Techniques Applied in Characterising Non-starch Polysaccharides in Underutilised Crops in Sub-Saharan Africa

The use of some crops in Sub-Saharan Africa is currently limited to local culinary uses despite promising characteristics of their non-starch polysaccharide. There is very little information on the properties of their non-starch polysaccharide which would stimulate expansion in their applications. Non-starch polysaccharides represent a group of heterogeneous compounds which differ considerably in chemical composition and physical properties both within and between plant sources. They show various physiological effects in the small and large intestine and therefore have important health implications for humans. The physiochemical and biological properties of these compounds correspond to dietary fibre. Their application/introduction in food may lead to diminished risk of serious diet-related diseases which are major problems in Western countries and are emerging in developing countries with a greater affluence. Insoluble NSPs (cellulose and hemicellulose) are effective laxatives whereas soluble NSPs (especially mixed-link β-glucans) lower plasma cholesterol levels and help to normalise blood glucose and insulin levels, making these kinds of polysaccharides a part of dietary plans to treat cardiovascular diseases and type 2 diabetes. In this review, techniques applied in characterising non-starch polysaccharides in five underutilised crops in sub-Saharan Africa were discussed.     

Acid hydrolysis of kappa‐carrageenan as a way of gaining new substances for freezing process modification and protection from excessive recrystallisation of ice

The effects of κ‐carrageenan and its hydrolysates on modification of the freezing process and also on inhibition of excessive recrystallisation of ice in sucrose solutions during storage were compared. Acid hydrolysis of κ‐carrageenan was carried out using sulphuric (H₂SO₄) and hydrochloric acid (HCl). Most effective in the hydrolysis process turned out to be H₂SO₄, which degraded κ‐carrageenan to a molecular mass of around 3 × 10⁶ Da, after 1.5 h of hydrolysis. Addition of 0.005% of the new poligeenan (degraded carrageenan), to a sucrose solution (30%), frozen at ?20 °C, caused a nearly 50% reduction in the phase‐change stages, and consequently, the total time of freezing was shorter. Significant retardation of recrystallisation was observed for both types of poligeenan, but a stronger effect was observed for the oligosaccharides obtained after HCl hydrolysis, and after 96 h of storage at ?8 °C, the equivalent diameter of ice crystals was not greater than 11 μm.     

Calibration models for routine analysis of cider by mid-infrared spectroscopy

Partial least square regression was used to develop different calibration data sets for multi-parameter routine analysis of ciders. Parameters included were those related with the monitoring of fermentation process and cider quality: specific gravity, total and volatile acidities, alcoholic proof, pH and fructose. Calibration performances were evaluated by means of the prediction residual sum of squares (PRESS), the root mean squared prediction error of cross-validation (RMSECV) and the residual predictive deviation (RPD) values (ratio of the standard deviation of the population to the standard error of cross-validation). Validation of the models was assessed in terms of accuracy and precision. Mean recoveries of the predicted results compared to the reference values were close to 100%, with repeatability and reproducibility similar to those of the reference methods.     

Evaluating and comparing three community small-scale wind electrification projects

Electrification systems based on renewable energy have proven suitable for providing electricity autonomously to rural communities. Among the technical options available, wind systems are increasingly getting attention. In the northern mountains of Peru, at 3800 m.a.s.l., three community wind electrification projects have been implemented. The technical solutions used in each project are different: wind vs. hybrid photovoltaic-wind systems; individual equipment vs. microgrids. This study aims to describe, evaluate and compare these three small-scale community wind electrification projects. The evaluation of the three projects was carried out by comparing previous and present scenario; attention has been focused on project design and technical aspects, socio-economic impacts and sustainability and management model. These three examples shed light on both the advantages and disadvantages of different technological options as well as on appropriate community-level management models.     

Household energy use,energy efficiency,emissions, and behaviors

Energy and greenhouse gas (GHG) emissions generally aim to (i) reduce energy use and hence emissions, (ii) steer consumers away from fossil fuels and/or electricity generated from fossil fuels, and (iii) align demand and supply, making sure that the existing infrastructure can handle times of high demand. Policies thus include a variety of pricing schemes, taxes on energy inputs, energy efficiency standards and incentives, and renewables standards and incentives. Ex ante and ex post analyses of their effectiveness thus rely crucially on understanding how consumers respond to pricing schemes, taxes, and other policies. This paper presents an overview of the challenges faced when empirically estimating household energy demand. It describes the difficulties associated with estimating the price elasticity of demand, discussing behavioral responses that may make consumers relatively insensitive to price changes or taxes. It also surveys empirical evidence about non-price policies, such as clearer information or real-time feedback about energy use, and appeal to norms. The paper concludes discussing evidence about the rebound effect, the energy efficiency gap, and how suppliers respond to a variety of policies.