Grape news: New treatment combination safe alternative to sulfur dioxide

Apr 16, 2010
These are commercially packed cluster grapes showing typical decay after four months. Credit: Photo by Liping Kou

Packaged fresh-cut grapes are becoming increasingly popular with consumers who like the convenience and health benefits of these ready-to-eat fruits. To keep table grapes fresh and increase shelf life, scientists are seeking advanced techniques that provide healthy, safe alternatives to conventional packing methods. Researchers from the U.S. Department of Agriculture's Agricultural Research Service (USDA ARS) have developed and tested an effective new technique that combines hot water treatment, rachis removal, and modified atmosphere packaging (MA) to extend the shelf life of table grapes.

Commercially packaged table grapes stored in clusters in perforated packaging have a short shelf life—typically 8 to 10 weeks—as a result of their exposure to the environment. shelf life is often shortened by factors including fruit weight loss, stem browning, softening, shattering, and decay. Because of its effectiveness in delaying stem browning and decay, (SO2) is currently the treatment of choice in many countries for prolonging shelf life of grapes. There are disadvantages to sulfur dioxide use, however. The concentration of SO2 necessary to inhibit may induce injuries in grape fruits and stems, and sulfite residues pose a health risk for some individuals. Applications of SO2 have been restricted in many countries, making it essential to identify safe, alternative technologies that effectively control fungal growth and assure high-quality fruit.

Yaguang Luo and William Conway from the USDS ARS, in collaboration with Liping Kou, Wu Ding, and Xinghua Liu from China's Northwest A&F University, recently published a report in HortScience that explored alternatives to for maintaining quality of table grapes, including various combinations of rachis removal, chlorinated wash, hot water treatment, and modified atmosphere packaging.

Grapes were prepared by cutting off the rachis 1 to 2 mm from the fruit or by keeping the clusters intact. After initial preparation, short-stem and cluster grapes were subjected to chlorinated wash and/or hot water (45ºC for 8 minutes) treatment and packaged in plastic trays sealed with a gas-permeable film. The treated grapes, as well as the commercially packed grapes in their original packages, were stored at 5ºC for up to 4 weeks.

According to the Kou, a visiting scientist from China and the study's lead researcher, the hot water treatment resulted in significantly higher oxygen retention and lower carbon dioxide accumulation in packages, firmer texture, higher overall visual quality, lower decay rate, and lower microbial populations than other treatments or commercially packed grapes. Grapes that were cut from the rachis and treated with hot water and chlorine maintained the highest quality for 4 weeks, with the least decay among all treatments. A chlorine prewash treatment significantly reduced microbial populations on cluster grapes and maintained better overall quality.

Kou concluded that "the combination of these treatments maintained excellent visual quality throughout the entire storage duration, whereas the commercially packaged grapes became decayed and their quality declined to a level that was unacceptable. The combination treatment was successful in reducing spoilage microbes, preventing dehydration, and delaying softening and senescence of grapes."

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/44/7/1947

Provided by American Society for Horticultural Science

5 /5 (1 vote)
add to favorites email to friend print save as pdf

Related Stories

Grape expectations for healthier wine

Feb 12, 2007

A new technique that uses ozone to preserve grapes could help prevent allergies and boost healthy compounds at the same time, reports Jennifer Rohn in Chemistry & Industry, the magazine of the SCI. The same technique could ...

Red wine grapes may help prevent tooth decay, research shows

Jan 29, 2008

Red wine has long been known to contain a substance, resveratrol, that is heart-healthy. Now research shows that both red wine grapes and winemaking residue, known as pomace, contain substances that may help prevent tooth ...

Protecting wine grapes from heat and drought

Feb 17, 2009

Deficit irrigation is an agricultural technique used to achieve a variety of results depending on the crop. For white wine grapes, it balances the crop load by limiting the canopy size so there aren't too ...

Apples, apple juice shown to prevent early atherosclerosis

May 03, 2008

A new study shows that apples and apple juice are playing the same health league as the often-touted purple grapes and grape juice. The study was published in the April 2008 issue of Molecular Nutrition and Food Research.

Wine With a Double Shot of Vitamin C?

Mar 21, 2006

Genetically designed grapes with elevated levels of vitamin C may be more than wishful thinking, according to researchers at the University of California, Davis, and the University of Adelaide, Australia, who ...

Finding the white wine difference

Mar 05, 2007

A CSIRO research team has pinpointed the genetic difference between red (or black) and white grapes – a discovery which could lead to the production of new varieties of grapes and ultimately new wines.

Recommended for you

Offspring benefit from mum sending the right message

4 minutes ago

(Phys.org) —Researchers have uncovered a previously unforeseen interaction between the sexes which reveals that offspring survival is affected by chemical signals emitted from the females' eggs.

Ranchers benefit from long-term grazing data

48 minutes ago

Scientists studying changes in the Earth's surface rely on 40 years of Landsat satellite imaging, but South Dakota ranchers making decisions about grazing their livestock can benefit from 70 years of data ...

Diverse gene pool critical for tigers' survival

1 hour ago

(Phys.org) —New research by Stanford scholars shows that increasing genetic diversity among the 3,000 or so tigers left on the planet is the key to their survival as a species.

Building better soybeans for a hot, dry, hungry world

1 hour ago

(Phys.org) —A new study shows that soybean plants can be redesigned to increase crop yields while requiring less water and helping to offset greenhouse gas warming. The study is the first to demonstrate ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

mark0101
not rated yet Apr 16, 2010
Where do grapes last 8 weeks? Here they only last 5 weeks MAX then they go white or shriveled and squishy

More news stories

Ranchers benefit from long-term grazing data

Scientists studying changes in the Earth's surface rely on 40 years of Landsat satellite imaging, but South Dakota ranchers making decisions about grazing their livestock can benefit from 70 years of data ...

Floating nuclear plants could ride out tsunamis

When an earthquake and tsunami struck the Fukushima Daiichi nuclear plant complex in 2011, neither the quake nor the inundation caused the ensuing contamination. Rather, it was the aftereffects—specifically, ...

Unlocking secrets of new solar material

(Phys.org) —A new solar material that has the same crystal structure as a mineral first found in the Ural Mountains in 1839 is shooting up the efficiency charts faster than almost anything researchers have ...