Advances in large amplitude oscillatory shear Rheology of food materials

Abstract

Molecular interactions determine the microstructure of food, as well as its response to deformation and flow. In order to design efficient processing equipment, to produce high-quality, stable end products, to predict textural and sensory properties, and to ensure consumer acceptance, the characterization of food rheology is essential. Deformations are rapid and large during the processing of foods and during consumption. In food studies, large amplitude oscillatory shear (LAOS) has become increasingly popular due to its ability to mimic real-life processes. When food is subjected to dynamic oscillatory shear tests, a sinusoidal deformation is applied, the mechanical stress (or strain) is probed, and the response is recorded. This chapter summarize main methods to extract meaningful rheological parameters from complex LAOS response of selected food materials. A time-resolved nonlinear rheology method, sequence of physical processes (SPP), gave detailed interpretations of transient microstructures, whereas the Fourier Transform coupled with Chebyshev decomposition (FTC) method provide static measurements at specific strains. LAOS behavior and its relationship to food microstructures and texture still needed to be studied in depth. By constructing more accurate mechanical models of complex food systems, the fundamental knowledge can be applied to evaluate the nonlinear rheology of food for consumer acceptance and efficient processing.

Wheat Flour Quality Assessment by Fundamental Non-Linear Rheological Methods: A Critical Review

“…The comparison of the second harmonic intensity to the third harmonics ( I 2 /I 3 ) has been shown as the confidence metric for too noisy MAOS data, while the ratio of the fifth harmonic intensity to the third harmonic intensity ( I 5 /I 3 ) has been suggested as the confidence metric for too non-linear MAOS data [ 79 ]. Using these metrics, Erturk et al [ 18 ] provided an evaluation of the I values obtained from the LAOS tests ( ω : 10 rad/s) conducted on soft wheat, hard wheat, and durum wheat flours. The lower strain limits ( I 2 /I 3 < 0.1) and the upper strain limits ( I 5 /I 3 > 0.1) of the MAOS region were 0.1–0.4% for soft wheat flour dough, 0.16–1.3% for hard wheat flour dough, and 0.27–2.2% for durum wheat flour dough.…”

“… a Uthayakumaran et al [ 8 ], b Uthayakumaran et al [ 80 ], c Yazar et al [ 21 , 26 ], d Erturk et al [ 18 ], e Ng et al [ 86 ], f Yazar et al [ 22 ], g Li et al [ 31 ], h Yazar et al [ 90 ], i Zheng et al [ 92 ], j Osorio et al [ 94 ], k Cuq et al [ 28 ], l Kim et al [ 19 ], m Bonilla et al [ 97 ], n Vidal et al [ 32 ], o Wang and Sun [ 33 ], p Van Bockstaele et al [ 34 ], q Rouillé et al [ 24 ], r Ktenioudaki et al [ 101 ], s Turbin-Orger et al [ 29 ], t Ktenioudaki et al [ 103 ], u Sliwinski et al [ 47 ], v Dobraszczyk and Salmanowicz [ 107 ], w Vanin et al [ 7 ], x Alpers et al [ 30 ], y Vidal et al [ 110 ]. …”

“…These findings obtained through the LAOS tests indicating the effect of wet gluten content in wheat flour on the strain stiffening behavior of the resulting dough cannot be obtained quantitatively using the empirical dough testing methods. LAOS test was also used by Erturk et al [18] to unravel the impact of protein content in wheat flours on the viscoelastic properties of the resulting doughs under large deformations. In this study, a different approach was used, and harmonical intensities (I) were evaluated to determine the MAOS (Medium Amplitude Oscillatory Shear) region and the onset of the LAOS region [18].…”

“…A frequently used fundamental method for rheological testing of doughs is the Small Amplitude Oscillatory Shear (SAOS) test, which analyzes the linear viscoelastic response by observing the strain and frequency dependence of the elastic modulus (G′) and viscous modulus (G″) at small strains without disturbing the 3D structure of dough [ 16 , 17 , 18 ]. Small deformation tests are advantageous in understanding molecular interactions and microstructure [ 19 ].…”

“…Alternatively, large deformations can be applied at frequencies or deformation rates ranging from low to high in order to approximate the deformations wheat flour dough experiences during mixing, sheeting, or proofing [ 21 , 25 , 26 ]. Moreover, certain dough samples may show similar linear rheological properties but can exhibit distinct nonlinear rheology, which is why probing nonlinear rheological properties can provide information that is not available from small deformation measurements [ 18 , 22 , 27 ]. Especially if the material contains high molecular weight (HMW) polymers [ 9 ], such as glutenin in wheat flour, measurements under large deformations often show very different rheological responses to those in small deformation.…”