## 3 Results and Discussion
### Effect of Coatings on the Hardness of Fresh-Cut Parsley during Storage  
The changes in the hardness parameter of the parsley are presented in Table 2. It was observed that, during storage, in all tested samples, there were abrupt changes in the hardness parameter, and after 7 days of storage, in all the samples, there was an increase in hardness compared to the samples that were not stored. After 14 days of storage, all tests showed a decrease in the value of the hardness parameter, and after 21 days, an increase in the hardness was once again observed.  
Parsley rings coated with whey protein isolate with the addition of jojoba oil at concentrations of 1 and 2% showed the ability to remain and increase hardness after 28 days. The highest value of the hardness parameter (72.28 \(\pm\) 6.78 N) was achieved by the samples coated with a whey protein isolate with the addition of jojoba oil at a concentration of 2% after 21 days of storage, which could have been caused by an increase in the moisture barrier due to the content of hydrophobic jojoba oil belonging to lipid compounds.  
\begin{table}
\begin{tabular}{c c} \hline
**Tested Feature** & **Mean \(\pm\) Standard Deviation** \\ \hline Dry matter (\%) & 15.61 \(\pm\) 0.09 \\ pH & 5.75 \(\pm\) 0.02 \\ Hardness (N) & 89.09 \(\pm\) 3.75 \\ L* & 84.49 \(\pm\) 2.41 \\ a* & \(-\)1.29 \(\pm\) 0.19 \\ b* & 11.15 \(\pm\) 1.34 \\ Hue tone (\({}^{\circ}\)) & 83.21 \(\pm\) 1.85 \\ Content of polyphenols (mg gallic acid/g d.m.) & 6.54 \(\pm\) 0.17 \\ Content of flavonoids (mg quercetin/g d.m.) & 49.96 \(\pm\) 0.16 \\ \hline \end{tabular}
\end{table}
Table 1: Characteristics of the raw material—root parsley.  
The presence of a water barrier allows food products to be crunchy, and the use of edible coatings may delay the deterioration of vegetables by slowing down the loss of moisture. It was observed that the storage time significantly affected the changes in parsley hardness. Taking into account the type of coating used, no statistically significant differences were found between the uncoated sample and the sample coated with whey protein isolate, which is in contrast to the samples coated with the whey protein isolate with the addition of jojoba oil at concentrations of 1 and 2%, where these differences were statistically significant (\(p<0.05\)). In general, the differences in the values of the hardness of root vegetables can be attributed to the anatomy of their roots and their two types of structures: xylem (the inner part) and phloem [25]. However, in the studies involving the coating of apples, potatoes, and carrots with whey protein/pectin/transglutaminase coatings, the hardness parameter of carrot samples after 10 days of storage was found to increase by about 34% compared to that of uncoated samples. The uncoated samples were characterized by a decrease in the hardness parameter from 190 \(\pm\) 12 N to 130 \(\pm\) 24 N. Moreover, the coating of carrot samples reduced the growth of microorganisms and retained the contents of phenols and carotenoids [26]. The increase in the hardness of the tested samples may be due to dehydrated tissues resulting from weight loss, which are characterized by a more fibrous structure during storage and, therefore, are of low quality [27].