Flashcards in CHAPTER 7: GLUTEN Deck (228)
Is gluten one one the three main structure builders in baked goods?
Yes, egg proteins and starch are the other two.
What is the most difficult structure builder to control? Why? What about in yeast doughs?
Gluten, because small changes in a formula or mixing method have large effects on gluten development.
Why is gluten important especially important in yeast baked doughs?
They rely heavily on gluten for unbaked dough structure. Without gluten, yeast-leavened dough is not good at retaining gases produced during the fermentation process. The dough does not expound well, if at all, and the expansion does not hold throughout the baking process. Cell wall tear, and the final crumb is dense.
Flour consists mainly of a solid what?
Solid matrix of proteins embedded with starch granules.
What proteins are unique to the wheat endosperm?
Gliadin and glutenin.
What happens to gliadin and gluten when water is added to flour?
They absorb water and swell.
Does mixing promote the absorption of water? How?
Yes, by exposing new surfaces of flour to particles of water.
Besides water absorption, how else does mixing help (3 things)?
It incorporates oxygen, which oxidizes and strengthens gluten; wears down particles, until they are small and no longer spherical; distributes particles evenly throughout the dough, so that ultimately a strong, continuos gluten network form.
Does gluten become stronger as it is mixed?
Gluten--and dough--is considered fully developed when it is what?
Strong, cohesive and elastic.
Glutenin is thought to provide what?
The strength and cohesiveness of the gluten network, as well as its springiness or elasticity.
Gliadin is thought to contribute what?
Stretchiness and extensibility.
Why should dough be mixed evenly in all direction when gluten is involved?
Because gluten strands align in the directions they are mixed.
How must dough be kneaded by hand? What if it's laminated dough?
Dough must be turned 90º with every knead. Likewise, when laminated doughs are folded or sheet, the dough is rotated with each fold or run through the sheeter. Otherwise, gluten strands align in one direction. This becomes especially evident when dough is not allowed to relax before being shaped and baked.
How can you tell if dough hasn't been kneaded properly before being shaped and baked?
The dough will tend to shrink in whatever direction that the gluten strands are oriented.
The backbone of the gluten network consists largely of what? What does it look like? What about gliadin?
The largest glutenin molecules, or subunits, aligned and tightly linked to on another. These tightly linked glutenin subunits associate more loosely, along with gliadin, into larger gluten aggregates.
Portions of ________ are thought to loop, making gluten stretchy and flexible.
Gluten is further made flexible by the presence of compact, coiled _______ molecules interspersed throughout.
At the next level of gluten structure, gluten aggregates interact to form a tangled network of larger gluten particles that loosely interact with what?
Starch granules, fats, sugars, and gums.
Altogether, does it seems like gluten structures are held together by some very strong and many more weak bonds that break and reform easily? Explain.
Many bonds break, in particular, during mixing, only to reform around the surfaces of expanding air bubbles during proofing and the early stages of baking. It is this combination of strong and weak forces breaking and reforming that contributes to the unique nature of gluten.
Fully developed dough has what type of appearance?
Dry, silky appearance. It stretches into a smooth, thin film without tearing or breaking, yet still retains some ability to spring back.
Bakers use what test to see if dough is fully developed?
How do you make a windowpane?
Pull off a piece of dough about 1 inch or so in diameter. Roll it between your hands to shape into a ball, then gently pull the dough between your hands. Rotate the dough as you do this so that you are pulling it in all direction, forming a paper thin sheet of dough. Fully developed dough should form a thin film without tearing.
Although changes to gluten network cannot be seen, what happens, how are they reflected by what is seen?
Batters and doughs become smoother, stronger, and less lumpy as they are mixed and kneaded, and they are better able to stretch and trap solid particles, liquids, and gases as they expand.
When batters and doughs are baked, what happens to most of the moisture?
It's either absorbed by gelatinized starch granules or evaporates.
With the loss of moisture and in the presence of heat, what happens to gluten? Is it unique to gluten?
Gluten coagulates into a firm and rigid yet porous structure that holds up its shape. While not unique to gluten (egg proteins, when heated, also coagulate into a firm,rigid structure), this is nonetheless and important feature of gluten.
Can doughs have too much gluten? What is it called when dough is too tight and bouncy?
Yes, it's usually called "bucky."
What is the problem with "bucky" dough?
Bread tends to be tough and chewy, have a low volume because they cannot stretch, and develop soft and thin crusts.
What happens of parties have too little gluten?
Pie crusts crumble easily, cakes collapse and baking powder biscuits slump.