Tempeh vs Natto: Which Fermented Soybean is Better for Fermenting?

Tempeh and natto are both traditional fermented soybean products with distinct textures and flavors; tempeh is firm and nutty, ideal for grilling or frying, while natto is sticky with a strong aroma often enjoyed with rice. Tempeh fermentation uses Rhizopus mold, producing a dense cake rich in protein and fiber, whereas natto employs Bacillus subtilis, resulting in a slimy texture and beneficial enzymes. Both offer probiotic benefits and enhance nutrient absorption, making them valuable additions to a plant-based diet focused on gut health.

Table of Comparison

Introduction to Fermented Soybeans: Tempeh and Natto

Tempeh and natto are traditional fermented soybean products with distinct textures and flavors, central to Indonesian and Japanese cuisines respectively. Both undergo microbial fermentation, enhancing nutrient availability and digestive benefits.

• Tempeh fermentation - utilizes Rhizopus mold to bind soybeans into a firm, cake-like form rich in protein and probiotics.
• Natto fermentation - employs Bacillus subtilis bacteria, producing a sticky texture and strong aroma with high nattokinase enzyme content.
• Health benefits - include improved digestion, increased vitamin K2 levels, and potential cardiovascular support from bioactive compounds.

Origins and Cultural Background

Fermentation Processes Compared

Tempeh and natto are both traditional fermented soybean products, but they utilize different microbial cultures and fermentation conditions. Tempeh fermentation involves Rhizopus mold under aerobic conditions, while natto relies on Bacillus subtilis in an anaerobic environment.

• Microbial Culture - Tempeh uses Rhizopus oligosporus mold, producing a firm cake structure, whereas natto uses Bacillus subtilis, which creates a sticky, stringy texture.
• Fermentation Environment - Tempeh ferments at around 30-37degC with ample oxygen, while natto ferments at roughly 40degC in low oxygen conditions.
• Fermentation Duration - Tempeh typically ferments 24-48 hours, whereas natto requires 18-24 hours for optimal flavor and texture development.

These differences in fermentation processes result in distinct flavors, textures, and nutritional profiles in tempeh and natto.

Key Ingredients and Starter Cultures

Tempeh and natto are both traditional fermented soybean foods with distinct starter cultures and preparation methods. Tempeh uses Rhizopus mold as its key fermenting agent, while natto relies on Bacillus subtilis bacteria for fermentation.

1. Key Ingredient - Both tempeh and natto use whole soybeans as the primary ingredient before fermentation.
2. Starter Culture for Tempeh - Tempeh fermentation is initiated by Rhizopus oligosporus mold spores that bind soybeans into a firm cake.
3. Starter Culture for Natto - Natto fermentation depends on Bacillus subtilis var. natto bacteria, which produce a sticky, stringy texture and pungent aroma.

Nutritional Profiles: Tempeh vs Natto

Tempeh offers a rich source of protein, dietary fiber, and manganese, with approximately 19 grams of protein and 10 grams of fiber per 100 grams serving. It also contains significant amounts of calcium, iron, and magnesium, supporting bone health and metabolic functions.

Natto is notable for its high vitamin K2 content, crucial for cardiovascular health and bone density, alongside 18 grams of protein and probiotics that enhance gut microbiota. It also provides nattokinase, an enzyme linked to improved blood circulation and reduced blood clot risk.

Health Benefits and Probiotic Content

Tempeh is rich in protein, vitamins B12 and K2, and contains beneficial antioxidants that support heart health and bone strength. Its dense probiotic content promotes a balanced gut microbiome by enhancing digestive enzymes and nutrient absorption.

Natto is exceptionally high in vitamin K2 and nattokinase, an enzyme linked to improved cardiovascular health and blood flow. The potent probiotics in natto, including Bacillus subtilis, assist in boosting immunity and reducing inflammation.

Taste, Texture, and Appearance Differences

Tempeh has a firm, cake-like texture with a nutty and earthy flavor, while natto is sticky and slimy with a strong, pungent aroma and a somewhat bitter taste. Tempeh appears as a dense white cake with visible soybean shapes, contrasting with natto's glossy, sticky, and brownish soybeans coated in a mucilaginous film. These differences in taste, texture, and appearance reflect their unique fermentation processes and microbial cultures.

Culinary Uses and Cooking Methods

How do culinary uses and cooking methods differ between tempeh and natto? Tempeh is commonly sliced and grilled, stir-fried, or baked, offering a firm texture ideal for savory dishes like sandwiches and salads. Natto, with its sticky texture and strong flavor, is typically eaten raw over rice or incorporated into soups and dressings, emphasizing fermentation's impact on taste and digestion.

Storage, Shelf Life, and Safety

Tempeh should be stored in the refrigerator at 1-4degC and typically has a shelf life of about 5 to 10 days when kept properly sealed. Natto, stored under similar refrigeration conditions, can last up to 2 weeks, benefiting from its natural antimicrobial properties due to Bacillus subtilis fermentation.

Both tempeh and natto must be handled with clean utensils to prevent contamination, and any off odors or discoloration indicate spoilage. Safe storage involves airtight containers to minimize exposure to oxygen and moisture, which accelerates degradation. Fermented soy products, when stored correctly, maintain beneficial probiotics that contribute to digestive health and food safety.

Related Important Terms

Mycelium Morphotypes

Tempeh fermentation involves Rhizopus mold forming dense, white mycelium morphotypes that bind soybeans into a firm cake, enhancing texture and nutritional content. In contrast, Natto fermentation utilizes Bacillus subtilis, producing slimy, stringy mycelium-like structures that impart a sticky texture and strong aroma distinctive to its fermented soybeans.

Bacillus-Spore Tempeh

Bacillus-spore tempeh utilizes Bacillus subtilis spores to ferment soybeans, resulting in a firm texture and nutty flavor distinct from natto, which relies on Bacillus natto and produces a sticky, stringy consistency with a strong aroma. The fermentation process in Bacillus-spore tempeh enhances digestibility and increases protein bioavailability compared to traditional natto fermentation.

Polyglutamic Acid (γ-PGA) Synthesis

Tempeh fermentation primarily involves Rhizopus molds, which produce limited polyglutamic acid (g-PGA), while natto fermentation, driven by Bacillus subtilis, results in high g-PGA synthesis, contributing to its distinctive sticky texture and enhanced health benefits. The elevated g-PGA content in natto improves bioavailability of minerals like calcium and promotes probiotic activity, distinguishing it from tempeh in terms of nutritional and functional properties.

Funky Umami Profile

Tempeh offers a nutty, earthy umami profile with subtle savory depth due to Rhizopus mold fermentation, while Natto provides a stronger, pungent funk characterized by Bacillus subtilis activity, resulting in a sticky texture and intense aroma. Both fermented soybeans deliver distinct umami experiences enhanced by their unique microbial flora and fermentation processes.

Dehulling Pre-inoculation

Dehulling soybeans prior to inoculation enhances fermentation efficiency in both tempeh and natto production by improving microbial access to the cotyledon, accelerating enzyme activity and nutrient conversion. In tempeh, dehulling facilitates Rhizopus oligosporus penetration, while in natto, removal of hulls promotes Bacillus subtilis natto proliferation, resulting in distinct texture and flavor profiles.

Sense-Active Volatiles

Tempeh and natto both produce distinct sense-active volatiles during fermentation, with tempeh generating a mild, nutty aroma dominated by phenols and alcohols, while natto emits stronger, pungent compounds like ammonia and pyrazines that contribute to its characteristic earthy and cheesy scent. The enzymatic activity of Rhizopus oligosporus in tempeh versus Bacillus subtilis in natto results in differing volatile profiles that significantly influence their sensory perception and flavor complexity.

Glycine Betaine Accumulation

Tempeh and natto, both traditional fermented soybean products, differ significantly in their glycine betaine accumulation, with natto exhibiting higher levels due to Bacillus subtilis fermentation, enhancing its osmoprotective properties. This glycine betaine concentration contributes to natto's unique texture and potential health benefits related to cellular hydration and stress resistance.

Probiotic-Enhanced Natto

Probiotic-enhanced Natto contains Bacillus subtilis, a potent probiotic that supports gut health and boosts immune function more effectively than tempeh, which primarily relies on Rhizopus mold fermentation. The nattokinase enzyme found in Natto further aids cardiovascular health by reducing blood clot risks, offering unique benefits absent in tempeh.

Tsukemono-Style Tempeh

Tsukemono-style tempeh offers a unique take on traditional fermented soybeans by combining the dense, nutty flavor of tempeh with the tangy crispness of Japanese pickles, or tsukemono, enhancing its probiotic benefits. Unlike natto, which is characterized by its strong aroma and sticky texture due to Bacillus subtilis fermentation, tsukemono-style tempeh uses Rhizopus mold, resulting in a milder taste and firmer texture preferred in various culinary applications.

Tempeh vs Natto for fermented soybeans Infographic