Tag: foams

  • Making Yeast-Free Pizza

    Making Yeast-Free Pizza

    Yeast is a key ingredient in many pizza doughs; as the yeast ferment sugars in the dough, they produce carbon dioxide which bubbles into the dough, creating the light and airy texture necessary for a good crust. It’s a slow process, though, often requiring several hours for the dough to rise. Recently, researchers studied an alternative pizza-making method that generates bubbles in the dough via pressurization — with no yeast required.

    The new technique is similar to the process used to carbonate sodas. The team mixed flour, water, and salt and placed the dough in an autoclave, which allowed them to control both temperature and pressure during baking. They dissolved gas into the dough at high pressure and then carefully released the pressure during baking, allowing the bubbles to grow. They used rheological measurements to compare the characteristics of yeasted and yeast-free doughs at various stages in the leavening and baking processes.

    Now that they have the methodology down, they’ve purchased a food-grade autoclave and are looking forward to taste testing their yeast-free creations — none more so than their team member who has a yeast allergy! Since the pressures required for their method are quite mild, they hope it’s a technique that restaurants will take on. (Image credit: B. Huff; research credit: P. Avallone et al.)

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    What Keeps a Foam Intact

    Beer, soda, soap, meringue – foams are everywhere in our lives. But have you ever wondered why some foams disappear so quickly while whipped egg whites stick around? That’s the subject of this Gastrofisica video, which is in Spanish but has English captions.

    Foams form when air gets introduced into a liquid, but for those bubbles to stick around, they need a certain special something. With soapy water, that ingredient is surfactants, molecules with both hydrophobic (water-fearing) and hydrophilic (water-loving) ends, which line up at the interface of the foam and help hold it together. But surfactants are relatively weak, especially compared to to the albumin proteins in an egg white. By whipping egg whites, you’re effectively untangling those proteins, and, like surfactants, they line up at the interface of the foam so that their hydrophobic and hydrophilic parts can hang out in their preferred mediums. With so many similar molecules crowded together, the proteins coagulate, adding extra strength and stiffness to your whipped egg whites. (Video and image credit: Tippe Top Physics; h/t to MinutePhysics)

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    Fluids Round-Up

    Time for another fluids round-up! Here are some of the best fluids-related links I’ve seen around:

    – Above The Brain Scoop tells us about beetles that spend their whole lives underwater. They carry a little bubble of air with them in order to breathe!

    – Microfluidics are helping reveal how cancer cells metastasize and spread through the bloodstream.

    – It’s official! NASA’s going to build X-planes again.

    – See how snake venom kills by changing the fluid properties of a victim’s blood. (via Gizmodo)

    Metallic foams can stop bullets and radiation, spawning many potential future uses here on Earth or in space.

    Why nature prefers hexagons, especially in honeycomb, bubbles, and foam.

    – Earth has beautiful auroras, but if you could look at Jupiter with x-ray vision, you’d see something even more spectacular – a non-stop aurora that brightens on a regular schedule.

    SciShow asks where the water goes in Minnesota’s Devil’s Kettle Falls. Conservation of mass says it has to go somewhere!

    And, in case you missed it, you can check out the latest FYFD video and learn more about the Brazil Nut effect over at Gizmodo.

    (Video credit: The Brain Scoop)