Previously frozen bread and dry bread are healthier

It does not matter if the bread is whiter or darker, when freezing it the structure of the starch is modified, which in part becomes resistant, and acquires fiber-like properties. This makes the bread much healthier.

The glycemic index of bread (the rate at which its sugars are converted to blood glucose) changes when it is thawed, compared to fresh bread. If it is defrosted by toasting it, it becomes even more resistant.

Frozen bread provides fewer calories and benefits the microbiota

A study from Oxford Brookes University published in the European Journal of Clinical Nutrition explains that the resistant starch that forms due to freezing does not break down under the action of digestive enzymes from the mouth and intestine, cas it happens to fresh bread.

with freezing, the glycemic index is reduced by 31 percent. Once the starch structure has changed on freezing, it does not return to its original state on thawing. In fact, it becomes even less assimilable, according to the study. And even more if it is toasted a little.

For most people, this is a good thing, as the higher proportion of “resistant” starch means the bread is more slowly digested by the body, causing a milder rise in blood sugar than fresh bread, potentially reducing the risk of overweight, obesity and type 2 diabetes.

Reduces the risk of colon cancer

The study also indicates that previously frozen bread could reduce the risk of colon cancer, because intestinal bacteria that feed on resistant starch produce short-chain fatty acids that improve the condition of the intestinal mucosa. These fatty acids also stimulate the hormones that tell the brain that we are full and therefore help prevent or reduce overweight.

Bread with resistant starch provides fewer calories and better nourishes the beneficial bacteria of the intestinal microbiota. Some people may experience bloating and gas when digesting it. This problem tends to be reduced when the digestive system gets used to receiving resistant starch.

The only difference between breads is not based on whether or not they have been frozen. There is a wide variety, including ultra-processed white breads, made with refined flours and fast fermentation, which can incorporate added sugars, and breads made only with wholemeal flour, which can be wheat or other cereals, and slow fermentation with sourdough, which in moderate amounts are a nutritious food, rich in B group vitamins and minerals.

Dry bread is also better than fresh.

Another investigation, carried out at the Royal Melbourne Institute of Technology (Australia), determined how the starch in bread is transformed by subjecting it to different temperatures for variable times.

According to the study authors, bread that is slowly dried in the bread bin contains even more resistant starch than frozen bread.

The Oxford Brookes University study found that fresh toasted bread produced a 25 percent lower blood sugar response than fresh bread. If frozen and then roasted, the reduction is 40 percent.

But while lightly toasting bread destroys some of the B vitamins, burnt toast increases the level of acrylamides, a compound that forms in starchy foods during high-temperature cooking methods, such as roasting, baking, and frying. High amounts of acrylamide may increase the risk of cancer.

Human research remains inconclusive, but recommendations are that toasting bread should not go beyond a light golden color. The darker, the more acrylamides.

Scientific reference:

P Burton and HJ Lightowler. The impact of freezing and toasting on the glycemic response of white bread. European Journal of Clinical Nutrition.