional beverages could maintain drink clarity at a pH near to the isoelectric point of proteins, which is about 4.6 [20], as found in this research for the pear-based beverage. The very low turbidity values found in this research could be due to both the low number of total proteins in the filtered RCW used to prepare drinks (4 g/L) [31], and to its composition, i.e., ≈46% non-protein-nitrogen (urea, ammonia, creatina, creatinine, uric acid, orotic acids, and very low molecular weight components), ≈24% caseinomacropeptide, and ≈38% peptides [31].…”

Encapsulation of Lactobacillus rhamnosus GG in microparticles: Influence of casein to whey protein ratio on bacterial survival during digestion

“…However, the protein composition can also influence other factors like porosity, surface and internal microstructure (Matalanis et al, 2011). Indeed, the nature of the proteins presenting variable physical properties (density, refractive index), size, charge, and stability may be of influence (LaClair & Etzel, 2010). By modifying these properties a more or less porous structure may be obtained.…”

Elaboración de una bebida utilizando subproductos de la industria láctea

“…Como se observa en la Tabla 5 el pH de los tratamientos estuvo entre 3,50 y 3,59. En cuanto al suero ácido, algunos autores concuerdan que el pH influye en las propiedades de la proteína de suero, pues tiene una carga positiva a un pH menor que el punto isoeléctrico (5,2) comportándose como un catión (Gangurde et al, 2011), con aumento de la solubilidad y disminución de la turbidez (LaClair & Etzel, 2010;Park, Bastian, Farcas, & Drake, 2014).…”