Most of the processed foods that we consume everyday are cocktails of chemicals. Defatted soy chunks and veggie patties are around for a while now catering to the protein needs of vegans. However recent studies shows that the defatted soy chunks and soy protein isolates are not 100% safe.
Lot of research is going on Soy protein as a supplement for body builders, because of the rising estrogen (female hormone) levels in the body, in addition to that the hexane residue in soy protein and defatted soy chunks are seen as a major health issue of the future. It is now proven that soy products may contain traces of the neurotoxin hexane. The FDA does not currently impose a ceiling on hexane residue in soy foods, but it does limit how much of the chemical can be left in fish protein isolate (5 parts per million), as well as in hop extract and spice resins (25 ppm). The study on soy protein shows that 21 ppm of hexane in generally found in soy meal—the defatted soy flakes that are used in products like energy bars and veggie burgers. Some other testing shows that concentration may be as high as 50 ppm. Though the hexane limits are precautionary, it is important to keep them under safe levels.
The reason for the presence of neurotoxin ‘Hexane’ in soy products is because of the Soy processors used to divide the beans into fat and protein. The beans are cracked, heated, and rolled into flakes, which are soaked in a hexane bath to extract the oil. Then the oil and defatted flakes are each steamed to evaporate the hexane. The crude soy oil is shipped to vegetable oil manufacturers—most vegetable oils are made from soy—to have the remaining proteins and free fatty acids removed. (Studies find 10 -20 ppm of hexane in vegetable oils.) The defatted soy flakes can be further processed and included in a wide variety of foods, veggie burgers included. Soy protein can also cause uneasiness in stomach.
The best way to consume soy is to opt for organic soy powder, and in case of soy oil, it is better to opt for expeller pressed oils. There are other good sources of protein like hemp and pea protein, which are healthier and safe.