Several recent TikToks have claimed that freezing bread makes it healthier. Some of them mention that there is research that supports these claims.
But is this cooking hack as good as social media influencers suggest?
The science behind it is actually solid, if a little confusing. But the real health effects are not as great as claimed.
When the bread is baked, it transforms the soft, bubble-filled dough into a soft, chewy loaf. The heat of the oven, combined with the water in the dough, causes the starch in the flour to swell and gelatinize. The same thing happens when flour is added to a sauce and cooked until it thickens.
These gelatinized starches are easier to digest, making the glucose (sugars) these starches contain more easily assimilated by our cells. This is true for many freshly baked starchy foods, especially those low in fiber or made from finely ground flours – like white bread or potatoes.
Some evidence suggests that this type of quickly available glucose might increase insulin levels right after eating. Although insulin is important because it helps our cells use glucose for energy (or store it for energy later), too much insulin could make you hungrier and possibly even gain weight.
But when foods containing these gelatinized starches are cooled, the expanded starches shrink, becoming what is called resistant starch. These collapsed starches are harder for the enzymes in our digestive tract to break down – which means it’s also harder for our cells to get the sugar these starches contain. This means that resistant starches are less likely to cause a “spike” in blood sugar and insulin after eating them.
The degree to which resistant starch forms depends on the baking temperature of the bread and whether it is then refrigerated or frozen. The contraction rate is almost twice as high in the freezer as in the refrigerator, meaning a more resistant starch will form.
Additionally, freezing bread traps water, keeping it fresher and softer than if you kept it in the refrigerator, where the water will be lost, making the bread tough.
Should you freeze your bread?
A study of ten healthy people examined the effect of freezing white bread and then toasting it. They compared store-bought breads with homemade bread.
For the homemade bread samples, freezing and thawing the bread reduced the increase in blood sugar levels by 31% within two hours. Interestingly, toasting fresh bread also reduced the rise in glucose by 25 percent.
This effect was even greater when the homemade bread was frozen, thawed, and then toasted, reducing the blood sugar response by 39 percent. This effect could potentially help fight hunger, as glucose and insulin levels won’t increase as much after eating frozen bread.
But when store-bought commercial white bread was used, freezing it before toasting did not improve the body’s blood sugar response. This could reflect the different ways commercial bread is made versus homemade bread. The ingredients used or the way the bread is baked and then cooled can reduce the effect of freezing on the formation of resistant starch. The evidence is not entirely clear.
Other more recent research has also shown similar results. So, although some studies are limited, the effect of freezing bread appears consistent and studied extensively in the laboratory.
But it should be noted that these effects only exist a few hours after eating bread. So even if you freeze your bread before eating it, it can help reduce blood sugar levels at one meal (and have a slight effect on the next meal as well), the long-term effects on appetite , weight gain or the risk of certain diseases (such as type 2). diabetes) is not known – and is probably very low.
Resistant starch can be found in many other cooked and refrigerated starchy foods such as potatoes, pasta, and some (but not all) types of rice. Basmati rice in particular seems to form a more resistant starch than fluffier types of rice (like arborio rice).
In addition to being more difficult to break down than freshly cooked starch, resistant starch provides nutrients to the microbes living in our colon. This helps maintain a healthy balance of bacteria in our gut. These bacteria then release chemicals onto the cells lining the colon, which helps us maintain a healthy metabolism.
Resistant starch has also been shown to help insulin work better by somewhat increasing insulin sensitivity. This can help our bodies use blood sugar more efficiently, which is linked to better health because it can be used more efficiently as fuel by our muscles.
The benefits of resistant starch may even extend to other aspects of our metabolism, as it may also help lower cholesterol. This effect is thought to be due to short-chain fatty acids produced by gut bacteria when they ferment resistant starches. Lower cholesterol levels can mean a lower risk of heart disease.
Although these changes may seem quite dramatic, they are short-term and therefore their long-term effects on our health are more modest. But that doesn’t mean you shouldn’t freeze your bread. Putting a loaf of bread in the freezer can reduce food waste with some added health benefits, however small.
Duane Mellor, Head of Evidence-Based Medicine and Nutrition, Aston Medical School, Aston University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
News Source : www.sciencealert.com
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