Growing Season Weather Impacts On The Physicochemical Properties And Quality Of Sunflower Oils Cold-Pressed From Hybrids Groven In The Republic Of North Macedonia

The purpose of the research was to determine the physicochemical properties of sunflower oils extracted from hybrids cultivated under environmental conditions in the Republic of North Macedonia. During 2016 and 2017, twelve sunflower hybrids were used as an experimental material in order to analyse some physicochemical properties of sunflower oils, such as free fatty acid, peroxide value, density, iodine measurement, saponification value and oxidative stability. The results were evaluated by LSD test, principal component analysis, linear correlation and cluster analysis. The free fatty acid values of the tested sunflower oils varied between 0.17% and 0.36%. The average value for peroxide measurement for all analysed oils was 0.93 O-2/kg. Fortimi and Neoma had the highest iodine value (134.5 and 131.0 g I-2/100 g, consequently) and the lowest was re corded by Experto (87.5 g I-2/100 g), followed by Talento (88.5 g I-2/100 g).Significant differences were noticed between oils on their oxidative stability. Talento hybrid showed the highest oxidative stability for both years, which can be linked with high-oleic sunflower oil as more suitable for frying and thermal processing of food. Drastically lower oxidative stability for other sunflower oils might be an indication for high-linoleic sunflower oils which are usually recommended for thermally non processed food. Although Experto and Talento hybrids had the lowest iodine values which caused separation in the same cluster, the value of oxidative stability was drastically lower for Experto hybrid which can be linked with high-linoleic sunflower oils or lower amount of Vitamin-E-active compounds and phenolic compounds presented in sunflower oil as natural antioxidants.Principal component analysis was utilised to examine the variation and to estimate the relative contribution of analysed properties to total variability. Three main components with Eigen value greater than one were extracted and contributed 88.44% of the total variability. PC1 accounted 44.88% of the total variability and showed positive factor loading for iodine value (0.59) and density (0.57). PC2 accounted 25.99% of the total variation and was positively correlated with saponification value (0.67) and oxidative stability (0.42) but with high negative factor loading for free fatty acid (-0.52) at the same time. The third PC component had 17.57% of variance and was positively linked with free fatty acid (0.59), peroxide value (0.52) and oxidative stability (0.47). On the other site, significant positive correlation was established between iodine value and density (r = 0.935). Oxidative stability was in negative correlation with iodine number (r = - 0.621).