November 13, 2014 – Protein and fiber are added to food systems for many reasons, both functional and nutritional. However, with their addition comes the need for ingredient and processing adjustments, depending on the final food and its desired characteristics, which is why it’s important to understand both challenges & solutions when working with protein & fiber in food formulation.
“The approach that works for us,” explained Martha Porter of Merlin Development, “is to first identify all issues through searches of literature, marketplace, patents, competitive products (both retail and restaurant) and analogous foods. Then robust experimental design optimizes taste, cost, process and shelflife. Finally, confirmation runs verify the design predictions.”
Porter went on to highlight key considerations when using protein in low-, intermediate- and high-moisture systems. Low-water Systems: In low-water systems, such as protein bars, texture changes over shelflife. Protein tends to increase firming over time, beyond the normal firming that takes place. Proteins are not fully hydrated immediately
and, over time, they draw moisture from syrups generally used to hold bars together. Fiber, if it is not fully hydrated, can also draw moisture from the syrup. The continuous syrup phase then becomes more concentrated, contributing to the loss of pliability.
“Strategies to overcome these issues include use of multiple sources of protein and fiber,” said Porter. In addition to protein powders, nuggets or crisps can be high in protein and also contain fiber. Coatings can be protein- or fiber-fortified.
Cereal pieces, like oats, wheat flakes, nuts, pulse flour, or pieces and seeds, are other sources of protein and fiber. Protein hydrolysates are helpful to mitigate firming. Low-DE syrups promote chewiness and help maintain pliability. They contain longer-chain carbohydrates that hold onto water better and provide cohesiveness.
Higher-DE syrups add sweetness; multiple forms of sugar (sucrose, fructose, etc.) in the same binder system can hinder recrystallization. Sugar alcohols control water activity and browning. Typically, granola or cereal bars need a water activity below 0.65, with pH in the acidic range.
Intermediate-water Systems: Intermediate-water systems like bread have sufficient water to hydrate ingredients, such as fiber and protein, but there is limited room for their fortification due to other necessary functional components. For example, dilution of gluten creates problems with volume and texture in bread.
In bread, protein considerations include clean flavor and color, especially in white bread. Non-white breads can incorporate pigmented particulates, like nuts, seeds and other whole-grain ingredients. Fibers can include resistant starches and maltodextrins, which are digestion-resistant, but behave like starches and maltodextrin. They can help mitigate the heavy texture seen with high-cellulosic fiber breads. A blend of different fiber sources may be necessary to achieve both nutrient content and organoleptic quality. Other formula and processing adjustments may be necessary as well, said Porter.
High-water Systems: In beverages, protein selection depends on the desired characteristics of the final product. If clarity is desired, acidified proteins are needed. The proteins used will also depend on the desired function of the beverage or nutrition claims.
Ionic strength, pH, fat, carbohydrate content and processing parameters, such as temperature and shear, affect final product characteristics. For fiber, the focus is on nutrition, but beverages need fibers with a minimal impact on viscosity, explained Porter.
High-protein and -fiber solutions can be gritty, which can be masked by viscosity. Soluble fibers may be more helpful, as can smaller particle size. Processing parameters in beverages that need consideration include rehydration time; heat stability of the protein; and turbidity after heat treatment and fiber dispersibility. Homogenization and emulsion formation, batching temperatures, order of ingredient addition (critical for an acidification step) and packaging (clear or opaque) also help determine final product qualities.
In summary, determination of the rationale behind product fortification is first and foremost. Different moisture levels determine how to approach the formulation issues. Protein and fiber selection can be critical to product success. Process considerations also matter.
Martha Porter, Scientist, Merlin Development Inc., mporter@merlindev.com, www.merlindevelopment.com
The summary above is an excerpt from the “2014 Protein Trends & Technology Seminar Magazine: Formulating with Proteins”
