Abstract
Castor (Ricinus communis L.) oil is an important raw material for the chemical industry. The industrial process of castor oil extraction exposes the material to chemical, thermal, and mechanical treatments that influence the properties of the proteins in the meal. This study tested the hypothesis that the regular industrial process of castor oil extraction with solvent changes properties of the meal like the profile of proteins, the nematicide efficiency, and its toxicity. The changes made by the process of oil extraction create opportunities for adding value to this by-product. Samples of castor cake and meal were collected along the process of oil extraction under the regular operation of an industry. The samples were analyzed for chemical composition, hemagglutination activity, nematicide efficiency, and toxicity for feeding broilers and sheep. It was found that the step of solvent evaporation is responsible for the most relevant modifications in the meal, with significant changes in the protein profile, loss of hemagglutination capacity, and reduction of toxicity and nematicide efficiency. The castor meal produced just after the solvent evaporation has the toxicity reduced to a level that was tolerable to be used in the ration of small ruminants without detectable loss of performance or clinical signs of intoxication. The castor meal was toxic for broilers. The nematicide capacity of castor meal against larvae of Haemonchus contortus is reduced after the step of solvent extraction, but it is still significant and detected in doses as low as 5 mg/g. When castor meal was separated in fractions by sieving, the fine fraction (particles smaller than 0.5 mm) had high protein content (60.2%), low fiber content (6.0%), and high water holding capacity (164.2% of its dry weight).
•The industrial process of oil extraction affects properties of castor meal proteins.•The step of solvent evaporation reduces the nematicide efficiency of castor meal.•Sheep tolerated solvent-extracted castor meal without additional detoxification.•Sieved castor meal has high protein (60.2%) and low fiber (6%) content.•Castor meal and cake have nematicide activity against Haemonchus contortus.