It isn’t every day that you find out a processed food product might offer more nutrients than its unprocessed counterpart. But that is exactly the case when it comes to the lycopene content of tomato paste and ketchup, versus that of fresh tomatoes. Lycopene is a reddish carotenoid found in fruits and vegetables, such as tomatoes, red peppers, watermelon, guava, and pink grapefruit. And it’s true that the bioavailability of lycopene from tomato paste is higher than that of fresh tomatoes.
The explanation for this seemingly odd occurrence is that the processing of tomatoes into thick, concentrated paste may result in the lycopene being converted mostly to the cis isomer, which is how lycopene presents in human serum and tissue, whereas fresh tomatoes and some other tomato products contain all trans-lycopene.
Another surprising fact about lycopene is that temperature and time may affect the concentration of this nutrient in foods. For example, compared to fresh-picked watermelon, watermelons stored for 14 days at 21 degrees Celsius (almost 70 degrees Fahrenheit) had increases in lycopene of 11-40%. (The beta-carotene content increased by a whopping 50-139%!)Read More