Citrus fruits are a rich source of antioxidant substances. The antioxidants contained therein, especially apigenin and naringenin, are of vital importance for the proper functioning of human body. Among other things, they support the prevention of cardiovascular and cancer diseases. Regular consumption of citrus fruits can have a beneficial effect on human health. Citrus fruits are quite often consumed by the Polish consumers owing to their physicochemical parameters, valuable nutritional properties and sensory values. Thus, on the Polish market continuously appear citrus fruits that are unknown to the Polish consumers, for example a fruit of kumquat that is characterised by good antioxidant properties. The objective of the research study was to compare the antioxidant properties of pomelo and kumquat with those of oranges and clementines. The research study involved the determination of the total content of polyphenolic compounds [mg GAE/100 g] and antioxidant activity [%]. Additionally, there were determined the content of general extract [%] and the content of reducing sugars [%]. Based on the analysis of the results obtained, it was found that, compared to other fruits analysed, the kumquat fruit had the highest total polyphenol concentration (52.82 mg GAE/100 g) and that it was characterised by the highest antioxidant activity (60.03 %) and, at the same time, by a low content of directly reducing sugars (10.93 %); therefore the kumquat appeared to be the most valuable fruit in terms of nutrition.
citrus fruits, kumquat, polyphenols, antioxidant activity, reducing sugars, general extract