Luckily (or rather, the result of over 100 years of development), modern, plant-based emulsifiers are available that can go a lot of the way toward protecting ice creams from heat shock.
As Figure 3 visualises, emulsifiers are surface-active ingredients due to their hydrophilic-lipophilic properties, placing themselves in the interfacial layer between the fat/protein and water and helping to improve or control:
- Fat emulsification in the mix
- Fat agglomeration and coalescence
- Air incorporation
- Dryness on extrusion
- Melting resistance
- Heat-shock stability
- Smoothness and creaminess
The most common emulsifiers used in ice cream are mono-diglycerides (E471), lactic acid esters (E472b), propylene glycol esters (E477) and blends of these.
Generally speaking, good compositions can be made with most of the widely-used emulsifiers and stabilisers such as mono- and diglycerides, carrageenan and locust bean gum. If, that is, they are used in the right amount and compositions to suit each recipe.
Adding propylene glycol esters such as propylene glycol monostearate (PGMS), for example, protects against the Heat Shock Effect by ensuring small ice crystals are created during freezing and reducing their tendency to grow during the journey to the consumer’s table, as shown in Figure 4.