Bioactivity and nutritional properties of hardy kiwi fruit Actinidia arguta in comparison with Actinidia deliciosa 'Hayward' and Actinidia eriantha 'Bidan'.

The aim of this research is to identify and compare the bioactive compounds, antioxidant capacities and binding potentials to human protein in different varieties of hardy kiwi (Actinidia (A.) arguta), 'Hayward' (Actinidia deliciosa) and less - known 'Bidan' (Actinidia eriantha). Polyphenols, flavonoids, flavanols, tannins, vitamin C, lutein, zeaxanthin and dietary fibers were significantly higher in cultivar 'M1' among the A. arguta than in 'Hayward'. The binding properties of studied kiwi fruits were determined by interaction of polyphenols with human serum albumin (HSA). An internal standard FTIR technique allowed the quantitative comparison of specific IR absorption bands (Amides I, II, III) of different kiwi fruit samples after interaction with HSA. It was shown that the antioxidant and binding capacities and FTIR quantitative estimations of A. arguta fruits were significantly higher than in 'Hayward', but lower than the 'Bidan'. In MS spectra were found some slight differences in A. arguta kiwis in comparison with 'Hayward' and 'Bidan'. Two A. arguta cultivars were similar to 'Bidan'. The interaction of polyphenols with HSA, evaluated by fluorometry/FTIR, made it possible to compare the bioactivity of different cultivars and families. In conclusion, for the first time fruits A. arguta, cultivated in Poland, were compared with widely consumed kiwi fruits, using advanced analytical methods. The high bioactivity and nutritional value of A. arguta fruits from Polish ecological plantation enables us to recommend them for marketing and consumption.