Formulating with inclusions requires management of free-water mobility, temperature, freezing points, osmotic pressure differences and other factors for both frozen dessert and each inclusion. The following considerations apply.
1. Compositional compatibility
The ice cream composition must be compatible with any added colorant or liquid flavor (that is, adequate sweetness, color, body and texture) and, at the same time, with each added inclusion.
2. Amount/type of inclusions
Use rates of 10% for particulates and 15% for syrups, based on the weight of the frozen dessert are typical. Thus, it is possible to have up to 50% (two particulates and two syrups) as inclusions. That puts physical and chemical stress on an already stressed system.
3. Microbiological quality
Since inclusions are added post-pasteurization, they need to be either pathogen-free or rendered pathogen-free. Methods used must not affect ease of handling or sensory properties.
4. The delicate balance
It is necessary to balance freezing performance (tied to freezing point management and water mobility control), flow, handling and sensory appeal to the rigors of distribution and consumption. This means management of mix composition, freezing performance, water mobility and other factors, all of which affect both ice cream and inclusions.
5. Weight per finished gallon
Inclusions are typically heavier than the frozen dessert into which they are added. That makes the final product heavier than simple straight flavored ice cream (for example, vanilla). To maintain a specified finished weight, the addition of more overrun (air) may be necessary.
Adding overrun can reduce air-bubble strength and sensitize the air bubbles to physical abuse by larger particulates and actively variegated syrups. If overrun adjustment is undesirable, it may be necessary to create specific mix compositions.
Inclusions should be added at as low a temperature as possible to minimize localized heat shock. Inclusions also need to be injectable under conditions of use. This minimizes the development of iciness due to melting and refreezing. As temperature decreases further, there can be shrinkage of ice cream or inclusions away from each other. This creates cracks, voids and opportunities for secondary defects.
7. Mechanical affects
The ability of any given inclusion to retain its preferred physical form, shape and eating character is critical. That applies to syrups as well. In most cases, mechanical ways to deliver desirable thickness, visual appeal and flavor delivery vary from plant to plant. In any case, to provide for clear differentiation of inclusions from ice cream, syrups should be injected after addition of particulates.
Inclusions may be more expensive than the frozen dessert into which they are added. That means, as inclusions are considered for novel features and benefits, careful assessment is necessary to insure compliance with whatever line-cost-averaging guidelines exist. This can offer positive influence on economic return within and between product lines. The opposite is possible as well.
9. Physical behavior
Ultimately, the flow behavior of ice cream with inclusions added is determined by what is necessary to allow the finished product to uniformly fill packaging or the ability to make molded, filled or extruded novelties.
10. Maintaining integrity
Frozen desserts are designed to be eaten frozen. Most inclusions are not.
Textural challenges may run counter to each element. That is, keeping ice cream smooth, creamy, rich, not sticky and not gummy versus maintaining the dry, crunchy, crisp, soft, thick or gooey features of any given inclusion or combination of inclusions.
Notwithstanding all the above, an ice cream processor can deliver the desired sensory “promise” with proper formulation, inclusion selection, common use rates and conditions of injection.
Ask Tharp and Young
Attend Tharp and Young’s webinar on April 29. Register at dairyfoods.com. For in-depth coverage of particulate and variegated inclusions, selection, use, management, economics and related considerations, join Bruce Tharp and Steven Young at “Tharp & Young on Ice Cream: Technical Short Course, Workshops, and Clinics.” Go to www.onicecream.com or call 610-975-4424 or 281-782-4536 for venues, coverage, registration, discounts and book orders.