PROCESS EXPO | Expert in Residence
Hydrocolloids and Specialty Starches
Dave Krishock | Kansas State University
Or do you know them as gums/stabilizers and modified starches?
I recently presented two lectures to my Baking Science II students at Kansas State University, the first on Specialty Starches (Not Wheat or Maize) and the second on Hydrocolloids, a.k.a food stabilizers or gums. After my students expressed confusion over the applicability of both ingredients, I suggested we first refer to the 2016 Milling and Baking Buyers Guide for greater appreciation of the plethora of both minor, but most critical, ingredients currently available to product developers in the food industry.
Under the heading “Gums,” there were sub categories of cellulosic, microbial, plant extracts, plant exudates, seaweed extracts, and gums from seed sources. Flipping over to the listing for starches, there were sub headings of dextrins, maltodextrins, modified, resistant pregelatinized, and raw (or native).
So how can a baking student, food scientist, baker, or product developer make sense of all the possible uses singularly or synergistically?
This article is intended to give a very brief overview of both hydrocolloids and specialty starches. In future pieces, the functionality and more “product specific” applications will be discussed.
Hydrocolloids are polymers or long chains of polysaccharides of high molecular weight that can be extracted from plants, seaweeds, seeds, and saps. They can be synthesized in the lab, or they may be of animal origin in the case of gelatin. Gelatin is not a polysaccharide but rather a protein derived from collagen, which ensures the mechanical properties of bones, hides, and connective tissue.
Hydrocolloids form colloidal dispersions in water and they modify the mobility of water and, thus, affect textural properties such as mouthfeel, rheology, uniformity of appearance, machinability, and the physical stability of foods and baked goods from processing through distribution and ultimately to consumption. Since they are used at ultra-low levels, one percent in icings, maybe as high as two percent in frostings, and much less in doughs and batters (usually less than 0.5%), hydrocolloids do not significantly affect any nutritional property of the foods to which they are added.
Specialty starches are native or raw starches that are chemically or physically modified to provide greater functionality for high heat, high shear, high pH, and freeze thaw environments most common in today’s high throughput production lines.
While starches are useful in providing thickening, body, and improved mouthfeel, native or raw starches do not provide the stability to maintain their integrity or remain stable. Pastes or gels produced by native starches will release water (syneresis), shrink, become opaque, or produce sloppy edges when cut or divided.
While all starches will thicken if processed correctly, the thickening power of specialty starches is much greater when hot; when hot they can absorb large amounts of water. The exception would be pregelatinized and instant starches, which can swell rapidly in cold water. Instant starches are used quite extensively in convenience foods that are high in starch, such as instant puddings, mashed potatoes, and microwaved-reconstituted foods.
Confusing? Most definitely. However, with future articles we’ll delve deeper into specific applications of both hydrocolloids and specialty starches.
Bakers National Education Professor
Dept. of Grain Science and Industry
Kansas State University