Frequency Dependence of Viscoelastic Properties of Bread Crumb and Relation to Bread Staling

Abstract

Cereal Chem. 79(1):108-114The viscoelastic behavior of bread crumb was studied using dynamic mechanical analysis (DMA) in the compression mode with the frequency sweep. The dynamic storage modulus (E′), loss modulus (E″), and tanδ (E″/E′) were measured for bread crumb aged up to three days at ambient temperature. The viscoelastic properties of bread crumb showed a characteristic frequency dependence similar to that of a soft rubberlike solid. Typical behavior of bread crumb involved a transition from rubberlike to glasslike consistency with increasing frequency. At a low frequency region, the E′ and E″ values were relatively small and nearly constant, showing characteristics of the rubbery plateau. Then, they increased rapidly with increasing frequencies and approached a glasslike state. Tanδ was low and almost constant at low frequencies before the transition, then went through a prominent peak with increasing frequency. The frequency at which the tanδ of bread crumb started to rapidly increase was defined as the onset frequency (f o ) of the transition. The f o values increased with the aging of bread crumb samples, which correlated highly to bread staling (r = 0.942). Both dynamic moduli E′ and E″at f o also increased with the aging of bread, which correlated highly to firmness obtained using a texture analyzer in a static compression mode (r = 0.941 and 0.943, respectively). DMA measurements could be helpful in characterizing bread staling.

Relationships between dough and bread viscoelastic properties in enzyme supplemented wheat samples

“…The onset frequency of the transition at which tan d starts to rapidly increase (f 0 ) and the glass transition temperature (T g ) are important parameters that can be obtained respectively with DMA and TMA measurements (Bollaín et al, 2005). In addition the storage modulus (E 0 ) at f 0 , T g , and at the rubbery plateau, where E 0 is poorly dependent on temperature (E 0 plt ), give information about the mechanical properties of crumb, generally used to evaluate staling of baked goods (Bollaín et al, 2005;Davidou et al, 1996;Wang & Sun, 2002). Multivariate analysis of analytical data of the rheological profile of doughs and breads was performed to evaluate potential relationships between functional properties.…”

“…Dynamic mechanical (DMA) and thermal mechanical analysis (TMA) have been used to determine dynamic rheological properties of polymeric material including foams. Recently, they have also successfully been used for textural characterization of different food matrixes including bakery products (Baik & Chinachoti, 2000Bollaín, Angioloni, & Collar, 2005;Davidou, Le Meste, Debever, & Bekaert, 1996;Kayacier & Singh, 2002;Vittadini & Vodovotz, 2003;Wang & Sun, 2002). These tests solve the limitations of a shear rheometer employed on solid materials by operating in an oscillatory compressive mode (Weipert, 1997).…”

Changes in the Texture and Viscoelastic Properties of Bread Containing Rice Porridge during Storage

“…The changes in moisture content in the three types of bread over the 3 d storage ranged from 42.31% to 42.33% for the wheat flour bread, 42.57% to 42.68% for the rice flour bread, and 43.08% to 43.00% for the rice porridge bread. Although bread crumb hardening during storage is related to moisture loss in crumbs, 20) such small changes have no significant effect 21,22) on bread texture. In addition, the moisture differences among three types of bread were also small.…”

Studies on glass transition and starch re-crystallization in wheat bread during staling using electrical impedance spectroscopy

“…there are 7 samples from each crumb and crust. All samples are dried in vacuum oven for 16 h at 75°C and moisture content (MC wb ) (wet basis) is calculated (Wang & Sun, 2002) …”