Abstract

Indigenous fermentation of Parkia biglobosa seeds rely on back slopping, so there is no control of organisms that ferment the seeds or a definite standardization of innocula during the fermentation. This study is aimed at evaluating the physiochemical, microbiological, nutritional and sensory acceptability of fermented Parkia biglobosa seeds (daddawa) using different densities of Bacillus subtilis. Isolation of B. subtilis was carried out using MYP agar and the identification was done using biochemical and molecular techniques. During the process of fermentation, the Parkia biglobosa seeds (daddawa) were assessed for pH, titrable acidity, temperature, aerobic mesophilic bacterial count, proximate composition and sensory evaluation using standard procedures. Results show that highest increase was observed in pH (6.3±0.01 to 7.41±0.01) and a corresponding highest decrease in titrable acidity was observed (0.05±0.00 to 0.01±0.00) in Parkia seeds innoculated with 6.0×108 CFU/ml during the fermentation. An increase in temperature (24 to 30oC), aerobic mesophilic bacterial count (6.01±0.01 to 6.78±0.51) in uninnoculated Parkia seeds was also observed at 72h of fermentation. There was highest increase in protein content from 39.79±0.01 at 0hr to 47.73±0.00 in Parkia seeds innoculated with 3.0×108 CFU/ml at 72h of fermentation, but the content was not statistically different when compared with the other treatments. Highest decrease was observed in carbohydrate from 23.73±0.00 at 0hr to 17.70±0.00 in Parkia seeds innoculated with 6.0×108 CFU/ml at 72h of fermentation. Sensory evaluation showed that the judges preferred fermented Parkia biglobosa seeds treated with 1.5×108 CFU/ml of innoculum and control with a percentage likeness of 100% compared to the other treatments (3.0×108 CFU/ml, and 6.0×108 CFU/ml) with a percentage likeness of 40% and 0% respectively after 72h of fermentation. Statistically, there was no significant difference (p˃0.05) between the different treatments in terms of protein contents. However, there is a general lower nutritional content observed in the uninnoculated Parkia seeds. Better texture, color and odor were also observed in the Parkia seeds innoculated with starter cultures as compared to the uninnoculated Parkia seeds. Conclusively, it was observed that the use of starter culture in higher density does not necessarily increase its nutritional value but rather, speed up the fermentation process.

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