Effect of heat and alkaline hydrolysis on the amino acid profile of <i>Jatropha curcas</i> seed cake

Abstract

In recent times, Jatropha curcas has attracted attention of various research
organizations, governments, public and international developmental  agencies and industries in the tropics and subtropics due to its adaptability to semi-arid marginal sites, the possibility of using its oil as a diesel fuel substitute and its role in erosion control. In tropical countries it is well known for its medicinal properties and as an oilseed. The seeds of J. curcas are a good source of oil, yielding between 40 – 80 % oil. Although the seed cake meal is rich in protein, it is toxic to rats, mice, ruminants and humans due to the presence of antinutritional factors; thus, its use as food or feed
source has not been encouraging. However, recent findings indicate that after a proper detoxification process the seed meal can serve as a protein substitute in feed meals of animal feeds. The seeds of J. curcas were collected, dehulled, grounded and defatted to obtain the seed cake. The seed cake was divided into five portions, 60 g of each of the cake portion was separately moistened with 1 M, 2 M, 3 M, 4 M and 5 M NaOH solutions, respectively and autoclaved. Each of the autoclaved samples was washed
with water and later with ethanol. A 60 g of the seed cake which was not treated with NaOH, water and ethanol was labeled untreated. The treated and untreated seed cakes were thus analyzed for their crude protein contents as well as amino acid profile. The untreated seed cake afforded 63.02 % yield of crude protein, while the crude protein content of the treated seed cake was 70.53, 71.46, 67.76, 60.82 and 56.19 % for the 1
– 5 M NaOH treated seed cake, respectively with the 2 M NaOH treated seed cake having the highest yield. The amino acid profile of the treated seed cake was similar and comparable to the values of WHO/FAO standard and those of soybeans. The seed can thus be used as an alternative  protein source in animal feed formulation after it has been properly  detoxified. If well processed, it would reduce competition between man and livestock for the conventional sources of proteins.

Key words: Amino acid, Jatropha curcas, protein detoxification