# Changes in Oil Quality and Peroxidase Activity during Germination of Rape Seeds and Mustard Seeds
## 3 Results and Discussion
### Oil Quality  
The peroxide value reflects the quantity of peroxides present in the oil. For rapeseed oil from ordinary seeds, it equaled 11.53 meq O\({}_{2}\)/kg, while for mustard oil, it was value of 7.47 meq O\({}_{2}\)/kg. For both mustard and rapeseed, the peroxide value decreased in the oils obtained from seeds after days 1, 2, and 3 of germination. After day 3, it was 1.58 meq O\({}_{2}\)/kg for rapeseed oil, and 2.14 meq O\({}_{2}\)/kg for mustard seed. All peroxide values do not exceed the maximum values set by the Codex Alimentarius [4]. However, the initial peroxide value (day 0) is closer to the upper limit of the maximum value. Reducing the peroxide value during seed germination improves the quality of the oil, it contains less compounds of primary fat oxidation. Peroxide and acid values are presented in Table 2. Peroxides formed during the oxidation process easily break up into secondary compounds of the oxidation process, e.g., aldehydes or esters. For this reason, the amount of peroxides decreased during seed germination. In addition, the presence of the peroxidase enzyme (Section 3.6) reduced fat oxidation. The reverse properties can be seen in oils obtained from roasted rapeseeds--the longer the seeds are roasted, the more the peroxide value increases [38]. The acid value describes the quantity of free fatty acids in an oil; it was 5.61 mg KOH/g for the oil from ordinary mustard seeds and 0.67 mg KOH/g for the rapeseed oil. By the first day of germination, the acid value had decreased significantly in the mustard oil to 3.80 mg KOH/g, but then increased in the days following germination, reaching 5.61 mg KOH/g on the third day. In the case of rapeseed oil, the acid value increased on each subsequent day of germination, until it reached 10.31 mg KOH/g on the third day. The increase in the amount of free fatty acids is associated with the start of hydrolysis, which leads to the breaking of ester bonds between glycerol and fatty acid. The effect of this is an increasing amount of free fatty acids, which are determined by the acid number [46]. The acid values of rapeseed oil exceed the permissible values specified by the Codex Alimentarius only on the third day of germination. In the case of mustard, all values exceed the permissible value set by the Codex Alimentarius [4], except for the oil obtained from the seeds on the first day of germination. Similar results have been seen for flax seeds, but there both the acid value and the peroxide value increasing over each of four days of germination [18]. There was also a significant increase in the acid number during the germination of _Moringa peregrina_ seeds [46]. The quality of the oil depends primarily on the oil extraction technique, but also on the quality of the seeds used to obtain the oil. In order to be able to use inferior quality seeds, the oil of which will be characterized by high peroxide and acid values, it is possible to apply earlier treatment of these seeds, i.e., seed germination, which will reduce the peroxide and acid values. The possibility of lowering the peroxide and acid number by germination can be also used in subsequent studies on other seeds with high peroxide and acid values.