Glucose‐fructose‐glycine time–temperature integrator and its potential application in heating process control of food softness

Abstract

AbstractThe objectives of this investigation were to evaluate the nonenzymatic browning (NEB) color development characteristics of glucose‐fructose‐glycine solutions for their potential as a colored time–temperature integrator (TTI) function for indicating pumpkin softness during steaming. The solutions with different substrate concentrations and incubated temperature values showed the same pattern of browning development. The pattern was visually distinguished into three different consecutive zones, colorless to yellow, yellow to dark brown and constant dark brown. These zones were well represented (R2 ≥ .975) by the s‐curve kinetics of % unaccomplished transmittance by the natural logarithmic function and modified Gompertz models. The Arrhenius equation (Ea 90.1–118.7 kJ/mol, R2 ≥ .9285) described the temperature dependence of kinetic parameters. A method to generate a NEB‐TTI conceptual framework of time–temperature applicable range was described to represent the three color zones. The framework functions as a guideline to design a NEB‐TTI system for a food attribute with the same time–temperature range and Ea of interest. Pumpkin softness change was modeled (modified Michaelis–Menten and Arrhenius equations; Ea 97.25 kJ/mol, R2 = .9994). A glucose‐fructose‐glycine TTI tag prototype well represented pumpkin softness during steaming. It is promising for a sugar‐amino acid system as a colored TTI to represent historical food quality change during heating.Practical ApplicationsThis work provided an approach to develop colored TTIs from a nonenzymatic browning reaction which is beneficial as the reactive substrates are stable, cheap, and can be stored at room temperature. The % unaccomplished transmittance parameter was proposed as well representing the browning color change in time in the s‐curved manner and corresponding to the three different color changing zones. This parameter is more practical for TTI color interpretation for specific uses. Suitable mathematical models to describe the color change characteristics of glucose‐fructose‐glycine TTI and softness of pumpkin were described and are possibly applicable to other NEB‐TTI and food types. A conceptual framework of NEB‐TTIs was proposed to facilitate food‐TTI matching. This work also showed that without sample destruction, food softness change in response to time–temperature history during steaming can be monitored and managed through the gradient colors of the NEB TTI tag. Controlling food quality and safety during heating using colored TTIs as a nondestructive approach is potentially possible.Highlights Variation of NEB color in three different phases is useful for colored TTI development. A new, meaningful parameter, the % unaccomplished transmittance, was proposed to represent TTI color change pattern. A conceptual framework was proposed to facilitate food‐TTI matching. NEB‐TTI is potentially useful for nondestructive & real‐time monitoring of food quality during heating