Tiny, invisible ingredients

There are several advantages to using nanocapsules. Formulators can have higher dose-loading with smaller dose volumes for a more attractive nutrition and ingredient panel. Nutrients are protected from degradation during storage for better shelf life and handling cost. Higher bioavailability eliminates the common practice of adding more to compensate for processing-related dissipation.

For ingredient suppliers, nanotechnology offers many opportunities. Volatile flavors often in liquid form can be transformed into a powder, which generally is easier to handle. Active flavors that may interact with the other food ingredients can be stabilized for longer product shelf life.

Nanocapsules helped Chicago-based Nu-Mega (www.nu-mega.com) and Clover Corp. incorporate tuna fish oil, a source of omega-3 fatty acids, into Tip-Top Up bread in western Australia. Nu-Mega claims the nanocapsules open only when they have reached the stomach, thus avoiding the unpleasant taste of the fish oil.

Encapsulation technologies can deliver strong taste, but taste is often unevenly distributed.

“You may have a strong burst of taste from a big capsule, but you won’t have the same burst of taste throughout,” says Qingrong Huang, a food scientist at Rutgers University (www.foodsci.rutgers.edu/caft), New Brunswick, N.J. “Nano particles are more interactive. They cover more of the tongue.”

Bioavailability of potentially healthful micronutrients that are commonly lost in the gastrointestinal tract can be enhanced similarly with nanotechnology, Huang says. Teas, cranberry juice, blueberry juice, and wine are but a few of the beverages that might deliver on their health promise in nano form.

“It’s hard to absorb the tea components,” says Huang, “but with nano particles, their availability will be much better. You don’t want to wait until you have a problem with obesity or cancer or heart disease. You want to prevent them from occurring. We are working on a beverage product with active ingredients from tea, blueberry and grapes that can improve your health and help prevent disease.”

Whereas nanocapsules are carriers composed of an oil core surrounded by a polymeric wall, nanospheres consist of a polymeric matrix with several phases in suspension.

Nanospheres of omega-3 oils have very low surface oil (less than 0.5 percent) at very high payloads (40­50 percent) compared to 1-3 percent surface oil and 20 percent payload of some conventional spray-dried particles using hydrocolloids or starch and other microcapsule forms of omega-3.

Flavor manufacturers find the moisture-sensitive matrix provides excellent retention of flavors that tend to be highly volatile, especially over an extended period of time. The technology also minimizes flavor fade during product shelf life. Encapsulant hydrophobicity prevents the encapsulated bitter ingredients from going into solution and interacting directly with taste receptors.

Olala Foods (www.olalafoods.com), Northbrook, Ill., designed nanospheres to be dissolved by saliva and shear, delaying the release of nano-encapsulated cocoa butter in Olala’s Chocola chocolate chewing gum. Michael Gurin, the inventor, explained that nanocapsules also created a creamy texture in the gum without affecting its stability.

Flavor manufacturers can encapsulate and stabilize citral (the lemon flavor used in many Key lime formulations) at the pH of fruit juices for release in the mouth upon drinking. Because hydrophobic nanospheres are temperature-sensitive, they are ideal for releasing active ingredients and flavors when a drink or soup is heated.

An electronmicrograph of a vitamin A micelle shows it to be smaller than 50nm, its size making it more easily absorbed by the body.

Invisible in the market, too

"Every major food corporation has a program in nanotechnology or is looking to develop one,” according to Jozef Kokini, director of the Center for Advanced Food Technology at Rutgers University. In fact, nanotechnology ingredients already are appearing in food.