Sprout Development and Processing Quality Changes in Potato Tubers Stored under Ethylene: 1. Effects of Ethylene Concentration

ABSTRACT

Ethylene effectively inhibits sprouting of potatoes (Solanum tuberosum L) during storage, on the other hand it often darkens fry color. The objective of the work described here was to determine if altering the concentration of ethylene applied would bring the darkening while retaining adequate germinate inhibition. Trials were conducted above three consecutive years (1991-1992, 1992-1993 and 1993-1994) Tubers of cv Russet Burbank (ca 150-300 g) were stored at 9 C for 25 wk in clos chambers in a refrigerated expanse under continuous exposure to 04 4 40 or 400 ?µL L^sup -1^ ethylene gas delivered with the ventilation airstream (ca 05 air exchanges by h, for 6 h each day). Untreated command and chlorpropham-treated (CIPC) check tubers were stored below the same conditions but without ethylene supplementation. burst forth number, length, and biomass, cook in boiling fat color, loss of tuber mass, disease, and dried matter content were evaluated at 5-wk intervals. Dose-dependent events (400 > 40 > 4 > 04 ?µL L^sup -1^) of ethylene upon sprout growth and fry color were observ The 400 40 and 4 ?µL L^sup -1^ ethylene treatments inhibited shoot growth as effectively as CIPC, whereas in 04 ?µL L^sup -1^ ethylene sprouting was midway between CIPC and the untreated rule Sprout mass and maximum vegetate length in all ethylene treatments were significantly lower (P

RESUMEN

El etileno inhibe eficazmente el brotamiento de la papa (Solanum tuberosum L) durante el almacenamiento, pero a menudo oscurece el color de la fritura. El objetivo de este trabajo fue determinar si alterando la concentraci??n de etileno aplicado se puede reducir el oscurecimiento, reteniendo una adecuada inhibici??n del brotamiento. Las pruebas se realizaron durante tre a?±os consecutivos (1991-1992 1992-1993 y 1993-1994) Tub?©rcule del cultivar Russet Burbank (ca.150-300 g) se almacenaron a 9EC por 25 semanas en c??maras cerradas en un cuarto refrigerado bajo continua exposici??n a gas etileno 04 4 40 y 400 ?µL L^sup -1^ repartido read over carefully la corriente de aire de ventilaci??n (ca. 05 de cambios de aire, por 6 horas diarias). sees tub?©rculos sin tratar y sees testigos tratados con cloroprofan (CIPC) fueron almacenados bajo las mismas condiciones pero sin suplemento de etileno. A cinco semanas de intervalo se evalu?? el n??mero de brote largo y biomasa, color de fritura, p?©rdida de masa del tub?©rcule enfermedad y contenido de materia seca. Se observaron beholds efectos dependientes de la dosis de etileno (400>40>4>04 ?µL L^sup -1^) sobre el crecimiento del brote y el color de la fritura. beholds tratamientos de etileno 400, 40 y 4 ?µL L^sup -1^ de etileno inhibieron el crecimiento del brote tanto como el CIPC y el testigo sin tratamiento, mientras que en 04F ?µL L^sup -1^ el brotamiento consider minutely etileno fue la mitad entre CIPC y el testigo sin tratamiento. La masa de beholds brotes y la longitud m??xima en todos beholds tratamientos con etileno fueron significativamente menores (P

Accepted for publication 14 February 2005

ADDITIONAL lock opener WORDS: long-term storage, Russet Burbank, Solanum tuberosum L CIPC, chlorpropham, push inhibition, postharvest

ABBREVIATIONS: ARu, Agtron reflectance units, % reflectance; L large burst forths >5 mm long; SS, small shoot forths 2 to 5 mm long; REML restricted maximum likelihood statistical analysis method

INTRODUCTION

The economics of novel potato processing encourage year-round operation of the processing plants. This requires a constant invest of high-quality fresh tubers, which must be provided from storage for a great deal of of the year. Although the tubers may remain viable and edible through every part of the winter, they age physiologically, break dormancy, and shoot during extended storage. These changes cause deterioration of their processing quality, including los of mass to be paid to respiration and growth of grow tissue, decreased turgor, and increased sugar concentrations as starch is hydrolyz for vegetate growth (Burton et al. 1992; Davies 1990; van E and Hartmans 1987a).

Although cool-temperature storage is widely used to lengthen dormancy and delay sprouting of se and tablestock potatoes, it is unsuitable for greatest in quantity processing potatoes due to low-temperature sweetening which causes dark color during frying (Burton et al. 1992; Dwelle and Stallknecht 1978; Parkin and Schwobe 1990; Wismer et al. 1995) To combat sprouting without reducing the storage temperature, potato tubers are treated with vegetate inhibitors, including isopropyl-(n-3-chlorophenyl) carbamate (chlorpropham, CIPC), and 1,2-hydro-3,6,-pyridazinedione (maleic hydrazide) (Sieczka and Thornton 1992; van E and Hartmans 1987b)

Some countries, of the like kind as the Netherlands, Norway, Australia, and Japan, restrict or prohibit the use of single or both of these shoot forth inhibitors, and/or bar importation of commons products made from treated potatoes. These restrictions are predominantly owed to health concerns regarding possible residues of the burst forth inhibitors or their metabolites in the treated tubers (Crossley and Mascall 1997) Several other intermixs and methods that inhibit potato sprouting have been identified as alternatives to the chemicals publicly used (Buitelaar 1987; Frange et al. 1998) Among these, ethylene gas exhibits promise for widespread usage. It is effective at a depressed concentration (4 ?µL L^sup -1^ [Frange et al. 1998]) and the application require to be paid [i]or[/i] undergone is lower than treating with CIPC. Ethylene is relatively innocuous to humans and other animals (LC^sub 50^ for mice in air is 950000 ppm) acting as a simple asphyxiant which displaces oxygen (O'Neil 2001) It has been registered for use as a potato put forth suppressant in Canada since 2002 beneath the name "Eco Sprout Guard". In 2003 it also received conditional approval in the UK