Rheology of Muffin Batters by Line Spread Test and Viscosity Measurements
This work was aimed to quantify the flow properties of muffin batters by Line Spread Test (LST) and to establish a valid correlation between their line spread distance and viscosity. LST is a quick and inexpensive method for comparing relative viscosities of food slurries or a solid-liquid suspension type of food materials, like muffin batters. The rheological proper ties of muffin batters formulated using gluten free flours were studied. Five different combinations of rice flour and quinoa flour were studied as gluten free flour combinations. Control muffin batters were formulated using 100% wheat flour, which is a gluten positive flour. Density, pH, line spread distance and viscosity were measured for all six batter formulations including control. All tests were performed in triplicate and all data were analyzed statistically. In general, gluten free flour reduced the density and increased the acidity of muffin batters. Whereas, line spread distance was increased and viscosity was decreased with replacement of quinoa flour to rice flour in the muffin batters. A valid correlation between line spread distance and viscosity was observed. The inverse of LST in cm/sec was observed to be close to the viscosity in poise for muffin batters in this study.
Rheological properties of batter systems containing different combinations of flours and hydrocolloids
The rheological properties of batters formulated using different combinations of wheat, corn, and rice flours with two types of hydrocolloids, namely methylcellulose (0.5%, 1% and 1.5%) or xanthan gum (0.2%), were studied. Control samples were formulated with combinations of flours without the added hydrocolloids. The effects of hydrocolloids on rheological characteristics of the batter systems were measured using a controlled stress rheometer at a temperature of 15 °C. The effects of hydrocolloids on dynamic viscoelastic parameters as functions of temperatures were evaluated. All the batters showed shear thinning behaviour with flow behaviour indices in the range 0.34–0.67. Addition of xanthan gum lowered the flow index values, imparting a higher degree of pseudoplasticity to the batter samples compared to methylcellulose. The consistency index of the control batter samples varied from 0.46 to 69.2 Pa sn. Addition of xanthan gum or methylcellulose significantly increased the batter consistency index value. The gums changed the onset temperature of structure development, and the storage (G′max) and loss moduli (G″max) of the batter systems. However, no statistically significant effects were observed on the peak temperature of batter systems in which the G′ reached a maximum value. Xanthan gum increased both G′max and G″max, whereas at higher concentrations methylcellulose increased G′max but lowered G″max. Copyright © 2007 Society of Chemical Industry
Impact of acetaldehyde‐ and pyruvic acid‐bound sulphur dioxide on wine lactic acid bacteria
Aims:  To investigate the impact of acetaldehyde‐ and pyruvic acid‐bound sulphur dioxide on wine lactic acid bacteria (LAB).