From Soybean to Chunk: Inside Our Steam-Extrusion Process

What Are Soya Chunks?

Soya chunks - also called textured vegetable protein or TVP - are made from defatted soy flour through a process called steam extrusion. They contain 52g of protein per 100g, making them one of the most protein-dense plant foods available. Popular in Indian cooking as a meat substitute, they are affordable, shelf-stable for 12 months, and absorb flavors from marinades and curries exceptionally well. Unlike tofu or tempeh, soya chunks have a fibrous, meat-like texture that holds up during cooking and provides a satisfying bite. They are naturally cholesterol-free, low in fat (0.5g per 100g), and contain all nine essential amino acids, earning a perfect PDCAAS score of 1.0. For vegetarians, athletes, and anyone looking to increase protein intake without relying on animal products, soya chunks offer an economical and nutritious solution.

The Steam Extrusion Process: Step by Step

1. Sourcing non-GMO soybeans from verified farms in Madhya Pradesh - We work exclusively with farmers who provide traceability documentation and adhere to sustainable farming practices. Each incoming lot is sampled and tested for protein content (minimum 36%), moisture levels, and purity. Approximately 15% of incoming lots are rejected if they fail to meet our standards.
2. Cleaning and removing stones and impurities - Soybeans pass through mechanical sieves and air separators that remove dirt, stones, broken beans, and foreign matter. This step ensures only clean, whole soybeans enter the processing line, preventing equipment damage and ensuring product safety.
3. Dehulling to separate the protein-rich inner kernel - The outer hull (rich in fiber but low in protein) is mechanically removed, leaving the protein-dense cotyledon. Dehulling increases the protein concentration from 36% in whole soybeans to approximately 50% in defatted soy flour.
4. Grinding into fine defatted soy flour - The dehulled beans are ground into a fine flour with uniform particle size. The term "defatted" refers to the low oil content - most of the natural soybean oil has been removed through pressing or extraction, concentrating the protein and extending shelf life.
5. Mixing with precisely measured water to form dough - The flour is combined with water in exact ratios to achieve optimal moisture content for extrusion. Too much water results in a mushy texture, while too little prevents proper fiber formation. This dough consistency is critical for the next stage.
6. Feeding into twin-screw extruder where steam, pressure, and mechanical shearing restructure protein fibers - Inside the extruder, the dough experiences temperatures of 130-160°C, pressures of 50-100 bar, and intense mechanical shearing from the twin screws. This combination denatures and realigns soy proteins into fibrous structures that mimic meat texture. The process uses steam as the heat source, not direct flame, which provides more even temperature distribution.
7. Cutting and drying in controlled environment to optimal moisture for shelf stability - As the extruded protein exits the die, it expands and is cut into chunks. These are then dried in temperature-controlled chambers to reduce moisture content to 8-10%, which prevents microbial growth and ensures a shelf life of 12 months when stored properly.
8. Final quality testing: protein content, texture analysis, microbiological safety - Every batch undergoes lab testing using the Kjeldahl method for protein content (minimum 52g per 100g), sensory evaluation for texture and chew, and microbiological plate counts to ensure zero pathogens. Only batches meeting all specifications are approved for packaging.

Why Steam Extrusion, Not Chemical Processing?

Steam extrusion is a purely physical process that uses only heat from steam, pressure, and water - no chemical solvents, no artificial binders, and no synthetic additives. Many cheaper soya products rely on chemical texturization involving alkali treatment or chemical cross-linking, which can leave residues and alter the nutritional profile. Our steam-extrusion method operates within a narrow temperature band (130-160°C) that restructures soy proteins through mechanical shearing and thermal denaturation without destroying amino acids. This is why our soya chunks retain a PDCAAS score of 1.0, indicating complete protein with all essential amino acids intact. The process is also more sustainable - it uses significantly less water than traditional soy processing and generates no chemical waste. What you get is a clean-label product with one ingredient: defatted soy flour.

Quality Standards: How We Test Every Batch

Nutritional Comparison: Soya Chunks vs Raw Soybeans

Frequently Asked Questions