Industrial production of processed meal from commercial soybeans involves cleaning and drying of soybeans that are subjected to cracking and aspiration to remove hulls from the seed meat
(cotyledons) which are subsequently broken into pieces. The seed meat is conditioned to 10–11% moisture at temperatures ranging from 71 to 79 C and flaked using smooth rolls to increase surface area for hexane extraction of soybean oil. The hexane is removed by steaming the soybean flakes which toasts the defatted meal to inactivate trypsin inhibitors and lectin antinutrients and also denatures other soy proteins (Hettiarachchy and Kalapathy, 1999). The seed meats can also be run through an expander/extruder to make collets (95–120 C) that increases surface area to improve the extraction efficiency for removing soybean oil. Extraction of soybean oil from the collets is accomplished with hexane (49–60 C for 30 min), repeated two more times for durations of 15–30 min each cycle. The oil is further processed and contains very little soybean protein. Oil spent collets are placed in mixer, steam injected to reach 105–114 C for 20–30 min to remove hexane (Berk, 1992). An example flow diagram for industrial scale soybean processing is presented in Fig. 2.