Aj. Ramos et al., Calorific losses in maize in relation to colonisation by isolates of Aspergillus ochraceus under different environmental conditions, J CEREAL SC, 29(2), 1999, pp. 177-183
The effect of water activity (a(w), 0.85-0.95), temperature (15-30 degrees
C) and incubation period (2-4 weeks) on growth and calorific losses in rela
tion to colonisation by three mycotoxigenic isolates of Aspergillus ochrace
us was studied on maize-based substrates. The calorific losses (kJ) of maiz
e flour due to fungal growth in relation to temperature and a(w) were quant
ified and found to be maximal at 20-30 degrees C (10.52-16.18%, after 4 wee
ks at 0.95 a(w)), with only slight losses at 0.85 a(w) (0-7.14%), at both 1
5 and 20 degrees C. This suggests that growth of mycotoxigenic Aspergillus
spp. can significantly contribute to nutritional losses of this staple agri
cultural food. Calorific values correlated inversely with fungal biomass, w
ith the latter being greatest at 0.95 a(w) after both two and four;weeks, a
nd maximal at 30 degrees C. Most of the single, two-, three- and four-way i
nteractions of a(w), temperature, time and isolate had a statistically sign
ificant (p<0.01) influence on calorific losses and fungal biomass. (C) 1999
Academic Press.