Questions & Answers
from "On Ice Cream" featured in Dairy Foods magazine
and sourced from "On Ice Cream" technical short courses.

Gumminess in Ice Cream:

Question: What factors cause ice cream to get gummy?

Answer: The term gummy is used to describe ice cream that is sticky or stringy when dipped. In the mouth it offers strong resistance to structure loss and mechanical manipulation. The effect is reminiscent of eating a gumdrop, hence the name.

Gumminess is related to the rheology of the unfrozen portion of ice cream, which in turn is related to the nature and degree of water immobilization. Although water immobilization is important to control ice crystal growth, a point is reached where the unfrozen product becomes sticky and very cohesive, i.e., gummy. Sometimes some gumminess is desired in ice cream; however in most cases, manufacturers do not want a gummy ice cream. To reduce the degree of gumminess in a product that currently shows that characteristic, several factors should be considered.

The primary considerations affecting water immobilization and therefore gumminess, include the nature and level of stabilizing colloids, high-molecular weight components of corn syrup solids (CSS), some bulking agents (in the case of lower fat products) and milk protein. To reduce (or manage) the degree of gumminess, the amounts and/or types of these components should be adjusted.
The stabilizing colloid most likely to be involved with gummy ice cream is guar gum. If guar gum is a major component of a stabilizer system and gumminess is a problem, the use of an alter-native stabilizer like carboxymethyl cellulose can be helpful. Most of the time hydrocolloid level stays the same.

Likewise, water immobilization increases as the CSS dextrose equivalent (DE) decreases. However, the relative benefits of products like 36 DE CSS to ice cream quality and economics are so great, that it is highly desirable to use 36 DE CSS and manipulate the degree of gumminess by adjusting the level of 36 DE CSS or other ingredients.

In similar ways, the water-holding activity of milk proteins impacts gumminess; therefore take care when selecting and using milk proteins in order to manage gumminess effectively.