Structure–composition relationships of the traditional balsamic vinegar of Modena close to jamming transition (part II): Threshold control parameters

Determination of rheological property and its effect on key aroma release of Shanxi aged vinegar

“…This indicated long-time ageing process of vinegar might result in the variation of microstructure. The previous study proposed that the formation of polydisperse melanoidins was responsible for change of rheological property (from Newtonian to shear-thinning fluid) of traditional balsamic vinegar (Falcone et al 2012). Therefore, the contribution of certain macromolecule formed in SAV during the ageing process to its rheological property (both K and n value) can not be ruled out.…”

Rheological properties of traditional balsamic vinegar: New insights and markers for objective and perceived quality

“…The molecular size and molecular size distribution as well as the self-assembling and jamming properties of melanoidins present in long-aged traditional balsamic vinegars were discussed in previous works Falcone et al, 2012). To get a fundamental insight about the effect of jamming properties on the overall flow behaviour for the vinegar samples, flow curves were analyzed using a modified Krieger-Dougherty equation (Krieger & Dougherty, 1959) for relative viscosity.…”

“…With this aim, we attributed the observed intermittent flow to the progressive evolution of the viscoelastic structure of colloidal melanoidins under mechanical shearing. Recent studies showed that long-aged traditional balsamic vinegars with high Brix values (over 75°Bx) show yield stress and viscoelastic behaviour under sweep experiments from 10 to 200Hz (Falcone et al, 2012). With this in mind, two structuring, competing phenomena were hypothesized, one on them becoming dominant depending on the flow conditions: (i) reversible restructuration at long-range scales of the locally-discontinuous network of colloidal melanoidins due to the inter-chain entanglements (elastic contribution to colloidal jamming), that may oppose the starting flow (yield stress) and/or the flow at lower shear rates (intermittent flow behaviour) and (ii) irreversible restructuration at shortrange scales of viscous local bonds through local reptation of the chain backbone of polymeric melanoidins(viscous contribution to sub-colloidal jamming), that may result in homogeneous flow regime with shear-thinning or shear-thickening behaviour depending on the effective hydrodynamic interactions.…”

“…The shear rates ranging between 1 s −1 and 60 s −1 are long-term, even though they are the most frequent shear rate condition experienced by many fluid foods in the mouth during tasting (Wood, 1968;Shama, Parkinson, & Sherman, 1973). Falcone et al (2012) showed that the size of the colloids of vinegar melanoidins spreads in a wide range (from sub-colloidal to macroscopic) with the most frequent around 50 -100 microns. It happens that this size is similar to the size that humans can sense with the tongue, and thus they are expected to affect the stress stimuli during vinegar tasting.…”

“…"Jamming" is a term widely used in the science of food structure for soft materials (Mezzenga, Schurtenberger, Burbidge, & Michel, 2005;Ubbink, Burbidge, & Mezzenga, 2008) in order to describe how their constituents may result metastable structures that reach a minimum free energy as well as how some external parameters including density, temperature, and mechanical stress can influence such out-of-equilibrium structures by enhancing, reducing or eliminating the ability to flow (Liu & Nagel, 1998;Cates, Wittmer, Bouchaud, & Claudin, 1998;Trappe, Prasad, Cipelletti, Segre, & Weitz, 2001;Liu & Nagel, 2001). Falcone et al (2012) attributed vinegar jamming to the selfassembly properties of vinegar melanoidins due to their molecular properties: (i) the wide range of molecular size distribution that spreads from 200Da to beyond 2000kDa (ii) the distribution on the chain backbone of attractive net charges and bulky aromatic phenolic residues. Other compositional factors were also hypothesized to play a role in the extent of colloidal jamming in longaged vinegars: Fe and Mg content were higher and pH was lower in jammed fractions of the vinegar rather than flowing ones.…”