Post Fermentation Quality Changes in Bobozi Produced from Cassava (Manihot Esculenta Crantz) and the Effects of Sodium Metabisulphite Soaking in Combination with Refrigeration

Abstract

Changes in the microbiological, physico-chemical and organoleptic quality of bobozi (African snack) produced from cassava (Manihot esculenta Crantz) during processing and the effects of sodium metabisulphite or in combination with refrigeration at 10^oC were investigated results shows that the bioload increased from 0.3 x 10¹cfu/g to 1.0⁴ x 10⁵ at the 96th hours of fermentation and thereafter decreased gradually. Post fermentation soaking in 5% sodium metabisulphite decongest and reduced the bioload to 0.9 x 10¹ cfu/g. Extended storage of 48hrs fermented samples indicates slightly high count which peaked at 1.11 x 10⁴ at 21st day of storage for samples stored at ambient temperature (30±2^oC) whereas the bioload of refrigerated (10^oC) samples were stable all through the 28 days of storage. Six bacteria genera (Bacillus, Streptococcus, Staphylococcus, Leuconostoc, Lactobacillus, and Corynebacterium, E Coli, Klebsiella and Salmonella) and few fungi genera (Candida, Geotrichum, Aspergillus and Penicillum dominated the preboiling and fermentation phase while (3) three bacteria genera (Bacillus, Streptococcus and Lactobacillus) and three (3) fungi group (Geotrichum, Aspergillus, and Penicillum) dominated the post fermentation and extended storage phase. However, E coli, Klebsialla and Salmonella) were eliminated after boiling and were not detected after 24hour of fermentation. The P^H decreased from 4.58±0.01 to 3.75±0.02 at the end of the fermentation period. Although slight increase as to 4.31±0.02 was recorded after soaking in Sodium metabisulphite. Further decreased to 3.61±0.01 was recorded in samples held at 30±2^oC whereas it was fairly stable in refrigerated samples all through the storage period. However, reverse pattern of changes was observed and recorded in the titratable acidity. Steady increase from 31.20±0.5 to 46.6±0.4 was recorded for the moisture content at the end of the fermentation period. Slight increase was recorded in the post fermented sample held at 30±2^oC. Nevertheless, sample stored at 10^oC were fairly stable. The hydrocyanic acid decreased through out the processing and storage period. Overall sensory acceptability scores shows that refrigerated samples were highly acceptable even though freshly prepared samples were preferred.