R&D Applications Seminar: Smoother Sauces and Dressings -- December 2007
Replacement with Modified Gum AcaciaEmulsions are kinetically stable systems that have the tendency to revert to their original state of two immiscible liquids (i.e., a two-phase system). One of the most interesting physical properties of an emulsion is its stability. However, emulsion instability is promoted by three distinct phenomena: creaming (or sedimentation); flocculation (droplet aggregation); and droplet coalescence, ultimately resulting in phase separation.
Stabilizers in emulsions are functional ingredients that improve stability. Emulsifiers function as surface-active molecules that adsorb at the oil/water interface and form a protective film. Weighting agents are ingredients that match the densities of the dispersed and continuous phases. Viscosifiers are molecules that increase viscosity.
Modified gum acacia ingredients can enhance stability of emulsions through a number of means, with the potential to replace gum Arabic and modified food starches, which have been used for this function in the past.
For example, acacia Senegal has been used as a substrate for modification, but it is labor-intensive, has a fluctuating price and limited growing area. It is, however, an excellent emulsifier and non-GMO. The advantages of acacia Seyal as a substrate for modification are that less labor is needed to obtain it, it is less expensive, it grows in a wider area and it is non-GMO. However, it is a poor emulsifier.
Modified gum acacia has unique benefits as a high surface-active gum, which can stabilize high oil load emulsions. A “high emulsification” modified gum acacia is a powerful emulsifier for systems with 8-12% oil for excellent stability and cloud. Spray-dried gum Arabic is a natural emulsifier for the same 8-12% oil systems and also provides excellent stability and cloud.
Modified gum acacia provides a low-cost, effective and non-GMO emulsifier. As an excellent emulsifier for high oil load emulsions, it is also a good encapsulating agent for flavor and nutritional oil.
“Modified Gum Acacia: A Potential Replacer for Gum Arabic and Modified Food Starch,” Nabil Naouli, Ph.D., principal scientist, TIC Gums, email@example.com, www.ticgums.com
--Summary by Elizabeth Mannie, Contributing Editor
The Basics of GumsGums are hydrocolloids—“hydro” meaning water and “colloid” meaning dispersion of small particles in another medium. Hydrocolloids are water-soluble macromolecules of high molecular weight that bind large quantities of water. They modify the rheology of aqueous systems to which they are added.
When gums are added to a liquid, it is important to keep the particles separated, so they do not clump together in the liquid. It helps to initially disperse the gum in another non-aqueous liquid (such as vegetable oil or with another powdered ingredient to isolate the particles) in order to avoid lump formation when it comes into contact with water. Also important is adding the powder slowly during high-shear mixing. Making sure that each particle is an individual entity in the mixture creates efficient dissolution of a gum.
The functions of gums in foods are numerous, and they are used at very low use levels (typical use is 0.05%-0.5%). They provide little or no flavor and often can be considered “all-natural,” “organic” and “gluten-free.”
Xanthan gum is one of the most widely used gums in sauces, dressings, dry mixes and still beverages. It is acid- and heat-resistant, and some grades can be highly tolerant to salt. An excellent suspending agent, it forms a thick interfacial layer. Its pseudoplasticity allows yield stress to maintain emulsion, but thins out with shear for better pouring and mouthfeel. Xanthan and guar act synergistically. High concentrations of xanthan can form very elastic solutions with irregular flow, but the addition of guar can solve the elasticity problem.
Guar gum is cold water-hydrating, relatively viscous, heat-tolerant, acid-resistant, a soluble fiber source and inexpensive. Guar adds cling to marinades and viscosity to instant sauces, soups and gravies. It reduces starch pastiness in sauces and is used in ice cream for crystal size reduction.
Locust bean gum (LBG) forms a smooth-flowing pseudo-gel, requiring heat to become viscous. LBG is excellent at controlling syneresis, especially in frozen foods. It is also synergistic with xanthan, forming gels. Using LBG in combination with gelling carrageenans also helps control syneresis.
Although these are some of the most commonly used gums, numerous others exist—each with specific functions and applications.
“Gum 101,” Allen Freed, CEO, Gum Technology Corporation, firstname.lastname@example.org, www.gumtech.com
--Summary by Elizabeth Mannie, Contributing Ed.