Stabilizers and emulsifiers are “mighty mites” — with low use rates, they have a major influence(s) on the chemistry, physics and behavior of ice cream. But are they really necessary? It depends.
Ice cream is one of the only foods designed, formulated, manufactured, stored, distributed and sold with the full intent of being consumed frozen. Typically, the feature that fails first is eating quality — i.e., loss of textural shelf life, which can be protected by managing the behavior of water and fat. That’s what stabilizers and emulsifiers do. Typically, the amounts and types of each to be used are regulated.
More commonly, the term stabilizer refers to blends of select hydrocolloids that manage water/ice. Emulsifiers manage fat so to improve body (bite/chew), texture (smoothness, creaminess) and resistance to heat shock across the full intended shelf life of the ice cream.
Ice creams can be formulated and manufactured without stabilizers as long as water/ice and fat are properly managed. However, with time and as conditions of the supply chain change, the risk to designed textural qualities at points of consumption becomes greater. Thus, there is an ongoing need to stabilize.
Hydrocolloids are high-molecular-weight compounds that may also have significant structural features that interfere with the mobility of water in the unfrozen portion of the ice cream. They are usually of vegetable origin (gelatin is an exception.)
There is always a small percentage of water in any ice cream even under -20 degree Fahrenheit storage. If all water was immobilized, there would be no significant ice crystal growth. Common hydrocolloids (gums) include guar, cellulose gum, locust bean, tara and xanthan. Carrageenan is usually used, not to directly interfere with water mobility, per se, but to protect proteins from the rigors of manufacturing and heat shock.
Lesser known gums include acacia, agar, pectin (multiple types) and gellan. The use of all of these gums is usually dependent on their individual functionalities, nuances and potential interaction among each. In general, use rates are only a few tenths of a percent of each; in combination, well below 1.0%.
Emulsifiers (may also be called surfactants) have hydrophobic and hydrophilic properties that manage the functionality of fat (and, in some instances, the behavior of air) in ice cream. Usually vegetable-derived, emulsifiers do more to promote de-emulsification (i.e., fat agglomeration), which in turn contributes to structure, texture and shelf life of the finished ice cream.
Use rates are often well below 0.50%. Most familiar are mono-and diglycerides and the polysorbates. Lecithin offers a much different effectiveness, with use rates near 1.0-1.5%, creating other potential problems (e.g., flavor of the ingredient itself.)
Stabilizing systems (i.e., blends) are the thoughtful combination of hydrocolloids and emulsifiers for the express purpose of improving a given ice cream in some way. Improvements take many forms, from better texture and flavor release, shelf-life extension and cost reduction to even manufacturing assistance.
One criticism is that these are “chemicals” added to cheapen the product. While there are instances where a specific blend may be used to help reduce milkfat or, perhaps, assist with taking and holding air (overrun), it should be noted that these blends are almost always more expensive than other ingredients used. As such, when properly considered, stabilizer blends add value and provide real consumer benefits, including retention of eating quality, shelf-life management and caloric reductions.
Consider the nearly identical, 10% milkfat ice creams in the table.
A comparison of two 10% milkfat ice creams
|Ice cream 1||Ice cream 2|
|Objective(s)||“Clean label,” all natural, upscale||Classic|
|Distribution||Local||National, high altitude expected|
|Skim milk solids||10.0%||10.0%|
|36 DE corn syrup solids||6.0%||6.0%|
|Pounds per gallon mix||9.16||9.23|
|Pounds per gallon ice cream||5.50||4.60|
|Ingredients||Milk, cream, sugar, corn syrup, locust bean gum*||Milk, cream, sugar, corn syrup, monodiglyceride (MDG)**, carrageenan**, cellulose gum, cellulose gel**|
** MDG for structure; carrageenan to protect proteins; cellulose gum for water/ice control; cellulose gel for high altitude protection.
Thus, it is important to know and understand what you will be making and under what conditions, as well as what may need to be declared (claimed), supply chain conditions (i.e, distribution/marketing/sale) and the impact on cost of goods sold. It sounds simple, yet the calculus is complex, requiring careful thought, work and a dose of insight and experience.
The good news? Your suppliers can usually provide that insight and experience.