CONCEPT 26: POTATO STARCH CAN BE CONTROLLED

Question 1

Are there simple steps to remove or activate starch in potatoes?

Answer 1

Yes

Question 2

Starch granules in a potato begin to absorb moisture at what temperature?

Answer 2

140 degrees Fahrenheit.

Question 3

At what temperature to starch granules swell intensely?

Answer 3

160 degrees Fahrenheit.

Question 4

What happens when starch granules get too hot and absorb too much water?

Answer 4

They can rupture, spilling out a sticky gel made of amylose.

Question 5

What happens if potato cells holding these starch granules also explode?

Answer 5

The released amylose will create a gluey mess.

Question 6

At what temperature does a “gluey mess” become a significant problem? What is happening?

Answer 6

At 180 degrees, pectin–which acts as a glue surrounding the cells and within the cell walls–begins to break down, becoming water-soluble, and dissolves, causing the cells to separate and cell walls to break open, releasing gel.

Question 7

Is overcooking the only way to create gluey potatoes?

Answer 7

No, these starch granules can also explode if the potatoes are overworked after cooking.

Question 8

To prevent a gluey dish, when can you rinse potatoes?

Answer 8

Before, during or after cooking.

Question 9

What are two ways you can manipulate free starch when needed for a more sticky, tacky texture?

Answer 9

Stirring or a food processor.

Question 10

Is the potato starch amylose held within starch granules before cooking?

Answer 10

Yes

Question 11

When starch granules burst and release amylose, what does it form?

Answer 11

A gluey gel.

Question 12

TEST KITCHEN: FOLDED MASHED POTATOES AGAINST FOOD PROCESSOR.

Answer 12

Folded were remarkably fluffy while food processor created a sticky, gummy substance; closer to glue than mashed potatoes.

Question 13

How much water does a Russet potato contain?

Answer 13

About 79%

Question 14

How much water root vegetables like carrots, parsnips, celery root and turnips contain?

Answer 14

Between 80 to 92%

Question 15

How much starch do root vegetables like carrots, parsnips, celery root and turnips contain?

Answer 15

Between 0.2 and 6.2% wet weigh

Question 16

Many root vegetables are noticeably ______ or slightly ______.

Answer 16

sweet, bitter

Question 17

When mixing other root vegetables with potatoes, what is a good ratio? Why?

Answer 17

1:3 vegetables to potato is good for two reasons. One, root vegetable flavor can overwhelm the mild potato and, two, the root vegetables have far more moisture in them.

Question 18

Do you wash away excess potato starch when boiling and braising? Explain.

Answer 18

When boiling peeled chunks of potato, you wash away excess starch as part of the cooking process. Braising, however, means the finished dish will contain all the starch.

Question 19

What is potato Rösti (Roesti)?

Answer 19

A Swiss dish consisting mainly of potatoes. It was originally a common breakfast eaten by farmers in the canton of Bern, but today is eaten all over Switzerland and also in many restaurants in the western world. Many Swiss people consider rösti a national dish.

Question 20

Is Roesti traditionally cooked in butter?

Answer 20

Yes

Question 21

Best way to prepare Roesti?

Answer 21

Shred, rinse and squeeze

Question 22

What will excess starch and moisture do to the center of a Roesti?

Answer 22

Cook up gummy in the middle; precooking potatoes helps control this problem.

Question 23

When make Roesti, washing away too much starch will cause potatoes to do what? How is this fixed?

Answer 23

Lose their cohesiveness and fall apart when sliced. Adding cornstarch helps bind, crisp and brown the potato cake.

Question 24

Lightly packing the shredded potatoes in Roesti does what?

Answer 24

Allows a place for steam to escape.

Question 25

Name two dishes that would require extra free starches.

Answer 25

Cheesy mashed potatoes or roasted potato slices with a great exterior browning.

Question 26

What is French aligot?

Answer 26

A dish traditionally made in L'Aubrac region in southern Massif Central of France made from melted cheese blended into mashed potatoes, often with some garlic.

Question 27

Why would Yukon Gold potatoes be a good fit for alight? Explain.

Answer 27

Russets have an enjoyable, earthy flavor for mashed potatoes but, with all the stirring, they can become far too gluey; Yukon Gold has just enough starch.

Question 28

Two things that causes potato starch granules to burst.

Answer 28

Rough handling and overcooking.

Question 29

Why would you add butter to potatoes before milk and cheese?

Answer 29

Coating of butter makes starch molecules more compatible with cheeses so they are more able to combine with proteins. If milk is added first, the starch become so wet it resists interaction with fatty cheese.

Question 30

Why add mozarella and Gruyère to alight?

Answer 30

Mozarella supplies stretch, Gruyère supplies nuttiness.

Question 31

Is cheese the lone component that gives aligot its super stretch? Explain.

Answer 31

Unlike starch from other plants, the molecules in potato starch contain a small number of negative electrical charges. When combined with cheese proteins, parts of which contain positive electrical charges, an electrical bond between the two is created; when curly amylose molecules bond with cheese proteins, the combination becomes very springy and stretchy.

Question 32

How long should you stir alight for the right consistency?

Answer 32

3 to 5 minutes.

Question 33

What draws potato starch and sugar to the surface?

Answer 33

A quick simmer.

Question 34

For browning, why are disks better than chunks?

Answer 34

Discs have more surface area to brown.

Question 35

How do potatoes rely on moisture for browning?

Answer 35

Moisture must be present for starch granules to swell and release amylose. In turn, amylose will break down into glucose which darkens when exposed to high heat.

Question 36

Is the oven alone effective enough to brown potatoes? Explain.

Answer 36

In the dry heat of an oven, caramelization is a lengthy process because starch granules swell slowly. Parboiled potatoes are swimming in the requisite moist heat, releasing a lot of amylose on the potatoes surface; transfer from one to the other, they'll brown immediately.

Question 37

How do you rough up potatoes before roasting? Why does this work?

Answer 37

Vigorously tossing them in oil and salt will riddle potatoes with tiny dips and mounds. This creates a more exposed surface area and escape routes for moisture--browning is even faster.

Question 38

Will preheating the baking sheet cook potatoes faster? Explain.

Answer 38

Yes, it allows a faster cooking time; greater moisture retention.

Question 39

Crisping and browning begins after what evaporates?

Answer 39

Surface moisture

Question 40

Does five square miles of Colorado's mountain region have more surface area than 5 square miles of the Kansas plains?

Answer 40

Yes, try walking them both.

Question 41

Why are Yukon Golds best for roasting?

Answer 41

Enough moisture so the interior is cream, enough starch so the exterior is crispy.

Question 42

When parboiling potatoes, what helps break down the exterior faster?

Answer 42

An alkaline environment with baking soda.

Question 43

Ratio of baking soda to water for parboiled potatoes.

Answer 43

10 cups water to 1/2 teaspoon baking soda.

Question 44

How does baking soda turn the outsides of potatoes to mush in 1 minute?

Answer 44

Alkaline baking soda triggers a chain reaction that literally unzips the backbone of pectin molecules, causing them to fall apart.

Question 45

How much alkali do you need?

Answer 45

Only enough to raise the pH of the water high enough to start a reaction., after which it becomes self-sustaining; 8.1 was the books number.

Question 46

How could you boil potatoes to keep their shape for a salad?

Answer 46

Add vinegar to drop the pH around 3.