The degree of ripening of fruits and vegetables can affect both the flavor and the nutrients they contain. And, as this process progresses, the resistant starch present in some foods such as bananas, potatoes, peas or corn breaks down and simple sugars are formed. It was explained by the collaborating professor of Health Sciences Studies at the Open University of Catalonia (UOC), Amparo Gamero, in an article recently published by the center. “That’s why green fruits or vegetables are more acidic and when they ripen they are sweeter,” says the expert.
But this not only affects its sweetness. Gamero gives an example to explain it. “When the banana is somewhat ripe (the moment it turns from green to yellow) it is rich in fiber and low in sugar, but when it ripens a little more (its skin has black dots), in addition to still maintaining a high fiber content , increases the amount of antioxidants,” he says. At this point, this fruit may be suitable for those intolerant to certain simple sugars.
The nutritional level of the banana changes again when the skin turns black. “Vitamins and minerals fall here, and starch breaks down into simple sugars,” says Gamero. The same thing happens to tubers such as potatoes and sweet potatoes: if they are kept cold (below 8 degrees), they become sweeter over time.
But the ripening process is not the only thing that modifies starch. It also changes when cooked and subsequently cooled. “In this case, the starch gelatinizes and then retrogrades, and part of this retrograde starch becomes resistant starch,” says the expert, which happens especially with bread, pasta and cereals.
It is called resistant starch because it is not digestible by our digestive enzymes and reaches the colon intact, where it ferments and promotes the development of beneficial bacteria. “In addition, it makes the food have a lower glycemic index, that is, it causes fewer spikes in blood glucose and, therefore, it is healthier because in the long run there is less risk of suffering from diabetes,” says Gamero.
The expert ends by explaining that this type of starch has beneficial properties for the development of the microbiota and, therefore, can help prevent and treat various metabolic disorders, including diabetes.
