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Phosphonates are systemic fungicides that work by blocking enzymes that are essential for the growth and reproduction of targeted pathogens. Under EU legislation, phosphonates were classified as fungicides in 2013 and 2014 are therefore not allowed in organic farming. Growers often encounter findings of phosphonate residues in samples of fruit, organic food and samples intended for baby and infant nutrition, although these substances were not used in a given year. The question is therefore the origin of these substances of interest, which is the subject of several studies. Some studies focus on abiotic and biotic sources, others on anthropogenic sources, even so it is problematic to distinguish between deliberately applied phosphonates and phosphonates from natural sources. An important factor for the occurrence of phosphonate is also the historical load and the influence of the living environment. The issue of phosphonate is a hot topic not only for fruit growers, but also for food processors, e.g. for baby food. The aim of this work was to introduce the findings regarding phosphonates in fruit with regard to their behavior in plants and degradation.

Apples are an important source of polyphenolic substances that contribute to the antioxidant activity of the fruit. Presence of apples in the diet significantly contributes to the intake of polyphenols. Apple consumption is associated with prevention of degenerative diseases. Polyphenolic profiles of apples from different regions of the Czech Republic and Poland were analyzed using high-performance liquid chromatography with diode array detection. Four phenolic substances quercitric, epicatechin, phloridzin, and chlorogenic acid were determined in selected apples samples. No statistically significant differences between the regions of the given country were determined for the varieties ‘Golden Delicious’ and ‘Idared’. Chlorogenic acid was the major polyphenol in apples from Poland and its content tended to be higher being 45.4 ± 20.2 µg/g for the ‘Golden Delicious’ and 74.1 ± 2.6 µg/g for the ‘Idared’ varieties, while in the Czech Republic it was 34.2 ± 14.0, respectively 44.3 ± 21.3 µg/g. In contrast, Czech apples contained more epicatechin and quercitrin in these varieties.

Sweet cherries are a very good source of phenolic compounds in our diet, including health-valuable anthocyanins, which have anti-inflammatory, antiviral and anti-tumor effects. This study concerned the determination of chemical attributes of three cherry varieties: ‘Regina’, ‘Kordia’, and ‘Tamara’ from organic and integrated production in four regions in the Czech Republic. The total antioxidant activity of the varieties, the content of total polyphenols, and anthocyanins were compared. The highest antioxidant potential was found for the variety ‘Kordia’ from the organic planting in Ostroměř thanks to the high value of the total antioxidant activity 179.0 ± 14.3 μmol Trolox/100 g fresh fruit, the content of total polyphenols 138.6 ± 15.7 mg gallic acid equivalent/100 g fresh fruit, and the content of anthocyanins 54.4 ± 6.8 mg/100 g fresh fruit.

Sweet cherries (Prunus avium L.) contain numerous phenolic compounds that contribute to the overall antioxidant activity. Several studies have demonstrated that the content of antioxidants and polyphenols plays a positive role in the prevention of cardiovascular and oncological diseases. We determined the total antioxidant activity, content of total polyphenols, anthocyanins, and vitamin C in the selected cherry fruit cultivars bred in the Research and Breeding Institute of Pomology Holovousy Ltd.The total antioxidant activity ranged from 74.3 to 115.2 μmol Trolox equivalent and the total polyphenol content ranged from 19.9 to 63.1 mg gallic acid equivalent related to 100 g fresh fruit. The content of major anthocyanin cyanidine-3-rutinoside in sweet cherries was between 2.0 and 23.4 mg and the content of vitamin C ranged from 3.6 to 12.1 mg related again to 100 g of fresh fruit.

Apricots and other fruits contain a number of beneficial substances, a significant group of those compounds are phenolic substances. The validated method of high performance liquid chromatography with diode array detector was used to compare the content of phenolic substances in fresh material and after 20 days of storage in 1-methylcyclopropene. Four substances, namely chlorogenic acid, catechin, epicatechin, and rutin, were quantified in the samples. The contents also changed during storage. Furthermore, samples in which plant protection products were used were compared with a sample with no treatment. The overall polyphenolic profile was also determined using the liquid chromatography method with CoulArray™ detector. The results obtained using both methods were comparable and correlated well with each other in terms of the contents of individual phenolic substances.

Pesticides and their residues fell in a wide range of substances that can contaminate food. We studied the effect on dynamics of reduction in content of residues of selected pesticides in apricot fruits related to various long-term storage technologies comprising low oxygen atmosphere, storage in bags with modified atmosphere, post-harvest treatment with 1-methylcyclopropene and ozone. We monitored contents of the combined active substances including acetamiprid, thiacloprid, pirimicarb, fenpyrazamine, myclobutanil, boscalid, fenhexamide, pyraclostrobin and trifloxystrobin. None of the variants exceeded the maximum residue levels. Postharvest ozone treatment of apricots causes more efficient degradation of pesticides during storage. Other effective types of storage include storage in modified atmosphere bags and the using of the active compound 1-methylcyclopropene. The contents of boscalid and pirimicarb exhibited statistically significant differences among the tested storage technologies. A statistically significant difference was observed after storing under low oxygen conditions and in bags with modified atmosphere where lower levels of pesticide residues were measured.

The new screening method for rapid evaluation of major phenolic compounds in apples has been developed. Suitability of coupling HPLC/UHPLC separation with the diode-array detection and universal charged aerosol detection with respect to the presence of interfering substances was tested. Characteristics of both detection techniques were compared and method linearity, limits of detection and quantitation, and selectivity of them determined. Student t-test based on slopes of calibration plots was applied for the detailed comparison. The diode-array detection provided the best results regarding sensitivity and selectivity of the developed method in terms of evaluation of phenolics profiles. The response of the charged aerosol detector was negatively affected by co-eluting substances during rapid-screening analyses. Coulometric detection was used for advanced characterization of extracts in terms of antioxidant content and strength to obtain more complex information concerning sample composition. This detection also allowed evaluation of unidentified compounds with antioxidant activity. HPLC/UHPLC separation using a combination of diode-array and coulometric detectors thus represented the best approach enabling quick, yet complex characterization of bioactive compounds in apples.

Dynamics of pesticides decomposition in sweet cherry fruits at different technologies of long-term storage, ultra-low oxygen and modified atmosphere packing, and after post-harvesting application of 1-methylcyclopropen and ozone has been studied. We assumed that type of pesticide and fruit storage conditions may have a profound effect on pesticide residues content. Therefore, levels of residues after applying combinations of active ingredients including acetamiprid, boscalid, cyprodinil, fenhexamid, fenpyrazamine, fludioxonil, fluopyram, pyraclostrobin, pirimicarb, tebuconazole, thiacloprid, and trifloxystrobin were monitored. We found these contents below tolerated maximum residue limits when applied at recommended times and depended on period prior to withdrawal. Low contents of acetamiprid, boscalid, fenpyrazamine, thiacloprid, pirimicarb, and fludioxonil were found when fruit were stored in modified atmosphere packages. Ozone affected degradation of tebuconazole, pyraclostrobin, and cyprodinil. However, differences between storage regimens were not statistically significant (p ≥ 0.05). Kinetic of degradation was studied with fruits stored after treatment with 1-methylcyclopropen and ozone.