Reassessment of treatments to retard browning of fresh-cut Russet potato with emphasis on controlled atmospheres and low concentrations of bisulphite

Abstract

The cultivar Pacific Russet with high browning susceptibility was used for most testing. Controlled atmospheres (0.3%, 3% and 21% O 2 in combination with 0%, 6% or 12% CO 2 ) and anti-browning chemicals were studied in relation to quality retention and wound-induced phenolic metabolism of fresh-cut slices for up to 16 days at 5°C. The 3% O 2 + 12% CO 2 atmosphere was most effective among those tested, and retarded increases in phenolics and phenylalanine ammonia lyase activity, but had only slight benefit on visual quality. A 1.25% ascorbic acid +1.25% citric acid treatment was ineffective, but when combined with 3% O 2 + 12% CO 2 , it was comparable with 0.025% sodium bisulphite. Bisulphite concentrations from 0.05% to 0.25% provided similar effective control of discolouration. Bisulphite as low as 0.025% with 3% O 2 + 12% CO 2 resulted in a visual quality score at the limit of marketability after 8 days at 5°C. Chemical treatments did not retard increases in phenolic concentrations or phenolic enzyme activities.

Aceptabilidad de lechuga de hoja fresca troceada, tratada con ácido ascórbico mediante hidroenfriamiento

“…Se ha reportado que la preparación de lechuga como producto fresco cortado (fresca, troceada y empacada) induce cambios fisiológicos y bioquímicos que incluyen daños en paredes celulares y tejidos (Zhan et al, 2009;Wagstaff et al, 2010), incremento en ritmo respiratorio y producción de etileno, inducción de síntesis de metabolitos secundarios, activación de mecanismos defensivos (Ma et al, 2010), y disrupción de membranas (González y Barret, 2010). Asimismo, los productos frescos troceados en general sufren pérdida de la estructura celular durante las operaciones de corte, lo cual permite interactuar a la polifenol oxidasa (PPO) con compuestos fenólicos oxidables presentes naturalmente en el producto, causando oscurecimiento de las superficies cortadas (González y Barret, 2010).…”

“…It has been reported that the preparation of lettuce as a freshcut product (fresh cut and packaged) induces biochemical and physiological changes which include damage to cellular walls and tissues (Zhan et al, 2009;Wagstaff et al, 2010), increased respiration rate and ethylene production, induction of secondary metabolite synthesis, activation of defense mechanisms (Ma et al, 2010), and disruption of membranes (González and Barrett, 2010). Additionally, cut fresh products generally suffer loss of cellular structure during cutting operations, which allows polyphenol oxidase (PPO) to interact with oxidized phenolic compounds naturally present in the product, causing browning of the cut surfaces (González and Barret, 2010).…”

“…Los sulfitos son efectivos agentes inhibidores que previenen reacciones enzimáticas (inhibidores competitivos de la polifenol oxidasa), y reacciones de oscurecimiento no enzimático (Ma et al, 2010). Sin embargo, la FDA ha prohibido el uso de sulfitos en productos vendidos como no procesados debido a reportes de reacciones adversas en la salud de personas asmáticas atribuibles a su consumo (Sapers, 1993).…”

“…Éste compuesto hidrosoluble, también conocido como vitamina C, es uno de los antioxidantes más abundantes en los productos vegetales, cuya principal función es proteger a la planta contra estrés oxidativo (Ma et al, 2010;Ibrahim et al, 2012). Además, este agente reductor tiene propiedades bactericidas (Burnham et al, 2001), y generalmente es reconocido como seguro como aditivo alimenticio.…”

Antibrowning and antimicrobial effects of onion essential oil to preserve the quality of cut potatoes

“…hOsOda and co-workers (2003) showed the effect of 0.05 and 0.2% of OEO as an antibrowning treatment in shredded lettuce, observing 20 and 70.4% of browning inhibition, respectively. The treatment of potato slices with sodium bisulphite 0.25% and ascorbic acid 1.25% + citric acid 1.25% in combination with controlled atmospheres showed no efficacy inhibiting PPO activity during storage (Ma et al, 2010).…”