Nondestructive determination of the rheological properties of liquid food in sealed retort pouches

Abstract

We investigated an external, nondestructive method to determine the viscosity of liquid food that is packaged in a retort pouch by dynamic viscoelastic measurement. Two thickening agents were used to model liquid foods. Various concentrations of these liquid foods were packaged into retort pouches. The dynamic viscoelasticity of the packaged liquid food was measured by a uniaxial compression vibration test by using a rheometer. The storage modulus E′ and loss modulus E″ increased with increasing concentrations of thickening agents. However, the measured values were affected by the rigidity of the retort pouch. We could correct E′ and E″ for the influence of pouch rigidity. The corrected E′ and the apparent viscosity had a strong positive correlation. These results indicate that, by using the proposed method, the apparent viscosity of liquid food in retort pouches can be evaluated by using the corrected storage modulus. Practical applications The physical properties (e.g., viscosity) evaluation of liquid food that is packaged in a retort pouch is extremely important in quality control. If the viscosity of the liquid food in the pouch can be measured without opening the pouch, an inspection of the liquid food product becomes possible. In this study, a simple method to evaluate the physical properties of liquid food from outside the pouch by using a dynamic viscoelastic measurement was examined. We obtained a good correlation between the storage modulus and the apparent viscosity. This result is effective for the quality control of liquid food products (e.g., juices, soups, and care foods) that are packaged in such pouches.

Rheological characteristics of reconstituted freeze‐dried dragon fruit pulp powder: Effect of concentration and temperature

“…The dynamic frequency sweep test measures the storage modulus ( G ′) and loss modulus ( G ″) with respect to frequency to study the viscoelastic nature of the sample (Liu et al, 2022). The storage modulus and loss modulus explain the elastic and viscous properties of the liquid foods at small amplitudes, respectively, and these properties are studied without varying the structural properties of the sample (Tazoe et al, 2018).…”