Soy Protein: Clear Advantage

March 25, 2011

A new innovation for including soy protein in acidic beverages.

Soy protein is a high-quality protein, with a Protein Digestibility Corrected Amino Acid Score (PDCAAS) comparable to that of animal-derived proteins such as beef, milk, and eggs. Consumption of soy protein and its associated minor components has been linked to a reduced risk of a number of illnesses. Its benefits for heart disease are particularly well recognized, with health claims permitted in the United States and other countries.

Fortification of acidic beverages with soy protein has traditionally been limited by the poor solubility of protein ingredients at the pH of these beverages. Products such as carbonated and noncarbonated soft drinks, sports drinks, fortified waters, energy drinks, and juices are classified as acidic beverages.

Insoluble protein particles typically preclude the production of a transparent beverage. Texture and mouthfeel of the beverage are also issues, given the presence of the protein particles and the added stabilizers typically used to keep them suspended. Many soy protein ingredients also have a characteristic beany flavor that some consumers find objectionable.

Intensive research and development work at Burcon NutraScience’s R&D facility in Winnipeg, Manitoba, Canada, over the last few years has led to the development of a novel soy protein isolate that is ideally suited to fortifying acidic beverages. Called Clarisoy, the isolate is 100% soluble, completely transparent, and exhibits low viscosity in acidic solutions with pH values from 2.5 to 4.2.

Protein solutions prepared in this pH range are also heat stable, allowing thermal processing such as hot fill, without any loss of clarity or notable change in viscosity. Given the complete solubility of the isolate, it is not necessary to employ additives or special processing steps to keep the protein suspended or in solution. Clarisoy has a very clean flavor and does not have the beany taste typically associated with soy protein. This novel soy protein isolate can be used in the production of transparent acidic beverages, or a clouding agent can be added if an opaque, protein-fortified beverage is desired.

In addition to its use in ready-to-drink acidic beverages, the soy protein isolate may also be used to fortify acidic powdered beverages. Powdered drink mix is a growing category; single-serving packs that can be added to a bottle of water are particularly popular. The excellent solubility of the protein powder allows it to be dry-blended with other drink mix ingredients.
 

Combination with Whey

This soy protein isolate can be used in acidic, protein-fortified beverages in place of-or in combination with-whey protein isolate.

Replacement of whey protein with soy protein may provide advantages in terms of cost because the production of plant proteins is often less expensive than the production of animal proteins. Plant protein production also offers a lower environmental impact and greater sustainability than the production of animal protein. Choosing soy protein isolate over whey protein isolate also allows the production of acidic beverages suitable for consumers allergic to milk, those who are lactose intolerant, or those who choose not to consume animal-derived products.

Alternatively, a blend of soy and whey protein isolates could be used to combine the nutritional and health benefits offered by each type of protein. Also, the digestion rate of soy protein has been reported to be somewhat slower than the digestion rate of whey protein. This has implications in sports nutrition-by consuming the proteins together, the time frame over which amino acids are supplied to muscle tissue is extended, and benefits may result in muscle synthesis and recovery from exercise.