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  • Author or Editor: H. T. Chan x
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Abstract

Papayas (Carica papaya L.) were stored at 5° or 10°C for 1, 4, 7, 14, or 21 days. Chilling injury was detectable as visible skin discolorations after 4 days at 5°. Differences in electrolyte leakage and Hunter “L” values between fruit stored at 5° and 10° were not significant until after 7 days of storage. Fruit stored at 5° for more than 4 days also produced more ethylene upon transfer to warmer temperatures than did fruit stored at 10°. Differences in ethylene production between fruit stored under chilling temperatures, 5°, and nonchilling temperatures, 10°, increased with length of storage. Papayas chilled for 14 days at 5° retained a capacity to convert ACC to ethylene.

Open Access

Thermal death kinetics, decimal reduction times (D-values), and rate constants, k, at 43 to 49 °C were determined for spore or cell suspensions of Colletotrichum gloeosporiodes (Penz.) Penz. & Sacc. in Penz., Guignardia psidii Ullasa & Rawl, Guignardia sp. Viala & Ravaz., and Enterobacter cloacae (Jordan) Hormaeche & Edwards. D-values for Monilinia fructicola (Wint.) Honey, Rhizopus stolonifer (Ehr.: Fr.) Vuill., and Stemphylium lycopersici (Enjoji) Yamamoto were calculated and extrapolated from published reports. We compared the relative heat resistances of the various postharvest pathogens to their expected survival during quarantine heat treatments and found that Guignardia, Rhizopus, and E. cloacae could be expected to survive quarantine heat treatments.

Free access

Phytotoxicity from hydrogen cyanide (HCN) fumigation was measured in several varieties of Hawaiian cut flowers and foliage (Zingiberaceae, Heliconia, Orchidaceae, Marantaceae, Lycopodiaceae, Agavaceae, Proteaceae) as a potential disinfestation treatment. Concentrations tested were 2500, 3700, 4600, and 5500 ppm HCN for 30 min. All foliage and most heliconia were undamaged at fumigation levels of 5500 ppm HCN; most protea and `Midori' anthuriums were uninjured at 4600 pm HCN; red and pink ginger were uninjured at 3700 ppm HCN; and all pincushion protea showed phytotoxicity to HCN. Red ginger was quickly damaged when exposed to sunlight immediately after treatment at 2500 ppm HCN. No injury was observed in simulated shipment tests of red ginger and `Ozaki' anthuriums fumigated at 2500 ppm HCN. Wet, red ginger flowers longer than 6 cm were damaged at 2500 ppm HCN, whereas shorter flowers were uninjured. Wet `Ozaki' anthuriums showed phytotoxicity only at 4600 ppm HCN. Wet, treated lycopodium and bamboo orchid foliage was not injured. The number of marketable days and shelf life of the treated plant material were estimated from the visual ratings.

Free access

Abstract

Body transmittance spectroscopy and analytical measurements of chlorophyll, carotenoids, and soluble solids concentrations were used to develop a nondestructive technique for estimating the maturity of papayas (Carica papaya L.). Optical measurements were taken between 500−900 nm with a scanning monochromator and a tilting-filter, abridged monochromator. Immature and mature-green fruit which were indistinguishable by visual examination could be separated by body transmittance spectroscopy into nonripening and ripening groups.

Open Access