Shelf life and acceptability of steamed bambara groundnut (<i>Voandzeia subterranea</i>) pudding spiced with garlic, ginger and nutmeg

Abstract

Background: The increasing demand for foods with long shelf-life, devoid of chemical preservatives has led to increased pressure on food industries to adopt natural alternatives to achieve its goals concerning microbial safety.

Objective: The study assessed the shelf life and acceptability of steamed bambara groundnut (Voandzeia subterranea) pudding spiced with garlic, ginger and nutmeg.

Methods: Bambara groundnut pudding was prepared with bambara ground flour, red oil, iodized salt, ground red pepper and spices (garlic, ginger, nutmeg) as well as mixture of the spices at varying concentrations (1,2, 3g) per 150ml, mixed with the slurry and wrapped in polythene bags. The samples containing no spices, served as controls. All the samples were steamed at 100ᵒC for 32 minutes (using kerosene stove), allowed to cool and then stored for 3 days at ambient temperature (25-27ᵒC). The samples were subjected to microbial analysis - total plate count, bacteria and fungi culture. Biochemical tests were conducted to characterize bacteria species observed and slide culture technique was applied to identify and characterize fungi present, Sensory evaluation was done on the freshly prepared bambara groundnut pudding for appearance, texture, taste and aroma.

Results: Storage stability tests revealed that all the samples at varying concentrations had lower counts of mesophilic bacteria and fungi which were significantly (p < 0.05) lower than the control, with samples containing 3g garlic/ginger mix having no bacteria and fungi growth after 72 hours of storage. The controls were the most accepted for appearance and texture, while the sample with 2g ginger was most accepted for taste and aroma.

Conclusion: The use of garlic, ginger and nutmeg was desirable not only for the flavouring attributes, but also for the ability to enhance shelf-life of the steamed bambara groundnut pudding.

Keywords: Bambara groundnut, garlic, ginger, nutmeg, shelf life