Understanding How High-Protein Bar Formulations Impact Their Mechanical and Wear Behaviors Using Response Surface...

High-protein bars are popular snack items that can have significant processing issues like sticking, clogging, and cold flow. These issues are primarily problematic during formulation development because current predictive testing is reliant on highly empirical bench tests or pilot plant testing, which is expensive and time-consuming. Wear testing, which has been used in the medical field to evaluate the lifetime of soft materials used in joint replacements, may have promise in evaluating food processing ability. Wear and rheological testing were used to better understand high-protein bar processing ability. The objective of this study was to determine bench-level instrumental tests that would be able to predict processing ability for a given formulation. Two response surface designs were used for formulations of model bar systems comprising whey protein isolate (WPI), high fructose corn syrup (HFCS), and either canola oil or vegetable shortening. Ingredient formulation affected processing ability, wear behaviors, and rheological behaviors. Formulations with high ratios of WPI to HFCS and either shortening or oil exhibited good processing ability, lower wear rates, and increased elastic-type behavior, indicating that processing ability is related to formulation. The results of this study indicated that material mechanical and wear behaviors were related to processing ability; both were controlled by formulation. Because it was shown to be a good indicator of high-protein bar processing ability, wear testing of food has potential significance in benchtop testing. PRACTICAL APPLICATION: Understanding of how high-protein bar formulations impact their mechanical behaviors can help streamline their formulation development and scaling from bench to industrial production. Processing ability may be predicted with a quick wear test, providing a rapid testing method that requires little sample for evaluating bar formulations.