Influence of Blanching on the Drying Characteristics of Convective Hot Air Dried Aerial Yam

A research on the drying characteristics of aerial yam using convectional hot air was done. The raw unblanched and blanched samples were dried using convectional hot air. Fan speed, temperature and slice thickness were varied to determine the change in moisture content. The Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) were done to determine the functional groups and surface morphology respectively for each sample. FTIR results revealed the presence of some important functional groups such as esters, ethers and nitro-compounds, and shows that drying at this temperatures (40-70oC) does not alter the nutrient components of this variety of yam. The SEM results showed that important cells were not destroyed at the drying temperature. Batch studies on the drying process also showed that increase in temperature and air speed increased the drying process, but decreases with increase in slice thickness. Effect of drying rate on the sample showed that drying rate increase with increase in temperature and air speed but decrease with increase in slice thickness. After 90 minutes of drying, the drying rate of the 2 mm slice thickness was 0.353 g/g.min for drying of aerial yam while for 4 mm and 6 mm slice thickness, the drying rate were 0.261 and 0.169 g/g.min respectively, for effect of drying rate on sample thickness. It showed also that blanched aerial yam sampleshad a higher drying rate than the unblanched aerial yam sample at the same conditions. Therefore, the economic advantages of this yam species can be optimized by blanching

Biokinetics of Anaerobic Digestion of Municipal Waste

A study of the biokinetics of anaerobic digestion of municipal solid waste (MSW) was carried out using anaerobic batch digester. From the experimental results, the kinetic parameters (coefficient values) of the digestion of the MSW were determined. The maximum rate of substrate utilization (K), saturation constant (Ks), endogenous decay coefficient (Kd), biomass Yield or microbial growth yield (Y) and maximum specific growth rate (μmax) were found to be 0.144 day -1, 21.23 mg/L, 0.038 day -1, 0.367, and 0.053 day -1 respectively. These values indicate that practical digesters for MSW will require inoculation of the feed with microorganism to increase the rate of digestion. The biokinetics of anaerobic digestion of MSW was well described by first order kinetic model