Managing the addition and mixing of emulsifiers and stabilisers to an ice cream mix is crucial if the full effect of the ingredients is to be obtained.
Insufficient agitation of the mix during the addition of traditional emulsifier-stabilizer blends may lead to an inhomogeneous distribution, causing ice cream failures such as fast melt-down or reduced creaminess.
Palsgaard claims that its new ED Series of self-dispersing emulsifier-stabilisers can minimise these risks. The firm says that each product in the series is easily dispersed in water or milk, even without stirring.
The ED Series is based on mono-diglycerides and various hydrocolloid compositions, which Palsgaard claims makes them especially suitable for extruded ice cream and low fat formulations. An ice cream produced using a product from the range should have superior melting resistance, very high creaminess, heat shock resistance and a fresh-eating profile.
But first and foremost, the ED Series is designed to eliminate any potential risks of product loss or inferior ice cream quality due to poor dispersability of the functional ingredients.
As Palsgaard group manager Michael Bern points out, no two ice creams in the world are completely identical. Legal requirements and local consumer expectations with respect to taste and mouth feel differ from country to country.
The ED Series is therefore available in a number of different compositions. Ice cream technicians can also assist in co-developing and implementing the chosen solution at the customer's site. In manufacturing environments where less than optimal mixing is possible - such as slow or no agitation - the ability of the emulsifier-stabiliser blend to disperse in the milk becomes a key issue for ensuring the high and uniform quality of the end product.
In addition, dry-blended solutions, even when pre-blended with sugar, risk loosing effect due to lump formation. Integrated blends show a tendency to float on the top, leading to an inhomogeneous distribution of the emulsifiers and stabilizers in the mix.
In some instances filters are placed before the final pasteurisation temperature is reached, presenting the problem of un-dissolved ingredients becoming caught in these filters.
Emulsifiers and stabilisers are present in ice cream and other types of frozen desserts at very low dosages, typically around 0.5 per cent. The most commonly-used emulsifier type is a standard mono-diglyceride based on vegetable fat sources, but lecithin and polysorbates are also frequently applied, depending on the product requirements and local legislation.
Stabilisers are typically used in a combination of two or more, and may be sourced from a vast group of hydrocolloids deriving from seaweeds (carrageen and alginate) and plants (locust bean gum, guar, CMC), but can also be microbiologically produced, such as xanthan gum.
The emulsifier locates at the interface between the fat and the serum phase in the emulsion during pasteurisation and homogenisation. During the ageing time of the ice cream emulsion, the emulsifier helps to desorb the milk proteins from the fat globule surface, leaving the fat exposed and subject to mechanical destabilisation in the cylinder of the ice cream freezer during aeration and freezing.