Can Science Keep Produce Fresh Longer?
UNH research focuses on extending the shelf life of fruits and vegetables
Tuesday, November 18, 2025
Picking a ripe tomato

Tomatoes are an important crop, and Duoduo Wang is researching how to extend ripeness to lessen waste and improve quality.Ěý

Once the stem snaps at harvest, a race begins between biology and decay, and when produce begins to decay, farmers lose income, grocers lose stock, and consumers lose flavor. Researchers at UNH are exploring the complex process of ripening, with the goal of developing ways to maintain post-harvest firmness and flavor for far longer than currently possible.

The research into preserving ripeness, led by Duoduo Wang, assistant professor and NH Agricultural Experiment Station scientist, has the potential to provide a win-win for producers and consumers in New Hampshire and far beyond, as growers will be able to sell more of their produce and consumers will have better, tastier options at the market.

"Our goal is to enhance ripening to extend shelf life and improve post-harvest traits such as flavor, color, and texture."

Tomatoes are a good case in point: only 60% to 75% of those currently harvested reach consumers while still fresh and salable. For the more than 200 commercial tomato growers in New Hampshire, extending the ripeness window can substantially increase the return on a high value crop that can generate more than $8,000 per acre per year.

“Fruit ripening is a highly dynamic and tightly regulated process controlled by intricate genetic networks that integrate multiple regulators, hormones, and other molecular mechanisms,” says Wang. “I’m looking to move the research ahead by identifying additional regulatory factors and downstream genes involved with ripening that specifically affect firmness and flavor. Understanding the details of ripening will allow us to develop plants that produce appealing, flavorful fruit with a much longer shelf life.”

Engineering ripeness

Ripeness is fleeting for a reason. In the wild, if the fruit is not consumed before it falls to the ground, it needs to break down quickly so the seeds inside are still able to enter the soil. Commercial farmers suffer the consequences of this natural process when the fruit degrades or is attacked by bacteria or a fungus before it can be brought to market or sold once there.

To counter the natural tendency toward decay, Wang is investigating the genetic and molecular processes that control ripening and softening. She uses high tech research methods that are based in the laboratory instead of the greenhouse, at least at first. Her tools include advanced “’omics” technologies that, combined with extensive genetic and genomic information, provide a comprehensive picture of the ripening process. She then uses CRISPR, a genetic engineering method, to precisely modify gene activity and fine-tune traits that influence fruit firmness, flavor, and shelf life. Ěý

What is CRISPR gene editing?

Researchers discovered strange repetitive DNA sequences in bacteria nearly 40 years ago and named them Clustered Regularly Interspaced Short Palindromic Repeats, or CRISPR for short. It was 20 more years before they figured out that the sequences were part of an elegant system that protects bacteria from viral infection. They match viral DNA and produce RNA that is paired with a protein that cuts DNA, called Cas-9. When a virus attacks and injects its DNA into the bacteria, the RNA binds to it and Cas-9 chops it up, neutralizing the threat.

It didn’t take scientists long to figure out that the CRISPR/Cas-9 system could be tweaked to bind to and cut any DNA sequence. They also found that it works just fine in every cell type they tried, including in plants and mammals. By 2014 CRISPR/Cas-9 was making genetic engineering—which had previously been difficult, costly, and time-consuming—cheap, fast, and relatively simple for researchers all over the world.

With continued tweaking over the past decade, CRISPR genetic editing methods have gotten even more accurate, easier to deliver into cells, and more versatile than just chopping and disabling genes. They are essential tools in many areas of research, including Duoduo Wang’s sophisticated plant engineering. They are also beginning to enter clinical medicine. There have been several dramatic successes in curing genetic diseases over the past year, with more to come.

Using genetics to improve crop characteristics is far from a new concept. People have been breeding plants and selecting for favorable traits for centuries. Today, produce such as sweet corn and broccoli bear little resemblance to the plants from which they were derived. But to achieve something as complicated as extending ripeness, researchers need more efficiency and precision than traditional plant breeding methods provide.

“The tomato is an ideal model for fruit biology research because so much genetic and genomic information is already available,” says Wang. “Our goal is to enhance ripening to extend shelf life and improve post-harvest traits such as flavor, color, and texture. Targeting upstream regulators requires precision — if done incorrectly, the fruit may remain green and firm and never fully ripen, making it unappealing to eat.”

A fresh start at UNH

Wang’s research career has spanned the globe. She earned her Ph.D. at the University of Nottingham (U.K.), did postdoctoral research at the University of Florida and Cornell University, and has also worked in her native China. She has previously worked with other crops, including maize, sugarcane, and Brassica napus (best known as the source of canola oil). Now she is excited to refocus on tomatoes — and more — as she establishes her research program at UNH, which has pioneered efforts to extend the produce growing season in cold climates through the use of high tunnels and other growing methods.

While tomatoes are her initial crop, Wang’s long-term goals include applying her knowledge of ripening to other local species, such as kiwiberries.

“COLSA is a great place for me to work,” says Wang. “I have many colleagues who have long-term projects in plant science, as well as others with expertise in genetic engineering in the department of molecular, cellular, and biomedical sciences.”

College of Life Sciences & Agriculture

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