The Effect of Composition of the Atmosphere and Duration of Exposure on Brown Stain of Lettuce1,2

Abstract

The severity of brown stain on crisphead lettuce (Lactuca sativa L., cvs. Calmar and Great Lakes 118) held at 0° or 2.5°C for 10 days increased with increasing CO2 (1 to 5%) and decreasing O2 (21 to 1%) levels. Very slight or no brown stain developed on lettuce subjected to 0, 1, or 2% CO2 in combination with 10 or 21% O2 for 10 days or on that held in 2.5 or 5% CO2 + 2% O2 for 4 days at 2.5°C. In 2.5 or 5% CO2 + 2% O2, brown stain intensified with duration of exposure (2 to 30 days) at 0° or 2.5°C.

Effects of CO2 on Total Phenolics, Phenylalanine Ammonia Lyase, and Polyphenol Oxidase in Lettuce Tissue

“…In most instances the symptoms of injury include a brown chlorotic area inside or on the surface of the commodity (11,23). Brown stain is a C 0 2induced physiological disorder in lettuce (1,2,3).…”

El efecto de las atmósferas ricas en CO₂ en los patrones de acumulación de etanol, pH, acidez titulable, sólidos solubles y ácidos orgánicos en diversos productos hortofrutícolas

“…Algunas isozimas mostraron ser formas de la ADH termolábiles y, las menos activas, eran formas de la enzima lentas para migrar (Crawford, 1978). Brecht et al, (1973a) y Lipton (1987) encontraron que el daño por CO 2 , expresado como mancha parda en cultivares selectos de lechuga, era mayor a 0°C que a 2.5°C cuando se almacenaban en atmósferas con niveles de 5% de…”