xamples. The coefficient of determination (R2) values for
zero-order model varied from 0.973 to 0.993 in uncoated
samples and 0.938 to 0.984 in coated samples, whereas, the
R2 values varied from 0.922 to 0.993 in uncoated samples
and 0.948 to 0.977 in coated samples for first-order model.
There was not much difference in the R2 values of colour
parameters for the two models. Therefore, both the models
fitted well with the data of colour parameters in both coated
and uncoated samples. The regression explained more than
95% of the variation in all the colour parameters except few
cases. The “b*” and E value in coated sample in zeroorder
model explained 94% and 93% variation in the colour
value, respectively. The “a*” value of uncoated sample
explained 92% variation, whereas, “b*” value of coated
sample explained 94% variation for first-order model by
regression analysis. The R2 value of colour parameters, which
was more than 0.95 indicated that there was good agreement
between the model predicted values and experimental values.
Overall, both the zero-order and first-order model described
adequately the change in colour parameters over the entire
storage period.