Issue 1: Nigerian Journal of Postharvest Research
Articles in This Issue
From Waste to Worth: Utilizing Agro-Residues in Climate-Smart Feed Systems to Reduce Nigeria’s Agricultural Postharvest Losses. Nigerian Journal of Post-Harvest Research, 3(1), 1-11.
Agro-residue utilisation presents a transformative opportunity to reduce postharvest losses and improve livestock feed systems within climate-smart agriculture frameworks. This systematic literature review evaluates how crop by-products are repurposed for sustainable animal nutrition in Nigeria. Drawing from 75 publications screened between April and May 2025 across Scopus, JSTOR, ScienceDirect, and institutional repositories (FAO, ILRI, FMARD), the review synthesises evidence published between 2015 and 2025. Thematic analysis followed Braun and Clarke's six-step approach, with triangulation applied to balance peer-reviewed sources and grey literature. The review identified five core themes: types and regional availability of agro-residues, nutritional composition and processing innovations such as fermentation and urea-ammoniation, socioeconomic benefits including feed cost reduction and rural employment, environmental advantages such as reduced methane emissions and soil enrichment, and policy enablers and barriers shaping adoption pathways. Findings reveal that while cassava peels, maize stover, and legume haulms offer viable feed alternatives, adoption is constrained by weak infrastructure, fragmented policies, and limited access to affordable processing equipment. Recent innovations, such as community-based feed hubs and microbial detoxification, have shown measurable improvements in feed quality and climate resilience. The review recommends coordinated policy implementation, decentralised processing investments, and gender-inclusive extension systems to accelerate scale-up. These strategies are essential for embedding agro-residue valorisation into Nigeria's livestock value chain and advancing food system sustainability.
Effect of Senna occidentalis Seed Extract and Hyptis suaveolens Essential Oil on Aflatoxin B1 Contamination of Stored Maize. Nigerian Journal of Post-Harvest Research, 3(1), 12-23
Aflatoxin B1 contamination in stored maize, primarily caused by Aspergillus flavus, poses a significant threat to food safety and public health. This study aims to evaluate the antifungal efficacy of Senna occidentalis seed extract and Hyptis suaveolens essential oil as natural alternatives to synthetic fungicides. A. flavus was isolated from infected maize kernels and confirmed through DNA extraction, PCR amplification of the ITS region, and BLAST analysis, which revealed 100% sequence identity with GenBank accession OR646810.1. Plant materials were extracted using ethanol maceration (S. occidentalis) and steam distillation (H. suaveolens), followed by GC-MS profiling. Maize grains were treated with 5 mL, 10 mL, and 15 mL doses of each extract and stored for 30 days at 30 °C. Aflatoxin B1 levels were quantified using high-performance liquid chromatography (HPLC). The research findings showed that untreated maize contained 101 ± 1.0 µg/kg aflatoxin B1, while grains treated with synthetic fungicide (SAAF) had 5.0 ± 0.1 µg/kg (98% inhibition). S. occidentalis extract reduced aflatoxin levels to 15.3 ± 1.0, 10.3 ± 1.0 and 6.3 ± 1.0 µg/kg at 5 mL, 10 mL, and 15 mL doses, respectively (85–94% inhibition). H. suaveolens essential oil achieved reductions to 20.3 ± 1.0, 13.3 ± 1.0 and 8.3 ± 1.0 µg/kg (80–92% inhibition). The 15 mL dosage was the most effective for both treatments, approaching the efficacy of the synthetic fungicide. The antifungal activity is attributed to phytol, linoleic acid and esters in S. occidentalis, and terpenes such as eucalyptol and caryophyllene in H. suaveolens. These findings demonstrate the potential of plant-based treatments as eco-friendly and effective alternatives for aflatoxin mitigation in maize storage systems.
Comparative Evaluation of Rotary and NSPRI Model-B Smoking Kilns for Quality Assurance of Smoked Catfish. Nigerian Journal of Post-Harvest Research, 3(1), 24-32
Fish is a perishable food product, making it easily susceptible to microbial attacks. Therefore, adequate drying becomes paramount to make fish shelf-stable. In the quest for food safety, the Nigerian Stored Products Research Institute developed a rotary smoking kiln to reduce product-human contact and contamination. This study, therefore, evaluated the performance of the new kiln and the existing model-B, concerning some quality attributes of smoked fish. Catfish (Clarias gariepinus) was used for the evaluation, and charcoal and gas were used as an energy source. Quality assessments were conducted on the fish products using standard methods. The proximate qualities of the samples in the two kilns were not significantly or negatively affected. The two kilns lowered the level of heavy metals in the fish within the global permissible limits. Additionally, the PAHs of the products from the two kilns, regardless of the energy source, were lower than the global permissible limit. Out of the total PAHs recorded in the fish dried in the rotary kiln powered with charcoal (8.43 µg/kg) and gas (18.08 µg/kg), only 0.42 and 0.26 µg/kg, respectively, were carcinogenic. Similarly, 0.40 and 0.26 µg/kg were carcinogenic out of the total PAHs recorded in the samples dried in the model-B kiln powered with charcoal (9.19 µg/kg) and gas (16.54 µg/kg), respectively. The products from both kilns received good overall acceptability. Therefore, considering the addressed challenge of opening the model-B kiln before trays could be changed, resulting in reduced risk of product contamination, the rotary kiln is an improved version/model of the NSPRI smoking kiln.
Quality Evaluation of Fleshy Mesocarp and Stored Chips of African Bush Mango (Irvingia spp.). Nigerian Journal of Post-Harvest Research, 3(1), 33-39
African bush mango has fleshy mesocarp (pulp) rich in vitamins, essential minerals, and phytochemicals. This essential part is usually wasted due to a lack of knowledge of the processing and storage methods. This study aimed to determine the quality evaluation (proximate compositions, microbial loads, and sensory evaluation) of fleshy mesocarp and stored chips of African bush mango. African bush mango fruits were obtained from a farmer in Effraya, Etung Local Government Area, Cross River State. The fruits were sorted, and the hard ones were washed and used for this experiment. The exocarp of the fruits was slightly peeled, and the fleshy pulps were then sliced thinly. The sliced pulps were dried using a multi-crop dryer (at an average temperature of 56.61±1.577 °C). The proximate composition and the sensory evaluation of the fresh pulp and chips (dried pulp) were evaluated. Then, the chips were stored for 6 weeks, and the proximate and microbial analyses were conducted using standard laboratory methods (at 3-week intervals). Except the moisture content, all other proximate contents —ash, fat, fibre, protein, and carbohydrate—showed higher values in the chips (dried pulp) compared to the fresh pulp, with respective values of 3.20%, 1.10%, 10.50%, 5.20%, and 72.10% in the chips, as opposed to 0.89%, 0.65%, 1.65%, 2.43%, and 13.83% in the fresh pulp. The values of sensory scores obtained for both samples were more than 6. Furthermore, the retention of proximate nutrients and observing low microbial loads in the chips during storage suggest that the product remains safe and suitable for consumption during the off-season. Therefore, the chips could be maximally utilised to reduce wastage.
Food Safety and Quality Implications of Using Calcium Carbide and Other Substances for Ripening Bananas and Plantains. Nigerian Journal of Post Harvest Research, 3(1), 40-46
The use of calcium carbide (CaC2) as a fruit ripening agent has been associated with the presence of various pollutant indices, which include phosphorus. This study evaluated the effects of three ripening agents: CaC2, African bush mango (ABM), and ethanol, on the ripening time and safety of banana and plantain. Two sample groups were examined: retailers' and intermediaries' fruit handlers. Six lots of banana and plantain were treated with CaC2 (1 g, 2 g, and 5 g per 2 kg fruit), ABM, ethanol, and control. After treatments, they were divided into washed and unwashed sub-groups, peeled, and dried using the Nigerian Stored Products Research Institute's Parabolic Shaped Solar Dryer. Sensory evaluation was conducted on banana and plantain immediately after ripening, while phosphorus analysis was carried out on the dried samples following standard procedures. Results revealed that bananas treated with CaC2 ripened in three days, while those treated with ABM and ethanol became fully ripe in five days. Plantains treated with CaC2, ABM, and ethanol became ripe in 5 days, while the control banana and plantain did not ripen during these 5 days. Phosphorus content of banana samples from retailers ranged from 7.296 to 12.544 mg/kg, while that of plantains ranged from 5.819 to 9.400 mg/kg. For middle holders' samples, phosphorus content ranged from 6.064 to 12.163 mg/kg and 6.881 to 15.293 mg/kg for banana and plantain, respectively. The findings in this study showed no statistical differences in the treatments of banana and plantain with respect to different ripening agents and washing.
Effects of Thermal Pretreatments on the Yield, Quality, and Phytochemical Profile of Ugba Seed Oil. Nigerian Journal of Post Harvest Research,,3(1), 64-76.
Traditional extraction of Ugba seed oil from raw seeds offers limited insight into the effects of pre-treatment; therefore, this study examined how different pre-treatment procedures influence the yield and chemical properties of Ugba seed oils. The seeds were subjected to different pre-treatments, such as cooking and roasting, and later blended into powder. Oil was extracted from each pre-treated powder by deploying the Soxhlet extraction protocol. The recovered oil was analysed for yield, quality attributes, chemical composition, and phytochemical contents. The oil yield for raw Ugba seeds was 46.88%, 42.38% for cooked Ugba seeds, and 58.19% for roasted Ugba seeds. The results showed peroxide values ranging from 2.51 to 6.84 meq O2/kg fat, free fatty acids ranged from 0.25 to 7.37%, while thiobarbituric acid values ranged from 0.03 to 1.84 mg/g. The iodine value, saponification value, unsaponifiable matter, smoke point, and viscosity values exhibited significant differences (p<0.05) among themselves, ranging from 85.10 to 124.55 g of I2/100 g, 176.45 to 211.37 mg KOH/g, 0.84 to 2.09%, 191.86 to 233.00°C, and 15.55 to 35.13 Pa.s, respectively. Flavonoids ranged from 0.01 to 1.40 CE mg/g, tannins from 0.00 to 1.02 mg/100 g, saponins from 0.00 to 4.49 mg/100 g, and alkaloids from 0.00 to 8.82 mg/100 g. Roasted seeds recorded the highest percentage oil yield, but with oil products of lower chemical stability, while raw seeds provided higher quality oil. This underscores the critical role of pre-treatment in optimising oil yield and quality.