Tofu | Science in the City | Exploratorium

Summary

Tofu, a staple for nearly 5,000 years originating from China, is made from high-protein soybeans sourced from organic farmers in the U.S. The tofu-making process involves six steps: soaking and grinding soybeans into a slurry, cooking the slurry to break down proteins, separating the okara (bean pulp) from the soymilk, adding calcium sulfate as a coagulant to form curds, pressing the curds into firmer tofu, and finally packaging it. Additionally, Yuba, known as tofu's 'sexier cousin,' is created by simmering soymilk to form a flexible, chewy protein. The focus is on maintaining traditional flavors and quality.

Takeaways

• 🌱 Tofu has a rich history, originating from China nearly 5,000 years ago.
• 🌾 It is made from soybeans, which are a widely consumed type of bean.
• 🔍 High-protein soybeans are sourced from organic farmers in the U.S.
• 💧 The first step in tofu production involves soaking dry soybeans overnight to rehydrate them.
• 🔥 Cooking the soaked soybeans is crucial, as raw soybeans are indigestible.
• 🧀 Tofu production is similar to cheese-making, using a coagulant to form curds from soy milk.
• 🧪 Calcium sulfate is used as a coagulant to bind protein in the soymilk, forming curds.
• 📦 The curds are pressed into molds to create a firmer tofu product.
• ✨ Okara, the byproduct of tofu-making, is utilized and sold to dairy farms.
• 👗 Yuba, often referred to as the 'sexier cousin' of tofu, is made from the cream of soy milk.

Q & A

What is the origin of tofu?

Tofu has been around for nearly 5,000 years and was discovered in China.

What are the main ingredients used to make tofu?

The primary ingredient in tofu is soybeans, which are a type of bean rich in protein.

How many steps are involved in the tofu-making process?

The tofu-making process involves six main steps.

What is the significance of sourcing high-protein soybeans?

High-protein soybeans are crucial because they ensure the nutritional quality of the final tofu product.

Why is it necessary to soak the soybeans before grinding?

Soaking the soybeans overnight rehydrates them, making them soft and easier to grind into a slurry.

What happens to the soybeans during the cooking process?

Cooking the soybeans breaks down proteins, allowing for better digestion and absorption by the body.

What is Okara, and what is done with it after tofu production?

Okara is the solid by-product of soy milk production. It is a food-grade product that is sold to dairy farms for use in various applications.

How does the process of making tofu compare to cheese-making?

Both processes involve coagulating a protein-rich liquid. In cheese-making, bacteria is added, while tofu-making uses a mineral coagulant like calcium sulfate.

What is the role of pressing in the tofu-making process?

Pressing removes excess moisture from the curds, resulting in a firmer texture for the tofu.

What is Yuba, and how is it related to tofu?

Yuba, also known as tofu skin, is a flexible, chewy form of protein made by simmering soymilk to create a protein skin on the surface.

What commitment does Hodo have regarding tofu production?

Hodo emphasizes maintaining the quality and traditional methods of tofu-making, ensuring that the final product preserves authentic flavors.