The Ancient Origins of Soya Processing
The history of soya processing is deeply intertwined with East Asian culinary traditions. Long before modern machinery, ancient civilizations in China, and later Japan and Korea, developed ingenious methods to make the nutrient-dense soybean digestible and palatable. The earliest processes were centered on fermentation, which not only extended the shelf-life of the beans but also broke down anti-nutritional factors and enhanced their flavor.
Fermentation: The Original Processing Method
Fermentation was a critical step in early soya production. By fermenting the beans, ancient food producers created a diverse range of products that became staples in Asian cuisine. This traditional method, which often takes months, relies on controlled environments to produce complex flavors and aromas. Key examples include:
- Soy Sauce (Shoyu/Jiangyou): The process begins with steaming cooked soybeans and roasted wheat, then combining them with a specific mold culture, Aspergillus oryzae (koji). This mixture is then added to salt water (moromi) and allowed to ferment for several months, sometimes up to a year.
- Miso: This fermented paste is made by inoculating soybeans with koji, along with salt, and allowing the mixture to ferment. Miso is used as a base for soup, marinades, and glazes.
- Tempeh: Originating in Indonesia, tempeh is created by fermenting whole, cooked soybeans with a mold culture, Rhizopus oligosporus, which binds the beans into a firm, edible cake.
Making Soy Milk and Tofu
Parallel to fermentation, methods for creating non-fermented products also emerged, notably soy milk and tofu. Legend attributes the invention of tofu to Prince Liu An of the Han Dynasty around 164 BCE. The process was analogous to dairy cheese production, involving the extraction and coagulation of soy milk.
Here’s a look at the traditional process for making tofu:
- Soaking: Dried soybeans are soaked in water, often overnight, to rehydrate and soften them.
- Grinding: The soaked beans are ground into a slurry with added water.
- Boiling: The slurry is boiled to neutralize anti-nutritional factors and to cook the beans.
- Filtering: The boiled mixture is strained through a cloth (like cheesecloth) to separate the soy milk from the fibrous pulp, known as okara.
- Coagulation: A coagulant, such as calcium sulfate (gypsum) or nigari (magnesium chloride) is added to the hot soy milk, causing it to curdle.
- Pressing: The curds are pressed into a mold, releasing excess liquid (whey) and forming a solid block of tofu. The firmness is determined by how much liquid is pressed out.
Modern Industrial Soya Processing
In the 20th century, particularly in the West, industrial processes revolutionized how soya is made, shifting the focus towards high-volume oil and meal production, as well as refining techniques for products like soy milk and meat alternatives.
Industrial Extraction of Oil and Meal
The majority of modern soya production is used to create oil and defatted meal. The process looks very different from traditional methods:
- Cleaning: Raw soybeans are cleaned to remove debris and then cracked and dehulled.
- Flaking: The dehulled beans are conditioned with heat and rolled into thin flakes to increase surface area.
- Oil Extraction: The oil is extracted from the flakes using a solvent wash, typically hexane, in a process that is highly efficient for mass production.
- Refining: The crude oil is then refined, bleached, and deodorized to create a clear, odorless oil.
- Meal Production: The defatted flakes are dried, toasted, and ground into soybean meal, a high-protein ingredient for animal feed and various food products.
Comparison of Soya Processing Methods
| Feature | Traditional Fermentation | Modern Oil & Meal Extraction |
|---|---|---|
| Primary Goal | Create flavorful, digestible food staples | Maximize oil yield and produce meal |
| Key Products | Soy sauce, miso, tempeh | Soybean oil, defatted soybean meal |
| Process Duration | Months to years | Hours to days |
| Key Ingredients | Soybeans, koji mold, salt | Soybeans, hexane solvent (industrial) |
| Flavor Profile | Complex, umami-rich | Bland, neutral (refined) |
| Nutritional Impact | Enhanced digestibility, probiotic qualities | High protein concentration in meal |
Modern Innovations in Soya-Based Foods
Modern technology has expanded the range of soya products far beyond traditional items. This includes refining soy protein to create highly concentrated forms and developing new textures.
Textured Vegetable Protein (TVP)
TVP is a popular meat substitute created from defatted soy flour. The process involves extrusion, where the soy flour is mixed with water, heated under pressure, and forced through a die. This texturizes the protein, giving it a fibrous, meat-like consistency. The extruded product is then dried, ready to be rehydrated and used in dishes.
Refined Soy Milk
While traditional soy milk can have a 'beany' flavor, modern processing techniques address this to appeal to Western palates. Many manufacturers use a 'hot grind' method or blanch the beans to deactivate the lipoxygenase enzyme, which is responsible for the off-flavor. This results in a cleaner, more neutral taste preferred by many consumers, and has facilitated its widespread adoption as a dairy alternative.
Conclusion
The journey of soya, from an ancient fermented food in East Asia to a modern industrial commodity, is a testament to human ingenuity. The answer to how did they make soya is not a single process, but a rich tapestry of traditional craftsmanship and scientific innovation. Whether fermented, coagulated, or extruded, the versatile soybean has been transformed over millennia into a cornerstone of global food production. Today, modern techniques focus on efficiency and flavor refinement, continuing to expand the role of this remarkable legume in diets worldwide. The story of soya is an ongoing narrative of adaptation, driven by both ancient wisdom and modern scientific understanding.
The Versatility and Processing of Soya
- Ancient Domestication: Soya was first domesticated in north-central China between 6,000–9,000 years ago.
- Fermentation as a Staple: The earliest recorded processing involved fermentation, resulting in products like soy sauce, miso, and fermented black beans.
- Tofu's Origins: The creation of tofu dates back to ancient China, involving the coagulation and pressing of soy milk.
- Modern Industrial Scale: The majority of modern soya production focuses on extracting oil using solvents, leaving behind a high-protein meal.
- Texturized Protein: Defatted soy flour is extruded under high pressure and heat to create textured vegetable protein (TVP) for meat alternatives.
- Global Commodity: Brazil and the United States now lead the world in modern soya production, with most of the crop used for animal feed.
- Flavor Refinement: Modern soy milk production often employs heat treatments to reduce the 'beany' flavor, making it more palatable for a wider audience.
- Multiple Applications: Beyond food, processed soy is used in industrial applications such as biofuels, adhesives, and paints.
FAQs
Q: How was soya originally made in ancient China? A: In ancient China, soya was primarily made through fermentation to create products like soy sauce, miso, and fermented bean paste, which improved digestibility and flavor.
Q: How do they make tofu? A: Tofu is made by first creating soy milk through soaking, grinding, and boiling soybeans. A coagulant like calcium sulfate or nigari is then added to curdle the milk, and the resulting curds are pressed into solid blocks.
Q: Is the modern process for making soya different from the traditional method? A: Yes, modern industrial processes focus on maximizing oil extraction using solvents, which creates defatted soy meal as a byproduct. Traditional methods centered on fermentation or coagulation for whole-bean food products.
Q: What is textured vegetable protein (TVP) made of? A: Textured vegetable protein is made from defatted soy flour, which is a byproduct of oil extraction. The flour is processed through a high-temperature, high-pressure extrusion process to create a meat-like texture.
Q: Why does some soy milk taste different than others? A: The difference in taste is often due to processing. Traditional methods can result in a more pronounced 'beany' flavor, while modern techniques often use heat to deactivate enzymes and create a more neutral-tasting product.
Q: What is the main use of soya today? A: The majority of today's soya production is used to create defatted soy meal for animal feed, with the extracted oil being used for cooking and industrial applications.
Q: Can soya be made at home? A: Yes, products like soy milk and tofu can be made at home with simple equipment. The process involves soaking, blending, boiling, and straining soybeans.
