Soy pulp or Okara is used as the basic ingredient for soy yarn. Okara is a white or yellowish pulp consisting of the insoluble parts of the soybean which remain after filtering mashed soybeans for the production of soy milk. Okara is hence a by-product of soy milk and tofu manufacturing. It is primarily used as feed for cattle and pork but as well as food in different Asian countries.
Unfortunately there is limited visibility around involved processed, chemicals and their related environmental impact, in the transformation of Okara into fibres ready for spinning.
Soybean fibres are
Soybean Protein Fibre comes from China and processes described above are thought to be chemical intensive. There is however a lack of transparency about the exact nature of the chemistry used in this process.