New Zealand Journal of Crop and Horticultural Science abstracts

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Ripening behaviour, postharvest quality, and physiological disorders of coated pears (Pyrus communis )

Cassandro Amarante¹

Nigel H. Banks²

Centre for Postharvest and Refrigeration Research
Institute for Food, Nutrition and Human Health
Massey University
Private Bag 11 222
Palmerston North, New Zealand
¹ Present address: Centre of Agricultural, Horticultural and Veterinary Sciences, Santa Catarina State University, C. Postal 281, CEP 88502-970, Lages, SC, Brazil. email: amarante@cav.udesc.br
² Present address: Kiwifruit New Zealand Research Limited, P.O. Box 4043, Mt Maunganui South, New Zealand. email: banksn@kiwi.co.nz

Abstract   Pear (Pyrus communis L.) cultivars 'Bartlett', 'Bosc', 'Comice', and 'Packham's' were treated at harvest or after cold storage with a carnauba-based wax emulsion at concentrations of 0, 5, 10, 20, 40, and 100% (v/v) of the commercial formulation. Fruit coated at harvest were assessed for internal partial pressure of O₂ and CO₂ , ripening, physiological disorders, and sensory attributes when held at 20°C and 60–70% relative humidity after achieving the chilling requirement to ripen, whereas fruit coated after cold storage were only assessed for physiological disorders. With the exception of 'Bosc', increasing the coating concentration improved the finish of the skin. Only 'Bosc' developed off-flavours when treated with the undiluted coating. Increasing coating concentration reduced fruit internal partial pressure of O₂ , suppressed ripening and reduced the incidence of senescent breakdown. 'Comice' pears treated at harvest with >=40% coating concentration and cold stored for 6 months had delayed ripening, no senescent scald and no internal disorders after a 7-day shelf-life period. 'Bartlett' and 'Bosc' treated at harvest with coating concentrations >10% and >40%, respectively, developed an internal disorder possibly associated with excessive internal atmosphere modification during 0°C storage. They did not develop the disorder when treated after cold storage. These findings show that response differences related to cultivar and storage temperature after coating must be taken into account in the optimisation of surface coatings for pears. Also, a given surface coating treatment may impair postharvest quality because treated pears may soften without changing colour.

Keywords   Pyrus communis; surface coating; internal atmosphere; respiration; softening; skin colour; gloss; flavour; senescent breakdown; senescent scald; internal disorder; gas injury; low temperature injury

H01032 Received 27 June 2001; accepted 2 November 2001
New Zealand Journal of Crop and Horticultural Science, 2002, Vol. 30 : 49–59
0014–0671/02/3001–0049 $7.00 © The Royal Society of New Zealand 2002

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