**5. Vitamins**

Vitamins are necessary for normal growth, and their deficiency can cause health Complications (see **Table 4**). Vitamin C or ascorbic acid is a natural antioxidant that helps prevent different diseases by reducing oxidative stress [93]. Radish is a major source of vitamin C with 38.83 10–2 g/kg of vitamin C as compared to turnips and carrots; however slight change in vitamin C accumulation is seen in plants grown in high CO2 conditions [86]. The ascorbic acid content of sweet potato is comparable to radish. Different cultivars, including white, orange, and purple sweet potato, have indicated vitamin C content ranging from 17 to 37 mg/100 g DW [94]. Turnip greens and turnip tops are good sources of vitamin C; however, the heat processing leads to a significant loss of vitamin C. Steaming can result in approximately 60% vitamin C loss, while boiling and high-pressure cooking can completely diminish vitamin C content from a turnip [31]. Other than heat treatment, the vitamin C content is also sensitive to long-term storage. A study on carrot cultivars reported 88–132 mg/kg vitamin C content in fresh carrots, which decreased by 58% (on average) upon 30 days of storage [95]. Vitamin E refers to a group of lipid-soluble antioxidants that play an essential role in cell signal regulation and proliferation [96]. Among different types of vitamin K, α and γ tocopherol are the most prominent types [89]. Carrots serve as an excellent source of vitamin E; however, orange and purple carrots varieties have higher vitamin E content than white carrots [90]. Green leafy plant sections contain higher vitamin E content than roots, as determined in radish leaves containing up to 48.5 μg/g DW of vitamin E with α-tocopherol as major vitamin E. At the same time, roots only contain up to 0.17 μg/g DW with γ-tocopherol in the highest quantity; however, vitamin C and E are also sensitive to post-harvest storage. Vitamin K is also found in root vegetables but is predominant in green leafy portions. Phylloquinone, commonly known as vitamin K1, is the predominant form of vitamin K and is reported in considerable amounts in radish leaves [89]. As discussed in the previous section, carrots are rich in carotenoids, among which α-carotene and β-carotene are major pro-vitamin A compounds that are converted into vitamin A (retinol) in a biological system. According to the US National academy of science, 24 μg of pro-vitamin, A carotenoid is equivalent to 1 μg of vitamin A (retinol) [80, 81].


#### **Table 4.**

*Major root vegetable sources of vitamins and health conditions related to deficiency.*
