CHICAGO — Proteins flocculate and float in beverages. Minerals precipitate, forming a layer of sediment. Color emulsions break down, discoloring the neck of a bottle. These are some of the formulation flaws that may occur in ready-to-drink beverages, in particular the growing number of complex systems serving as a carrier for better-for-you ingredients.

While directions to shake before consumption may provide an immediate fix, it’s the appearance on shelf that deters purchase, because not only do we eat with our eyes — we drink with them, too. This is why many beverages include texturants, a type of ingredient that stabilizes the system by keeping additives ranging from colors and flavors to vitamins and minerals to fiber and protein in suspension.

Texturants also impact the rheological properties of a beverage such as viscosity, as well as appearance and drinking sensation. This includes how the beverage appears when it’s being poured. It might be smooth or lumpy, thick or thin. It also includes how the beverage coats the inside of the bottle as well as inside the mouth, as well as the oral sensation with the first gulp.

Appearance matters. It provides the consumer a cue to the flavor and mouthfeel of a beverage and is influenced by both color and visual texture. Opaque, for example, suggests thick with a white hue communicating creamy/milky and dark brown conveying rich chocolate. The consumer expects hydrated chia seeds to have a slightly slimy mouthfeel while oat flakes will be a little chewy.

Consumers often think they taste texture, but in reality texture is a flavorless attribute. Texture may, however, impact flavor perception derived from basic tastes and aromas. There are five basic tastes: bitter, salty, sour, sweet and umami. These are not to be mistaken with aromas, the flavors processed by olfactory cells in the nose. Together the basic tastes and aromas comprise the flavor of a beverage. Thick systems may slow the diffusion of tastes and aromas, while thinner systems often hit the taste buds as soon as a beverage touches the lips.

Texturants generally are added to stabilize a fluid system into a homogeneous, smooth beverage. This includes keeping fruit particulates in suspension in juices and smoothies, preventing separation of cocoa powder in chocolate milk and keeping essential oils in solution. They also may be used to enhance the mouthfeel of reduced-sugar and reduced-fat beverages, as both sugar and fat contribute to the body of a beverage. When they are reduced or removed, texturants are added to simulate the sensory experience consumers expect.

Surprisingly, texture is a beverage attribute that for a long time was not considered during the early stages of product development. It was only once the prototype went out for consumer testing and feedback was negative regarding visual appearance and mouthfeel, that formulators addressed texture. At this point, it’s often too late. Texture is best addressed during ingredient selection, as some issues may be overcome through ingredient selection. This includes the use of complementary ingredients that want to stay in solution. And for those challenging situations, texturants are included.

Most texturants used in beverages are carbohydrates and belong to the broad ingredient category called hydrocolloids. The primary function of all hydrocolloids is alluded to in the name, where the prefix “hydro” means water and “colloid” means a gelatinous substance.

Hydrocolloids are a group of long-chain polymers — polysaccharides (mainly fibers, starches and gums) and proteins — that are characterized by their ability to form viscous dispersions or gels by binding water and keeping ingredients in suspensions. Secondary functions include emulsification, aeration, suspension and encapsulation. These functions vary by application and by hydrocolloid.

Fruits and purees also function as texturants in beverages. They build viscosity and contribute mouthfeel, in addition to improving a beverage’s nutritional profile. They also keep labels clean and simple. Depending on the beverage, they may be considered too costly. Texturants can help. In some juice beverages, specialty starches can contribute a pulpy texture, which is expected in this type of beverage. This allows for a reduction in costly real fruit pulp.

The high-protein challenge

Most beverage formulators agree the greatest stabilizing challenge is with high-protein drinks. This includes beverages designed to refuel, replenish, rehydrate, satiate and nourish. There are numerous hurdles to overcome, including initial solubility, interaction with other ingredients, impact of heat process, pH changes, and temperature abuse over shelf life, among others.

There is a growing trend in blending proteins, often dairy with plant, or multiple plant proteins, and even various forms of dairy proteins, in order to differentiate by offering more protein per serving than the competition. Because vegetable proteins and dairy proteins have different molecular structures, when they are blended, they may interact and create stabilizing issues unique to the specific ratio or blend of proteins.

These concentrated levels of protein are being added to everything from flavored water to juice to coffee. Each product matrix has a unique set of challenges as well, as processing parameters, pH and other ingredients all impact beverage stability. It is paramount that the added protein be an invisible addition, thus stabilization is necessary.

These varied proteins also each tend to respond differently to texturants. This is why texturants in highly complex systems often will include multiple ingredients to help create a stable system.

Instability is intensified with beverages processed using ultra-high-temperature pasteurization or retort temperatures. These high temperatures often result in protein denaturation, causing them to sediment out of solution, producing a chalky mouthfeel. Low-acid, high-protein beverages, such as those with a fruit juice base, are particularly sensitive to the high temperatures, because here the higher pH also may cause denaturation.

Protein-fortified beverages also risk discoloration. These products typically have just the right amount of carbohydrates and proteins that when heat processed, Maillard browning may take place. The right texturants may prevent or slow the reaction.

Texturants also may mask off flavors associated with certain types of proteins, namely some plant proteins that have flavors described as grassy, green and grainy.

Formulators must remember that texturant systems are application specific. A protein beverage that comes in chocolate, strawberry and vanilla flavors might require a different stabilizing system for each. This is because the cocoa requires suspension, while the colors and flavors used in the other two will likely vary in composition, in particular, essential oil content of the flavors and heat, light and pH stability of the colors, if naturally sourced versions are used.

Simulating deliciousness

Many high-protein beverages also emphasize a reduction in added sugars to further assist with positioning as a health and wellness beverage. Sugar contributes solids to a beverage. Removing or reducing them decreases solids content, which impacts appearance and mouthfeel.

Texturants may be used to manipulate perceived sweetness and flavor. This is a growing issue as beverage formulators blend sweeteners with different taste curves or rely on flavor modulators to achieve a target sweetness level while keeping added sugars at bay.

The same is true when fat is removed or reduced in beverages like smoothies, meal replacements and refuel drinks. In some fat-containing beverages, there’s a desire to provide the perception of a higher fat content but the calories are not welcome. Think of a child’s breakfast drink made with low-fat milk but designed to taste more like a milkshake. Texturants help to build back deliciousness.

Oftentimes higher-protein, lower-sugar and reduced-fat beverages are enhanced with functional ingredients that bring additional issues for the formulator to tackle. Add on the desire to make these ambient beverages with lengthy shelf lives, and formulators are faced with even more stabilizing challenges. This is due to interactions between functional ingredients and other ingredients in the formulation, which may affect flavor and texture attributes.

Over time, viscosities may change, too. Ingredients can settle and other unintended issues can arise. To minimize this impact, it is critical to fully understand all potential ingredient interactions and identify potential instabilities early in the development process and incorporate the most effective texturant system.

Texturants in action

Texturants assist with innovation. Oat-based milk alternatives are an emerging beverage category. HP Hood L.L.C., Lynnfield, Mass., introduced Planet Oat Oatmilk. This new full-bodied milk alternative is naturally sweet and boasts the nutritional benefits of oats, including fiber and protein content. While oats are naturally creamy in both taste and texture, formulators included gellan gum to give the beverage extra creaminess.

Bohemia, N.Y.-based Worldwide Sport Nutritional Supplements blends three dairy proteins — milk protein isolate, calcium caseinate and whey protein concentrate — to deliver 30 grams of protein in every 11-oz Pure Protein Shake. To provide a smooth, creamy beverage, the product relies on cellulose gel, cellulose gum and carrageenan.

New Odwalla Smoobucha from The Coca-Cola Co., Atlanta, blends fruit and vegetable juices with kombucha. The product touts containing 40% less sugar and fewer calories than top smoothie items. To keep the complex system in suspension, the blend includes gellan gum and pectin.

Plant-based beverage manufacturer Koia, Los Angeles, is expanding its offerings with Koia Fruit Infusions and Koia Keto. Both blended beverages start with a base of almond and coconut milk that is enriched with the company’s proprietary blend of brown rice protein, pea protein and hemp protein. Locust bean gum and gellan gum keeps the beverage smooth and the complex ingredients system in suspension.