The purpose of this research is to evaluate the effect of conventional, biodynamic, and organic cultivation methods on the contents of polyphenols and carotenoids in tubers of potato cultivars with different colored flesh: “Red Emmalie”, “Salad Blue”, “Violetta”, “Tornado”, and “Laura”. These bioactive compounds were determined by the high-performance liquid chromatography method. The data received were analyzed with ANOVA and further explored and visualized by principal component analysis. Higher contents of polyphenols (sum), phenolic acids (sum), chlorogenic acid, p-coumaric acid, and caffeic acid were found in biodynamic and organic samples compared to the conventional tubers. Moreover, organically and biodynamically produced potatoes (except “Salad Blue” cultivar) were significantly richer in flavonoids and anthocyanins. The highest contents of carotenoids (sum), lutein, and β-carotene were found in biodynamic potatoes. Among the tested cultivars, “Tornado”, with white flesh, was richest in polyphenols (sum), phenolic acids (sum), chlorogenic acid, and p-coumaric acid. “Violetta”, with dark purple flesh, accumulated the highest contents of flavonoids (sum), anthocyanins (sum), petunidin-3,5-di-O-glucoside, pelargonidin-3,5-di-O-glucoside, and peonidin-3,5-di-O-glucoside. Carotenoids were only found in “Laura” tubers, and the dominating carotenoid was lutein.

Our research was aimed at assessing the effect of accumulation of carotenoids, polyphenols, vitamin C and ripening stage in the rosehip fruits of two species—Rosa canina, Rosa rugosa and two cultivar—Rosa rugosa ‘Rubra’ and Rosa rugosa ‘Alba’. The amounts of carotenoids, polyphenols and vitamin C were determined using the high-performance liquid chromatography (HPLC) method. The obtained results showed that the significantly highest amount (107.15 mg 100 g⁻¹) of total carotenoid was determined in the fruits of Rosa canina at ripening Stage V. While results indicated that significant amount of total polyphenols were established at Stages I and II in the Rosa Rugosa ‘Alba’ and Rosa rugosa ‘Rubra’ cultivars (110.34 mg 100 g⁻¹, 107.88 mg 100 g⁻¹ and 103.20 mg 100 g⁻¹ 103.39 mg 100 g⁻¹). At ripening Stage I, in the fruits of Rosa rugosa the greatest increases were established in the contents of vitamin C (3036.08 mg 100 g⁻¹).

The aim of the research was to evaluate the influence of the ripening stage on the accumulation of polyphenols and antioxidant activity in fruits of Solanum species. The experiment included two factors: I—four different Solanum species (S. melanocerasum, S. nigrum, S. villosum, and S. retroflexum) and II—three ripening stages. High-performance liquid chromatography (HPLC) was used to analyze the individual phenolic compounds (flavonoids and phenolic acids), and the spectrophotometric method was applied to determine antioxidant activity. The results revealed that the accumulation of polyphenols and antioxidant activity in fruits of Solanum species depends on the stage of ripening and species. All studied Solanum species fruits had the highest content of total phenolic acid at ripening stage III and the greatest antioxidant activity at ripening stage I. Fully ripe fruits of S. melanocerasum contained significantly more total flavonoids, whereas S. nigrum contained significantly more total phenolic acids than other investigated Solanum species fruits. The significantly highest antioxidant activity was found in S. melanocerasum fruits at ripening stage I.

Studies on the determination of the optimal harvest time of rosehips are very limited. Therefore, the aim of this research was to ascertain the effect of the ripening stage on the quality and content of fatty acids of organic rosehip seeds. A two-factor field experiment with two rosehip species and cultivars (Rosa rugosa, Rosa canina, and Rosa rugosa cv. ‘Rubra’, Rosa rugosa cv. ‘Alba’) was conducted during two growing seasons (2018–2019) on an organic farm. The fruits were harvested five times per season. The fatty acid composition of rosehip seeds was determined using a Gas Chromatograph with Split/Splitless Injector Liners. The highest amounts of fat were recorded in all rosehip seeds at ripening stage IV. The most dominant fatty acids in the seed samples were polyunsaturated fatty acids (PUFAs) (73.88–79.52%), followed by monounsaturated fatty acids (MUFAs) (14.67–18.89%) and saturated fatty acids (SUFAs) (5.22–7.36%). The highest amount of PUFAs was established in Rosa rugosa cv. ‘Alba’ seeds harvested at fully ripe stage V. It can be concluded that the rosehip seeds may be utilized as a source of fatty acids, especially PUFAs.

Coloured potato chips, due to a higher concentration of bioactive compounds, may be healthier compared to traditional chips. This study examined the effect of cultivar and different slice thicknesses and frying temperatures on the physico-chemical and sensory characteristics of coloured potato chips. Potatoes chips were prepared from three coloured potato cultivars. Frying experiments were conducted at 160 and 180 °C using potato slices with thicknesses of 1.00 and 2.00 mm. The quality of the raw potatoes tubers and chips were estimated. A principal component analysis was applied to describe the differences in the physico-chemical characteristics between the potato chip samples processed with different conditions. The results showed that, significantly (p < 0.05), the highest amounts of total phenolic content, total anthocyanins, dry matter and starch were accumulated in raw tubers of potato cv. Blaue Anneliese. The highest amount of total phenolic content and anthocyanins was found in 1 mm chips of cv. Blaue Anneliese fried at 160 °C. An increased frying temperature significantly (p < 0.05) decreased the content of these compounds. The amount of fat in the chips was higher when they were fried at 160 °C than at 180 °C. Chips processed from potatoes cvs. Blaue Anneliese and Rosemarie showed a typical colour as a raw material. The hardness of the chips significantly (p < 0.05) increased with an increase in slice thickness. The flavour, odour and colour of the 1 mm chips of cv. Blaue Anneliese fried at 180 °C gained the highest rating.

Studies on the mineral content of different rosehip species/cultivars during the ripening period are very limited. Therefore, the objective of this research was to evaluate the content and composition of the mineral elements of two species and two rosehip cultivars growing on an organic farm. The rosehip fruits were harvested at different ripening stages, five time per season. Mineral composition (K, Ca, Mg, P, Fe, Na, Ti, Cu, B, Mn, Al, Zn, Cr, Co, Ni, As, Mo, Cd and Pb) was analyzed by means inductively coupled plasma mass spectrometry (ICP–MS). The results showed that the ripening stage and species/cultivars had an effect on the contents of the mineral elements. Significantly, the highest content of mineral elements was determined at ripening stage I (Ca, Mg, Ti, Mn, Al and Cr) and IV (K, P, Fe, Cu and B). Species of the Rosa canina accumulated the highest content of mineral elements. Correlation analysis showed that the hue angle had a positive and very strong relationship with six mineral elements: K (r = 0.909), Ca (r = 0.962), Mg (r = 0.965), P (r = 0.945), Fe (r = 0.929) and Ti (r = 0.944).