Reduction of aflatoxin in freshly harvested maize using solar dryers.

BACKGROUND: Aflatoxin-contaminated grain consumption over the years has been known to result in serious health hazards for its consumers. The present study investigated the effects of harvest seasons and drying methods on aflatoxins in freshly harvested maize. A 2 × 3 × 3 × 3 × 3 factorial design was used; two harvesting seasons (dry and wet), maize varieties (P3966W, P4063W and P4226), moisture contents (0.15, 0.12, and 0.10 g kg-1 ), modern fabricated solar dryer (MFSD), hybrid biomass dryer (HBD) and open-air drying (OAD) methods, and packaging materials (plastic, jute and polyethylene bag) were studied, respectively. In total, 162 samples (n = 162) of maize grains (250 g each) were dried. The freshly harvested maize was shelled, dried, stored and analyzed for aflatoxins using high-performance liquid chromatography. The data obtained were subjected to statistical analysis. RESULTS: P3966W and P4063W with an initial moisture content of (0.226 and 0.234 g kg-1 ) reached a safe level of 0.10 g kg-1 using MFSD within 2-3 days, HBD within 2-3 days and OAD within 5 days. Variety P4226 with an initial moisture content of 0.228 g kg-1 reached a safe moisture level of 0.10 g kg-1 in 2, 3, and 7 days using MFSD, HBD and OAD, respectively. Aflatoxin concentration (56.00 ± 8.89 µg kg-1 ) was highest in P4063W at 0.15 g kg-1 moisture content, which exceeded the maximum permissible limits of 4 µg kg-1 recommended by the World Health Organization. CONCLUSION: Variety, type of dryer and season affect aflatoxin contamination of maize. The adoption of MFSD drastically reduced the duration of drying and consequently controlled contamination by aflatoxins. © 2022 Society of Chemical Industry.

Ascorbic Acid Production by Aspergillus flavus and Aspergillus tamarii; Kinetic and Thermodynamic Study.

This study investigated the fermentation kinetics and thermodynamics of ascorbic acid production from Brewery Spent Grain (BSG) using Aspergillus flavus and Aspergillus tamarii. Ascorbic acid fermentation of A. flavus and A. tamarii was performed at a temperature of 30 °C, agitation speed of 100 rpm and pH 5.0 at 96 h of fermentation. The thermodynamics, kinetics of the growth parameters and ascorbic acid production were studied using Monod, Contois and Teisser models. Teisser model gave the best fit as it obtained the highest maximum specific growth rate (µmax) and correlation coefficient of 0.184 h-1 and 0.997, respectively, at 40 °C, pH 5.0 and 0.6 g of BSG. The result showed that Teisser model gave a better description of each growth parameter. Hence, the production of ascorbic acid by A. flavus and A. tamarii is growth-associated.