What is Sorbitan Monostearate (E491) in food and yeast? Uses and Safety

Production | Uses | Safety | FAQs 

Sorbitan monostearate (abbreviation SMS), or Span 60, is an emulsifier esterified from sorbitol and stearic acid with the European food additive number E491. This ingredient is mostly used in baking yeast by improving the activity of instant dry yeast when the yeast is rehydrated before use. 

How is Sorbitan monostearate made?

Generally, sorbitan monostearate can be made from direct esterification of sorbitol and stearic acid. Sorbitan tristearate (E492) would be generated in the production if too much stearic acid is involved.

Sorbitol 

Sorbitol is a sugar alcohol with a sweet taste and can be used as a sugar replacement and humectant in chewing gum, mints, cookies, bread, and cakes. It is commonly made from starches of corn and potato and follow the hydrogenation process. 

Stearic Acid

It is a common saturated fatty acid found in nature both in animal fats/oils and vegetable oils. It can also be used in the production of soaps, cosmetics, and detergents. 

The commercial food grade stearic acid may contain 48.7–50.0% palmitic acid.

As sorbitol has six hydroxyl groups and that’s why sorbitan monostearate may also contain palmitic acid esters of sorbitol, sorbitan and isosorbide besides sorbitol, sorbitan, and isosorbide esters of stearic acid.

Properties

Appearance

A white to yellow waxy bead or flake with a slight characteristic smell.

Hydrophilic-Lipophilic Balance (HLB)

With the HLB value 4.7, meaning it is lipophilic and soluble in oil instead of water. It will form W/O (water-in-oil) type emulsion, and it is a strong emulsifying dispersion and has a wetting effect.

Solubility

• Not soluble in cold water, but can be dispersed in hot water.
• Soluble in ethanol, mineral oil, and vegetable oil. 

Structure

Image Source

What’re the Uses of Sorbitan monostearate?

Sorbitan monostearate is used as an emulsifier, commonly together with polysorbates to keep water and oil mixed in many food products. 

It is commonly used in instant dry yeast, fat and oil emulsions, desserts, food supplements, cake, spread, margarine, coffee whiteners, and so on. 

The following are its main uses and functions in food:

• Dry yeast: maintain the moisture, increase the shelf life of dry yeast, and help the rehydration of yeast cells before blended with other dough ingredients.
• Ice cream: promote emulsifying of dairy fat, prevent the formation of ice crystals, and improve the mouthfeel. 
• Margarine: improve emulsion stability and reduce sandiness. 
• Whipping cream: improve foam volume and contribute to a nice and stiff foam.
• Bread & Cake: increase the loaf volume and improve the texture of bread and cake.
• Confections and chocolate: stabilize the emulsion of oils and fats. 

Meanwhile, it can be condensed with ethylene oxide to synthesize polyoxyethylene (20) sorbitan monostearate (polysorbate 60), which is also a food emulsifier.

Is Sorbitan monostearate Safe to Eat?

Yes, it almost has no side effects and the safety has been approved by the U.S. Food and Drug Administration (FDA) and European Food Safety Authority (EFSA), as well as the Joint FAO/WHO Expert Committee on Food Additives (JECFA).  

FDA

Sorbitan monostearate may be safely used as an emulsifier in the following food, sometimes together with polysorbate (60, 65, 80) (¹):

• Whipped edible oil topping
• Cakes and cake mixes, icings and fillings
• Nonstandardized confectionery coatings and standardized cacao products
• Edible vegetable fat-water emulsions in beverage coffee

It can also be used as a rehydration aid in the production of active dry yeast with the maximum usage 1%. It may also be safely used in mineral premixes and dietary supplements for animal feeds. (²)

EFSA

Sorbitan monostearate (E491) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized in “ additives other than colours and sweeteners” (³).

Safety re-evaluation in 2017

EFSA changed the ADI of 25 mg/kg bw per day set by The Scientific Committee on Food (SCF) in 1974 and established a group ADI of 10 mg/kg bw per day for sorbitan esters (expressed as sorbitan) , and the ADI of sorbitan monostearate is 26 mg/kg bw per day. (⁴)

Approved uses

Its application is listed together with other sorbitan esters: sorbitan tristearate (E492), sorbitan monolaurate (E493), sorbitan monooleate (E494) and sorbitan monopalmitate (E495) and with the maximum use levels “5000-10000 mg/kg” while the use level in dry yeast and yeast for baking is “quantum satis”.

The following food may contain it (⁵): 

• Flavoured fermented milk products   
• Beverage whiteners 
• Fat and oil emulsions 
• sugar confectionery 
• Chewing gum  
• Decorations, coatings and fillings    
• Fine bakery wares 
• Emulsified sauces 
• Desserts

UK Food Standards Agency

Categorized in “Emulsifiers, stabilisers, thickeners and gelling agents” (⁶)

Food Standards Australia New Zealand 

It is an approved ingredient in Australia and New Zealand with the code number 491. (⁷)

JECFA 

Function Class: food additives, emulsifier. (⁸) 

Acceptable daily intake: ADI “0-25 mg/kg bw” set in 1973. (⁹)

Frequently asked questions

Is SMS Halal?

Yes, it is is a synthetic ester that would be halal complying with the Muslim policy if the fatty acid stearic acid derived from vegetable oils instead of animal origins.

Is SMS Vegan?

Yes, it is corn derivative and vegan if the raw material stearic acid from vegetable oils as the manufacturing process without the use of animal matter or products derived from animal origin.

However, some manufacturers may use stearic acid from animal sources. Therefore, vegetarians should avoid it.

Conclusion

Now you may have a knowledge of the emulsifier – Sorbitan monostearate (E491), from the following aspects:

• Production process
• Uses
• Safety
• FAQs

What kinds of food labels have you found this ingredient in? Or if you have any questions or remarks about this additive, feel free to let me know in the comments.