The challenge of formulating plant-based frozen desserts
Flavoring plant-based frozen desserts presents chemical and physical challenges
The perception of any flavor (F) is a combination of appearance (A), aroma (A), acidity (A), taste (T), texture (T) and temperature (T), or “FAAATTT.” Although these attributes hold for most foods and food ingredients, they do not capture the whole of the chemical and physical challenges in flavoring plant-based frozen desserts.
For most frozen dessert brands, vanilla accounts for approximately 30% of sales, and chocolate accounts for approximately 15% of sales. The sum of all vanilla, chocolate and vanilla/chocolate-based flavors can be nearly two-thirds of all flavors offered.
These nonacid flavors are particularly sensitive to the amount and type of ingredients used in plant-based mixes, not just the amount or type of flavorants applied. Fruit-flavored products are much easier to execute, but represent a much lower percentage of sales.
Base mix ingredients
Ingredients have flavors/tastes of their own, which are concentrated during whipping/freezing/hardening in the “unfrozen” portion of any mix. Consider the influence of these components on added flavors.
Plant proteins are typically of high molecular weights and tend to interfere with the perception of constituents of flavors. The chemistry of plant proteins may be modified by adding acid to reduce the ability to negatively influence the perception of any flavor.
That’s great for acid flavors, but not for nonacid flavors. Tweaking the acidity (not necessarily the pH) in/around plant proteins can be done via acidulants that deliver “high” acid but “low” tartness.
Ironically, the stronger the acid, the less “tart” it is. However, care is necessary, as too much acid can cause protein destabilization, loss of solubility and loss of other critical mix functionalities that will reflect in the finished frozen dessert. The amount/type of acid is critical as specific acids (e.g., citric, tartaric, ascorbic, etc.) can enhance flavor delivery in properly matched fruit-flavored products, but not with nonacid flavors.
There is a strict requirement for at least some fat/oil to be included in any plant-based frozen dessert mix. This is due to the need to carry and, ultimately, release fat-soluble volatile components under the right conditions to deliver the complexity/nuances of any given flavor.
This does not mean plant-based mixes need be “high-fat/oil” (> 10%) to carry the most fine of flavors (e.g., vanilla). Further, the amount, type and stability of the protein portion of the mix is ever so critical for emulsification and mix stability.
Luckily, bitter side chains of proteins may become embedded in the fat/oil portion of the mix. Adding to the complexity is that nearly all plant-based fats/oils function differently from each other and from milk fat.
The old adage that any fat/oil should mimic the functionality and melting properties of milk fat is far too simplistic, given the broad array of plant fat/oil options available. Each fat/oil will have its own flavor and compatibility with any added flavors. In most cases, 4-8% fat/oil should be sufficient for nonacid flavors; < 4% fat/oil for more acidic fruit flavors.
Sweeteners and bulking agents
Usually, the theoretical sweetness and management of water-soluble bulking agents are very much the same in plant-based mixes as in dairy mixes. However, while taking into account the amount/type of proteins and fats/oils to be applied, an unusually high percent of sweeteners and/or bulking agents may be necessary to properly balance the rest of the mix to achieve the desirable freezing performance and eating quality (body and texture) while delivering sufficient flavor-specific sweetness.
Emulsifiers and stabilizers
The same amount/type of emulsifiers used in dairy-based frozen desserts can used in plant-based frozen desserts. Remember, the functionality of emulsifiers is to enhance fat agglomeration during whipping/freezing and is not as likely in plant-based mixes. Plant proteins behave differently than dairy proteins in influencing fat agglomeration.
It may be possible to omit added emulsifiers to seek mix compositions that allow for more mechanical enhancement of fat agglomeration. Emulsifiers may contribute a very slight flavor of their own and, thus, influence flavor delivery in more delicately flavored nondairy frozen desserts.
Much the same is true with hydrocolloid stabilizers, as each interferes with the flow of liquid water during whipping/freezing and under thermal abuse (“heat shock”) during distribution and storage. The movement of water, or lack thereof, can significantly interfere with flavor release.
Some hydrocolloids may contribute a very slight flavor of their own. For clean flavor release, or when delicate flavors are used, pectin, gelatin and locust bean gum are good choices. However, guar may add a slight “beany” flavor at higher levels and, under the influence of “freeze concentration,” can deliver subtle off-flavor(s). Cellulose gums typically do not contribute a flavor of their own, and carrageenans, when used properly, are rarely a source of flavor problems.
Particulate and syrup inclusions
Just about any inclusion can be formulated to be compatible with a plant-based finished product. Since no real standards exist, good places to start are approximately 10% particulate inclusions and/or approximately 15% syrup inclusions based on the weight of the frozen dessert.
Just as in any other frozen dessert, the quality of the flavor delivery should have the mix “match” the amount/type of inclusions to be added. This is particularly true when considering fruit preparations to be added, whether as a particulate inclusion and/or as a compounded variegating sauce.
When all is considered, it may also be appropriate to consider an “unflavored” variant of any plant-based mix simply declared as “original.” If properly formulated, why not?