Effect of Heat Treatment and Fermentation on Anti-Nutrients Content of Lima Bean (Phaseolus lunatus) During Production of Daddawa Analogue.

ABSTRACT

Aim: To produce daddawa analogue (a fermented condiment) from Lima bean (Phaseolus lunatus) seeds which should have safe levels of anti-nutrients comparable to daddawa from locust bean (Parkia biglobosa) seeds. Design of the Study Lima bean and locust bean seeds were separately heat-processed and subjected to natural fermentation for 72 hours to produce daddawa analogue and daddawa respectively. Place and Duration of Study Department of Food Science and Technology and Central Science Laboratory, Obafemi Awolowo University, Ile-Ife, Nigeria between March 2010 and June 2011. Methodology: The pH, titratable acidity, and the anti-nutrients (tannin, phytate, cyanide, trypsin inhibitor) of the fermenting samples were evaluated every 12 hours during fermentation. Results: pH increased (P = .05) from 7.46 at 0 h to 8.50 after 72 h and from 7.50 at 0 h to 8.74 at 72 h of fermentation in lima bean and locust beans respectively. Titratable acidity decreased in the fermented lima beans from 0.216 at 0 h to 0.045 mg lactic acid/g at 72 h of fermentation. All anti-nutrients analyzed decreased with fermentation time. Tannin content decreased significantly (P = .05) from 19.0 ± 0.10 at 0 h to 2.0 ± 0.01mg/kg at 72 h and from 9.50 ± 0.02 at 0 h to 3.06 ± 0.01 mg/kg at 72 h of fermentation in lima beans and locust beans respectively. Fermentation significantly decreased phytate content (P = .05) from 22.0 ± 0.03 at 0 h to 7.0 ± 0.01mg/kg at 72 h in lima beans. Cyanide content decreased significantly (P = .05) from 0.97 ± 0.01 at 0 h to 0.25 ± 0.01mg/kg at 72 h and from 15.0 ± 0.05 at 0 h to 0.29 ± 0.10 mg/kg at 72 h of fermentation in lima beans and locust beans respectively. Trypsin inhibitor content also decreased significantly (P = .05) from 4.40 ± 0.10 at 0 h to 1.76 ± 0.02 mg/kg at 72 h and from 0.24 ± 0.0 at 0 h to 0.10 ± 0.1 TIU/g at 72 h of fermentation in lima beans and locust beans respectively. Conclusion: The study has shown that daddawa analogue from lima beans was comparable to daddawa from locust beans in terms of anti-nutritional contents.