Do lemons start losing vitamin C as soon as you cut them?

I'm not very sure of the answer myself but I will answer as much as I know from what I've learnt. Hope it helps :) Lemons have a powerful anti-oxidizing agent. read more

But after being cut, they lose their antioxidant and vitamins if you keep them in air tight containers also. Being juicy, lemons have several droplets of water around their surroundings and cut lemons have more droplets of water all over them which start oxidizing even in tight containers. read more

As far as the beneficial nutrients in lemons, such as citric acid, vitamin C, potassium, calcium, phosphorous and magnesium, these should be mostly preserved in the properly stored cut lemon for 2 to 4 days. Lemons are also rich in enzymes, which will start to diminish once the lemon is cut and exposed to air. read more

Here’s the nutrient scorecard of cut fruits that are most resistant to vitamin loss after spending six days in the fridge, according to a University of California study: Mangoes, strawberries and watermelon lost 5 per cent of vitamin C; pineapple and kiwifruit lost 10 per cent; and rockmelon lost 20 per cent. read more

Vitamin C Content. A 100-gram serving of orange or lemon provides you with 53 milligrams of vitamin C, which is 88 percent of the daily value of 60 milligrams per day. This serving equals either one small orange or slightly less than two lemons. read more