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The aim of this investigation was to determine the bioactive compounds in kiwifruit as an indication of quality after extraction using methanol and ethyl acetate. Using FTIR and three-dimensional fluorescence spectroscopy and electrospray ionization/MS, the contents of polyphenols, flavonoids, flavanols, and tannins, and the level of the antioxidant activity by 2, 2-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt, 1, 1-diphenyl-2-picrylhydrazyl, ferric-reducing/ antioxidant power, and cupric reducing antioxidant capacity assays were determined and compared. It was found that the methanol extracts of kiwifruit showed significantly higher amounts of bioactive acetate extracts. The cultivar Bidan, in comparison compounds and antioxidant activities than the ethyl with the classic Hayward, showed significantly higher bioactivity. For the first time, Bidan organic kiwifruit was analyzed for its antioxidant activities and compared with the widely consumed Hayward organic based on its bioactive compounds and fluorescence properties. Relatively high content of bioactive compounds and positive antioxidant and antiproliferative properties of kiwifruit determined by the advanced analytical methods justify its use as a source of valuable antioxidants. The methods used are applicable for bioactivity determination, in general, for any food products.

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The bioactivity of two kiwifruit's cultivars growing under organic and conventional conditions were studied and compared. The bioactive compounds were extracted with water and ethanol using similar conditions which are applied in pharmaceutical applications and for daily fruit consumption such as tea drink. Antioxidant radical scavenging assays [ferric-reducing/antioxidant power (FRAP); cupric reducing antioxidant capacity (CUPRAC); 2, 2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS)], fourier transform infrared (FT-IR) and ultraviolet spectroscopy, two (2D-FL) and three-dimensional (3D-FL) fluorometry were used for the detection of biologically active metabolites derived from kiwifruits (total phenols, flavonoids, chlorophylls, carotenoids and ascorbic acid). The correlation between the total phenol content (TPC) and other bioactive compounds, and their total antioxidant capacities (TAC) was calculated for studied kiwifruit's extracts. The interaction between drugs and human serum albumin (HSA) plays an important role in the distribution and metabolism of drugs. The properties of kiwifruit's phenol extracts showed their ability to quench HSA, forming the complexes similar to the ones between the proteins and pure flavonoids such as quercetin. The cultivar 'Bidan' exhibited significantly higher TAC than the classic 'Hayward'. In conclusion, for the first time 'Bidan' organic kiwifruit was analyzed and compared with widely consumed 'Hayward', using its bioactive and fluorescence properties. The influence of physiologically active kiwifruit's compounds on human health, through our investigations in vitro and scientifically proven information, was explained. Relatively high content of bioactive compounds, high antioxidant and fluorescence properties of kiwifruit justify its use as a source of valuable antioxidants.

Comparison between organic and conventional kiwifruit cultivars 'Hayward' and 'Bidan', which was done by four radical scavenging assays, ESI-MS, and DSC measurements, showed significant differences between the cultivars. Such results were not estimated in kiwifruit growing under organic and conventional conditions. The extraction of bioactive compounds was done by two different methods: sequential extraction with ethyl acetate followed by methanol and maceration with methanol and ethyl acetate. The highest yield of polyphenols was found in the new cultivar 'Bidan' in comparison with the classic 'Hayward', by direct extraction with methanol. This is the first investigation of 'Bidan' kiwifruit cultivar, grown under organic conditions and compared with 'Hayward' organic. High contents of bioactive compounds and antioxidant and antiproliferative properties of the two kiwifruit cultivars justify their use as sources of valuable antioxidants. It is necessary to continue this study as a long-term experiment to eliminate the influence of seasonality.