The potential of using sorghum milling waste for the development of a biorefining strategy for the production of bioethanol was investigated. Both red and white sorghum were processed using a traditional Nigerian wet-milling process to sorghum flour. The sorghum milling waste, sorghum bran, was hydrolysed using both enzymatic and dilute acid hydrolysis to produce a generable fermentation feedstock. The hydrolysates were subsequently investigated for fermentative biofuel production. Following a hydrolysis step, a medium containing ~ 61 g/L glucose was obtained. Trace presence of inhibitors was detected in the hydrolysates and sufficient nitrogen content to support microorganism growth and bioethanol production. In test bioethanol production experiments using the sorghum milling waste derived hydrolysates only, 24.35 g/L bioethanol was produced by a yeast Kluyveromyces marxianus, equivalent to a yield of 0.15 gram bioethanol per gram of sorghum milling waste.

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Submerged substrate fermentation of Jatropha seed cake, a by-product of oil extraction from Jatropha curcas seed was carried out using Aspergillus terreus for the production of itaconic acid. The Jatropha seed cake was initially converted into fermentable sugars by dilute acid hydrolysis using 50% sulphuric acid. The rate of hydrolysis was 1.04 gL -1 . The fermentation process was carried out at room temperature, agitation of 400 rpm and three physico-chemical parameters (pH, inoculum size and substrate concentration) were varied. Itaconic acid and glucose assays were carried out by spectrophotometry and Dinitrosalicylic acid methods respectively daily. Maximum yield of itaconic acid was 48.70 gL -1 at 5 ml of inoculum size, 50% substrate concentration and pH 1.5. The residual glucose concentration increased for the first two days of fermentation after which it began to decrease as the itaconic acid concentration increased. The least concentration of itaconic acid observed was 6.00 gL -1 , obtained after 24 hours of fermentation with 4 ml inoculum size, 50% substrate concentration and at pH 1.5. The findings of this work indicate that Jatropha curcas seed cake is a suitable substrate for itaconic acid production.

Custard is a convenient food product, similar to ogi in appearance and viscosity, but lacks the sour taste typical of ogi. In this study, extracts (10% w/w) from tamarind, soursop and lime was added to custard samples and the physicochemical and sensory properties of the mixture was analysed. Corn gruel was included as the reference sample. Carbohydrate was the major component of the corn gruel (61.72%) and custard samples (66.27-74.42%). Corn gruel had substantially higher protein content (18.03%) than custard samples (8.03-8.62%). Custard samples were more dispersible in water, showed higher swelling power and significantly higher peak and final viscosities than the corn flour sample. However, the addition of souring agent did not significantly alter the cooking time and pasting temperature of custard. Custard may be soured with lime, tamarind and soursop to improve dispersibility, consistency, appearance, viscosity and sourness without significant changes in the overall acceptability of the product.

A study was conducted to compare the effect of different levels of Eucalyptus oil (EO) and Lemongrass oil (LO) on the shelf-life of fresh West African soft cheese (wara) in a completely randomized design model for a 28-day period (n=60). The experiment consists of Treatment A (Control, Cheese kept in the whey), Treatment B (75% EO + 25% LO) and Treatment C (50% EO + 50% LO). The results showed similarity in the evaluated parameters (Crude protein, fat and dry matter contents). The ash content was numerically highest in C (5.75%) and least in A (5.00%). The sensory properties were described by positive attributes such as high general acceptability and flavor for Treatments B > C > A. While the microbial evaluation showed least colony unit for Treatment B followed closely by C and A in that order. In conclusion, while both Eucalyptus oil 75% plus 25% lemon grass had a positive impact on the nutritional, sensory and microbial values, whey had no quality to significantly enhance the nutritional, sensory and microbial qualities of West African soft cheese.

Large quantities of agricultural wastes generated annually from the processing of agricultural produce are disposed of indiscriminately in the environment, thus contributing to environmental pollution. Value addition to cassava (Manihot esculenta Crantz) peels, and a mixture of yam (Dioscorea spp.) and plantain (Musa paradisiaca) peels, which accumulate during manual peeling will help reduce this environmental impact in addition to being a source of income. The effects of fungal fermentation on their proximate composition and suitability for use as enriched animal feed were thus investigated in this study. Cassava peel and yam-plantain peel mixture were each o fermented with Aspergillus niger and Trichoderma spp. at 32 C at moisture content of 52% and 60% respectively for a week and the potential of the biomass was investigated in feeding trials of Wistar rats over a four-week period. After sacrifice, their sera and vital organs were analysed for key enzymes and metabolic products. It was observed that Aspergillus niger-fermented cassava peel (FCP) was the best treatment with increased protein content (from 6.73% to 19.3%) due to microbial biomass. While the carbohydrate content decreased following fermentation, the calorific value remained similar to that of the raw peel. No mortality was recorded in the experimental rats fed the FCP and standard commercial feed (CF) while 100% mortality was th observed by the 4 week in the control group fed unfermented cassava peel (UCP). Organ-body weight ratio and some biochemical parameters e.g. cholesterol, high density lipoprotein (HDL), urea of FCP-fed rats were similar to those of the CF group. Lower amounts of some markers e.g. aspartate transaminase (ALP) and alanine transaminase (AST) were observed relative to UCP group. This research demonstrates the potential of microbially-detoxified food waste to replace commercial feed as a cheap alternative with minimal undesirable physiological effects in the animal models.

PurposeBambara groundnut is a hard-to-cook grain and this has limited its utilisation to some extent. However, the grain is a good source of phytochemicals with antioxidant properties. This study investigated the total phenol content, antioxidant, anti-inflammatory and anti-microbial potentials of hot-water extract of four Bambara groundnuts differentiated by their seed coats (cream, black, maroon and brown).Design/methodology/approachBambara grains were heated in water at a ratio 1:20 (w/v) and the grains brought to boiling in a controlled water bath. As soon as boiling started, the temperature was reduced to 90 °C to reduce the evaporation rate. The extracts were withdrawn within 30 min, which was chosen from a preliminary study where beyond this time, the extract was drying off and the amount of solution obtained was not sufficient for the initial run. Grain colour and composition and antioxidant, antimicrobial and anti-inflammatory properties of the extract were determined using standard methods.FindingsProtein (20.57–26.31%) and carbohydrate (55.43–61.09%) were the major components of the grain. Grain type and boiling time generally affected the total phenolic content of the extract. Cream Bambara displayed substantially lower total phenolic content at all boiling times compared with the maroon, brown and black Bambara groundnuts. The total flavonoid contents and total phenolic contents of the Bambara groundnut extracts were dependent on the boiling time and type of grain. The extracts showed no activity against Candida albicans, but the maroon coat Bambara demonstrated a peak inhibition of 6.00 mm against Escherichia coli. The total phenolic, flavonoid contents and the antioxidant properties of the grains generally followed the order Maroon > Black > Brown.Originality/valueThis study has demonstrated the possibility of promoting the use of Bambara groundnut beyond the current level of usage by using simple processing method of boiling to extract phytochemicals with medicinal properties.

Smoke-dried fish is vulnerable to lipid peroxidation, which can reduce product quality and pose health risks to consumers. The study examined the antioxidant potency of Moringa oleifera marinade on oxidative stability of smoke-dried catfish in comparison with salt and Butylated hydroxyl anisole (BHA), a synthetic antioxidant. Seventy-two catfish (208±6 g) were processed, randomly assigned to six antioxidant treatment groups and hot smoked. The treatments are the control (0%), 1%, 2% and 3% (w/v) Moringa oleifera marinade (MOM), 5% Brine (w/v) and 0.2% BHA (w/v). The smoke-dried fish were stored at room temperature (35±1 0 C) for 8 weeks. Lipid peroxidation was monitored weekly using Thiobarbituric acid (TBA) assay. The results showed that Moringa oleifera marinade and BHA decreased lipid peroxidation more than (p<0.05) the control (0.94 mg/MDA/ kg) and salt (0.92 mg/MDA/kg) treated samples. This was shown by the lower Thiobarbituric acid reactive substance (TBARS) values of 1% MOM (0.84 mg/MDA/kg), 2% MOM (0.88 mg/MDA/kg), 3% MOM (0.85 mg/ MDA/kg) and BHA (0.80 mg/MDA/kg) treated samples. A general increase in oxidative spoilage was observed for all treatments as storage time progressed. However, the increment was more (p<0.05) intense in control and salt treated samples. No significant (p>0.05) difference was observed among all Moringa treated samples and BHA. Moringa oleifera marinade could be used as an alternative to BHA in suppressing lipid peroxidation in smoke-dried African catfish stored for 8 weeks.