This study was executed to investigate the potential of agar-agar, a nontoxic and non-degradable
gelling agent, as a promising coating agent to improve and protect banana fruit
against fungal postharvest diseases i.e., crown, finger, neck and flower end rots which are
caused by fungal isolates of Colletotrichum musae and Fusarium moniliforme. Coated-ba-nana
fruit samples with different concentrations of agar-agar suspension particularly at
2.0 g · l−1 exhibited a significant reduction in incidence and severity of postharvest diseases
compared to untreated fruit. Banana fruits dipped in agar suspension at 2.0 g · l−1 for 5, 10
and 15 min showed significant reduction in disease incidence and severity. Moreover,
application of agar suspension as a coating agent at 2.0 g · l−1 significantly decreased
weight loss (%), firmness loss (%), and soluble solid concentration of banana fruit for
15 days at 25 ± 2°C. Scanning electron microscopy observation confirmed that the fruit
coated with agar colloid at 2.0 g · l−1 had significantly fewer cracks and showed smoother
surfaces than untreated fruit. This explains the quality improvement in agar-coated fruit
compared to uncoated fruit. Overall, agar colloid, a safe coating agent, could be used to
protect banana fruit against postharvest rot diseases and extend fruit storage life during
ripening and storage.
Influence of Fusarium oxysporum f. sp. cubense (E.F. Smith) Snyder and Hansen on 2,4-diacetylphloroglucinol (DAPG) production in the rhizosphere of banana cultivar Rasthali by Pseudomonas fluorescens was investigated. The purified extracts of Pfm strain of P. fluorescens isolated from banana rhizosphere inhibited the growth and spore germination of F. oxysporum f. sp. cubense under laboratory conditions. DAPG extracted from the cultures of the strain was observed as distinct spots in thin layer chromatographic plates at Rf value of 0.88. The extracts of soil inoculated with P. fluorescens and challenge inoculated with F. oxysporum f. sp. cubense eluted at retention time ranges from 20.00 min to 21.30 min. The quantity of DPAG production was less in the extracts of soil inoculated with P. fluorescens and challenge inoculated with F. oxysporum f. sp. cubense as compared to P. fluorescens alone inoculated soil. The talc formulation of Pfm strain also reduced vascular discolouration due to the pathogen in banana plants when inoculated at 15 g/plant.
This article presents a quality analysis of convectively dried fruits and vegetables with preliminary osmotic dehydration. Tests were carried out on banana fruit and red beetroot samples. Hypertonic solutions of fructose for the banana and those of sucrose for the red beetroot were used, each one at three different concentrations. After osmotic dewatering treatment conducted at different time intervals and after osmotic dehydration the samples were dried convectively until an equilibrium with the surroundings was attained. Osmotic dehydration and convective drying curves were determined. The values of Solids Gain (SG), Water Loss (WL) and Weight Reduction (WR) were measured and changes in the samples’ colour and shape after convective drying with and without osmotic pretreatment were assessed.
Arsenic is one of the most harmful pollutants in groundwater. In this paper, the Nepali bio sand filter (BSF) was modi-fied with different bio-adsorbents, and proved to be an efficient method for arsenic removal from groundwater. Three dif-ferent bio-adsorbents were used to modify the Nepali BSF. Iron nails and biochar BSF, ~96% and ~93% arsenic removal was achieved, within the range of WHO guidelines. In iron nails, BSF and biochar BSF ~15 dm3∙h–1 arsenic content water was treated. In the other two BSFs, rice-husk and banana peel were used, the arsenic removal efficiency was ~83% of both BSFs. Furthermore, the efficiency of rice-husk and banana peel BSFs can be increased by increasing the surface area of the adsorbent or by reducing the flow rate.
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