Shelf stability of agidi produced from maize (Zea mays) and the effects of sodium benzoate treatment in combination with low temperature storage

Abstract

The shelf stability of agidi produced from maize (Zea mays) during ambient temperature (30.0±1.5°C) storage and the effects of sodium benzoate treatment in combination with low temperature storage (12-14°C) was evaluated for eight weeks. Results indicates high total aerobic bacterial count (1.05x1010 cfu/g) and fungi count 4.6x109 cfu/g) at the 12th day of storage and thereafter, decrease gradually till the end of the storage period. Treatment with 0.15% sodium benzoate and refrigeration at 12-14°C drastically retarded microbial growth up till the 21st and 28th day of storage. Seven bacteria genera (Bacillus, Staphylococcus, Streptococcus, Lactobacillus, Leuconostoc, Pseudomonas and Alcalegene) and seven fungi genera (Aspergillus, Penicillium, Alternaria, Fusarium, Rhizopus, Mucor and Geotrichum) were detected and isolated. The pH decreased from 4.15±0.01 to 3.10±0.02 at the end of storage period while the titratable acidity increased from 0.002±0.001 to 0.005±0.001. However, the pH and titratable acidity were fairly stable in samples treated with sodium benzoate and refrigeration of 12-14°C. An increase of 37.94% and 32.19% were recorded for the moisture and fibre contents, respectively. Conversely, a decrease of 12.92, 45, 81.32 and 44.95% were detected and recorded for the carbohydrates, lipid, protein and ash contents. However, treatment with 0.15% sodium benzoate and refrigeration at 12-14°C kept these parameters fairly stable all through the storage period. Overall sensory evaluation shows that sodium benzoate treated and refrigerated samples were highly acceptable even though freshly prepared samples were preferred.

African Journal of Biotechnology Vol. 4 (7), pp. 738-743, 2005