A new range of beverages from Califia Farms offers 8 grams of plant-based protein per serving.

KANSAS CITY — Protein, the most sought out nutrient by U.S. shoppers according to the “2016 Food and Health Survey” from the International Food Information Council Foundation, Washington, is fueling innovation in the beverage sector. Both ready-to-drink (R.-T.-D.) and powdered mix beverages appeal to consumers looking for quick and convenient ways to increase protein intake.

“Consumers are looking for more from their food,” said Emily Ross, beverage sales, Agropur Ingredients, La Crosse, Wis. “Beverages are no longer just hydrating. They are a protein source, a greens source, an energy source and more.”

Because of availability, and neutral color and flavor, whey and soy proteins have historically been the go-to proteins for beverage formulators. In recent years, ingredient suppliers have introduced myriad other animal- and plant-derived proteins, further driving innovation. More often than not, the formulation contains either animal or plant protein; however, there’s a growing trend to blend proteins in order to pack more into a serving and still maintain an affordable price point.

“What was once a market driven by weight management and sports nutrition is now driven by consumers seeking to achieve personal fitness goals and support healthy lifestyles,” said Jean Heggie, strategic marketing lead, DuPont Nutrition & Health, St. Louis. “As the market moves mainstream, flavor and affordability become more important considerations, and that is what is driving the popularity of blending proteins.

“Increasingly we are seeing formulators move from all-dairy formulations toward soy and dairy blends, not only to improve costs, but drive better flavor profiles,” Ms. Heggie said. “And with the rising popularity of non-dairy beverages, blending soy protein with other plant proteins may help achieve better flavor outcomes, drive to higher protein levels and manage variability in supply.”

This is particularly true when prioritizing protein content claims. Formulators often strive for developing a beverage that contains 20% of the Daily Value of 50 grams of protein, or 10 grams of protein per serving. The products may be described as “high” or “excellent” sources of protein. Those with 10% to 19% of the Daily Value are “good” sources.

Fairlife has introduced a line of milkshakes with 15 grams of dairy protein.

Concerns about solubility

Protein beverage mixes are more forgiving when it comes to ingredient selection, as the mix gets solubilized and consumed almost immediately. With R.-T.-D. beverages, ingredients must remain dissolved through shelf life. This can be challenging with protein.

“There are some basic properties to understand for each type of protein ingredient that will help a formulator avoid some performance issues in R.-T.-D. beverages,” said Kimberlee Burrington, dairy ingredient applications coordinator at the University of Wisconsin — Madison. “For starters, proteins are charged molecules, and the charge will change depending on the pH of the environment that they are exposed to. Each protein has an isoelectric point, which is the pH where the protein has a balance of positive and negative charges and a net charge of zero.”

The balance of charges creates a situation where the proteins have a high level of attractive force between the molecules. The attraction creates an unstable situation in terms of the solubility of proteins.

“For this reason, it is very difficult to formulate a beverage at the isoelectric point of that protein,” Ms. Burrington said. 

Processing and other ingredients also must be considered. For manufacturing and food safety purposes, beverages are categorized by pH. They are either low acid (pH above 4.6) or high acid (pH below pH 4.6). The pH and shelf requirements of the beverage — if it will be shelf stable or refrigerated — impact heat processing parameters and further influence protein stability in solution.

“While protein may be one of the most common fortifying ingredients in R.-T.-D. beverages, it can be the most complicated one,” Ms. Ross said. “No matter what protein source you use, when you heat it up and leave it in a bottle in liquid form for months, you are going to have some chemistry going on between the ingredients. The goal of the product and application will dictate what protein source you use.”

Rosa Sanchez, group manager/beverage innovation at DuPont, said, “The main processing consideration would be hydration of the protein to ensure the protein will be fully hydrated to provide a smooth mouthfeel, excellent suspension and emulsion stability. To ensure a uniform and consistent emulsion quality over shelf life, it is important to keep in mind the homogenization pressure during processing. We recommend 2500/500 psi and two-stage homogenization.”

Ms. Ross compared working with protein in beverages to a bottle of glitter. When the glitter is by itself and safe in a bottle, there are no issues. Once you open the bottle, the glitter goes everywhere.

“When you heat proteins up, you ‘open the bottle,’ and the protein starts attaching and reacting with whatever else is in its vicinity,” Ms. Ross said. “For a R.-T.-D. beverage, that can be fortifying minerals, functional ingredients or even other proteins.”

Every beverage system is different, which makes adding protein to the system challenging. Potential reactions must be identified and properly addressed.

For example, when milk protein concentrate is used in aseptic beverages, the high heat process creates holes in the protein micelle, enabling calcium to be released and react with other micelles and charged ingredients.

“By adding the right buffering system you can protect the micelle during the heating process and ensure shelf life by limiting the reactions of the calcium with the protein,” Ms. Ross said.

Recognizing the challenges of formulating R.-T.-D. protein beverages, and the growing trend to blend proteins, the Center for Dairy Research (C.D.R.) at the University of Wisconsin — Madison partnered with Dairy Management Inc., Rosemont, Ill., and the U.S. Dairy Export Council, Arlington, Va., on research to explore functional and nutritional interactions of dairy and plant proteins in beverages. The results will be presented at the International Whey Conference in September.

DuPont is introducing an isolated soy protein designed to improve the profitability of R.-T.-D. high-protein beverages. The ingredient enables replacement of up to 50% of the dairy protein in beverage formulations without compromising sensory performance or protein nutrition.

It is an exciting time for protein beverage innovation. However, the R.-T.-D. industry is expanding so rapidly that many companies find themselves in the position of mixing and processing ingredients in a way that has not been done before, let alone studied on an academic level, Ms. Ross said. 

“This means it’s on the formulators to explore what is actually happening in the bottle, from batching to processing to one year into the shelf life,” she said. “If you are seeing stability issues with your product, a good way to identify the problem is to perform a matrix study with the ingredients. Systematically remove one ingredient at a time to try and identify the single or multiple ingredients that could be reacting and causing the defect. Once you have those identified you can start to look at what is really going on and address it.”