Effects of Different Ripening Stages on the Content of the Mineral Elements and Vitamin C of the Fruit Extracts of Solanum Species: S. melanocerasum, S. nigrum, S. villosum, and S. retroflexum.

Studies on the mineral and vitamin C contents of different species and ripening stages of Solanum fruits are very limited. The aim of the research was to evaluate the content of the mineral elements and vitamin C of four different Solanum species (S. melanocerasum-SM, S. nigrum-SN, S. villosum-SV and S. retroflexum-SR), and three ripening stages. The mineral composition of Solanum fruits was detected using a CEM MARS 6® (Matthews, NC, USA) digestion system outfitted with a 100 mL Teflon vessel, by microwave-assisted extraction (MAE). In total, eleven mineral elements were detected (K, Ca, Mg, P, Fe, Na, Cu, B, Mn, Al, and Zn). Vitamin C content was assessed by a spectrophotometric method. Depending on the ripening stage/species, content of microelements ranged from 756.48 mg kg-1 DW in SV fruits at ripening stage III, to 211.12 mg kg-1 DW in SM fruits at ripening stage III. The dominant microelement was Fe. The total content of macroelements in Solanum fruits ranged from 26,104.95 mg kg-1 DW in SV fruits at ripening stage II to 67,035.23 mg kg-1 DW in SR fruits at ripening stage I. The dominant macroelement was K. The data from two experimental years showed that the significantly highest content of vitamin C was in SM fruits and ranged from 48.15 mg 100 g-1 at ripening stage I to 45.10 mg 100 g-1 at ripening stage III.

The Effect of Ripening Stages on the Accumulation of Polyphenols and Antioxidant Activity of the Fruit Extracts of Solanum Species.

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.

Changes in Fatty Acid Content in Solanum spp. Fruits during Ripening.

This study aimed to determine the effects of the ripening stage and species on the contents of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids in Solanum spp. fruits. A two-factor field experiment with four different Solanum spp. species (S. nigrum, S. melanocerasum, S. retroflexum, and S. villosum) and three ripening stages was conducted over two growing seasons (2020-2021). The fatty acid composition of the Solanum fruits was characterized using gas chromatography with a flame ionization detection. The results show that PUFAs are the dominant type of fatty acid in Solanum fruits, followed by MUFAs and SFAs. Overall, the highest PUFA contents were observed in S. nigrum fruits in the ripening stage I, and the highest MUFA and SFA contents were observed in S. melanocerasum fruits during ripening stages I and II, respectively.