Pages: (1-8 )
Abstract
The firm tofu production process in Nigeria was evaluated for contaminants and biodeteriogens involved in the degradation of the food material under stated conditions with the view of determining its biodeterioration pattern and shelf-life. Aspergillus niger, Cladosporium sp., Mucor sp., Schizosaccharomyces, Saccharomyces spp., Bacillus sp., B. subtilis, Micrococcus luteus, Streptococcus sp. and Pseudomonas sp. were implicated as processing contaminants. Successional studies at 8h intervals for 72h yielded a total of 29 isolates consisting of 9 bacteria and 5 fungi with B. cereus and A. niger being the most frequently occurring bacteria and fungi, respectively. The activities of the deteriogens brought about a progressive reduction in pH (5.77–4.89), protein (24.98–0.81%) and lipids (22.00–10.10%) but a constant increase in ash content (4.20–9.60ppm). Available moisture content increased and decreased based on prevailing activities in the microenvironment. Bacillus strains were better producers of amylase, lipase and protease, than other bacteria while the late fungal colonizers showed a higher lipase and protease activity. The shelf-life without refrigeration was 24h.
Keywords: Tofu; biodeterioration; deteriogens; succession; enzyme; shelf-life,