An organic agricultural system based on natural methods and means of production is an alternative to intensive agriculture. The available research suggests that organic crops, in comparison to the conventional ones, are richer in phenolics and other antioxidants while containing less undesirable pesticide residues and nitrates. The aim of this study was to determine concentrations of polyphenols, lutein, vitamin C, and nitrates in eight potato cultivars (Mazur, Justa, Lawenda, Lech, Tacja, Laskana, Otolia, Magnolia) grown organically and conventionally in a controlled field experiment in Poland. Significant differences between potato tubers of the tested cultivars coming from organic and conventional production were identified for the majority of parameters. Higher concentrations of nitrates and lutein were found in conventional compared to the organic tubers, while organic potatoes were, on average, richer in phenolic compounds. Among the tested cultivars, Magnolia, Otolia, and Laskara were richest in vitamin C and phenolics. Otolia and Laskara also accumulated the highest levels of nitrates. If further confirmed, these observations might be of importance for the producers and consumers, who increasingly search for foods from sustainable and well-controlled agricultural systems.

The apple (Malus domestica Borkh.) is one of the most widely cultivated temperate fruits globally, gaining scientific interest as a rich source of antioxidants with a demonstrated beneficial human health impact. Since a growing number of consumers are increasingly seeking safe and healthy food options, alternative fruit production systems such as organic farming, and their potential to provide safe and nutritious foods, have been gaining increasing attention in the last decades. The aim of the presented study was, therefore, to analyse and to compare the concentrations of selected health-promoting antioxidants, such as phenolic acids, flavonols, and vitamin C, in fruits of three apple cultivars (Champion, Gala, and Idared) grown in conventional and certified organic orchards in Poland. All analyses were performed using the high-performance liquid chromatography (HPLC) method. Organic apples tested within the study, compared to the conventionally grown ones, were characterised by significantly higher concentrations of phenolic acids (av. >31%) and flavonols (av. >66%) with the identified differences being consistent in all three cultivars and two seasons. The greatest production system effect was observed in the case of Idared. Significant cultivar and production season effects on the concentration of the measured fruit phenolics, with strong interactions between the two factors, were also identified. Vitamin C content in the fruits was strongly dependent on the year-to-year differences in the fruit growing conditions. The study suggests that the organic production system has a potential to provide apple fruits rich in selected health-promoting phenolic antioxidants.

In recent years, organic food, produced with the use of natural means and production methods, has been gaining more and more popularity among consumers. This is due, inter alia, to their belief that it is more abundant in health-promoting bioactive compounds and safer than conventional food. Consumers are increasingly aware of the harmfulness of plant protection products used in intensive agriculture, which are not allowed in organic production. At the same time, it is reported that a certain share of organic products on the EU market are contaminated with pesticide residues, which may raise consumer concerns and lead to a loss of trust in organic food. The aim of the present study was to investigate the problem of pesticide residues occurrence in random samples of organically produced fruits and vegetables (apples, potatoes, carrots, and beetroots) commonly used in the Polish households, and which are available directly from the organic producers in open markets in Poland. For simultaneous analysis of 375 pesticides, an LC-MS/MS system consisting of an Eksigent expert ultraLC 100-XL coupled to a triple quadrupole mass spectrometer QTRAP 6500 and GC Agilent 6890 N equipped with ECD/NPD system were used. Among the 96 vegetable and fruit samples studied, 89 samples (92.7%) were free from detectable pesticide residues, 7 samples (7.3%) of carrot (5) and potato (2) were contaminated, and in 1 of them (1.0%) the detected residues exceeded the maximum residue limit (MRL). None of the tested apple and beetroot samples were found to contain detectable residues. These findings are important for Polish consumers who look for high-quality organic food. However, the presence of detectable residues in a small proportion of the organic samples indicates a need to strengthen the monitoring of pesticides in organic crops, to educate farmers and to raise their awareness regarding the risks of unauthorized use of pesticides banned in organic farming, which can damage the reputation of the whole organic sector.

Here we report the results of a three-year replicated field trial on the effects of novel clover- and alfalfa-based fertilizer products (Ekofert^® K and Ekofert^® L), with the input levels equivalent to 120, 180, or 240 kg N ha⁻¹, on the yield and selected sensory and nutritional quality parameters of onion. The study showed that Ekofert fertilizer applied at all three levels produced similar or higher yields than the standard fertilization regimes used in conventional farming in all three seasons. Significant differences in onion composition profiles between fertilization treatments were detected within individual seasons; however, due to substantial interseasonal variation, no consistent differences could be detected between (i) mineral N and Ekofert fertilizer treatments, (ii) the two different Ekofert products, and (iii) contrasting Ekofert input levels. Results demonstrate that clover- and alfalfa-based pelleted organic fertilizer products are a suitable alternative for intensive organic field vegetable production.

Courgette is considered as a low-calorie vegetable with health-promoting properties. However, scientific publications focused on the profile and content of bioactive compounds in courgette, as well as the potential fruit quality modulating factors, are rare. Due to the high adaptability of courgette to weather and agronomic conditions, it is produced on a global scale. The aim of this study was to analyse the impact of organic versus conventional agronomic practices on the concentration of selected antioxidants in courgette fruits. Fruits of two courgette varieties (Astra Polka and Nimba) produced in an organic and conventional system were tested by high performance liquid chromatography (HPLC) to determine the content of polyphenols (flavonoids and phenolic acids), carotenoids, chlorophylls, and vitamin C. Organic courgette fruits were characterised by their significantly higher content of phenolic acids and flavonoids when compared to the conventionally grown fruit. The organic cultivation might be a good method to increase concentration of bioactive compounds with antioxidant properties in courgette fruits. Nevertheless, the identified trends should be further confirmed, with attention paid to other courgette varieties, as well as to the potential interactions between the plant genotype, agronomic system and the location-specific growing conditions.

Organic agriculture is considered one of the elements of sustainable food production and consumption, mainly due to its limited impact on the natural environment. At the same time, the quality features of organically produced foods, especially sensory attributes and health promoting values, are important factors determining consumers’ interest, and therefore play a key role in the organic sector’s development. The aim of this study was to investigate the sensory characteristics and concentrations of sugars and selected health-promoting bioactive compounds of organic courgette compared to conventionally grown courgette. In addition, untargeted metabolomic analysis of the courgette fruits was performed. The results of this study did not show a significant effect of the horticultural system (organic vs. conventional) on the concentrations of vitamin C, carotenoids, and chlorophylls in the courgette fruits. However, the fruits from the organic systems were significantly richer in sugars when compared to the conventionally cultivated ones (p = 0.038). Moreover, the organic fruits fertilized with manure contained significantly higher amounts of polyphenols, including gallic acid (p = 0.016), chlorogenic acid (p = 0.012), ferulic acid (p = 0.019), and quercetin-3-O-rutinoside (p = 0.020) compared to the conventional fruits. The untargeted analysis detected features significantly differentiating courgette fruits depending on the cultivar and horticultural system. Some significant differences in sensory values were also identified between fruits representing the two cultivars and coming from the horticultural systems compared in the study. Conventional courgettes were characterized by the most intensive peel color and aquosity, but at the same time were the least hard and firm compared to the fruits from the two organic systems. There was also a trend towards higher overall quality of the organically grown fruits. The presented study shows that the organic and conventional courgette fruits differ in a number of quality features which can influence consumers’ health and purchasing choices.