ISHS Acta Horticulturae 367: VI International Symposium on Pear Growing
LOW OXYGEN CONTROLLED ATMOSPHERE STORAGE OF RED PEARS |
| Authors: | Daryl G. Richardson, D. Kling, D. Sugar |
| Abstract:
The red pear varieties Crimson Gem, Cascade, Red Anjou, Rogue Red and standard varieties Comice, Packham's Triumph, and Bosc were harvested at optimal commercial maturity and held in low oxygen -1°C storage ( 0.25, 0.5, 0.75, 1.0, 1.5 or 2.0% O2 or in air) up to 10 months. Quality evaluations such as sweetness, acidity, astringency, aroma, texture, juiciness, off-flavor, and overall quality were ranked on a 0 to 15 point hedonic scale by a 30 member organoleptic panel. At the 10 month storage evaluation, Crimson Gem, Rogue Red, and Comice all responded favorably (scores above 7.5 for overall quality, aroma, texture, sweetness and juiciness, but very little (score < 3.0) off-flavor) to oxygen as low as 0.25%, while Red Anjou and Packham's Triumph were optimally stored at the 0.5 to 1.0% O2, whereas Bosc and Cascade were best at 1.0 to 2.0% O2 and showed considerable off-flavour development at lower oxygen concentrations. While the production of red-pigmented pear varieties has been increasing, little information on their postharvest behaviour, particularly in controlled atmosphere storage, has been developed. In several cases, these red pears are derived from parents which may have widely divergent storage characteristics. Thus it is important to obtain data as to the optimum conditions of CA and the duration of storage that might be expected from these new genotypes relative to standard varieties. We report here some results of low oxygen controlled atmosphere trials with the red varieties Rogue Red, Red Anjou, Cascade, Crimson Gem, and compare them with Comice, Bosc, and Packham's Triumph standard varieties grown at the OSU Southern Oregon Research and Extension Center near Medford, Oregon. Fruits were harvested in the high range of firmness for commercial maturity since the intent was to maximize CA storage potential. Fruits were chilled to -1°C for up to three weeks, then transported to the OSU Postharvest Lab in Corvallis for controlled atmosphere treatments. CA chambers were modified 220 L steel drums, fitted with inlet and outlet ports for atmospheric gas tubing, and a gas sampling septum. Carefully selected (no injuries, disorders, or indications of rot) pears of all seven varieties were dipped in 0.6 g/L (= 8 oz/100 gal) DuPont Benlate 50%WP (benomyl) fungicide, air-dried, and loaded into shelves in the drums. Combinations of air and nitrogen were proportioned to regulate oxygen concentrations at 0.25, 0.50, 0.75, 1.0, 1.5, 2.0 and 21% O2. Flow rates were adjusted between 50 and 400 mL/min so that | |
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