Irvingia (bush mango) species are economically important trees, but studies aimed at their prospect for domestication did not take into account the potential differences between members of the Genus. Hence fruit size, postharvest pathology and phytochemicals of I. gabonensis and I. wombolu were studied. Results showed that whilst the mean weight, length, width and thickness of fruits of I. gabonensis were 125.08g, 60.85mm, 62.66mm and 56.78mm, respectively, those obtained from I. wombolu were 86.08g, 54.23mm, 54.09mm and 50.97mm, respectively. Difference in brownish-black rot fruit disease between the two Irvingia species was not significant (P=0.05), but disease severity increased correspondingly with increase in storage days. Four genera of fungi (Aspergillus, Penicillium, Rhizopus and Mucor) were isolated from fruits of both Irvingia species, and I. wombolu was found to sustain a significantly lower fungal population (7.76E+07 cfu) than I. gabonensis (1.05E+08 cfu). High fungal population led to a correspondingly high severity of brownish-black rot disease. Fruits of both Irvingia species possessed all five phytochemicals (alkaloids, flavonoids, saponins, tannins and glucosides). However, whilst both species had the same amounts of flavonoids and glycosides, I. wombolu possessed relatively higher amounts of alkaloids, saponins and tannins than I. gabonensis. I. wombolu may be the preferred choice if domestication would be based on phytochemicals. In like manner, I. gabonensis may be the preferred choice for domestication if taste, weight and size of fruits were the parameters of interest.

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Differences in Fruit Size, Postharvest Pathology and Phytochemicals between Irvingia gabonensis and Irvingia wombolu

Irvingia gabonensis (Aubry-Lecomte ex O’Rorke) are especially valued for their fat and protein rich kernels but are often contaminated, while in storage, by spoilage fungi that are potentially hazardous to human and animal health. Hence in this research, the postharvest disease and fungal quality of Irvingia kernels was studied. Freshly harvested Irvingia kernels were subjected to three treatment methods (sun-dried, 0.9% NaCl and 3% KHCO 3 ) and stored in both sealed and open bags for 28 days. Results showed that fungal population and postharvest disease incidence of Irvingia kernels in storage were dependent on treatment methods, storage conditions and storage days. Overall mean log cfu of fungi on Sun-dried Irvingia kernels (5.60) was significantly ( P? 0.05 ) lower than those treated with 0.9% NaCl (5.95) or 3% KHCO 3 (5.99). Incidence and severity of diseased Irvingia kernels stored in sealed bags were significantly ( P? 0.05 ) lower than those stored in open bags. Disease incidence and severity of Irvingia kernels increased significantly ( P? 0.05 ) as storage period increased. Eight species of fungi Aspergillus niger (26.60%), Rhizopus stolonifer (21.28%), Aspergillus flavus (19.15%), Penicillium species (10.64%), Mucor species (8.51%), Candida tropicalis (5.32%), Phytophthora species (4.26%) and Fusarium oxysporum (4.26%) were isolated from the kernels after 28 days of storage. Results further showed that A. flavus , Penicillium and Fusarium species, known to produce mycotoxins were not isolated from kernels treated with NaCl or sun-dried and stored in sealed bags. It is therefore advisable to store Irvingia kernels in sealed bags after drying them under direct sun or treating with 0.9% NaCl. Keywords : Irvingia gabonensis , Postharvest disease, Postharvest treatment, spoilage fungi, storage.

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The effect of treatment methods and storage conditions on postharvest disease and fungal quality of Irvingia gabonensis (Aubry-Lecomte ex O’Rorke) kernels

Irvingia species are important fruit trees. Although the microbial postharvest quality of its fruits have been studied, the potential relationship between postharvest disease and the proximate composition of its fruit are yet unknown. Hence in this research, changes that occur in postharvest Irvingia fruit wastes on the 0 th , 3 rd and 6 th days after harvest (DAH) was assessed with respect to brownish-black rot disease and proximate components. Results showed that brownish-black rot disease advanced significantly (P≤ 0.05) as DAH increased. Mean weighted percentage brownish-black rot disease on 0 th , 3 rd and 6 th DAH were 2.37%, 22.24% and 87.86% respectively. Mean percentage moisture was 82.99% followed by dry matter (16.91g), Carbohydrate (15.00g), fibre (0.67g), protein (0.63g), ash (0.49g) and lipids (0.10g). Whilst differences in % moisture, dry matter and lipid with respect to DAH were not significant (P=0.05), differences in protein, ash, fibre, and carbohydrate contents were significant. Brownish-black rot disease was significantly, positively related to carbohydrate (r2 = 0.69; Pearson correlation coefficient = 0.83) whilst being significantly, negatively related to fibre (r2 = 0.92; Pearson correlation coefficient = -0.82), ash (r2 = 0.68; Pearson correlation coefficient = -0.96) and protein (r2 = 0.73; Pearson correlation coefficient = -0.86), respectively. Postharvest holding periods led to nutritive degradation of Irvingia fruits' proximate composition. Fruits should either be consumed soon after harvest or processed under infection-free conditions to lengthen their storage life

Effect of postharvest period on disease progression and proximate composition of Irvingia species fruit waste

OBJECTIVE: To study post-harvest fungal overgrowth on chewing sticks used for oral hygiene measures and role of disinfection. METHODS: The post-harvest fungal spoilage of chewing sticks (Garcinia kola, Glyphea brevis and Azadirachta indica) was investigated by subjecting the chewing sticks to different preparatory methods (some disinfected in 0.7% sodium hypochlorite before storage), storage conditions (unsealed or sealed in clear polythene) and different storage periods (2, 3 and 4 weeks). RESULTS: Significant differences (P = 0.05) in mean percentage fungal colonization were dependent on plant type and storage period, but not on preparative methods and storage conditions. There were, however, significant interactions between chewing sticks and preparative methods, storage conditions and storage periods, respectively. Azadirachta indica was observed to be more susceptible to post-harvest spoilage organisms than other test plants. Generally, percentage fungal colonization increased with increase in storage period. Four genera, Penicillium spp., Aspergillus spp., Mucor spp. and Botryodiplodia spp., were implicated with post-harvest colonization of chewing sticks after 4 weeks of storage. CONCLUSION: The use of harvested chewing sticks after prolonged storage period is therefore not advisable for oral hygiene measures.

AA Tasie

Papers

Post-harvest fungal quality of selected chewing sticks.