Turnips, like many root vegetables, undergo noticeable changes when exposed to certain environmental factors, notably sunlight. Typically grown underground, they are shielded from direct sunlight, retaining their various shades that can range from white to purple. However, when a turnip is exposed to sunlight for a prolonged period, it manifests a distinct change in color, predominantly turning green.
This greening of turnips occurs due to the development of chlorophyll, the green pigment common in plants which is crucial for photosynthesis. Sunlight acts as a catalyst in synthesizing this pigment. Sun exposure does not merely alter their external coloration but can also affect the nutritional profile and taste of the turnips. Typically, the formation of chlorophyll is accompanied by the production of solanine, a natural toxin found in some nightshade vegetables when they are exposed to too much light. Although this is more commonly observed in potatoes, turnips can also develop a slightly bitter taste if the green is extensive, suggesting a change in their chemical composition.
In culinary contexts, while the green parts of a turnip are not harmful and can be consumed, they may impart an undesirable flavor, thus cooks often remove these portions. From a gardening standpoint, to prevent this greening and ensure uniformity in texture and taste, it is advisable for gardeners to keep turnips adequately covered by soil and harvest them in a timely manner.
Moreover, the phenomenon indicates the robust adaptability of turnips, which can initiate photosynthesis, a typically surface-level activity, even though they are primarily root vegetables. This adaptability allows turnips to still be nutrient-rich, offering benefits from dietary fiber to Vitamin C. However, for optimal culinary quality and to avoid any bitter or unexpected flavors, limiting their exposure to sunlight and observing proper harvesting periods remain key practices.
