Beverage texture: A growing challenge
Jan. 17, 2013
by Donna Berry
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Pulp or no pulp? The pulp option in orange juice indicates consumers do have preferences about beverage consistency. But for the most part, many consumers don’t think about a beverage’s texture or mouthfeel unless it is offensive, which may be the case with too much pulp, or a gritty smoothie or slimy milk.
Managing texture and mouthfeel is particularly challenging in better-for-you beverages, such as those reduced in fat or sugar, or enhanced with nutrients such as fiber, protein, vitamins and minerals. Consumers expect nutritionally adjusted beverages to deliver the same consistency as their traditional counterparts and this may be challenging when certain ingredients are removed or extras are added to the formulation.
To assist with ensuring unobjectionable consistency, beverage developers often include texturizing ingredients, also known as texturants. The ingredients function by interacting with the major components in a formulation, which include proteins, fats, carbohydrates and water, as well as minor ingredients, such as flavorants, colors and aromas. They work together synergistically to create a stable, smooth and homogenous system that is maintained throughout a product’s shelf life.
As the term suggests, texturants impact a beverage’s texture. This is how the beverage feels and looks and how it adheres or pours from the container. Texturants also influence mouthfeel, which begins when the beverage touches the lips and lasts until swallowed.
Several senses perceive texture, said MaryAnne Drake, professor and director of the Sensory Analysis Center at North Carolina State University in Raleigh, which is funded partially by the Dairy Research Institute, Rosemont, Ill.
“Mouthfeel refers to the oral-tactile qualities perceived in the mouth including, but not limited to, astringency, viscosity, slipperiness and mouth-coating,” she said. “What is important to remember is that texture and mouthfeel are sensory terms. Texture and mouthfeel are perceived, and therefore measured by humans, not machines.
“The problem is that formulators generally think of these attributes in terms of mechanical and rheological properties. In some cases, texture and mouthfeel relate to these properties, but there are many aspects of texture and mouthfeel that do not directly relate to an instrumental measurement.”
In other words, if you do not have sensory measurements, you are only measuring physical properties. Thus, sensory evaluation is the only way to ensure that a beverage is on target with texture. A consumer’s decision to not repurchase indicates the bull’s-eye has been missed.
Texturizing options abound
Texturants are as varied as the beverage category. Some, such as maltodextrin and polydextrose, are used for the sole purpose of adding body and building total solids. Others, such as starches and gums, may build viscosity, provide body, contribute to mouthfeel and/or prevent phase separation.
The latter is referred to as emulsification, and this is critical to drinkability as well as visual appeal of the final product. Emulsifiers function by binding two typically non-combinable components: fat and water. This is particularly important in creamy beverages, where the two phases must come together as one homogenous system. It is equally important in water-based beverages that are flavored — and sometimes colored — with oil-based ingredients. Gum acacia, also known as gum Arabic, and select modified starches, are most often used in flavor and beverage concentrates and syrups to deliver a fully emulsified product, or an emulsion.
Some texturants will protect proteins from denaturing under otherwise unforgiving conditions such as high pH or high temperature. This is particularly important in the growing category of ready-to-drink dairy-based beverages such as drinkable yogurts, smoothies and coffee-milk beverages. The low-pH drinks contain protein molecules that may denature and aggregate, resulting in a gritty or chalky mouthfeel, as well as thinness due to the settling of insoluble ingredients and visual separation. Texturants, in particular pectin, enable the manufacture of creamy, homogenous protein-based beverages. They protect the proteins from aggregation during heat processing and stabilize the beverage over shelf life.
The issue of obesity has led to the emergence of a trend in lowering the sugar content of all types of beverages, as sugar is viewed as a major contributor of unnecessary calories. However, when sugar or similar caloric sweeteners are reduced from beverage formulations and replaced by high-intensity sweeteners to make low- or no-calorie products, sweetness is replaced but texture often suffers. This is due to the missing mouthfeel and viscosity that accompanies dissolved sugar or corn syrup. The caloric sweeteners also contribute to beverage stabilization by thickening, binding and film-forming. Such complex functionality also influences flavor and sweetness perception, making it especially challenging to replace sugar in many beverages.
To provide consumers with the same drinking experience as fully sugared beverages, it is necessary to add texture back to a formulation. Without the addition of texture modifiers, such drinks may seem thin and may lack body. Lower viscosity also often translates to a liquid that clears the palate too quickly, not allowing flavors to linger in the mouth or on the tongue, and thus, reducing enjoyment.
Suppliers have developed texturizing systems to replace the texture and mouthfeel lost when sugar is removed or reduced in flavor-infused refreshments. Bottlers of low- or no-calorie teas, soft drinks, energy drinks and coffees must remember that when traditional sweeteners are removed or even reduced from such products, they may need to add texturants to recreate a satisfying experience.
In lower-sugar juices, which are water-diluted real fruit juices enhanced with high-intensity sweeteners, flavor and/or color, texturants may provide the viscosity one would expect in a 100% juice product. Some texturants may even be manipulated to simulate pulp.
Interestingly, studies show it is not just the viscosity of sugar that provides body to beverages, but it is also the presence of various flavor sensations, including metallic, dryness or astringency. Therefore, when removing or reducing sugar from a beverage formulation, it is necessary to identify the optimal synergistic balance of texturants, sweeteners and flavors to use the minimum amount of ingredients to achieve the same texture and mouthfeel of the full-sugar product.
The flavored milk challenge
Sweetened, flavored milks have come under fire the past few years, in particular, the milks served at elementary schools, as some believe they are a contributor to childhood obesity. The National School Lunch and School Breakfast programs mandate that any flavored milk served through the program be fat free. There are no restrictions on calories or sugar content, but many dairies are focusing on keeping sugar and calories as low as possible in fat-free flavored milk and are relying on texturants to build back body.
Chocolate milk long has used hydrocolloids to suspend cocoa particles, with carrageenan historically having been the texturant of choice. In nonfat chocolate milk, especially versions with reduced sugar content, carrageenan tends to clear from the palate quickly. By slightly changing the stabilization system to include a blend of texturants, it is possible to build back texture and mouthfeel, recreating the sensory experience of 2% chocolate milk in a nonfat, lower-sugar variety.
Texturants also make it possible to create indulgent flavored milks that have all the texture and mouthfeel of full-fat, premium, milkshake-style beverages, but have a Nutrition Facts Panel that reflects a light product. The right texturant blend may make a milk beverage more indulgent without extra fat and sugar calories. It does this by enhancing mouth-coating properties that simulate the decadence provided by fat and sugar. Such flavored milks and similar dairy-style beverages, such as meal replacements and smoothies, for example, also may be effective carriers for all types of nutritional ingredients.
In addition to the on-trend uses of texturants in beverage product development, formulators may generate significant innovation by manipulating product texture. Of course, they should always use sensory science to confirm consumer acceptance. It is important to remember texture modifiers change the drinking experience, with impact varying by the type and amount used, as each texturant delivers a somewhat unique sensory effect. Further, pH and processing of the beverage brings its own set of challenges.