Emulsifiers

N\archive\communic\cheri\jobfiles\BST-residentcourse-Science\section9\science-sec9.pm65

Any reproduction of this material without the express writtenconsent of the American Institute of Baking is prohibited.

Bakery products, particularly bread and rolls, haveundergone many changes in recent years, includingthe use of oils instead of shortening, addition of highlevels of fiber, low caloric or light bread, reducedchemical oxidation, low sodium content, and reducedprocessing times. Surfactants, dough conditioners,dough strengtheners, crumb softeners, emulsifiers, allare terms describing ingredients used in bakery foodsto aid in production and/or improve certain qualityfactors. To make an intelligent appraisal of theseproducts for a specific system, knowledge of theactive components, their functions, and the comple-mentary or synergistic action of two or more ingredi-ents is critical.

Surfactants (surface active agents) used in bakingcan perform a variety of functions, some of which areextremely specific. Most surfactants used in breadsand rolls are either starch complexing (anti-staling orcrumb softeners) or protein interacting (doughconditioning or dough strengtheners). Other surfac-tants are true emulsifiers, stabilizing water in oil(such as in cake batters) or oil in water (such as inwhipped toppings). Still others aid in foaming andaeration (in batters and icings), modify finishedproduct texture, modify crystal structure (in fats andshortening), aid in wetting, promote dispersions, orpromote suspensions. The focus of the following textwill be on surfactants used primarily in breads androlls.

In the U.S., the Food and Drug Administration(FDA) regulates surfactants used in baked goods.Many countries around the world have their ownregulatory agencies. It is imperative that bakers check

with the appropriate agency in the country of saleprior to including any surfactant into a food.

Definition“Dough strengthener” generally implies an action

directly upon the colloidal character of the dough.This may be either through modification of thegluten, the state of oxidation, or the surface tensionbetween the aqueous and fat phases. Doughstrengtheners impact the machinability and gasretention of the dough, and thus are used to improveloaf volume, symmetry, texture, and grain of thefinished product.

“Crumb softener” generally indicates an ingredi-ent that is thought to complex with the starch (amy-lose and/or amylopectin) to retard the rate of crumbfirming or staling. The term is somewhat of a misno-mer because the surfactants may not actually softenthe bread, but rather retard the rate of crumb firming.The onset of firming will occur several hours afterbaking and increase progressively with time. Theeffectiveness of a particular surfactant may notbecome apparent until the second or third day afterproduction, or even later.

When the term “dough strengthener” or “crumbsoftener” is used to classify an ingredient, the termusually represents the predominate function of theingredient, and not necessarily its only function. Forexample, most dough strengtheners also have somecrumb softening characteristics, while many crumbsofteners also exhibit some degree of dough strength-ening.

©Copyright AIB International May not be reproduced without written permission.

Page 1

Commonly Used Surfactants

A large number of surfactants and blends areavailable worldwide. They come in different physicalforms and carry a wide variety of trade names (brandnames). The following discussion will not attempt toinclude any trade names, and will focus on surfac-tants commonly used in breads and rolls.

Mono- and DiglyceridesMono- and diglycerides are the most commonly

used surfactants in bakery products. They are pro-duced from fats or oils or fatty acids with glycerin,using a variety of techniques (direct esterfication,glycerolysis, or interesterification). Mono- anddiglycerides are very effective crumb softeners. Theirfunctionality depends upon raw materials used intheir production, percent monoglyceride, degree ofunsaturation, and the physical state of the product.

Soft monoglycerides are produced from partiallyhydrogenated fats. They are effective crumb soften-ers, but tend to yield a less resilient crumb that isoften described as “gummy”. Hard monoglyceridesare manufactured from fully hydrogenated or satu-rated fats, and are usually subjected to a moleculardistillation process that concentrated the alpha-monoglyceride content. They produce a soft crumbthat is very resilient, with excellent slicing andstacking characteristics.

Beads and powders (hard distilledmonoglycerides; 90% alpha-monoglyceride) aresomewhat difficult to disperse in dough systems, butare satisfactory for use where melting in the fat ispractical. Some powders are dispersible in doughs.Hydrates (15-25% alpha-monoglycerides) dispersereadily in doughs, but unless stabilized will tend toseparate if frozen or heated. Both soft and hardmonoglycerides are used in hydrates. Soft plastics(50-55% alpha-monoglycerides) are primarily the softmonoglycerides. They have a shortening-like consis-tency and disperse easily in doughs.

Ethoxylated Monoglyceride Blends (EOM)Ethoxylated monoglycerides have good dough

strengthening characteristics, but are not very effec-tive crumb softeners, so are most commonly used asblends with mono- and diglycerides. The EOM andmonoglyceride vary widely by product, so the ratio ofstrengthening to softening will also vary. Variousforms are available, ranging from hydrated blends tosoft, fat-based plastics, dry blends, flakes, or powder.

Succinylated Monoglycerides (SMG)Succinylated monoglycerides function as good

strengtheners and fair softeners, as well as emulsifi-ers. They are produced by the reaction of distilledmonoglycerides with succinic acid. SMG is a waxysolid, making it difficult to disperse unless meltedinto fat. The concentrate is sold in powdered form.SMG and mono- and diglycerides blends are avail-able as plastics or hydrates.

Sodium Stearoyl-2-Lactylate (SSL) andCalium Stearoyl-2-Lactylate (CSL)

SSL and CSL are excellent dough strengthenersand good softeners, because (it is theorized) theyfunction by complexing with protein and starch. Theyare generally used in combination with other soften-ers, such as mono- and diglycerides. They are avail-able in powder or beads, either of which will dispersein melted shortening or directly into most doughsystems. Blends (with softeners) are also available ashydrates.

Diacetyl Tartaric Acid Esters of Mono- andDiglycerides (DATEM)

These are the most popular surfactants in Europe,acting as both excellent dough strengtheners and faircrumb softeners. DATEM also function as trueemulsifiers, stabilizing oil-in-water emulsions. Thephysical and functional properties of DATEM dependupon the fatty acid composition of the raw materialsand the quantity of esterified tartaric acid.

PolysorbatesPolysorbates are sorbitan esters that are modified

with ethylene oxide to increase water solubility.Depending upon which and how many fatty acids areinvolved, various products result. Polysorbate 60(monostearate) is most commonly used in breads androlls as a mild dough strengthener and slight crumbsoftener. There is a synergistic effect with mono- anddiglycerides, increasing both strengthening andsoftening. Products range from liquid for purePolysorbate 60 to blends that are available as softplastic, beads, or flakes. Polysorbate 60 is hydrophilicand may cause foaming problems in brew systems.

Sucrose EstersSucrose esters are popular emulsifiers in Japan

and other parts of Asia. They function as emulsifiersas well as strengtheners and softeners.

©Copyright AIB International May not be reproduced without written permission.

Page 2

LecithinLecithin is a natural surfactant, obtained commer-

cially from the refining of soybean oil. It has excel-lent emulsification properties, and is often used as agood wetting and release agent (for example, incookies or sweet biscuits). Lecithin may be modifiedchemically, enzymatically, and/or by fractionation toimprove functionality. It can be purchased in powderform, diluted with oil, or as a highly viscous material.

In yeast-leavened doughs, lecithin functions toimprove dryness, extensibility, and machinability. Italso increases the function of added fat, and improvesvolume, symmetry, and shelf-life.

©Copyright AIB International May not be reproduced without written permission.

Page 3

©Copyright AIB International May not be reproduced without written permission.

Page 4