By Cindy Hazen, Contributing Editor
The components that make up a dairy product are as diverse as a group of people on a social networking site. Some may be intimate friends, while others are bare acquaintances. They may or may not get along outside the virtual world. And, like strangers stuck in a hot elevator, ingredients can be stressed when forced into uncomfortable surroundings. Any outburst can create great product harm. It can be pandemonium when an ingredient separates from the group.
Fortunately, the product developer has a few tricks to maintain harmony. The key is to know which tools to bring to the mix, because every product type will have a different requirement.
The big picture
Before we can develop a specific plan toward peace, we have to know not only which ingredients might pose problems, but also the conditions in which they might behave inappropriately. According to Donna Klockeman, Ph.D., dairy food scientist, TIC Gums, Belcamp, MD, proteins and fat provide challenges to the stabilization of dairy products. “Both are affected by temperature and stress of processing, and are directly involved in the delivery of ideal product characteristics," she says. “Potential interactions, positive or negative, between stabilizer components and these ingredients can limit the possible solutions for quality defects. Understanding these interactions is critical to the selection of the best stabilizer system in dairy applications."
Heat can exacerbate dairy stabilization problems because it denatures the protein. Yet many manufacturers seek to increase heat treatment to allow for longer refrigerated shelf life or to achieve shelf stability in nonrefrigerated products. “To ensure product quality through the increased temperature of processing, modifications or additions to the stabilizing and texture system may be necessary," says Klockeman. “Some components cannot withstand the extreme temperatures, rapid heating and cooling, and pumping shear used in the production of shelf-stable non-refrigerated products."
However, just as processing methods differ, so do hydrocolloids’ reactions to them. Linda Dunning, industry manager, dairy, Danisco USA, New Century, KS, notes: “Some ingredients, such as locust bean gum and kappa carrageenan, require heat for activation. If the product is cold-processed, then these would not be suitable stabilizer choices. Microcrystalline cellulose (MCC) provides excellent mouthfeel, heat-shock protection and air-cell stability in frozen desserts, but processing conditions must be considered when selecting the type of MCC."
For example, “an MCC that requires shear for activation will be fine when using a two-stage homogenizer at 2,000/500 psi. However, if a single-stage homogenizer is being used, it would be best to select an MCC that is less shear-activated," Dunning continues. “For hard-pack ice cream, carrageenan may need to be added if the ice cream is in large bulk containers or undergoes slow hardening. Additionally, the processing equipment may dictate characteristics of the gums that are needed. Proper dispersion of a stabilizer prior to hydration is essential for full functionality and to avoid ‘fish eyes,’ or clumping. If a manufacturer has poor agitation at the point of adding a stabilizer, then the stabilizer system needs to contain gums that are more easily dispersed, or blended with an appropriate dispersing agent."
