# Filtration Scheduling: Quality Changes in Freshly Produced Virgin Olive Oil
## 3 Results and Discussion
### Sensory Attributes  
In Figure 1, the evolution of the \"fruity\" attribute and \"fusty\" defect during 30 days of storage is reported. Up to four days of storage, judges were unable to detect any sensory defects in both filtered and veiled olive oil samples. However, filtered samples were perceived as less fruity than veiled samples (an average of 0.8 fewer points on a 9-point scale), which is consistent with the literature ([PERSON], 2016; [PERSON], 2016; [PERSON], 2016). After five days of storage, our judges started to perceive the fusty defect in veiled samples (0.8 \(\pm\) 0.3 intensity score) and not in filtered samples. At the same time, they started to describe filtered samples as fruitier than veiled samples. In Figure 1, it is possible to observe that the \"fruity\" score of veiled olive oil samples statistically significantly decreases (\(p\)-value \(<\) 0.05); instead, the \"fruity\" score of filtered olive oil samples do not change during 30 days of storage time. We can hypothesise that the appearance of the fusty defect caused the decrease in the fruity score of the veiled oils. Since olive oil is considered to be of the \"extra virgin\" category when the median of the defects is equal to zero ([PERSON], 2016), in our experiment, the veiled samples were downgraded from \"extra virgin\" to \"virgin\" olive oil after five days of storage. Between five days and 30 days of storage, judges noted a further increase in the fusty defect, but the 3.5-limit value for downgrading the sample to the \"lampante\" olive oil category was not reached. No rancid defect was perceived.  
\begin{table}
\begin{tabular}{c c c c c c} \hline  & \(\boldsymbol{F}\) & \(\boldsymbol{V}\) & & & \\  & \(\boldsymbol{t_{0}}\) & \(\boldsymbol{t_{1}}\) & \(\boldsymbol{t_{0}}\) & \(\boldsymbol{t_{1}}\) & \(\boldsymbol{t_{0}}\) & _Legal Limits for “Extra_ \\  & \(\boldsymbol{t_{0}}\) & \(\boldsymbol{t_{1}}\) & \(\boldsymbol{t_{0}}\) & \(\boldsymbol{t_{1}}\) & _Virgin\({}^{\#}\)_Category_(Sections) \\ \hline \multicolumn{6}{c}{Acidity (\% oleic acid)} & 0.35 \(\pm\) 0.09 \({}^{\rm{ac}}\) & 0.36 \(\pm\) 0.10 \({}^{\rm{ac}}\) & 0.32 \(\pm\) 0.02 \({}^{\rm{ac}}\) & 0.33 \(\pm\) 0.03 \({}^{\rm{ac}}\) & \(\leq\)0.8 \\ \multicolumn{6}{c}{Peroxide value (meqQ\({}_{\rm{3 kg}}\)\({}^{-1}\))} & 6.2 \(\pm\) 0.7 \({}^{\rm{bs}}\) & 6.2 \(\pm\) 0.8 \({}^{\rm{bs}}\) & 5.8 \(\pm\) 0.3 \({}^{\rm{ac}}\) & 5.9 \(\pm\) 0.4 \({}^{\rm{ac}}\) & \(\leq\)20 \\ \multicolumn{6}{c}{K232} & 1.59 \(\pm\) 0.06 \({}^{\rm{ac}}\) & 1.60 \(\pm\) 0.05 \({}^{\rm{ac}}\) & 1.59 \(\pm\) 0.07 \({}^{\rm{ac}}\) & 1.62 \(\pm\) 0.07 \({}^{\rm{ac}}\) & \(\leq\)2.50 \\ \multicolumn{6}{c}{K270} & 0.09 \(\pm\) 0.01 \({}^{\rm{bs}}\) & 0.09 \(\pm\) 0.02 \({}^{\rm{bs}}\) & 0.18 \(\pm\) 0.01 \({}^{\rm{bs}}\) & 0.18 \(\pm\) 0.01 \({}^{\rm{bs}}\) & \(\leq\)0.22 \\ \multicolumn{6}{c}{AK} & \multicolumn{1}{c}{-0.004 \(\pm\) 0.00 \({}^{\rm{bs}}\) & -0.001 \(\pm\) 0.02 \({}^{\rm{ac}}\) & -0.004 \(\pm\) 0.001 \({}^{\rm{ac}}\) & -0.003 \(\pm\) 0.003 \({}^{\rm{ac}}\) & \(\leq\)0.01 \\ \multicolumn{6}{c}{Microbial cell count (log CFU/g)} & 0.6 \(\pm\) 1.0 \({}^{\rm{bs}}\) & 0.0 \(\pm\) 0.0 \({}^{\rm{bs}}\) & 3.8 \(\pm\) 0.2 \({}^{\rm{ac}}\) & 3.5 \(\pm\) 0.3 \({}^{\rm{ac}}\) & - \\ \hline \multicolumn{6}{c}{a and b indicate significant differences (\(p<0.05\)) as a function of the treatment (with or without filtration), while x} \\ \multicolumn{6}{c}{and y indicate significant differences (\(p<0.05\)) as a function of the storage time. The legal limits of microbial cell count for “extra virgin” olive oil category is not reported in literature.} \\ \end{tabular}
\end{table}
Table 1: Legal limits for the chemical characteristics and mean microbial counts for olive oil samples after milling or filtration (t\({}_{0}\)) and after one month of storage (t\({}_{1}\)). F refers to filtered oil samples, and V refers to veiled oil samples.  
Figure 1: Mean contents of the “fruity” attribute and “fusty” defect scores in veiled (blue circles) and filtered (red circles) olive oil samples during storage.