The Science of Pizza PDF

The After ten minutes, stir in th...

The After ten minutes, stir in the flour, salt, and oil, and beat Science everything together until it’s smooth. This allows another chemical change to take place. of Pizza When yeast ferments (shown by the foaming action), that is a chemical reaction. When two proteins in the flour get wet, they join together and form Your parents said you long strands of gluten, which make can invite two friends over the texture both strong and elastic. The for pizza and a movie. You gluten and bubbles work together to considered ordering a pizza create a crust that’s strong yet fluffy. Credit: © iStock.com/CasarsaGuru from the neighborhood Pizza Crust Recipe restaurant or adding toppings Ingredients to a ready-made pizza crust. 1 (.25 ounce) package active dry yeast But you decided it would be 1 teaspoon white sugar fun to make the crust, too. 1 cup warm water (110°F/45°C) You’ve probably given some thought to what kind of 2 1/2 cups bread flour pizza you’ll make and how much you’ll look forward to 2 tablespoon olive oil taking the first bite (and the second... and the third...). 1 teaspoon salt Making a pizza is fun, and it also involves some really cool Directions science. Let’s begin! 1. Preheat oven to 450 degrees F (230°C). In a medium bowl, Credits: Top: © iStock.com/simonidadjordjevic; bottom: The first three ingredients in the pizza crust recipe are dissolve yeast and sugar in warm water. Let stand until creamy, about 10 minutes. yeast, sugar, and warm water. Yeast is a tiny one-celled organism that gets energy from sugar. When sugar 2. Stir in flour, oil, and salt. Beat until smooth. Let rest for 5 minutes. © Xavier Gallego Morell/123RF combines with yeast and warm water, the yeast cells 3. Turn dough out onto a lightly floured surface and stretch or roll immediately start dividing and producing foam. The into a crust. Transfer crust to a lightly greased pizza pan. Spread with pizza sauce and desired toppings. Bake in preheated oven for foam is the result of the yeast breaking down the sugar 15 to 20 minutes or until golden brown. Let baked pizza cool for and creating carbon dioxide gas—a chemical change 5 minutes before serving. right before your eyes! © Learning A–Z All rights reserved. 1 www.readinga-z.com 2  Now it’s time to add toppings. For this recipe, you’ll Food Changes Caused by Temperature Credits: Left to right, top to bottom: © iStock.com/Sergio Delle Vedove; © iStock.cm/etienne voss; © Aleksandr Mogilevetc/123RF; © iStock.com/Magnascan; © Prachenko Iryna/Dreamstime.com; use store-bought pizza sauce. Spread some on the crust and then add toppings such as sliced mushrooms or PHYSICAL CHANGES red bell peppers. Slicing these foods causes physical, not Matter changes shape, but its chemical identity stays the same. chemical, changes. You know this because no gas, liquid, or solid has been created or broken down. Slicing them just changes their shape and size. Grating mozzarella cheese to sprinkle on your pizza is also a physical change. Now the pizza is ready for the oven. (Ask an adult to melting ice melting butter help you.) While the pizza bakes, several things happen. Heat causes the cheese to melt and makes the existing carbon dioxide bubbles in the crust larger—two physical changes. The pizza also gets golden brown, which creates wonderful smells and flavors. These are chemical changes known as Maillard (my-YARD) reactions. They’re caused melting cheese boiling water freezing Popsicles © iStock.com/bradleyhebdon; © 9george/Dreamstime.com; © Andrey Armyagov/Dreamstime.com when heat affects sugars and amino acids, the building blocks of proteins. Before you know it, the timer goes off. CHEMICAL CHANGES Your amazing pizza is ready to eat! A chemical reaction occurs and forms a new kind of matter. Word W ise Maillard reactions are chemical reactions that were first identified by a French chemist named Louis-Camille boiling eggs Maillard. In a 1912 scientific paper, he described how Credit: © iStock.com/styxclick sugars and amino acids change when exposed to heat. His observations were among the making Jell-O pepperoni getting crispy first scientific studies of food. This fruit pie turned a beautiful brown thanks to a Maillard reaction. © Learning A–Z All rights reserved. 3 www.readinga-z.com 4