# Comprehensive Evaluation of the Nutritional Quality of Stored Watermelon Seed Oils
## 3 Results and Discussion  
### Fatty Acid Composition  
Fruit seed oils are mainly composed of triacylglycerlycerols. Therefore, the FA composition and distribution in TAG molecules are representative properties of the lipid fraction of fruit seeds. Table 1 presents the FA composition of the tested oils before and after three months of storage. Considering the average content of saturated fatty acids, it should be noted that, during storage, WO\({}_{1}\) exhibited the lowest (\(\sim\)17%) and WO\({}_{3}\) exhibited the highest (\(\sim\)26%) SFA content. In each of the analyzed oils, palmitic acid and stearic acid had the highest percentage of the total SFAs. The oils were characterized by a higher MUFA content than SFA, except for WO\({}_{3}\), which showed an inverse relationship. The results regarding monounsaturated fatty acids show that, after storage, the lowest MUFA content was recorded for WO\({}_{3}\), while WO\({}_{\text{ref}}\) had the highest MUFA content. In each analyzed oil, oleic acid was the predominant MUFA. Watermelon seed oils were rich sources of PUFAs. Linoleic acid (C18:2 n-6) was the predominant PUFA in the oils analyzed in this study. WO\({}_{\text{ref}}\) exhibited the lowest (52:90%), and WO\({}_{\text{ext}}\) had the highest (62.21%), PUFA content. A statistical analysis investigating the effect of storage time on the obtained SFA, MUFA, and PUFA levels indicated that storage period only had a significant impact on FA content for WO\({}_{3}\). The identified composition of FAs in the oils analyzed in this study was typical of watermelon seed oils. However, it can be concluded that the oil production method and the refining process significantly affect the FA profile. Differences in the FA contents between commercial oils may also result from the varying quality of the raw materials used for oil production. [PERSON] et al. [31] demonstrated that rapeseed oil obtained from damaged, broken, and contaminated seeds was characterized by a lower oleic acid content and a higher linoleic acid content. Similar conclusions were drawn in the present studies. The significantly lower share of C18:1 n-9 and higher share of C18:2 n-6 for WO\({}_{3}\) than for the other tested oils may indicate that WO\({}_{3}\) was obtained from seeds of inferior quality to those used in other commercial oils. [PERSON] et al. [32] determined the FA composition of cold-pressed watermelon seed oil purchased from a grocery store. The PUFA, SFA, and MUFA contents were 68.00%, 18.30%, and 12.40%, respectively. These results are different from those obtained in our study, as all tested WOs contained less PUFAs and more MUFAs compared to the results obtained by [PERSON] et al. [32]. [PERSON] et al. [20] obtained oil from watermelon seeds of two varieties using cold-pressing, chemical extraction, and ultrasound-assisted extraction. For cold-pressed watermelon seed oil obtained using the first/second variety, the following contents were obtained: 17.69/18.48% SFA of 14.95/19.30% MUFA of 67.36 and PUFA of 62.22% PUFA. For the oil extracted from watermelon seeds of the first (second) variety, the results were 17.49/19.37% SFA, 14.92/16.80% MUFA, and 67.59/63.83% PUFA. Dietary indices for assessing the risk of cardiovascular disease, such as the index of atheogenicity (AI) and the index of thrombogenicity (TI), can be calculated using fatty acid profiles. Oils recommended for consumption should have low atherogenicity (AI! 1.0) and low thrombogenicity (TI! 0.5), while also exhibiting a high health-promoting index (HPI) and a high hypocholesterolem/hypercholesterol ratio (h/H). The consumption of products with low AI is correlated with a reduction in total cholesterol and low-density lipoprotein cholesterol in human blood plasma, whereas the consumption of products with lower TI and a higher h/H ratio may be beneficial in the prevention of cardiovascular heart disease [26,30,33].