We have all heard processed foods have less nutritional value than fresh foods. Processing destroys vitamins and leads to nutritionally inferior foods? But is this always true? Recent research is helping to dispel some of these myths. In fact, for antioxidants processing seems to boost their effectiveness.
Fresh is best, right? Well, maybe not. Research has shown that cooked tomatoes like spaghetti sauce, or canned tomatoes has higher antioxidant levels than fresh tomatoes. How can this be? As far back as 2002, a study in the Journal of Agricultural Food Chemistry noted that heating tomatoes such as the heat involved in canning tomatoes, resulted in elevating not only the total antioxidant content of the tomato but also the lycopene content. Although some vitamin C was lost in processing, the antioxidant value was increased. Substances like lycopene help guard against some cancers and heart disease. It seems heating the tomatoes releases the antioxidants and lycopene by breaking down the cell walls.
So enjoy your canned tomatoes or tomato sauce and know that the antioxidants are not only preserved but enhanced.
Corn and Spinach
Heating corn or spinach also has nutritional benefits. Corn and spinach provide lutein, a substance that helps prevent macular degeneration of they eyes. Heating either cooking or in food processing helps release lutein. Like canned or frozen corn? Seems the carotenoid content (we make vitamin A from carotenoids), is increased in frozen and canned corn.
Everyone would think canning peaches would destroy nutritional value. Some vitamins are decreased but others are increased. Compared to a fresh peach, canned peaches have higher levels of vitamin C, antioxidants and the vitamin folate. However, the canning does lessen the vitamins A and E, and the carotenoid levels. But even though lessened, they were still comparable to fresh peaches.
So yes, fresh peaches offer fiber and great nutrition. But canned peaches also have nutritional value and there is no reason not to have them in one’s diet.
I have written previously how a handful of nuts a day is a great, healthy habit. So what happens if peanuts are boiled? Seems their antioxidant activity is increased. Not just increased but by 4 times the amount. How about roasting peanuts? Seems the heat doesn’t destroy antioxidants but ramps them up.
As summer draws to a close and winter nears, fresh peaches, fresh corn, fresh tomatoes are not as easy to find and not as reasonably priced. So enjoy some canned tomatoes, canned peaches and canned or frozen corn. These research findings give us more food options. We can enjoy some canned and frozen foods in our diet.
Sources: Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity