For example, meat proteins were extremely underestimated
by the proximate analysis compared with fish. Meat
proteins were more complex and could not be completely extracted
in a soluble form for colorimetric analysis. Comparing carbohydrate
and protein results for both meat and fish, it can be seen that the
estimated results using the developed procedure are more
consistent. Estimated results show the reality that both fish and
meat had more proteins than carbohydrates, while proximate
analysis shows the reverse. This was explained by the effect of
such outliers on regression and correlation parameters in Figure 2,
with a lower slope and larger intercept of the regression (trend) line
despite the high correlation. Exploitation of elemental mass and
COD continuity by the developed procedure keeps the results more
consistent. Also, erroneous results or records of practical measurement
input to the procedure were concealed in the results. For
example, the procedure overestimated proteins for the paper waste,
because its TAN content was not measured and all TKN was used
for the protein estimation. Because the procedure applies ordered
maximization, giving protein estimation precedence over carbohydrates,
estimated carbohydrate COD was reduced to compensate for
the extra COD estimated in protein, keeping the overall COD balance.
However, such COD reduction of paper waste carbohydrates
was less significant compared with the amount of fibers that could
not be extracted (see Figure 1).