EFFECT OF BOILING AND SOAKING DURATIONS ON THE PROXIMATE COMPOSITION, RICIN AND MINERAL CONTENTS OF UNDECORTICATED CASTOR OIL SEEDS (RICINUS COMMUNIS)
|Nsa, E. E1, Ukachukwu, S. N2, Isika, M. A1 and Ozung, P.O1
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Boiling and soaking methods for different time durations were employed in processing castor oil seeds (Ricinus communis) to improve its nutritive value. These processing methods were boiling for 0, 10, 20 and 30 minutes, where part of the samples from each lot were further soaked for 0, 24, 48, 72 and 96 hours before sun drying for four days, the beans were then milled, and a representative sample of the milled (castor oil seeds) from each of the processing methods along with a raw sample of the beans were taken to the laboratory for ricin, minerals and proximate analysis according to A.O.A.C. (1995). There were statistically evaluated using a 4x5 factorial format in a completely randomized design. Results indicated that boiling and soaking the castor oil seeds for different time durations affected the proximate composition, mineral and ricin component of the test ingredient. Boiling the seeds for more than 10 minutes resulted in significant (P<0.05) decrease in crude protein, ether extract and ricin content of the seeds, but with overall improvement in the Nitrogen Free Extract (NFE) of the test ingredient. Soaking the seeds for different time durations brought about decrease in the crude protein content, but became only significant at 72 and 96hours of soaking. NFE also showed significant improvement at 72 and 96 hours of soaking the seeds. Among the minerals only calcium and magnesium were affected by boiling durations, with a significant (P<0.05) decrease at 30 minutes of boiling. The interaction effect showed significant (P<0.05) decrease of crude protein content in 10 minutes boiled seeds that were soaked for 48 hours. 30 minutes boiled seeds that were soaked for 48 hours showed a significant (P<0.05) decrease in crude fibre content. Ether extract decreasing effect was significant (P<0.05) with seeds boiled for 10 minutes and soaked for 48 hours. Ash decreasing effect was significant (P<0.05) with 30 minutes boiled and 48. 72 and 96 hours soaked seeds. NFE improved significantly (P<0.05) from 20 minutes boiled, followed by 72 hours soaked seeds. Calcium and Magnesium component of the seeds values depressed significantly (P<0.05) with seeds that were subjected to 30 minutes boiling followed by 48, 72 and 96 hours of soaking. The ricin content of the seeds significantly(P<0.05) reduced with seeds boiled for 10 minutes followed by 0, 24, 48, 72 and 96 hours, and continued to reduce as boiling and soaking duration increased, with seeds that were boiled for 30 minutes and soaked for 96 hours having no ricin content. With appreciable level of crude protein (22.08%) and Nitrogen free extract (51.07%) and highest percentage reduction in ricin-the most potent toxin in castor oil seed, the seeds boiled for 30 minutes followed by soaking for 96 hours are therefore recommended as a treatment method for castor oil seed, as feedstuff in livestock feed.