The aim of this study was to estimate the content of exogenous antioxidants in kiwi fruits available in Gdynia, Poland, and their ability to reduce free radicals. The test material consisted of mini kiwi fruit (Actinidia arguta) of the ‘Hortgem Thai’ cultivar and kiwi fruit (Actinidia deliciosa) of the ‘Hayward’ cultivar. The carotenoid pigments were determined by the Lichtenthaler method, vitamin C in accordance with PN-A-04019:1998, polyphenols by the Folin-Ciocialteu method and the ability to reduce free radicals using a synthetic DPPH radical. One-way analysis of variance was used to determine the effect of fruit species on the quality traits analysed. The significance of differences between the means was determined using Tukey’s test. Relationships were considered statistically significant at p < 0.05. Correlation coefficients between the antioxidant activity of kiwi fruit and the content of exogenous antioxidants were also determined. The results showed that Actinidia arguta has significantly higher contents of exogenous antioxidants than Actinidia deliciosa. The antioxidant properties of this fruit were also found to be mainly due to its vitamin C content.

It is estimated that the transport of plant-based food may be responsible for 50% of total CO₂ emissions. The situation becomes highly unfavourable when the transported cargo deteriorates. Therefore, the optimisation of storage conditions during transport is a part of the concept of reducing food loss and waste. Moreover, it is an essential element of sustainable development. This study aimed to compare the stability of selected quality parameters of pomegranate juice under simulated conditions imitating maritime transport. The content of polyphenols and the ability to reduce free radicals were considered the critical quality parameters of this juice. The Folin–Ciocalteu method (polyphenols content) and the Brand-Williams method (ability to reduce free radicals) were used during the study. The simulation of maritime transport conditions consisted of different juice storage conditions. The differentiation was conducted regarding temperature, type of gas that filled the packaging, and mixing related to the ship’s motions during transport. The highest quality of pomegranate juice was ensured by modifying the atmosphere with nitrogen and lowering the temperature. It is also important that mixing the juice does not reduce its quality but stabilises it.

Freezing is the most commonly used method of preserving stone fruits. However, it is not the cheapest method. An alternative could be the pickling of fruits. Unfortunately, there is not much information in the literature on the effect of pickling on the health-promoting potential of stone fruits, including plums and cherries. This work focuses on assessing the impact of fruit pickling and storage on changes in the pro-health potential. Health-promoting properties were determined based on the content of anthocyanin dyes, vitamin C, total polyphenols, and the ability to inhibit free radicals. A substantial effect of pickling and storing pickled fruits on their health-promoting properties was observed. Pickling caused a decrease in the content of anthocyanins and vitamin C in the tested fruits. At the same time, the content of total polyphenols and the ability to reduce free radicals increased. It was also found that the content of bioactive compounds and the ability to reduce free radicals decreased during the storage of pickled cherries and plums. However, after 180 days of storage, pickled plums contained more polyphenols than fresh ones.