Inhibitory activity towards human α-amylase in cereal foods


Gélinas, P., McKinnon, C., Gagnon, F. (2018). Inhibitory activity towards human α-amylase in cereal foods. Food Science and Technology - LWT, [online] 93 268-273.

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Subject: Wheat-based foods may not be as indigestible as we thought.
Gélinas, P. & Gagnon, F. 2018. Inhibitory activity towards human α-amylase in cereal foods. LWT – Food Science and Technology, In press.
A) What was the problem or subject?
- Some people are sensitive to gluten; they do not have celiac disease but do not feel well after eating wheat.
- Wheat contains substances that inhibit amylases in human saliva, which can cause digestive problems due to the accumulation of undegraded carbohydrates in the intestines.
- We measured enzyme inhibitor levels in wheat-based foods (commercial or laboratory-produced).
B) Why is this so important and for whom?
- People with gluten sensitivity: They are concerned and believe that their health problems are caused by wheat enzyme inhibitors. In science, this is the most popular theory.
C) What answers have been found?
- There are very few enzyme inhibitors (α-amylases of human saliva) in wheat-based foods if they are very well cooked; toasting a slice of bread does not destroy them. There are a few exceptions: flour sprinkled on the surface of artisanal breads and a breakfast cereal made from undercooked gluten (Kellogg’s Special K®).
D) What are the benefits? What will happen next?
- Wheat breeders: There is little interest in developing wheat varieties that are low in α-amylase inhibitors (extracted from human saliva).
- People with gluten sensitivity: They must eat very well-cooked food.
- The next step: Since there are doubts, clinical studies should be conducted to confirm whether or not wheat enzyme inhibitors can cause digestive problems.
How can I get more details?
- Pierre Gélinas, PhD, Research Scientist, Saint-Hyacinthe Research and Development Centre, Agriculture and Agri-Food Canada;


Wheat flour and vital wheat gluten contain high levels of α-amylase inhibitors (AI), a potential trigger of non-celiac gluten or wheat sensitivity (NCGS). The aim of this study was to determine inhibitory activity towards α-amylase from human saliva in cereal foods. No AI activity was detected in commercial foods such as cake, cookie, cracker, muffin, pretzel or ready-to-eat (RTE) cereals, except one RTE cereal with minimally-cooked vital wheat gluten (IC50 = 418 μg mL−1). Commercial pan bread and earth-oven artisan bread had variable AI activity, from high (IC50 = 1100 μg mL−1) to non-detectable (10 000 μg mL−1). Little AI activity, from 3693 to 9732 μg mL−1, was detected in bread under-baked in the laboratory for 30 min at 190 °C and made without sugar, or with 6 g/100 g vital wheat gluten or 0.3 g/100 g emulsifiers (monoglycerides; SSL); there was no AI activity in bread baked at 225 °C. Very high AI activity was found in wheat flour dusting on bread crust, from 124 to 359 μg mL−1. If thoroughly-heated, cereal foods would be safe for individuals willing to limit exposure to wheat AI, except bread with much flour dusting and foods formulated with minimally-cooked vital wheat gluten.

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