Process optimization of extrusion variables and its effect on properties of extruded cocoyam (Xanthosoma sagittifolium) noodles

Abstract: The current industrial demand for starchy foods has been dominated by other roots and tubers, while cocoyam, despite being rich in fiber, minerals, and vitamins has remained under exploited. In this study, the effect of feed moisture content (FMC), screw speed (SS) and barrel temperature (BT) on the quality characteristics of cocoyam noodles (proximate, thermo-physical, physicochemical, texture, color, extrudate properties, and sensory characteristics) were investigated using central composite design (CCD) of response surface methodology (RSM). Flour was produced from fresh tubers of cocoyam (Xanthosoma sagittifolium) and subsequently processed into noodles using a twin screw extruder. Results showed that the proximate compositions, thermo-physical, physicochemical properties, and color of the cocoyam noodles were significantly (p < 0.05) influenced by the extrusion process variables. The texture and extrudate properties of cocoyam noodles were equally significantly (p < 0.05) different. The experimental data obtained and predicted values of the response models were comparable, with statistical indices [absolute average deviation (AAD, 0–0.23), bias factor (Bf, 1–1.08), and accuracy factor (Af, 1–1.23)] indicating the validity of the derived models. The optimal extrusion processing conditions for quality cocoyam noodles were FMC, SS, and BT of 47.5%, 700 rpm and 50°C, respectively, as cocoyam noodles obtained at these conditions had comparable properties and were most preferred and accepted by the sensory panelists

Biofuel production using thermochemical conversion of heavy metal-contaminated biomass (HMCB) harvested from phytoextraction process

Over the past few decades, bioenergy production from heavy metal-contaminated biomasses (HMCBs) has been drawing increasing attention from scientists in diverse disciplines and countries owing to their potential roles in addressing both energy crisis and environmental challenges. In this review, bioenergy recovery from HMCBs, i.e. contaminated plants and energy crops, using thermochemical processes (pyrolysis, gasification, combustion, and liquefaction) has been scrutinized. Furthermore, the necessity of the implementation of practical strategies towards sustainable phytoextraction and metal-free biofuels production has been critically discussed. To meet this aim, the paper firstly delivers the fundamental concepts regarding the remediation of the brownfields using phytoremediation approach, and then, reviews recent literature on sustainable phytoextraction of heavy metals from polluted soils. Thereafter, to find out the possibility of the cost-efficient production of metal-free biofuels from HMCBs using thermochemical methods, the impacts of various influential factors, such as the type of feedstock and metals contents, the reactor type and operating conditions, and the role of probable pre-/post-treatment on the fate of heavy metals and the quality of products, have also been discussed. Finally, based on relevant empirical results and techno-economic assessment (TEA) studies, the present paper sheds light on pyrolysis as the most promising thermochemical technique for large-scale electricity and heat recovery from HMCBs

Effective utilization of weighting adjustment for the estimates of means in survey non-response

This paper provides a useful application for comparison on the use of Adjusted Estimates (Weighting Adjustment) as against Unadjusted Estimates for estimate of Mean in survey Non-response .The use of response propensity and the predicted mean of the outcome variable for cell creation are stressed .The results from our empirical study emphasize the efficacy of Weighting Adjustment over the Unadjusted estimates .We adopt the following criteria: Variance, Bias and Mean Square Error in reaching our conclusion. Journal of the Nigerian Association of Mathematical Physics Vol. 10 2006: pp. 447-45