"Materials
Two types of spaghetti (regular No. 5 and gluten-free) produced by the Barilla company (Italy) were purchased in a supermarket."
Are you kidding me? You did a study and tested /one/ kind of gluten-free pasta?
There are so many different kinds from different companies. One type from Barilla is nowhere near representative to draw a useful conclusion.
Especially as unlike many other gluten-free pasta products it lacks an important binding agent.[1]
As someone with a gluten-allergic partner I regularly make pancakes and bake bread with (Italian!) rice-based flour.
And they are difficult to distinguish from the flour based ones, in taste, texture, fluffiness and and structural integrity.
The secret to this is xantham gum. It acts as a binding agent in gluten-free baking, providing the elasticity and stickiness that gluten typically offers. It helps to hold ingredients together and improve the texture.
I learned this when eating excellent gluten-free pinza, in a small place in Catania, Sicily, whose owner has celiac disease.
Ah yes, as far as pasta goes there is also research about this ofc[2]
[1] https://www.barilla.com/en-us/products/pasta/gluten-free/glu...
[2] "Incorporation of xanthan gum to gluten-free pasta with cassava starch. Physical, textural and sensory attributes"
https://www.sciencedirect.com/science/article/abs/pii/S00236...