Since the FDA approved the soy protein/heart health claim in October of 1999, many foods and beverages have sought to incorporate soy proteins and protein isolates. These endeavors have targeted not just the health food consumer. Rather, many beverages boasting soy isolates with vanilla, chocolate and juice flavors have found a mainstream audience. In 2002 alone, the number of soy-based beverages jumped by more than 200%.

What has prompted this growth? The FDA heart health claim not withstanding, soy beverages serve Baby Boomers seeking increased longevity and good health while providing a nutritious option for those who are lactose-intolerant. Furthermore, the technological improvements in processing and flavoring soy-based beverages have been a boon to the segment.

To gain the heart health claim, developers have to formulate products to include 6.25g of protein per serving. One difficulty has been keeping soy protein in suspension while still achieving a smooth mouthfeel, free of grittiness or chalkiness. Stabilizer blends help reduce the amount of sediment in beverages in several ways; one way is protecting the soy protein during heat processing and pasteurization.

Flavor also has proven an issue, though there are masking agents specifically designed to reduce the off-notes. In the process, the beany flavor associated with soy is masked, yet no additional, unwanted flavor is imparted. Further enhancing the taste, other flavors may be added to work synergistically with the masking system.

As the United Soybean Board (USB—Chesterfield, Mo.) advises, manufacturers should answer several questions before attempting to develop a soy beverage.

  • What is the age of the product's target audience?

  • What are the nutritional expectations of that audience?

  • Will the beverage boast reduced sugar and/or calories?

  • What finished product characteristics, i.e., clarity or pH, will influence the type of stabilizer needed?

  • What type of processing, packaging and distribution will be expected of the product?

  • What is the product's target price?

    Appropriate and economical beverage stabilization systems are a crucial part of the process, largely dependent on the type of beverage formulated, the ingredients used and the desired end product. Agglomeration, lecithination and changes in the protein's solubility will improve the protein's dispersibility.

    Agglomeration, in particular, has ushered in a new generation of soy-based ingredients. Soyfood companies have created an agglomerated product combining isolated soy protein, a soluble fiber and lecithin. The fiber serves to mask many of soy's off-notes by forming a complex with the protein, which prevents the tongue from detecting the off-flavor. Meanwhile, the lecithin aids dispersion. According to the USB, these agglomerated ingredients can be used at levels of 10g to 20g per serving in both powdered and RTD soy beverages.

    Easily incorporated into soy beverages without being detected, hydrocolloids and gums also provide useful functions. Gums serve to stabilize and add viscosity in liquid applications, and both provide pleasant mouthfeel and good suspension.

    Viscosity is of particular concern in soy beverages serving as high-protein meals. Combining soy protein with other stabilizers, emulsifiers and proteins makes the soy more palatable, while also helping the finished product mimic the consistency of a milkshake or freshly blended smoothie. The USB offers one important note about such applications: they require a highly dispersible and soluble soy protein isolate that offers very low viscosity.

    For more information:
    United Soybean Board,