Emulsifiers in

Birgitte Mikkelsen Danisco Ingredients

he habit of chewing for the sake of chewing is The most well known is the stabilization of water-in-oil Tapparently as old as mankind. Around the world and oil-in-water emulsions by the formation of an emul- there have been several archaeological finds of chewed sifier film at the interface between water and oil. In materials (e.g., pine tree ) dating back to prehis- emulsion systems the emulsifiers also act as destabiliz- toric time. Modern chewing gum dates back to the 19th ing agents by replacing the protein at the interface.This century and was in the beginning based on either coag- is an important phenomenon in whippable emulsions ulated tree sap or paraffin .Today, natural sources such as ice cream and imitation dairy creams. such as and jetulong are rarely used for gum In bakery products the surface active lipids interact base. Instead, synthetic polymers such as styrene-buta- with both the starch and the protein fractions in the flour, diene rubber, polyisobutylene and isobutylene-iso- which results in prolonged shelf life due to retardation prene are used for giving chewing gum the elastic, of the retrogradation of the starch and bigger volume resilient chew characteristics. Making modern chewing due to better entrapment of CO2 in the dough. gum from either synthetic or natural rubbers makes the Addition of emulsifiers to modifies the crystal for- emulsifiers a vital ingredient, giving the final gum a mation of -containing foodstuff. Examples are pre- softer and more pleasant chew. vention of sandiness caused by too big fat crystals in mar- garine and the delay of bloom in chocolate caused by the FAT-BASED EMULSIFIERS (SURFACE ACTIVE rearrangement of crystals. LIPIDS) In chewing gum and gum base the function of emul- Emulsifiers are a group of compounds with both sifiers as softening agents is known, but the underlying hydrophilic (water-loving) and lipophilic (fat-loving) principles are not understood. properties. This duality makes the emulsifiers surface active and capable of stabilizing emulsion systems (both Chemical Composition water-in-oil and oil-in-water emulsions) as they migrate Surface active lipids all originate from edible fats and oils to the interface. and they can be divided into two groups according to Many emulsifiers originate from edible fats and oils. their chemistry. They consist of a hydrophilic head group (such as glyc- The first group has been derived from mono and erol, sorbitan and propylene glycol) and a lipophilic diglycerides obtained by the glycerolysis between glyc- tail group consisting of fatty acids (Figure 1). erol and triglycerides, i.e., edible fats and oils of either A good definition for the fat-based emulsifiers is “sur- vegetable or animal origin. face active lipids” due to their surface activity and their ori- The glycerolysis produces a mixture of monoglyc- gin in fats and oils. Proteins which may also have emulsi- erides, diglycerides, triglycerides and glycerol.This mix- fying properties will not be dealt with in this article. ture can be purified to products containing either mono- glycerides and diglycerides (named mono-diglycerides) Functionality or very high amounts of monoglycerides (named distilled Surface active lipids play a variety of roles in foodstuff. monoglycerides).

The Manufacturing Confectioner • January 2000 63