## 2 Materials and Methods  
### Materials  
The amount of vitamin C was measured in three samples of plant juices (chives--_Allium schoenprasum_ L.; dandelion--_Taraxacum officinal_; and nettle-_Urtica dioica_ L.) and six samples of vegetable juices (tomato--_Solanum lycopersium_; carrot--_Daucus carota_ L.; salad cucumber--_Cucunis sativus_ L.; red pepper (capsicum)--_Capsicum annuum_ var. _annuum_; white pepper--_Capsicum annuuum_ var. _gross_; white cabbage--_Brassica oleracea_ var. capitata), partly from domestic sources. As far as the three plant species were concerned, they were obtained from the garden (Slovakia, GPS coordinates: 48\({}^{\circ}\)18\({}^{\prime}\)16.8\({}^{\prime\prime}\) N, 18\({}^{\circ}\)03\({}^{\prime}\)28.4\({}^{\prime\prime}\) E). The same was true for the selected vegetables (tomato--_Solanum lycopersicum_, _carrot--_Daucus carota_ L., and cucumber-_Cucunis sativus_ L.), i.e., they were organically grown vegetables (organic vegetables). Red pepper (capsicum) (_Capsicum annuum_ var. _annuum_), white pepper (_Capsicum annuum_ var. _grossum_), and white cabbage (_Brassica oleracea_ var. _capitata_) were obtained in a supermarket chain: Tesco Stores, SR, a.s. (GPS coordinates: 48\({}^{\circ}\)18\({}^{\prime}\)42.8\({}^{\prime\prime}\) N 18\({}^{\circ}\)04\({}^{\prime}\)10.5\({}^{\prime\prime}\) E). The chemicals used for analysis and the mass of vitamin C were as described in the study by [PERSON], [PERSON], and [PERSON] [31]. Chemical substances used in the determination were as follows: starch (Merck KGaA, Darmstadt, Germany), potassium iodate (KIO3, LABO, Bratislava, Slovakia), potassium iodide (KI, LABO, Bratislava, Slovakia), ascorbic acid (Merck KGaA, Germany), and sulfuric acid (H\({}_{2}\)SO\({}_{4}\), concentrated, purity p. a., LABO, Bratislava, Slovakia). Chemicals were weighed using a balance for analytical purposes, the RADWAG Company AS 110/C/2 (Max. 110 g, Min. 10 mg, d = 0.1 mg, Libra s.r.o., Bratislava, Slovakia). Characteristics of Chosen Plants and Vegetables  
In this analysis, three types of plant juices were used, including food flavouring (chives) and two types of medicinal plants (dandelion and nettle). The ecological equilibrium, particularly the genetic variety of the flora and animals in local environments, may be impacted by the production, e.g., of herbs [32]. Due to their distinctive aroma, chives (_Allium schoenprossum_ L.), an established annual herb, has become a necessary seasoning vegetable in everyday life [18]. It looks like tall, dark green blades of grass but is slender and hollow and grows in dense, hearty clumps. Chives is nutritious because it contains substances that offer numerous health advantages, like anti-inflammatory and sterilising activities that have an impact on the stomach and intestines, decreasing blood pressure and preventing cancer [33; 34]. Chives have a high content of phytoncides or antibiotic substances. They have a positive effect on our body; they heal the intestinal microflora, stomach, intestines, liver, and bile; increase the secretion of gastric juices; promote the digestion of fats and the excretion of sugars; purify the kidneys and urinary tract; and support the heart. Dandelion (_Taraxacum officinal_) is an annual plant with a wide geographic distribution in the northern hemisphere; dandelion is a member of the Asteraceae family and has long been used in Chinese traditional medicinal practices [35]. Dandelions have various medicinal uses (e.g., anticancer, antirheumatic, antimicrobial, anti-diabetic, and anti-inflammatory effects) [36; 37; 38], and the leaves are rich in provitamin A, vitamin C, and calcium. Fresh dandelion leaves have recently entered the marketplace for fresh vegetables and have a moderate, slightly bitter taste [39]. Modern research has shown that the bioactive components of fresh dandelion, such as tocopherols, cinnamic acid derivatives, flavonoids, triterpenoids, polysaccharides, and riboflavin, are responsible for its medicinal properties [40; 41]. Stingting nettle (_Urtica dioca_ L.) is a herb [42].