Vitamin that controls the browning in fruits by the help of enzymes is:

The vitamin that is primarily responsible for controlling the enzymatic browning of fruits is vitamin C, also known as ascorbic acid. The enzymatic browning occurs when the enzyme polyphenol oxidase reacts with oxygen and converts phenolic compounds into melanin pigments. Vitamin C is responsible for controlling the enzymatic browning of fruits in two different ways. First, vitamin C reduces o-quinones into phenolic compounds before the formation of melanin pigments. Second, vitamin C reduces the pH of the fruits' surface. Vitamin C is an acid that reduces the pH of the fruits' surface, thereby slowing down or completely inhibiting the activity of the enzyme polyphenol oxidase.