The Nigerian economy depended mainly on crude oil during the era of oil boom of 1973 which lasted up till1983. Agriculture was grossly neglected by successive governments. Following the economic recession that occurred years after and due to fall in crude oil price, the Nigerian government began to advocate for economic diversification. Consequently, agriculture became the area of interest and priority for industrial raw material sources. Unfortunately, Nigeria had imbibed the tradition of importing raw materials for all her industrial productions thereby creating unfavourable balance of trade between Nigeria and her foreign trading partners thus resulting in increase in the prices of finished products. Beer production is not exempted from the price increase since its raw materials are equally imported with their attendant problems on Nigeria’s foreign exchange. One of such raw materials is hops. The hop (Humulus lupulus L.) is a perennial dioecious climbing plant of hemp (cannabis) family and belonging to the order (urticales) which are grown in the temperate regions of the world, solely to meet the demand of the brewing industry. Hop extracts give beer its bitter taste, improve foam stability and act as antiseptics towards microorganisms. The quest to substitute hops with some tropical bitter vegetables in Nigeria’s brewing industry dates back to 1983 and since that time, many have compared hop extracts with those of Nigerian bitter plants such as Garcinia kola, Azadirachta indica, Vernonia amygdalina and Gongronema latifolium. This review takes a critical look on the efforts made so far since 1983 in investigating the potentiality of using Nigerian bitter plant extracts as suitable substitute for those of hop in the Nigerian brewing industry with special emphasis on Gas Chromatography Mass–Spectrometry (GC–MS) and Gas Chromatography–Flame Ionization Detector (GC–FID) techniques. It was concluded that none of the Nigerian plants has perfect potential as suitable substitute for hops in the Nigerian brewing industry. Consequently, further research efforts in the area of mixtures/blends of extract of plant species which mimic hop taste is strongly recommended.

The work aims to evaluate the effect of temperature and composition on the physical properties of ceramic electrical porcelain insulators, produced from locally sourced materials in Nigeria. The basic raw materials of triaxial porcelain (Kaolin, feldspar, and quartz) were pulverized, milled for 22 h, and sieved using a 200 μm mesh size. The chemical composition and characterization of the raw materials were obtained using X-ray diffraction (XRD) and X-ray fluorescence (XRF) analysis. The mixtures were formulated using sodium silicate as a deflocculant to help produce the ceramic porcelain samples. The green samples were weighed and fired at temperatures of 1200 °C and 1250 °C. The samples were subjected to 1 h of boiling plus 2 h of soaking. The slip casting technique was used in the production of porcelain insulators. The linear shrinkage, water absorbance, apparent porosity, and bulk density were measured and studied as a function of firing temperature. The apparent porosity and water absorption decreased as the firing temperature increased. The bulk density increased gradually from 1200 °C to 1250 °C and the percentage of moisture remained fairly unaffected by the temperature increase. The linear shrinkage was also found to increase as the firing temperature increased. Despite having the same composition, the average physical properties of the locally manufactured insulators revealed that those manufactured at higher temperatures provided a better insulating effect than those manufactured at lower temperatures. In other words, it shows that excellent ceramic porcelain insulators can be manufactured from locally sourced materials using the appropriate composition and firing temperature.