# Changes in Oil Quality and Peroxidase Activity during Germination of Rape Seeds and Mustard Seeds
###### Abstract  
Vegetable oils are selected by consumers based on the presence of multiple bioactive substances, including polyunsaturated fatty acids, sterols, and tocopherols. Another important factor in oils is their quality. This research involved analyzing the oils quality and quantity of bioactive substances obtained from rape seeds and white mustard seeds that underwent germination. The quality of the oils was compared by determining the acid and peroxide values. Germination lowered the peroxide value by 86.3% and 71.4% for rapeseed oil and mustard oil, respectively. This was due to the germination step of the seed use oxygen, which was the substrate for lipid peroxidation. The activity of peroxidase increased by 95% for rapeseed oil and 94% for mustard oil during germination. An increase in the amount of polyunsaturated fatty acids in mustard oil also was noted during germination.  
germination; cold press oils; mustard oil; rapeseed oil; peroxidase activity; peroxide value; acid value +
Footnote †: journal: Applied sciences  
reaction products may be formed during roasting, which may reduce the nutritional value of the raw material [9]. Germination is the process by which seeds that were previously dormant become imbibe and begin development by piercing the rootlets through the seed coat. Due to the changes taking place during germination, the level of fat is reduced, so the yield of the obtained fat is reduced [10]. Research on germination and metabolic mechanisms inside seeds is still ongoing [11; 12]. However, the number of studies related to the quality of oil obtained from germinating oilseeds is insufficient. In the literature, we found some information about changes in bioactive compounds in some different seeds during germination, for example: quinoa [13], amaranth [14], sacha inchi [15], sunflower seeds [16], soybean [17] or flaxseed [18]. Depending on the type of the seeds we can see different changes during germination. However, most often, seed germination leads to the accumulation of bioactive ingredients and the improvement of oil quality. In some cases, germination improved the fatty acid profile [13; 14; 15], ocopherol content [15; 16; 17] or increase concentration of phytosterols [16; 17].  
Peroxidase are family of isoenzymes and structurally can be described as heme-containing monomeric glycoproteins. Peroxidase oxidase some compounds in the presence of H\({}_{2}\)O\({}_{2}\)[19; 20]. During germination, peroxididases play a significant role in axis growth by producing 'OH from H\({}_{2}\)O\({}_{2}\)[21]. Reactive oxygen species such as 'OH, O\({}^{2-}\), and H\({}_{2}\)O\({}_{2}\) are usually considered toxic [22], but for seeds, H\({}_{2}\)O\({}_{2}\) is a germination promoting factor. The scavenging activity of H\({}_{2}\)O\({}_{2}\) is sufficiently high to result in the production of O\({}_{2}\) for mitochondrial respiration [23].  
Rapeseed oil is the third oil in the world in terms of consumption (first place--palm oil, second place--soybean oil) [24]. In Poland, rapeseed oil is a very popular oil due to its versatility, availability and affordable price. In addition, it is characterized by a high content of unsaturated fatty acids. Mustard oil is a niche oil, but it is also an oil characterized by a high content of unsaturated fatty acids. The new double-improved variety (less glucosinolates and less erucic acid) is a variety less sensitive to temperature changes during cultivations and can also be used for consumption purposes.  
In this study, we investigated the effects of germination of rape and mustard seed on the oil's quality and concentration of bioactive substances. The hypothesis is that the quality of the oils obtained from the seeds after germination will be improved. So far, there have been no studies of oil from germinating seeds combining both oil quality, changes in bioactive compounds and changes in the amount of peroxidase in rapeseed and mustard.