Use of Ethylene Gas for Degreening of Sweet Orange (<i>Citrus sinensis</i> Osbeck) ev. Mosambi

662-667Ethylene gas was applied by trickle method to ‘Mosambi’ sweet orange (Citrus sinensis Osbeck) fruits in a specially designed chamber (170 cm length × 170 cm width × 227 cm height, internal dimensions) for degreening. Three sprays of carbendazim (500 ppm) were applied to fruits on tree at 15 d interval prior to harvesting. Complete degreening of green but mature Mosambi fruits (TSS 9-10 per cent and titratable acidity nearly 0.30 per cent) was achieved within 48 h with 5-10 ppm ethylene at 27-29oC and 90-95 per cent RH with four air changes/h and air circulation of 0.5-0.6 L/s/kg fruit. Ethylene-exposed fruit developed bright yellow colour with hue angle less than 90o while non-exposed fruit remained green with hue angle of 100°. The 48 h treatment resulted in 1.95-2.15 per cent mass loss in ethylene-exposed and control fruits. Respiration rate increased from initial 35 to 80 mg CO2/kg/h in ethylene-exposed fruits in 48 h and slowly declined after removal from ethylene atmosphere. Fruit firmness, juice content and total soluble solids and ascorbic acid remained unchanged with ethylene treatment but titratable acidity declined significantly (p < 0.05). Fruit rind degreening continued in treated and untreated fruits during storage at 24±4oC. The hue angle was almost similar at the end of 30 d in degreened and non-degreened fruits but intensity and brightness were lower in the latter. Polyethyelene liner minimized mass loss during storage with no difference due to ethylene treatment (p > 0.05) but cumulative decay losses due to Geotrichum candidum were higher in non-degreened<span style="font-size:7.5pt;font-family:Fd470610-Identity-H; mso-bidi-font-family:Fd470610-Identity-H"> fruits (p < 0.05 ). </span

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Technical Bulletin No. 18

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Paper and Corrugated Boxes from Cotton Plant Stalks for Effective Packaging of Oranges

311-318Cotton plant stalk an abundantly available agro-waste material was successfully tried out as a substitute for wood in the manufacture of corrugated fibre board boxes for packaging of fruits. A process was standardised to prepare good quality kraft paper from Cotton plant stalks. The process was worked out by conducting large-scale trial in a paper mill. Corrugation trials were successfully conducted on the kraft paper prepared. The corrugated boxes of desired size and designs were prepared and evaluated for various properties. Suitability of these boxes for packaging of fruits like oranges was assessed through simulated laboratory as well as actual transportation trials. Details of the laboratory and the mill trials, simulated and actual packaging and transportation trials with oranges are presented and discussed in this paper. Results indicated that good quality kraft paper suitable for manufacture of CFB boxes can be prepared from cotton plant stalks. Uniform chipping of stalks and kraft liquor concentration of 18 per cent produced kraft paper with desired properties. The techno-economic feasibility worked out by conducting large-scale tri al in a mill indicated that the box prepared from cotton plant stalk kraft would be cheaper than that of commercially available box. Corrugated boxes were lighter in weight than wooden boxes and hence more CFB boxes could be transported thus reducing freight per box. CFB boxes prepared from cotton plant stalk kraft paper possessed desirable bursting and compressive strength. Lamination of CPS box with polypropylene film from outer side further improved strength and ability of these boxes to withstand moisture during prolonged cool storage under high humidity conditions. Results of the simulated and actual packaging and transportation trials demonstrated suitability of corrugated fibre board boxes for packaging, transportation and storage of Nagpur-mandarin oranges.</span