Formulating ice cream with novel functional ingredients
As complex new ingredients are introduced to the ice cream mix, much remains to be understood about influences on physical/chemical properties.
We have often noted the importance of various phenomena, including the agglomerated fat matrix and the size of ice crystals and air bubbles, to the sensory appeal and structural properties of ice cream. Key to managing these phenomena is a complex set of highly variable (sometimes unknown) functionalities.
Any given ingredient may offer benefits to a specific marketing promise while controlling acceptability through the behavior of water and fat. As complex new ingredients are introduced, much remains to be understood relevant to their influences on physical/chemical properties. Furthermore, complexity is introduced by the effects of freeze concentration.
Fats, oils and other lipids
Fractionated milkfat: Milkfat fractions (separate or recombined) can provide specific functionalities. How the amount and type of any such fractions function in any given formula(s) is worthy of study.
Non-milkfat, non-milkfat fractions and hydrogenated forms: In trying to match the functional and sensory properties of milkfat, it should be remembered that plant fats/oils are fundamentally different from milkfat and, sometimes, from each other when considering their influence on structure via fat agglomeration and melting-point variations.
Plant sterols: In many no-fat products, there remains a need to carry (and release) fat/oil-soluble flavoring components essential to the desired characterizing flavor. Small amounts of plant sterols can offer the ability to provide this necessary functionality.
Plant sterols are not “fat” for nutrition-labeling purposes, but they do provide calories. So how they are used, managed and declared needs to be carefully considered. Usually, application in near fat-free mixes shows the most flavor improvement.
Lecithin: Lecithin is Mother Nature’s “preferred” emulsifier. However, the functionality of any given source can be expected to vary substantially from other sources. Lecithin contains unsaturated fatty acids that are critical to its function but also create sensitivity to oxidative rancidity.
Propylene glycol monoester (PGME): Unlike traditional added emulsifiers (e.g., monodiglycerides, polysorbates), PGME functions to coat small ice crystals with a “fatty” film, preventing them from growing under heat shock. In context, PGME essentially creates a stable ice-in-water “emulsion.”
High-molecular-weight soluble “complex” carbohydrates: These include water-soluble dextrins, maltodextrins and higher-molecular-weight components of low dextrose equivalence (4-18). Most interesting are the more complex-structured digestion-resistant forms. These are totally water soluble with minor, but significant, influence on sweetness and freezing-point depression and a profound influence on the mobility of liquid water when freeze concentration is considered.
Micellular casein: Micellular casein delivered via milk protein concentrates and isolates is a relatively recent addition to the list of novel milk ingredients. It is not soluble — its influence on heat stability and structure is related to its influence on the surface chemistry of milkfat droplets via exchange with more lipophilic compounds in the mix.
“Modified” whey proteins: Their use is typically related to labeling (as components of total “whey”) and mix viscosities. Again, care is necessary to fully understand what is to be accomplished by what whey protein.
“Modified” egg proteins: As with whey proteins, egg albumin may need to be “modified” to function effectively in small amounts.
Plant protein concentrates (> 70% protein dry basis) or isolates (> 90% protein, dry basis): These proteins have varying sensitivity to heat and varying ability to interfere with (or enhance) the perception of flavor(s), whether added or not.
“Rare” sugars (allulose and tagatose): These have a near sucrose-like sweetness but negatively influence freezing point and the amount of water involved in heat shock. These sugars contribute low caloric levels (1.5 per gram for tagatose, virtually none for allulose) and are, therefore, useful in calorie reduction. They are, by current definition, “sugars” and would be considered “added sugars” for Nutrition Facts labeling purposes. This is not to say there is no utility in formulating with these when proper care is considered.
Sugar alcohols (sorbitol, lactitol, maltitol, polyglycitol, maltitol syrup, a maltitol/polyglycitol blend, etc.): Sugar alcohols need not be labeled as “added sugars.” It is important to ensure the amount used is well below the laxation threshold for the type. Maltitol, either per se or as maltitol syrup, is often preferred because of its sucrose-like sweetness and low laxation threshold.
Non-nutritive sweeteners: These are “natural” extracts that deliver intense sweetness but little to no solids (i.e., high-intensity sweeteners). Novel blends based on the sweetness contribution of each extract help focus on the objective of sucrose-like sweetness.
Probiotics: These are microbiological organisms that survive ingestion, grow in (but may not colonize in) the upper colon, and promote, either directly or indirectly, nutritional benefits to human health.
Prebiotics: These are normally large-molecular-weight compounds that may be totally or partially fermented in the colon by probiotic organisms. Again, they provide either direct or indirect nutritional benefits to humans.
A number of novel applications for hydrocolloid stabilizers exist, whether they be classical high-viscosity (and/or gelling) types or low-viscosity with novel functionalities in managing the behavior of liquid water.
One such ingredient said to have hydrocolloid functionality is described in a pending patent for a physically modified grain-based flour that may have application in frozen desserts. It is a syrup-like low-calorie ingredient with less than 1% “sugars” and is said to have texturizing, bulking, stabilizing and freezing-point depression properties.
In summary, in any formulator’s ingredient “toolbox,” there are a growing number of novel ingredients with positive and, potentially, negative influences on the physical/chemical behavior of any mix. Thus, identification, selection and use of any novel ingredient within any given context can be challenging.
To learn more about formulating with novel ingredients under highly variable conditions, approaches and objectives, join Dr. Bruce Tharp and Dr. Steven Young at “Tharp & Young on Ice Cream: Technical Short Course, Workshops and Clinics,” Dec. 4-6, 2019, in Las Vegas. Class size is limited! Special appreciation goes to Bill Sipple, a new member of the Tharp & Young on Ice Cream faculty, for his contributions to this column. For more information, go to www.onicecream.com.