Spss computer package version 16

Considering that in red meat a* value (redness) is the most critical determinant for consumer acceptance, it was also selected for modelling purposes. Thus, a* value was plotted vs. storage time and the apparent rate of colour deterioration k_colour (day⁻¹) was estimated per storage temperature, sampling side (surface and bottom) and treatment (controls and “tsipouro”) accordingly to the linear equation below:
where, a* is the a* value after storage time t (day), a₀* is the initial value at time zero.
The rate of colour deterioration (k_colour) of ground beef was further modelled as a function of storage temperature using the Arrhenius equation (Equation (5)) [25 (link)]: $\ln (k_{colour})= \ln (k_{ref}) - \left(\frac{E_a}{R}\right)\left[\frac{1}{T} - \frac{1}{T_{ref}}\right]$
where, k_ref (day⁻¹) is the constant rate of the degradation of a* value at the reference temperature T_ref (K), which was set at 4 °C, T is the absolute temperature (K), E_a is the activation energy (J/mol) and R is the universal gas constant (J/mol·K). E_a values were estimated from the slope of Arrhenius plots of ln (k_colour) vs. (1/T − 1/T_ref) by linear regression [27 ]. All model parameters were calculated using SPSS computer package Version 16.0 (SPSS Inc., Chicago, IL, USA).

Two independent storage experiments were performed and duplicate samples were used for each trial (n = 4). Statistical analysis was performed using the SPSS computer package Version 16.0 (SPSS Inc., Chicago, IL, USA). Analysis of variance (ANOVA) was performed on data to evaluate the effect of storage temperature and treatment on gas composition, microbial levels, pH, colour, ethanol content, and sensory attributes. Tukey’s b multiple range test was used for means comparison. Statistical significance was assessed at p < 0.05.