Vlatka Jurković

Relation between polyphenols content and skin colour in sour cherry fruits

Fruit skin colour plays a major role in quality assessment of food, significantly determining consumer`s choice. Colour of sour cherries depends on anthocyanins which are phenolic compounds (flavonoids) present in high amounts in fruits. The aim of this study was to determine a possible relation between polyphenols (total phenolics and anthocyanins) and colour parameters of fruit skin of sour cherries. The plant material used in this study was twenty two sour cherry genotypes from an orchard of Agricultural Institute Osijek. Total phenolics and anthocyanins contents as well as colour parameters (L*, a*, b*, h and C) of fruit skin were determined. Variability between sour cherry genotypes in total phenolics and anthocyanins as well as in colour parameters was revealed. Total polyphenols content varied from 462.7 to 1049.0 mg GAE/100 g of fresh weight, while total anthocyanins ranged from 160.1 to 495.6 mg CGE/100 g of fresh weight. A significant positive correlation was found between polyphenols and anthocyanins content. Total phenolics content had a significant negative correlation with colour parameters b* and h, while anthocyanins content negatively correlated with colour parameters L*, b* and h. According to the obtained results, genotypes Maraska, Heimanns Konservenweichsel and Rexelle are the richest genotypes in polyphenols and anthocyanins content.

Total phenolic and total flavonoid content variability of soybean genotypes in eastern Croatia

Phenols, along with flavonoids found in soybean seeds [Glycine max (L.) Merr.], are known as active antioxidants and are associated with numerous benefits to the human health, such as prevention of cancer, cardiovascular diseases, osteoporosis and menopausal symptoms. The aim of this study was to evaluate total phenolic content and total flavonoid content of 33 soybean genotypes grown in 2010 and 2011. Analysis of variance showed significant differences between the genotypes and genotype x year interaction for both investigated traits. The total phenolic content in 2010 ranged from 2.330 to 3.227, and in 2011 from 2.121 to 3.164 mg/g of dry weight, expressed as gallic acid equivalents. Flavonoid content in 2010 varied from 0.433 to 0.659, and in 2011 from 0.428 to 0.580 mg/g of dry weight, expressed as catechin equivalents. Genotypes OS-L-100, OS-L-12, and OS-L-17 were singled out for the highest content of total phenols while genotypes OS-L-113, OS-L-17 and OS-L-151 had the highest total flavonoid content on average for both years. Results of analyses presented in this paper contribute to the development of the genetic background for improving antioxidant properties of Croatian soybean varieties.