Fermented soy refers to soybean products that have undergone a controlled culturing process using beneficial bacteria or fungi, resulting in functional foods like Tempeh and Natto. In the NZ market, these nutrient-dense staples are gaining popularity for their superior protein bioavailability, potent gut-health properties, and distinct savory profiles suitable for diverse culinary applications.
What is Tempeh? A Nutty Protein Source
Tempeh is often described as the sophisticated, texturally complex cousin of tofu. While tofu is made from curdled soy milk, tempeh is a whole soybean product. Originating from Indonesia, specifically the island of Java, it is created by a natural culturing and controlled fermentation process that binds soybeans into a cake form. The magic ingredient is a fungus called Rhizopus oligosporus, often referred to as a tempeh starter.
Unlike many meat alternatives found in New Zealand supermarkets that rely on heavy processing and isolates, tempeh retains the whole bean. This gives it a chunky texture and a firm bite, making it an ideal substitute for meat in stir-frys, sandwiches, and salads. The flavor profile is distinctively different from the bland canvas of tofu; tempeh possesses a strong, nutty, and earthy taste, often likened to mushrooms or yeast.
The Fermentation Transformation
The fermentation process is what sets tempeh apart in the realm of plant-based nutrition. During incubation, the white mold (mycelium) permeates the beans, creating a solid block. This process does more than just bind the beans; it predigests the protein, making it more accessible to the human body. For Kiwis looking to increase their protein intake without relying heavily on animal products, this increased bioavailability is a significant advantage.
Tempeh Varieties in the Market
While traditional tempeh is made strictly from soybeans, the artisanal food movement in New Zealand has led to the availability of various mixtures. You may encounter tempeh made with added grains like brown rice, barley, or millet, and even seeds like flax and sesame. These additions can alter the texture and nuttiness, offering a broader range of culinary experiments for the home cook.
The Health Benefits of Fermented Soy
The conversation around soy can sometimes be controversial, but fermented soy nz health experts generally agree that fermentation drastically improves the nutritional profile of the bean. Fermentation breaks down anti-nutrients, such as phytic acid, which can inhibit the absorption of minerals like zinc and iron. By reducing these anti-nutrients, fermented soy products allow your body to absorb more of the goodness contained within the bean.
Probiotics and Gut Health
One of the primary reasons health-conscious New Zealanders are turning to fermented soy is for gut health. While tempeh is often cooked (which can deactivate some live cultures), the fermentation process produces paraprobiotics and beneficial byproducts that support the microbiome. Natto, typically eaten raw, is a powerhouse of live probiotics, specifically Bacillus subtilis, which promotes a healthy digestive tract and immune system.
Cardiovascular and Bone Health
Fermented soy is rich in isoflavones, compounds that have been linked to reduced cholesterol levels and improved heart health. Furthermore, these foods are excellent sources of minerals. Tempeh is high in calcium and magnesium, essential for bone density. Natto takes this a step further; it is one of the highest plant sources of Vitamin K2 (specifically MK-7). Vitamin K2 is crucial for directing calcium into the bones and keeping it out of the arteries, a vital factor in preventing arterial calcification.
For a deeper dive into the nutritional science of soy isoflavones, authoritative resources like the Harvard T.H. Chan School of Public Health provide extensive research on the cardiovascular benefits associated with soy consumption.
Cooking with Tempeh in NZ
Integrating tempeh into a standard New Zealand diet is easier than it seems. Its versatility allows it to bridge the gap between traditional Kiwi cuisine and modern plant-based trends. However, many beginners make the mistake of cooking it straight from the package, which can result in a slightly bitter taste.
Preparation: The Steaming Secret
To ensure the best flavor, it is highly recommended to steam fresh tempeh cubes for 10 minutes before marinating or frying. This step opens up the pores of the dense cake, allowing it to absorb marinades more effectively, and removes the natural bitterness associated with the fermentation culture. Once steamed, tempeh acts as a sponge for flavors.
Marinating and Frying
Tempeh loves strong flavors. Marinades involving soy sauce (or tamari), ginger, garlic, maple syrup, and liquid smoke work exceptionally well. A popular preparation in NZ plant-based cafes is “Tempeh Bacon”—thinly sliced strips marinated in a smoky, salty glaze and pan-fried until crispy. This makes for an excellent addition to a BLT or a Caesar salad.
Incorporating into Kiwi Classics
Tempeh can be crumbled and used as a mince substitute in Shepherd’s Pie or Spaghetti Bolognese. Its firm texture holds up well in slow-cooked stews, making it suitable for winter meals. For a summer BBQ, skewered tempeh cubes alternated with capsicum, onion, and pineapple make for a delicious and sturdy vegetarian option that won’t fall through the grill.
Natto: The Brave Foodie’s Guide
If tempeh is the accessible entry point, Natto is the advanced level of the fermented soy world. A staple breakfast food in Japan, Natto consists of whole soybeans fermented with Bacillus subtilis var. natto. It is famous—or perhaps infamous—for its unique texture, pungent aroma, and acquired taste.
Understanding the Texture
Natto is characterized by its sticky, slimy consistency, known in Japanese as neba-neba. When stirred, the beans produce long, stringy filaments similar to melted cheese or okra. For the uninitiated NZ palate, this texture can be challenging. The aroma is often compared to strong aged cheese or old socks, yet the flavor is surprisingly savory, nutty, and rich in umami.
How to Eat Natto
Natto is rarely eaten alone. It is traditionally served over hot steamed rice and mixed with karashi mustard and a special soy-based tare sauce (usually included in the packet). To elevate the experience and mitigate the sliminess, many people add chopped spring onions, kimchi, raw egg yolk, or avocado. The heat of the rice helps to soften the beans and release the aroma.
The Nattokinase Enzyme
Beyond its probiotic content, Natto is the only source of nattokinase, a potent fibrinolytic enzyme. This enzyme has been studied for its ability to break down blood clots and improve blood flow, making Natto a functional food of significant interest for cardiovascular support. Because nattokinase is sensitive to high heat, Natto should not be cooked at high temperatures if you wish to preserve this specific enzymatic benefit.
Sourcing and Storage in New Zealand
Finding fermented soy nz products has become significantly easier in recent years. While major supermarkets like Countdown and New World stock tempeh in the chilled vegetarian section, Natto usually requires a trip to a specialized Asian grocer.
Where to Buy
- Tempeh: Available in most mainstream supermarkets and health food stores (like Huckleberry or Commonsense Organics). Look for local artisan brands that are popping up in farmers’ markets across Auckland and Wellington.
- Natto: Almost exclusively found in the freezer section of Japanese or Asian grocery stores (such as Japan Mart or Tai Ping). It is sold in small styrofoam stackable containers.
Storage Tips
Tempeh is a living product. If you buy it fresh or vacuum-sealed, it should be kept refrigerated and consumed by the use-by date. You may notice small black spots on the white mold; this is normal sporulation and is safe to eat. However, if it smells like ammonia or feels slimy (distinct from Natto’s natural slime), it has gone off. Natto is best kept frozen until you are ready to eat it. Thaw it in the refrigerator overnight before consuming to maintain the integrity of the bacteria.
Frequently Asked Questions
Is fermented soy better than regular soy?
Generally, yes. Fermentation reduces anti-nutrients like phytic acid, which blocks mineral absorption, and breaks down complex proteins, making them easier to digest. This process often mitigates digestive issues like bloating that some people experience with unfermented soy products.
Where can I buy Natto in New Zealand?
Natto is typically not found in mainstream supermarkets like Countdown. You will need to visit specialized Asian supermarkets, particularly Japanese grocery stores like Japan Mart, where it is located in the freezer section.
Does Tempeh taste like meat?
Tempeh has a savory, umami quality and a firm texture that mimics the “bite” of meat, but it does not taste exactly like meat on its own. It has a nutty, mushroom-like flavor. However, it absorbs marinades exceptionally well, allowing it to mimic the flavor profile of bacon or sausage when seasoned correctly.
Is fermented soy good for the thyroid?
Concerns about soy and thyroid health usually revolve around goitrogens. However, fermentation significantly reduces the goitrogenic activity in soy. Moderate consumption of fermented soy is generally considered safe for healthy individuals, though those with existing thyroid conditions should consult a healthcare professional.
How do you stop Natto from smelling?
The smell of Natto is intrinsic to the fermentation process. However, mixing it thoroughly with mustard and soy sauce can mask the aroma. Eating it with cold rice rather than hot rice can also reduce the volatility of the scent compounds.
Can you freeze Tempeh and Natto?
Yes. Natto is almost always sold frozen and should be kept that way until use. Tempeh also freezes very well. If you don’t plan to use your tempeh within a few days of purchase, freezing it will preserve its quality for several months without altering its texture significantly.