Effect of different physical and chemical treatments on detoxification of ricin in castor cake

In spite of its high protein content, castor cake is not used as livestock feed due to the presence of toxic factors—ricin, ricinine and allergen. Of the three, ricin is the most detrimental to the animals. In order to detoxify the cake, a number of physical and chemical methods were employed. Soaking (3, 6 and 12 h), steaming (30 and 60 min), boiling (30 and 60 min), autoclaving (15 psi, 30 min; 15 psi, 60 min) and heating (100 °C 30 min; 120 °C 25 min) were the physical methods employed, while the chemical methods consisted of ammonia (7.5, 12.5 ml/kg of castor cake), formaldehyde (5, 10 g/kg), lime (10, 20 and 40 g/kg), sodium chloride (5, 10 and 20 g/kg), tannic acid (5, 10 g/kg) and sodium hydroxide (2.5, 5 and 10 g/kg). The efficacy of the treatments was assessed, based on the qualitative and quantitative changes in ricin content. Of all the methods employed, autoclaving (15 psi., 60 min) and lime treatment (40 g/kg) completely destroyed the toxin.