June 17/Journal of Technology -- According to recent research from Madrid, Spain, "Blends of kappa-carrageenan (K) and xanthan gum (X) were added to mashed potatoes. The product was tested by instrumental texture profile analysis and cone penetration tests, oscillatory and steady rheology, color, drip loss, total soluble solids and sensory analyses."

"A central composite rotatable design was used to study the effects of variation in levels of K (1.5-4.5g kg(-1)) and X (0.5-2.5g kg(-1)) concentrations. Addition of K had a major impact on gel strength, viscoelastic behavior, sensory attributes and overall acceptability, whereas addition of X influenced textural and steady properties and color. Mainly, elastic modulus (G') was strongly dependent on the K concentration in mashed potatoes containing amylose. As compared to mashed potatoes with 1.5g kg(-1) added X, additional incorporation of 5.12g kg(-1) K increased G' approximately twofold, possibly due to exclusion effect of the swollen starch granules and synergistic effect of K and denatured protein. The function of X in the mashed potatoes may in fact be confined to that of a filler rather than a dynamic constituent, although it does affect yield stress behavior. When K/X blends (each biopolymer at 1.5g kg(-1)) were included in the formulation, the product exhibited very acceptable sensory quality," wrote C. Fernandez and colleagues.

The researchers concluded, "K provided the appropriate texture, while X imparted creaminess and mouthfeel to the product."

Fernandez and colleagues published their study in European Food Research and Technology ("Quality of Mashed Potatoes: Effect of Adding Blends of Kappa-carrageenan and Xanthan Gum." European Food Research and Technology, 2009;229(2):205-222).

For additional information, contact M.D. Alvarez, CSIC, Institute Frio, Dept. of Plant Foods Science & Technology, Jose Novais 10, E-28040 Madrid, Spain.

From the June 22, 2009, Prepared Foods E-dition