The way bread is prepared is one of the main factors determining the glycemic index of this starchy food. This is a study of changes in blood sugar response when we eat steamed bread instead of baked in the traditional Western way.
The glycemic index (GI) of a food is the rate at which the blood glucose (glucose) rises in the blood of that food after entering the body. Foods with a high GI will have a higher rate of rise in blood sugar than foods with a low GI. In this work, the scientists made bread using two methods of baking and steaming to observe the differences in macronutrients, processing conditions, and the variation of glycemic index when eating. change the recipe and method of making bread.
Toast we still eat.
To make it, the scientists prepared four types of bread: toast, dumplings, improved toast, and improved steamed bread.
Improved steamed bread is bread made according to the recipe of Western toast and then steamed in the Eastern style, in this article, this type of food will be referred to as “steamed bread” for short. An improved toast is a bread made from an oriental dumpling recipe and then baked in a western style, hereinafter referred to as “baked bun”.
Comparing 4 types of cakes, we have the order from low to high of the ability to digest starch in the laboratory and create a blood sugar response in the body: dumplings are baked, followed by toast, dumplings and then steamed bread.
Thus, steamed bread has the lowest glycemic response. Specifically, the time to produce the highest glycemic response of steamed bread is 30 minutes, and that of regular Western-style toast is 45 minutes.
Photo of 4 types of bread tested by scientists: toast (upper left corner), toasted buns (upper right corner), dumplings (lower left corner), steamed bread (bottom left corner). bottom right) (Image: Elsevier)
“For the first time, there is a study showing that even when using a recipe with similar ingredients, the application of different processing conditions, such as kneading time, kneading strength, incubation time and method The baking method will lead to slower starch digestion in the lab and a reduced glycemic response in the real world.”, verbatim comments on the characteristics of steamed bread compared to toasted bread in the study.
In the study, the scientists steamed bread at 100°C for 10 minutes instead of baking it at 210°C for 11 minutes. The intensity and time of kneading the dough are both reduced, and the incubation time is also reduced by nearly half, from 70 minutes to 40 minutes.
“The modification of physical texture and starch digestibility has occurred because of differences in processing. A more compact bread structure could interfere with amylase’s ability to reach the starch granules. flour, resulting in a slower rate of glucose release and reduced glycemic responsiveness of oriental steamed buns and modified steamed buns.”, the researchers explained.
However, the overall average GI in the breads remained unchanged.
Even so, the researchers say, changes in blood sugar response through changes in processing could give manufacturers a “New approach to change the glycemic index of starchy foods”.
Traditionally, ingredients such as beta-glucan (an intermolecular sugar compound), galactomannan (a type of thickening agent), non-starch polysaccharides, and polysaccharides have been used to lower the glycemic index of foods. product has a high GI, but this study shows that it is possible to modify the glycemic response without changing the input material.
In addition, steamed bread has another minus point that its volume has been significantly reduced, despite being made from the high-protein flour commonly used to make toast.
Dumpling flour with low protein (7-9%) or medium (10-12%) is often used to make cakes with a soft, smooth, fluffy texture, while bread flour is required. High protein content (between 12-14%) gives the bread a supple and firm texture.
This could be due to the shorter kneading time and weaker kneading intensity, the researchers say, so the gluten network is not developed enough. “The low energy input during dough development plus the shortened fermentation time results in the improved steamed bread having the least porous structure compared to the other three breads.”
A gluten web is a web formed after kneading flour with water and letting it sit for a while. Gluten is made up of gliadin and glutenlin, the two main proteins in wheat flour, making up 80% of the flour. Gluten is both tough and elastic, has the effect of trapping air during fermentation, helping bread dough rise well when cooked. The air trapped by gluten contributes to the cake’s spongy, porous structure after baking.
Bread that hasn’t been tempered or kneaded properly will swell poorly, with a dense, not spongy core, as is the case with steamed bread in this article. Below is a photo illustrating two cases of bread baking well and poorly. Well-baked bread will have many large and small stomata, spongy intestines, while poorly hatched bread will have fewer air holes, and the intestines will be denser.
Illustration of bread that expands well, spongy, with many large and small stomata (left) and bread with poor expansion, denser intestines, fewer air holes (right) (Image: reddit, Bakers Journal)
This research project is titled “Can bread-making conditions alter the glycemic response?”, was published in Food Chemistry 2015. The work was carried out by scientists from the Singapore Clinical Science Research Institute (SICS) under the Science, Technology and Research Agency. save Singapore (A*Star).
Refer to Bakery and Snacks