It's elemental: Potato after-cooking darkening may be affected by nutrients

Apr 16, 2010
Researchers tested two potato cultivars to predict the occurrence of after-cooking darkening. Credit: Photo by Kris Pruski

Irish potato, one of the world's major food crops, is increasingly grown and processed for use in various products; consider the popularity of consumer favorites like French fries and potato chips. In the closely scrutinized food production industry, products are accepted or rejected on the basis of color and appearance, among other attributes. Quality defects such as after-cooking darkening, or ACD -- a change in potato's normal flesh color to gray, blue, purple, or black -- can affect the marketability of potatoes for both processing and fresh markets. With the current expansion of the potato-processing industry around the world comes a renewed interest in finding innovative methods to prevent ACD.

After-cooking darkening occurs when potatoes are exposed to air after cooking, including boiling, baking, frying, or dehydration. ACD has been reported from every potato-growing area in the world and is one of the most widespread, undesirable traits for potatoes and other tubers, even though it does not affect the flavor or of the crops. ACD is most common in boiled or steamed potatoes, but is also problematic in processed products such as oil-blanched , dehydrated potatoes, canned potatoes, prepeeled potatoes, and reconstituted dehydrated potatoes.

Researchers at Nova Scotia Agricultural College hypothesized that the concentration and distribution of elements in potato tubers could be used to predict after-cooking darkening. The objective of the study, published in a recent issue of HortScience, was to identify the elements (plant nutrients) whose content may relate to the severity of potato ACD. The researchers grew two common potato cultivars ('Shepody' and 'Russet Burbank') in three Eastern Canadian provinces for two seasons using various fertilization regimes. Fourteen elements were studied: phosphorus, calcium, magnesium, potassium, sulfur, iron, copper, sodium, zinc, boron, manganese, aluminum, silicon, and chlorine.

The "After Cooking Darkening" readings were found to be affected by fertilizer and a "cultivar-segment interaction". ACD readings were higher in tubers from fertilized plots compared with tubers from nonfertilized plots. The distribution of ACD was found to be similar in both cultivars studied, with the stem end being the darkest, the center segment being the lightest, and the flesh darkening again slightly toward the bud end. The elements most strongly correlated with ACD severity were phosphorus, calcium, copper, and magnesium. According to the researchers, the study provides a useful method to predict the severity of ACD, which could assist the processing industry in predicting the occurrence of ACD and in developing agronomic treatments to minimize it.

"This study demonstrated how information from element distribution can be used in predicting the occurrence of a tuber quality trait, specifically ACD", commented Dr. Gefu Wang-Pruski, corresponding author of the study.

The authors note that additional experiments to determine how tuber element content affects the change in ACD severity over time may make it possible to predict the severity of ACD in tubers in late stages of storage by determining the element concentrations and their spatial distribution of the same lot of tubers at harvest.

Explore further: Noted researchers warn that biomedical research system in US is unsustainable

More information: The complete study and abstract are available on the ASHS HortScience electronic journal web site: hortsci.ashspublications.org/cgi/content/abstract/44/7/1866

Provided by American Society for Horticultural Science

2.8 /5 (6 votes)
add to favorites email to friend print save as pdf

Related Stories

Iron and copper relationship is studied

Jul 24, 2007

U.S. scientists studying the relationship of iron and copper in the body have found when iron absorption by cells decreases, copper absorption increases.

Tough New Spuds Take on Double Trouble

Mar 03, 2010

(PhysOrg.com) -- Americans love potatoes, consuming about 130 pounds per person annually. But it's a wonder the spuds even make it to the dinner table, given the many fungal diseases that attack the tuber ...

Spud origin controversy solved

May 15, 2007

Molecular studies recently revealed new genetic information concerning the long-disputed origin of the “European potato.” Scientists from the University of Wisconsin-Madison, the University of La Laguna, and the International ...

Bacterium Identified as Potato Disease Culprit

Oct 14, 2009

(PhysOrg.com) -- Studies tying a new species of Candidatus Liberibacter bacteria to zebra chip (ZC) disease in potato should speed efforts to better protect the tuber crop from costly outbreaks.

Recommended for you

Plants with dormant seeds give rise to more species

Apr 18, 2014

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers successfully clone adult human stem cells

Apr 18, 2014

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

User comments : 0

More news stories

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.