A key principle is that pro-biotic bacteria and the ingredients they ferment must not be digested and must be present in critical alliance in the colon so that the nutritional benefits of each are realized. Pro-biotic bacteria and pre-biotic ingredients should enter the colon at essentially the same time and be matched and balanced to maximize the production of fermentation byproducts. This is necessary so that byproducts can render benefit without intestinal distress, like excess acid or gas.

Relative to intestinal distress, it may be desirable to select a pre-biotic that is slowly and/or partially fermented. The cultures and pre-biotics used need to be of sufficient concentration to offer clinically proven nutritional effects. Otherwise, defensible select structure/function claims about the finished frozen dessert may not be possible. In most instances, nutrient content claims may be available (such as: reduced/low/no fat; good/excellent source of dietary fiber content; no sugar added/sugar-free; or reduced/low calories) but full or qualified health claims probably will not be available.

Manufacturing concerns

Pro-biotics must survive the rigors of heat shock throughout distribution, storage and consumption in amounts sufficient for efficacious nutritional purposes. The processor must manage many other factors, including aeration of mix (overrun), stability and influence of air bubbles, amount of solubilized oxygen in the unfrozen portion of the mix  and heat shock.  This is not an easy task.

In the end, it’s a numbers game that involves matching the amount and type of beneficial bacteria to the amount and type of fermentable pre-biotic ingredient(s) delivered in each serving.

So, the question is: Where to add pro-biotics and pre-biotics to frozen desserts? Here are four answers.

• Mix making. Pre-biotics can be added easily during mix making. All survive pasteurization and can positively influence a number of physically functional characteristics of the frozen dessert. However, if consideration is taken to add pro-biotics pre-pasteurization, then very specific organisms must be selected that survive pasteurization.

• Culturing. As in frozen yogurt, there may be multiple ways to culture pro-biotics prior to freezing/whipping. New issues arise relative to sensory appeal of the finished food. If fermentation takes place under desirable conditions, then the potential downside of losing the pre-biotic ingredient may become an issue as well.

• Aging. The process known as cold inoculation can be used. In this case, organisms are added to cold pasteurized mix (the pre-biotic being in the mix) just prior to freezing/whipping. This can be done to bulk mix or to the mix at the flavor tank. The form (freeze-dried, refrigerated liquid, frozen) and stability of the culture needs to be considered. In many cases, cold inoculation is the preferred approach.

• Inclusions. An interesting approach to adding pre- and pro-biotic materials to ice cream is to add them in the context of variegating sauces and/or particulates. Of course, issues related to the amount and type of pro- and pre-biotics revert to the formulation and manufacturing of these bulky ingredients. Further discussion is complex, detailed and relies heavily on control of injection rates.

Heat shock is an undesirable phenomenon related to frozen dessert quality, not only for the frozen dessert itself but also for survival of pro-biotic bacteria. In most cases, pre-biotic compounds have a positive influence on the freezing point and can help protect the frozen dessert. In doing so, they indirectly protect the pro-biotics. However, at the use-rates necessary, the nutritional compatibility of pre- and pro-biotics may not match.

For any innovation worthy of consideration, work is required. Such is the case of delivering nutritionally efficacious pro-biotics and pre-biotics in a frozen dessert format. Interest, demand and markets are available. Now is the time to get to work.

Find out more about pro-biotic cultures and pro-biotic friendly ingredients at our Tharp & Young On Ice Cream seminar. It will be held Dec. 2-4 in Las Vegas. Find details at www.onicecream.com or call 610-975-4424 or 281-782-4536.   

  Tharp & Young's new book, “Tharp & Young On Ice Cream: An Encyclopedic Guide to Ice Cream Science and Technology,” will be published this year.