*3.8. Statistical Analysis*

The significance of the differences was checked for each term of analysis. The results were statistically processed using the analysis of variance in a two-factor random block design. Furthermore, the effect of storage time on the specified quality parameter of the control and ozonated fruit in terms of the value of the specified mechanical quality parameter and moisture content was determined using the analysis of variance in a three-factor random blocks design. The significance of differences with LSD of 0.05 was

evaluated using Tukey's multiple test. Statistical analysis of results was carried out using the ANALWAR—5.3 FR programme by Franciszek Rudnicki (University of Life Science and Technology in Bydgoszcz, Poland)

#### **4. Conclusions**

The results of the present study show the effect of ozone treatment on the quality of sea buckthorn (*Hippophae rhamnoides* L.) The study shows that the application of gaseous ozone leads to reduced microbial load and loss of water, and improved mechanical properties in the plant material. Furthermore, the findings show increased ascorbic acid content after ozone treatment (for 10 ppm at 30 min and 100 ppm at 15 min), and higher total content of polyphenols. Moreover, the observed increase was dependent on the applied dose of ozone. The current findings show that ozone treatment may effectively be used to extend the shelf life of sea buckthorn.

**Author Contributions:** Conceptualization, methodology, formal analysis and writing—original draft: A.Z., N.M., M.B. investigation— M.Z., T.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** The project is financed by the program of the Minister of Science and Higher Education named "Regional Initiative of Excellence" in the years 2019–2022, project number 026/RID/2018/19, the amount of financing PLN 9 542 500.00.

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

