Softening effect of Ikpiru and Yanyanku, two traditional additives used for the fermentation of African Locust Bean (<em>Parkia biglobosa</em>) seeds in Benin

Abstract

Ikpiru and Yanyanku are two additives used for the traditional alkaline fermentation of African locust bean (Parkia biglobosa. Benth) to produce food condiments in Benin. In this study, African locust beans (Parkia biglobosa. Benth) were fermented with or without Ikpiru and Yanyanku to assess the factors explaining the softening role of these additives during the fermentation process. Changes in microbial population, chemical components and texture parameters of the fermented cotyledons were determined during the fermentation process. Bacillus spp. predominated during the fermentation, with an upward trend. The use of Yanyanku or Ikpiru seems to increase Bacillus count during the earlier stage (between 0 and 18 hours) of fermentation, since the variations were 35% and 43% (growth rate of 0.13 and 0.16 Log10 h^-1) for trial with Yanyanku and Ikpiru respectively, versus 6% (0.02 Log10 h^-1) for the control. Despite this initial gap, the final count (after 48 h) did not show any significant difference between the control and samples with additives. Compressing forces were significantly lower between 12 to 24 h for cotyledons fermented with additives than for the control, suggesting a rapid disintegration, i.e., the softening effect of Yanyanku and Ikpiru during the fermentation of African locust bean seeds. No significant difference (p > 0.05) was observed between proximate composition of the samples fermented without additives and those fermented with additives.

Keywords: Fermentation, Bacillus, softening effect, softening